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Sun IC, Dumani DS, Emelianov SY. Applications of the Photocatalytic and Photoacoustic Properties of Gold Nanorods in Contrast-Enhanced Ultrasound and Photoacoustic Imaging. ACS Nano 2024; 18:3575-3582. [PMID: 38235729 DOI: 10.1021/acsnano.3c11223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
The applications of ultrasound imaging are often limited due to low contrast, which arises from the comparable acoustic impedance of normal tissues and disease sites. To improve the low contrast, we propose a contrast agent called gas-generating laser-activatable nanorods for contrast enhancement (GLANCE), which enhances ultrasound imaging contrast in two ways. First, GLANCE absorbs near-infrared lasers and generates nitrogen gas bubbles through the photocatalytic function of gold nanorods and photolysis of azide compounds. These gas bubbles decrease the acoustic impedance and highlight the injection site from the surrounding tissues. Second, GLANCE exhibits photoacoustic properties owing to the gold nanorods that emit photoacoustic signals upon laser irradiation. Additionally, GLANCE offers several benefits for biomedical applications such as nanometer-scale size, adjustable optical absorption, and biocompatibility. These distinctive features of GLANCE would overcome the limitations of conventional ultrasound imaging and facilitate the accurate diagnosis of various diseases.
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Affiliation(s)
- In-Cheol Sun
- Medicinal Materials Research Center, Biomedical Research Division, Korea Institute of Science and Technology, 5, Hwarang-ro, Seongbuk-gu, Seoul 02792, Republic of Korea
| | - Diego S Dumani
- School of Electrical Engineering, University of Costa Rica, San Pedro Montes de Oca, San Jose 11501-2060, Costa Rica
| | - Stanislav Y Emelianov
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30322, United States
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Kim M, Kim J, VanderLaan D, Kubelick KP, Jhunjhunwala A, Choe A, Emelianov SY. Tunable Interparticle Connectivity in Gold Nanosphere Assemblies for Efficient Photoacoustic Conversion. Adv Funct Mater 2023; 33:2305202. [PMID: 38495944 PMCID: PMC10939103 DOI: 10.1002/adfm.202305202] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Indexed: 03/19/2024]
Abstract
Manipulating matter at the nanometer scale to create desired plasmonic nanostructures holds great promise in the field of biomedical photoacoustic (PA) imaging. We demonstrate a strategy for regulating PA signal generation from anisotropic nano-sized assemblies of gold nanospheres (Au NSs) by adjusting the inter-particle connectivity between neighboring Au NSs. The inter-particle connectivity is controlled by modulating the diameter and inter-particle spacing of Au NSs in the nanoassemblies. The results indicate that nanoassemblies with semi-connectivity, i.e., assemblies with a finite inter-particle spacing shorter than the theoretical limit of repulsion between nearby Au NSs, exhibit 3.4-fold and 2.4-fold higher PA signals compared to nanoassemblies with no connectivity and full connectivity, respectively. Furthermore, due to the reduced diffusion of Au atoms, the semi-connectivity Au nanoassemblies demonstrate high photodamage threshold and, therefore, excellent photostability at fluences above the current American National Standards Institute limits. The exceptional photostability of the semi-connectivity nanoassemblies highlights their potential to surpass conventional plasmonic contrast agents for continuing PA imaging. Collectively, our findings indicate that semi-connected nanostructures are a promising option for reliable, high-contrast PA imaging applications over multiple imaging sessions due to their strong PA signals and enhanced photostability.
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Affiliation(s)
- Myeongsoo Kim
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, 30332, US
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
| | - Jinhwan Kim
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Don VanderLaan
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Kelsey P Kubelick
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Anamik Jhunjhunwala
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
| | - Ayoung Choe
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Stanislav Y Emelianov
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, 30332, US
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA
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Kim M, VanderLaan D, Lee J, Choe A, Kubelick KP, Kim J, Emelianov SY. Hyper-Branched Gold Nanoconstructs for Photoacoustic Imaging in the Near-Infrared Optical Window. Nano Lett 2023; 23:9257-9265. [PMID: 37796535 PMCID: PMC10603794 DOI: 10.1021/acs.nanolett.3c02177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 08/18/2023] [Indexed: 10/06/2023]
Abstract
In plasmonic nanoconstructs (NCs), fine-tuning interparticle interactions at the subnanoscale offer enhanced electromagnetic and thermal responses in the near-infrared (NIR) wavelength range. Due to tunable electromagnetic and thermal characteristics, NCs can be excellent photoacoustic (PA) imaging contrast agents. However, engineering plasmonic NCs that maximize light absorption efficiency across multiple polarization directions, i.e., exhibiting blackbody absorption behavior, remains challenging. Herein, we present the synthesis, computational simulation, and characterization of hyper-branched gold nanoconstructs (HBGNCs) as a highly efficient PA contrast agent. HBGNCs exhibit remarkable optical properties, including strong NIR absorption, high absorption efficiency across various polarization angles, and superior photostability compared to conventional standard plasmonic NC-based contrast agents such as gold nanorods and gold nanostars. In vitro and in vivo experiments confirm the suitability of HBGNCs for cancer imaging, showcasing their potential as reliable PA contrast agents and addressing the need for enhanced imaging contrast and stability in bioimaging applications.
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Affiliation(s)
- Myeongsoo Kim
- Petit
Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, United States
| | - Don VanderLaan
- School
of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Jeungyoon Lee
- School
of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Ayoung Choe
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, United States
- School
of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Kelsey P. Kubelick
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, United States
- School
of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Jinhwan Kim
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, United States
- School
of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Stanislav Y. Emelianov
- Petit
Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, United States
- School
of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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Lee J, Kubelick KP, Choe A, Emelianov SY. Photoacoustic-guided ultrasound thermal imaging without prior knowledge of tissue composition. Photoacoustics 2023; 33:100554. [PMID: 37693296 PMCID: PMC10492200 DOI: 10.1016/j.pacs.2023.100554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 08/23/2023] [Accepted: 09/01/2023] [Indexed: 09/12/2023]
Abstract
Thermal strain imaging (TSI) is a widely investigated ultrasound (US) thermometry technique that is based on the temperature-dependent change in speed of sound. However, a major challenge of TSI is a calibration process to account for material-dependent thermal strain. In this study, we leverage nanoparticle (NP)-mediated photoacoustic (PA) thermometry to calibrate thermal strain and guide US thermal imaging. By controlling the molecular composition of the sub-micrometer layer surrounding the NPs, PA thermometry becomes independent of the thermal characteristics of the overall background tissue where the NPs reside. Thus accurate temperature measurements are obtainable from sparse NP-mediated PA signals. These measurements are used to guide TSI, allowing US thermometry to produce an expanded temperature map over the entire region of interest without prior knowledge of tissue composition. Our feasibility study in tissue-mimicking phantoms demonstrates the potential to improve TSI by integrating a PA-based calibration method that complements and guides US thermometry.
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Affiliation(s)
- Jeungyoon Lee
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Kelsey P Kubelick
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
| | - Ayoung Choe
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
| | - Stanislav Y Emelianov
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
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Jhunjhunwala A, Kim J, Kubelick KP, Ethier CR, Emelianov SY. In Vivo Photoacoustic Monitoring of Stem Cell Location and Apoptosis with Caspase-3-Responsive Nanosensors. ACS Nano 2023; 17:17931-17945. [PMID: 37703202 PMCID: PMC10540261 DOI: 10.1021/acsnano.3c04161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 09/06/2023] [Indexed: 09/15/2023]
Abstract
Stem cell therapy has immense potential in a variety of regenerative medicine applications. However, clinical stem cell therapy is severely limited by challenges in assessing the location and functional status of implanted cells in vivo. Thus, there is a great need for longitudinal, noninvasive stem cell monitoring. Here we introduce a multidisciplinary approach combining nanosensor-augmented stem cell labeling with ultrasound guided photoacoustic (US/PA) imaging for the spatial tracking and functional assessment of transplanted stem cell fate. Specifically, our nanosensor incorporates a peptide sequence that is selectively cleaved by caspase-3, the primary effector enzyme in mammalian cell apoptosis; this cleavage event causes labeled cells to show enhanced optical absorption in the first near-infrared (NIR) window. Optimization of labeling protocols and spectral characterization of the nanosensor in vitro showed a 2.4-fold increase in PA signal from labeled cells during apoptosis while simultaneously permitting cell localization. We then successfully tracked the location and apoptotic status of mesenchymal stem cells in a mouse hindlimb ischemia model for 2 weeks in vivo, demonstrating a 4.8-fold increase in PA signal and spectral slope changes in the first NIR window under proapoptotic (ischemic) conditions. We conclude that our nanosensor allows longitudinal, noninvasive, and nonionizing monitoring of stem cell location and apoptosis, which is a significant improvement over current end-point monitoring methods such as biopsies and histological staining of excised tissue.
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Affiliation(s)
- Anamik Jhunjhunwala
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, United States
| | - Jinhwan Kim
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, United States
- School
of Electrical & Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Kelsey P. Kubelick
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, United States
- School
of Electrical & Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - C. Ross Ethier
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, United States
| | - Stanislav Y. Emelianov
- Wallace
H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, United States
- School
of Electrical & Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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Bahrani Fard MR, Chan J, Sanchez Rodriguez G, Yonk M, Kuturu SR, Read AT, Emelianov SY, Kuehn MH, Ethier CR. Improved magnetic delivery of cells to the trabecular meshwork in mice. Exp Eye Res 2023; 234:109602. [PMID: 37488007 PMCID: PMC10530071 DOI: 10.1016/j.exer.2023.109602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 07/22/2023] [Indexed: 07/26/2023]
Abstract
Glaucoma is the leading cause of irreversible blindness worldwide and its most prevalent subtype is primary open angle glaucoma (POAG). One pathological change in POAG is loss of cells in the trabecular meshwork (TM), which is thought to contribute to ocular hypertension and has thus motivated development of cell-based therapies to refunctionalize the TM. TM cell therapy has shown promise in intraocular pressure (IOP) control, but existing cell delivery techniques suffer from poor delivery efficiency. We employed a novel magnetic delivery technique to reduce the unwanted side effects of off-target cell delivery. Mesenchymal stem cells (MSCs) were labeled with superparamagnetic iron oxide nanoparticles (SPIONs) and after intracameral injection were magnetically steered towards the TM using a focused magnetic apparatus ("point magnet"). This technique delivered the cells significantly closer to the TM at higher quantities and with more circumferential uniformity compared to either unlabeled cells or those delivered using a "ring magnet" technique. We conclude that our point magnet cell delivery technique can improve the efficiency of TM cell therapy and in doing so, potentially increase the therapeutic benefits and lower the risk of complications such as tumorigenicity and immunogenicity.
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Affiliation(s)
- M Reza Bahrani Fard
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Jessica Chan
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - Marybeth Yonk
- College of Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Shreya R Kuturu
- Department of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - A Thomas Read
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, USA
| | - Stanislav Y Emelianov
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, USA
| | - Markus H Kuehn
- Departments of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, IA, USA; Veterans Administration Center for the Prevention and Treatment of Visual Loss, Iowa City VA Healthcare System, Iowa City, IA, USA
| | - C Ross Ethier
- Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA, USA; Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, USA.
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Choe A, Qin D, Yu AM, Chung E, Jhunjhunwala A, Rose JA, Emelianov SY. pH-responsive ratiometric photoacoustic imaging of polyaniline nanoparticle-coated needle for targeted cancer biopsy. Photoacoustics 2023; 31:100500. [PMID: 37187489 PMCID: PMC10176251 DOI: 10.1016/j.pacs.2023.100500] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/06/2023] [Accepted: 04/24/2023] [Indexed: 05/17/2023]
Abstract
Cancer microenvironment exhibits lower pH compared to healthy tissues, a characteristic which can be exploited using a pH-responsive needle to increase the accuracy of cancer biopsy. A needle, coated with pH-responsive polyaniline (PANI) nanoparticles (PANI-needle), is developed for the minimally invasive and quantitative pH analysis of tissue based on ratiometric photoacoustic (PA) imaging. The ratiometric PA signal from the PANI-needle within the 850-700 nm wavelength range shows a linear response as pH changes from 7.5 to 6.5. Owing to the high surface area of nanostructured PANI, the PA signal of PANI-needle exhibits a fast and reversible response of less than a few seconds. In a tissue-mimicking hydrogel phantom composed of two regions with different pH, PA ratios of PANI-needle successfully differentiate the local pH. The PANI-needle coupled with ultrasound-guided PA imaging is a promising technology for detection of malignant tissue through quantitative pH analysis during needle biopsy.
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Affiliation(s)
- Ayoung Choe
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - David Qin
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
| | - Anthony M. Yu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
| | - Euisuk Chung
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Anamik Jhunjhunwala
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
| | - Julian A. Rose
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
| | - Stanislav Y. Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Corresponding author at: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA.
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Cao Y, Dumani DS, Hallam KA, Emelianov SY, Ran H. Real-time monitoring of NIR-triggered drug release from phase-changeable nanodroplets by photoacoustic/ultrasound imaging. Photoacoustics 2023; 30:100474. [PMID: 37025112 PMCID: PMC10070823 DOI: 10.1016/j.pacs.2023.100474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 02/21/2023] [Accepted: 03/11/2023] [Indexed: 06/19/2023]
Abstract
Optical-responsive nanodroplets have recently been studied as a new mode of remotely controlled drug delivery. As a class of new emerging smart drug carriers, NIR-absorber-loaded perfluorocarbon nanodroplets can be converted into gas bubbles through laser stimulation, called optical droplet vaporization (ODV), which provides a potential strategy to deliver therapeutic agents to solid tumors on demand. However, there is a lack of suitable technologies to monitor these drug-loaded nanodroplet behaviors in vivo, and control the site and amount of drug released. In this study, ultrasound and photoacoustic imaging technology were applied to directly monitor optical-responsive, drug-loaded nanodroplets within the tissue. We explored the effects of laser energy, repetition rate, and number of pulses on the release profiles of the delivered drug as well as ultrasound and photoacoustic imaging signal-intensity curves. The conducted studies demonstrated that this noninvasive technology helped determine the optimum time point for laser activation on accumulated drug-loaded nanodroplets within tissues, allowing for the potential to effectively treat pathologies while minimizing drug-related toxicities.
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Affiliation(s)
- Yang Cao
- Chongqing Key Laboratory of Ultrasound Molecular Imaging, Institute of ultrasound imaging, Second Affiliated Hospital, State Key Laboratory of Ultrasound in Medicine and Engineering, Chongqing Medical University, Chongqing 400010, PR China
| | - Diego S. Dumani
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, United States
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States
- School of Electrical Engineering, University of Costa Rica, San Pedro, San José, 11501-2060 UCR, Costa Rica
| | - Kristina A. Hallam
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, United States
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States
| | - Stanislav Y. Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, United States
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, United States
| | - Haitao Ran
- Chongqing Key Laboratory of Ultrasound Molecular Imaging, Institute of ultrasound imaging, Second Affiliated Hospital, State Key Laboratory of Ultrasound in Medicine and Engineering, Chongqing Medical University, Chongqing 400010, PR China
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Liu J, Leer J, Aglayomov SR, Emelianov SY. A Scholte wave approach for ultrasonic surface acoustic wave elastography. Med Phys 2023. [PMID: 36971512 DOI: 10.1002/mp.16394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 03/10/2023] [Accepted: 03/16/2023] [Indexed: 03/29/2023] Open
Abstract
BACKGROUND Pathological changes in tissues are often related to changes in tissue mechanical properties, making elastography an important tool for medical applications. Among the existing elastography methods, ultrasound elastography is of great interest due to the inherent advantages of ultrasound imaging technology, such as low cost, portability, safety, and wide availability. Although ultrasonic shear wave elastography, as a platform technology, can potentially quantify the elasticity of tissue at any depth, its current implementation cannot assess superficial tissue but can only image deep tissue. PURPOSE To address this challenge, we proposed an ultrasonic Scholte-wave-based approach for imaging the elasticity of superficial tissue. METHODS The feasibility of the proposed technique was tested using a gelatin phantom with a cylindrical inclusion. To generate Scholte wave in the superficial region of the phantom, we proposed a new experimental configuration in which a liquid layer was introduced between an ultrasound imaging transducer and the tissue-mimicking phantom. We utilized an acoustic radiation force impulse to excite the tissue-mimicking phantom, analyzed the properties of the generated Scholte waves, and applied the waves for elasticity imaging. RESULTS In this study, we first reported the observation that Scholte (surface) waves and shear (bulk) waves were simultaneously generated, and they propagated in the superficial and deeper regions of the phantom, respectively. Then, we presented some important properties of the generated Scholte waves. For a 5w/v% gelatin phantom, the generated Scholte waves have a speed of around 0.9 m/s, a frequency of about 186 Hz, and thus a wavelength of about 4.8 mm. The speed ratio between the simultaneously generated Scholte wave and shear wave is about 0.717, which is 15% lower than the theoretical expectation. And we further demonstrated the feasibility of Scholte wave as a mechanism for imaging superficial tissue elasticity. Together with the simultaneously generated shear wave, the Scholte wave was shown to be able to quantitatively image both the background and the cylindrical inclusion (4 mm in diameter) of the tissue-mimicking gelatin phantom. CONCLUSIONS This work shows that the elasticity of superficial tissue can be evaluated by utilizing the generated Scholte wave alone, and it also shows that a comprehensive elasticity imaging of the tissue extending from the superficial to deep regions can be achieved by combining the proposed Scholte wave technique and the conventional shear wave technique.
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Affiliation(s)
- Jingfei Liu
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA
| | - Jurjen Leer
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Salavat R Aglayomov
- Department of Mechanical Engineering, University of Houston, Houston, Texas, USA
| | - Stanislav Y Emelianov
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, USA
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Thompson WR, Brecht HPF, Ivanov V, Yu AM, Dumani DS, Lawrence DJ, Emelianov SY, Ermilov SA. Characterizing a photoacoustic and fluorescence imaging platform for preclinical murine longitudinal studies. J Biomed Opt 2023; 28:036001. [PMID: 36895414 PMCID: PMC9990133 DOI: 10.1117/1.jbo.28.3.036001] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Significance To effectively study preclinical animal models, medical imaging technology must be developed with a high enough resolution and sensitivity to perform anatomical, functional, and molecular assessments. Photoacoustic (PA) tomography provides high resolution and specificity, and fluorescence (FL) molecular tomography provides high sensitivity; the combination of these imaging modes will enable a wide range of research applications to be studied in small animals. Aim We introduce and characterize a dual-modality PA and FL imaging platform using in vivo and phantom experiments. Approach The imaging platform's detection limits were characterized through phantom studies that determined the PA spatial resolution, PA sensitivity, optical spatial resolution, and FL sensitivity. Results The system characterization yielded a PA spatial resolution of 173 ± 17 μ m in the transverse plane and 640 ± 120 μ m in the longitudinal axis, a PA sensitivity detection limit not less than that of a sample with absorption coefficient μ a = 0.258 cm - 1 , an optical spatial resolution of 70 μ m in the vertical axis and 112 μ m in the horizontal axis, and a FL sensitivity detection limit not < 0.9 μ M concentration of IR-800. The scanned animals displayed in three-dimensional renders showed high-resolution anatomical detail of organs. Conclusions The combined PA and FL imaging system has been characterized and has demonstrated its ability to image mice in vivo, proving its suitability for biomedical imaging research applications.
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Affiliation(s)
| | | | - Vassili Ivanov
- PhotoSound Technologies, Inc., Houston, Texas, United States
| | - Anthony M. Yu
- Georgia Institute of Technology, Department of Biomedical Engineering, Atlanta, Georgia, United States
| | - Diego S. Dumani
- Georgia Institute of Technology, Department of Biomedical Engineering, Atlanta, Georgia, United States
| | | | - Stanislav Y. Emelianov
- Georgia Institute of Technology, Department of Biomedical Engineering, Atlanta, Georgia, United States
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11
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Liu J, Yoon H, Emelianov SY. Noninvasive ultrasound assessment of tissue internal pressure using dual mode elasticity imaging: a phantom study. Phys Med Biol 2022; 68. [PMID: 36562591 DOI: 10.1088/1361-6560/aca9b8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 12/07/2022] [Indexed: 12/12/2022]
Abstract
Objective.Tissue internal pressure, such as interstitial fluid pressure in solid tumors and intramuscular pressure in compartment syndrome, is closely related to the pathological state of tissues. It is of great diagnostic value to measure and/or monitor the internal pressure of targeted tissues. Because most of the current methods for measuring tissue pressure are invasive, noninvasive methods are highly desired. In this study, we developed a noninvasive method for qualitative assessment of tissue internal pressure based on a combination of two ultrasound elasticity imaging methods: strain imaging and shear wave elasticity imaging.Approach.The method was verified through experimental investigation using two tissue-mimicking phantoms each having an inclusion confined by a membrane, in which hydrostatic pressures can be applied and maintained. To examine the sensitivity of the elasticity imaging methods to pressure variation, strain ratio and shear modulus ratio (SMR) between the inclusion and background of phantom were obtained.Main results.The results first experimentally prove that pressure, in addition to elasticity, is a contrast mechanism of strain imaging, and further demonstrate that a comparative analysis of strain ratio and SMR is an effective method for noninvasive tissue internal pressure detection.Significance.This work provides a new perspective in interpreting the strain ratio data in medical diagnosis, and it also provides a noninvasive alternative for assessing tissue internal pressure, which could be valuable for the diagnosis of pressure-related diseases.
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Affiliation(s)
- Jingfei Liu
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30322, United States of America
| | - Heechul Yoon
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30322, United States of America.,School of Electronics and Electrical Engineering, Dankook University, Yongin-si 16890, Republic of Korea
| | - Stanislav Y Emelianov
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30322, United States of America.,Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30322 United States of America
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12
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Cao Y, Dumani DS, Chen Z, Emelianov SY, Ran H. Correction: In vivo photoacoustic image-guided tumor photothermal therapy and real-time temperature monitoring using a core-shell polypyrrole@CuS nanohybrid. Nanoscale 2022; 14:14808. [PMID: 36196683 DOI: 10.1039/d2nr90186b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Correction for 'In vivo photoacoustic image-guided tumor photothermal therapy and real-time temperature monitoring using a core-shell polypyrrole@CuS nanohybrid' by Yang Cao et al., Nanoscale, 2022, 14, 12069-12076, https://doi.org/10.1039/D2NR02848D.
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Affiliation(s)
- Yang Cao
- Chongqing Key Laboratory of Ultrasound Molecular Imaging, Institute of Ultrasound Imaging, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China.
| | - Diego S Dumani
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Ziqun Chen
- Chongqing Key Laboratory of Ultrasound Molecular Imaging, Institute of Ultrasound Imaging, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China.
| | - Stanislav Y Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Haitao Ran
- Chongqing Key Laboratory of Ultrasound Molecular Imaging, Institute of Ultrasound Imaging, Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010, China.
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13
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Kang J, Yoon H, Yoon C, Emelianov SY. High-Frequency Ultrasound Imaging With Sub-Nyquist Sampling. IEEE Trans Ultrason Ferroelectr Freq Control 2022; 69:2001-2009. [PMID: 35436190 PMCID: PMC10264145 DOI: 10.1109/tuffc.2022.3167726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Implementation of a high-frequency ultrasound (HFUS) beamformer is computationally challenging because of its high sampling rate. This article introduces an efficient beamformer with sub-Nyquist sampling (or bandpass sampling) that is suitable for HFUS imaging. Our approach used channel radio frequency data sampled at bandpass sampling rate (i.e., 4/ 3fc ) and postfiltering-based interpolation to reduce the computational complexity. A polyphase structure for interpolation was used to further reduce the computational burden while maintaining an adequate delay resolution ( δ ). The performance of the proposed beamformer (i.e., 4/ 3fc sampling with sixfold interpolation, δ = 8fc ) was compared with that of the conventional method (i.e., 4fc sampling with fourfold interpolation, δ = 16fc ). Ultrafast coherent compounding imaging was used in simulation, in vitro and in vivo imaging experiments. Axial/lateral resolution and contrast-to-noise ratio (CNR) values were measured for quantitative evaluation. The number of transmit pulse cycles was varied from 1 to 3 using two transducers with different fractional bandwidths (67% and 98%). In the simulation, the proposed and conventional methods showed the similar -6-dB axial beam widths (63.5 and 61.5 μm , respectively) from the two-cycle transmit pulse using the transducer with a bandwidth of 67%. In vitro and in vivo imaging experiments were performed using a Verasonics ultrasound research platform equipped with a high-frequency array transducer (20-46 MHz). The in vitro imaging results using a wire target showed consistent results with the simulation study (i.e., disparity at -6-dB axial resolution). The in vivo feasibility study with a murine mouse model with breast cancer was also performed, and the proposed method yielded a similar image quality compared with the conventional method. From these studies, it was demonstrated that the proposed HFUS beamformer based on the bandpass sampling can substantially reduce the computational complexity while minimizing the loss of spatial resolution for HFUS imaging.
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Kim J, Yu AM, Kubelick KP, Emelianov SY. Gold nanoparticles conjugated with DNA aptamer for photoacoustic detection of human matrix metalloproteinase-9. Photoacoustics 2022; 25:100307. [PMID: 34703762 PMCID: PMC8521288 DOI: 10.1016/j.pacs.2021.100307] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/07/2021] [Accepted: 09/24/2021] [Indexed: 05/11/2023]
Abstract
Matrix metalloproteinase-9 (MMP-9) plays major roles in extracellular matrix (ECM) remodeling and membrane protein cleavage, suggesting a high correlation with cancer cell invasion and tumor metastasis. Here, we present a contrast agent based on a DNA aptamer that can selectively target human MMP-9 in the tumor microenvironment (TME) with high affinity and sensitivity. Surface modification of plasmonic gold nanospheres with the MMP-9 aptamer and its complementary sequences allows the nanospheres to aggregate in the presence of human MMP-9 through DNA displacement and hybridization. Aggregation of gold nanospheres enhances the optical absorption in the first near-infrared window (NIR-I) due to the plasmon coupling effect, thereby allowing us to detect the aggregated gold nanospheres within the TME via ultrasound-guided photoacoustic (US/PA) imaging. Selective and sensitive detection of human MMP-9 via US/PA imaging is demonstrated in solution of nanosensors with the pre-treatment of human MMP-9, in vitro in cell culture, and in vivo in a xenograft murine model of human breast cancer.
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Affiliation(s)
- Jinhwan Kim
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Anthony M. Yu
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
| | - Kelsey P. Kubelick
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Stanislav Y. Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Correspondence to: School of Electrical & Computer Engineering, and Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA.
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Liu J, Toy R, Vantucci C, Pradhan P, Zhang Z, Kuo KM, Kubelick KP, Huo D, Wen J, Kim J, Lyu Z, Dhal S, Atalis A, Ghosh-Choudhary SK, Devereaux EJ, Gumbart JC, Xia Y, Emelianov SY, Willett NJ, Roy K. Bifunctional Janus Particles as Multivalent Synthetic Nanoparticle Antibodies (SNAbs) for Selective Depletion of Target Cells. Nano Lett 2021; 21:875-886. [PMID: 33395313 PMCID: PMC8176937 DOI: 10.1021/acs.nanolett.0c04833] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Monoclonal antibodies (mAb) have had a transformative impact on treating cancers and immune disorders. However, their use is limited by high development time and monetary cost, manufacturing complexities, suboptimal pharmacokinetics, and availability of disease-specific targets. To address some of these challenges, we developed an entirely synthetic, multivalent, Janus nanotherapeutic platform, called Synthetic Nanoparticle Antibodies (SNAbs). SNAbs, with phage-display-identified cell-targeting ligands on one "face" and Fc-mimicking ligands on the opposite "face", were synthesized using a custom, multistep, solid-phase chemistry method. SNAbs efficiently targeted and depleted myeloid-derived immune-suppressor cells (MDSCs) from mouse-tumor and rat-trauma models, ex vivo. Systemic injection of MDSC-targeting SNAbs efficiently depleted circulating MDSCs in a mouse triple-negative breast cancer model, enabling enhanced T cell and Natural Killer cell infiltration into tumors. Our results demonstrate that SNAbs are a versatile and effective functional alternative to mAbs, with advantages of a plug-and-play, cell-free manufacturing process, and high-throughput screening (HTS)-enabled library of potential targeting ligands.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jianguo Wen
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60517, United States
| | | | | | | | | | - Shohini K Ghosh-Choudhary
- School of Medicine, University of Pittsburgh, 3550 Terrace St., Pittsburgh, Pennsylvania 15213, United States
| | - Emily J Devereaux
- Orthopaedics Department, Emory University, Atlanta, Georgia 30322, United States
- Research Service, Atlanta VA Medical Center, Decatur, Georgia 30033, United States
| | | | | | | | - Nick J Willett
- Orthopaedics Department, Emory University, Atlanta, Georgia 30322, United States
- Research Service, Atlanta VA Medical Center, Decatur, Georgia 30033, United States
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Kubelick KP, Emelianov SY. A Trimodal Ultrasound, Photoacoustic and Magnetic Resonance Imaging Approach for Longitudinal Post-operative Monitoring of Stem Cells in the Spinal Cord. Ultrasound Med Biol 2020; 46:3468-3474. [PMID: 32988671 PMCID: PMC7709928 DOI: 10.1016/j.ultrasmedbio.2020.08.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 08/10/2020] [Accepted: 08/25/2020] [Indexed: 06/11/2023]
Abstract
Longitudinal monitoring of stem cells in the spinal cord could unveil critical information needed to understand regenerative processes, thereby expediting therapy development and translation. We introduce a post-operative trimodal imaging approach to monitor stem cells in the spinal cord over time. A key aspect of the approach is to label the stem cells with Prussian blue nanocubes (PBNCs), which simultaneously possess optical and magnetic properties for ultrasound-guided photoacoustic (US/PA) and magnetic resonance imaging (MRI) contrast. PBNC-Labeled stem cells were injected into the spinal cord of immunodeficient rats and tracked with US/PA imaging and MRI up to 14 d post-injection. Good agreement was observed between imaging modalities in vivo. Our results suggest that further development of the US/PA/MR imaging approach may create a powerful tool to aid development of regenerative therapies of the spinal cord, and the non-invasive imaging approach can ultimately be deployed in intra- and post-operative environments.
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Affiliation(s)
- Kelsey P Kubelick
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, USA; School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
| | - Stanislav Y Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, USA; School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
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17
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Kubelick KP, Emelianov SY. In vivo photoacoustic guidance of stem cell injection and delivery for regenerative spinal cord therapies. Neurophotonics 2020; 7:030501. [PMID: 32743015 PMCID: PMC7388074 DOI: 10.1117/1.nph.7.3.030501] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 07/14/2020] [Indexed: 05/16/2023]
Abstract
Significance: Stem cell therapies are of interest for treating a variety of neurodegenerative diseases and injuries of the spinal cord. However, the lack of techniques for longitudinal monitoring of stem cell therapy progression is inhibiting clinical translation. Aim: The goal of this study is to demonstrate an intraoperative imaging approach to guide stem cell injection to the spinal cord in vivo. Results may ultimately support the development of an imaging tool that spans intra- or postoperative environments to guide therapy throughout treatment. Approach: Stem cells were labeled with Prussian blue nanocubes (PBNCs) to facilitate combined ultrasound and photoacoustic (US/PA) imaging to visualize stem cell injection and delivery to the spinal cord in vivo. US/PA results were confirmed by magnetic resonance imaging (MRI) and histology. Results: Real-time intraoperative US/PA image-guided injection of PBNC-labeled stem cells and three-dimensional volumetric images of injection provided feedback necessary for successful delivery of therapeutics into the spinal cord. Postoperative MRI confirmed delivery of PBNC-labeled stem cells. Conclusions: The nanoparticle-augmented US/PA approach successfully detected injection and delivery of stem cells into the spinal cord, confirmed by MRI. Our work demonstrated in vivo feasibility, which is a critical step toward the development of a US/PA/MRI platform to monitor regenerative spinal cord therapies.
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Affiliation(s)
- Kelsey P. Kubelick
- Georgia Institute of Technology, Emory University School of Medicine, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, Georgia, United States
| | - Stanislav Y. Emelianov
- Georgia Institute of Technology, Emory University School of Medicine, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
- Georgia Institute of Technology, School of Electrical and Computer Engineering, Atlanta, Georgia, United States
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18
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Kubelick KP, Emelianov SY. Prussian blue nanocubes as a multimodal contrast agent for image-guided stem cell therapy of the spinal cord. Photoacoustics 2020; 18:100166. [PMID: 32211291 PMCID: PMC7082547 DOI: 10.1016/j.pacs.2020.100166] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 01/20/2020] [Accepted: 02/03/2020] [Indexed: 05/16/2023]
Abstract
Translation of stem cell therapies to treat injuries and diseases of the spinal cord is hindered by lack of real-time monitoring techniques to guide regenerative therapies intra- and postoperatively. Thus, we developed an ultrasound (US), photoacoustic (PA), and magnetic resonance (MR) imaging approach augmented with Prussian blue nanocubes (PBNCs) to guide stem cell injections intraoperatively and monitor stem cell therapies in the spinal cord postoperatively. Per the clinical procedure, a multi-level laminectomy was performed in rats ex vivo, and PBNC-labeled stem cells were injected directly into the spinal cord while US/PA images were acquired. US/PA/MR images were also acquired post-surgery. Several features of the imaging approach were demonstrated including detection of low stem cell concentrations, real-time needle guidance and feedback on stem cell delivery, and good agreement between US/PA/MR images. These benefits span intra- and postoperative environments to support future development of this imaging tool.
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Key Words
- AuNS, gold nanosphere
- DIUF, deionized ultra-filtered water
- IACUC, Institutional Animal Care and Use Committee
- LOD, limit of detection
- MRI, magnetic resonance imaging
- MSC, mesenchymal stem cell
- Magnetic resonance imaging
- Multimodal imaging
- Nanoparticles
- OR, operating room
- PA, photoacoustic
- PBNC, Prussian blue nanocube
- PBS, phosphate buffered saline
- Photoacoustic imaging
- SPION, superparamagnetic iron oxide nanoparticle
- Spinal cord
- Stem cells
- TE, echo time
- TEM, transmission electron microscopy
- TR, repetition time
- US, ultrasound
- Ultrasound
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Affiliation(s)
- Kelsey P Kubelick
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, 313 Ferst Dr NW, Atlanta, GA, 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Drive, Atlanta, GA, 30332, USA
| | - Stanislav Y Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, 313 Ferst Dr NW, Atlanta, GA, 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Drive, Atlanta, GA, 30332, USA
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Zhao L, Vanderlaan D, Yoon H, Liu J, Li C, Emelianov SY. Ultrafast ultrasound imaging of surface acoustic waves induced by laser excitation compared with acoustic radiation force. Opt Lett 2020; 45:1810-1813. [PMID: 32236005 PMCID: PMC8957894 DOI: 10.1364/ol.383932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 01/25/2020] [Indexed: 06/11/2023]
Abstract
Two generation mechanisms-optical perturbation and acoustic radiation force (ARF)-were investigated where high frame rate ultrasound imaging was used to track the propagation of induced SAWs. We compared ARF-induced SAWs with laser-induced SAWs generated by laser beam irradiation of the uniformly absorbing tissue-like viscoelastic phantom, where light was preferentially absorbed at the surface. We also compared the frequency content of SAWs generated by ARF versus pulsed laser light, using the same duration of excitation. Differences in the SAW bandwidth were expected because, in general, laser light can be focused into a smaller area. Finally, we compared wave generation and propagation when the wave's origin was below the surface. We also investigated the relationship between shear wave amplitude and optical fluence. The investigation reported here can potentially extend the applications of laser-induced SAW generation and imaging in life sciences and other applications.
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Affiliation(s)
- Lingyi Zhao
- Walter H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, USA
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Don Vanderlaan
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Heechul Yoon
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Jingfei Liu
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Changhui Li
- Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Stanislav Y. Emelianov
- Walter H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
- Corresponding author:
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20
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Dumani DS, Cook JR, Kubelick KP, Luci JJ, Emelianov SY. Photomagnetic Prussian blue nanocubes: Synthesis, characterization, and biomedical applications. Nanomedicine 2020; 24:102138. [PMID: 31846739 PMCID: PMC7160738 DOI: 10.1016/j.nano.2019.102138] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 11/15/2019] [Accepted: 11/19/2019] [Indexed: 10/25/2022]
Abstract
Nanoparticles play an important role in biomedicine. We have developed a method for size-controlled synthesis of photomagnetic Prussian blue nanocubes (PBNCs) using superparamagnetic iron oxide nanoparticles (SPIONs) as precursors. The developed PBNCs have magnetic and optical properties desired in many biomedical diagnostic and therapeutic applications. Specifically, the size-tunable photomagnetic PBNCs exhibit high magnetic saturation, strong optical absorption with a peak at approximately 700 nm, and superior photostability. Our studies demonstrate that PBNCs can be used as MRI and photoacoustic imaging contrast agents in vivo. We also showed the utility of PBNCs for labeling and magnetic manipulation of cells. Dual magnetic and optical properties, together with excellent biocompatibility, render PBNCs an attractive contrast agent for both diagnostic and therapeutic applications. The use SPIONs as precursors for PBNCs provides flexibility and allows researchers to design theranostic agents according to required particle size, optical, and magnetic properties.
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Affiliation(s)
- Diego S. Dumani
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332,School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332
| | - Jason R. Cook
- NanoHybrids, Inc., Austin, TX 78744,Department of Biomedical Engineering, The University of Texas at Austin, TX 78712
| | - Kelsey P. Kubelick
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332
| | - Jeffrey J. Luci
- Department of Biomedical Engineering, The University of Texas at Austin, TX 78712,Department of Neuroscience and Imaging Research Center, The University of Texas at Austin, Austin, TX 78712
| | - Stanislav Y. Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332,School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332,Corresponding author:
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Yu J, Yoon H, Khalifa YM, Emelianov SY. Design of a Volumetric Imaging Sequence Using a Vantage-256 Ultrasound Research Platform Multiplexed With a 1024-Element Fully Sampled Matrix Array. IEEE Trans Ultrason Ferroelectr Freq Control 2020; 67:248-257. [PMID: 31545718 PMCID: PMC7008949 DOI: 10.1109/tuffc.2019.2942557] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Ultrasound imaging using a matrix array allows real-time multi-planar volumetric imaging. To enhance image quality, the matrix array should provide fast volumetric ultrasound imaging with spatially consistent focusing in the lateral and elevational directions. However, because of the significantly increased data size, dealing with massive and continuous data acquisition is a significant challenge. We have designed an imaging acquisition sequence that handles volumetric data efficiently using a single 256-channel Verasonics ultrasound research platform multiplexed with a 1024-element matrix array. The developed sequence has been applied for building an ultrasonic pupilometer. Our results demonstrate the capability of the developed approach for structural visualization of an ex vivo porcine eye and the temporal response of the modeled eye pupil with moving iris at the volume rate of 30 Hz. Our study provides a fundamental ground for researchers to establish their own volumetric ultrasound imaging platform and could stimulate the development of new volumetric ultrasound approaches and applications.
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Laffey MK, Kubelick KP, Donnelly EM, Emelianov SY. Effects of Freezing on Mesenchymal Stem Cells Labeled with Gold Nanoparticles. Tissue Eng Part C Methods 2019; 26:1-10. [PMID: 31724492 DOI: 10.1089/ten.tec.2019.0198] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Stem cell therapies are a promising treatment for many patients suffering from diseases with poor prognosis. However, clinical translation is inhibited by a lack of in vivo monitoring techniques to track stem cells throughout the course of treatment. Ultrasound-guided photoacoustic (PA) imaging of nanoparticle-labeled stem cells may be a solution. To allow PA tracking, stem cells must be labeled with an optically absorbing contrast agent. Gold nanoparticles are one option due to their cytocompatibility and strong optical absorption in the near-infrared region. However, stem cell labeling can require up to 24-h incubation with nanoparticles in culture before use. Although stem cell monitoring is critically needed, the additional preparation time may not be feasible-it is cost prohibitive and stem cell treatments should be readily available in emergency situations as well as scheduled procedures. To remedy this, stem cells can be labeled before freezing and long-term storage. While it is well known that stem cells retain their cellular function after freezing, storage, and thawing, the impact of gold nanoparticles on this process has yet to be investigated. Therefore, we assessed the viability, multipotency, and PA activity of gold nanosphere-labeled mesenchymal stem cells (MSCs) after freezing, storing, and thawing for 1 week, 1 month, or 2 months and compared to unlabeled, naive MSCs which were frozen, stored, and thawed at the same time points. Results indicated no substantial change in viability as assessed by the MTT assay. Differentiation, observed through adipogenesis and osteogenesis, was also comparable to controls. Finally, strong PA signals and similar PA spectral signatures remained. Further studies involving more diverse stem cell types and nanoparticles are required, but our data suggest that function and imaging properties of nanoparticle-labeled stem cells are maintained after freezing and storage, which improve translation of stem cell monitoring techniques by simplifying integration with clinical protocols. Impact statement Although stem cell tracking techniques are critically needed, stem cells must be labeled with contrast agents in advance of procedures, which is not clinically feasible due to increased procedure time. As a solution, a stock of labeled stem cells could be frozen and stored, ready for immediate use. Results showed that gold nanosphere-labeled stem cells can be frozen and stored long-term without impacting cellular function or photoacoustic imaging contrast, supporting further investigation of other contrast agents and cell types. Creating a bank of nanoparticle-labeled stem cells advances translation and scalability of stem cell tracking methods by improving integration with clinical protocols.
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Affiliation(s)
- Makenna K Laffey
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia
| | - Kelsey P Kubelick
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia
| | - Eleanor M Donnelly
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia
| | - Stanislav Y Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia.,School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia
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23
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Hallam KA, Emelianov SY. Toward optimization of blood brain barrier opening induced by laser-activated perfluorocarbon nanodroplets. Biomed Opt Express 2019; 10:3139-3151. [PMID: 31360596 PMCID: PMC6640833 DOI: 10.1364/boe.10.003139] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 05/30/2019] [Accepted: 05/30/2019] [Indexed: 05/09/2023]
Abstract
The blood brain barrier (BBB), a component of the brain's natural defense system, is often a roadblock for the monitoring and treatment of neurological disorders. Recently, we introduced a technique to open the blood brain barrier through the use of laser-activated perfluorohexane nanodroplets (PFHnDs), a phase-change nanoagent that undergoes repeated vaporization and recondensation when excited by a pulsed laser. Laser-activated PFHnDs were shown to enable noninvasive and localized opening of the BBB, allowing extravasation of various sized agents into the brain tissue. In this current work, the laser-activated PFHnD-induced BBB opening is further explored. In particular, laser fluence and the number of laser pulses used for the PFHnD-induced BBB opening are examined and evaluated both qualitatively and quantitatively to determine the effect of these parameters on BBB opening. The results of these studies show trends between increased laser fluence and an increased BBB opening as well as between an increased number of laser pulses and an increased BBB opening, however, with limitations on the extent of the BBB opening after a certain number of pulses. Overall, the results of these studies serve as a guideline to choosing suitable laser parameters for safe and effective BBB opening.
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Affiliation(s)
- Kristina A. Hallam
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Stanislav Y. Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
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Yoon H, Zhu YI, Yarmoska SK, Emelianov SY. Design and Demonstration of a Configurable Imaging Platform for Combined Laser, Ultrasound, and Elasticity Imaging. IEEE Trans Med Imaging 2019; 38:1622-1632. [PMID: 30596572 PMCID: PMC7286075 DOI: 10.1109/tmi.2018.2889736] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This paper introduces a configurable combined laser, ultrasound, and elasticity (CLUE) imaging platform. The CLUE platform enables imaging sequences capable of simultaneously providing quantitative acoustic, optical, and mechanical contrast for comprehensive diagnosis and monitoring of complex diseases, such as cancer. The CLUE imaging platform was developed on a Verasonics ultrasound scanner integrated with a pulsed laser, and it was designed to be modular and scalable to allow researchers to create their own specific imaging sequences efficiently. The CLUE imaging platform and sequence were demonstrated in a tissue-mimicking phantom containing a stiff inclusion labeled with optically-activated nanodroplets and in an ex vivo mouse spleen. We have shown that CLUE imaging can simultaneously capture multi-functional imaging signals providing quantitative information on tissue.
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Dumani DS, Sun IC, Emelianov SY. Ultrasound-guided immunofunctional photoacoustic imaging for diagnosis of lymph node metastases. Nanoscale 2019; 11:11649-11659. [PMID: 31173038 PMCID: PMC6586492 DOI: 10.1039/c9nr02920f] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Metastases, rather than primary tumors, determine mortality in the majority of cancer patients. A non-invasive immunofunctional imaging method was developed to detect sentinel lymph node (SLN) metastases using ultrasound-guided photoacoustic (USPA) imaging combined with glycol-chitosan-coated gold nanoparticles (GC-AuNPs) as an imaging contrast agent. GC-AuNPs, injected peritumorally into breast tumor-bearing mice, were taken up by immune cells, and subsequently transported to the SLN. Two-dimensional and three-dimensional USPA imaging was used to isolate the signal from GC-AuNP-tagged cells. Volumetric analysis was used to quantify GC-AuNP accumulation in the SLN after cellular uptake and transport by immune cells. The results show that the spatio-temporal distribution of GC-AuNPs in the SLN was affected by the presence of metastases. The parameter describing the spatial distribution of GC-AuNP-tagged cells within the SLN was more than 2-fold lower in metastatic lymph nodes compared with non-metastatic controls. Histological analysis confirmed that the distribution of GC-AuNP-tagged immune cells is changed by the presence of metastatic cells. The USPA immunofunctional imaging successfully distinguished metastatic from non-metastatic lymph nodes using biocompatible nanoparticles. This method could aid physicians in the detection of micrometastases, thus guiding SLN biopsy and avoiding unnecessary biopsy procedures.
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Yarmoska SK, Yoon H, Emelianov SY. Lipid Shell Composition Plays a Critical Role in the Stable Size Reduction of Perfluorocarbon Nanodroplets. Ultrasound Med Biol 2019; 45:1489-1499. [PMID: 30975536 PMCID: PMC6491255 DOI: 10.1016/j.ultrasmedbio.2019.02.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 02/04/2019] [Accepted: 02/07/2019] [Indexed: 05/20/2023]
Abstract
Perfluorocarbon nanodroplets (PFCnDs) are phase-change contrast agents that have the potential to enable extravascular contrast-enhanced ultrasound and photoacoustic (US/PA) imaging. Producing consistently small, monodisperse PFCnDs remains a challenge without resorting to technically challenging methods. We investigated the impact of variable shell composition on PFCnD size and US/PA image properties. Our results suggest that increasing the molar percentage of PEGylated lipid reduces the size and size variance of PFCnDs. Furthermore, our imaging studies revealed that nanodroplets with more PEGylated lipids produce increased US/PA signal compared with those with the standard formulation. Finally, we highlight the ability of this approach to facilitate US/PA imaging in a murine model of breast cancer. These data indicate that, through a facile synthesis process, it is possible to produce monodisperse, small-sized PFCnDs. Novel in their simplicity, these methods may promote the use of PFCnDs among a broader user base to study a variety of extravascular phenomena.
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Affiliation(s)
- Steven K Yarmoska
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, USA
| | - Heechul Yoon
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Stanislav Y Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, USA; School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
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Santiesteban DY, Hallam KA, Yarmoska SK, Emelianov SY. Color-coded perfluorocarbon nanodroplets for multiplexed ultrasound and Photoacoustic imaging. Nano Res 2019; 12:741-747. [PMID: 31572565 PMCID: PMC6768563 DOI: 10.1007/s12274-019-2279-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 12/19/2018] [Accepted: 12/25/2018] [Indexed: 05/19/2023]
Abstract
Laser-activated perfluorocarbon nanodroplets are an emerging class of phase change, dual-contrast agents that can be utilized in ultrasound and photoacoustic imaging. Through the ability to differentiate subpopulations of nanodroplets via laser activation at different wavelengths of near-infrared light, optically-triggered color-coded perfluorocarbon nanodroplets present themselves as an attractive tool for multiplexed ultrasound and photoacoustic imaging. In particular, laser-activated droplets can be used to provide quantitative spatiotemporal information regarding distinct biological targets, allowing for their potential use in a wide range of diagnos tic and therapeutic applications. In the work presented, laser-activated color-coded perfluorocarbon nanodroplets are synthesized to selectively respond to laser irradiation at corresponding wavelengths. The dynamic ultrasound and photoacoustic signals produced by laser-activated perfluorocarbon nanodroplets are evaluated in situ prior to implementation in a murine model. In vivo, these particles are used to distinguish unique particle trafficking mechanisms and are shown to provide ultrasound and photoacoustic contrast for up to 72 hours within lymphatics. Overall, the conducted studies show that laser-activated color-coded perfluorocarbon nanodroplets are a promising agent for multiplexed ultrasound and photoacoustic imaging.
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Affiliation(s)
- Daniela Y. Santiesteban
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Kristina A. Hallam
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
- School of Electrical & Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Steven K. Yarmoska
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
| | - Stanislav Y. Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30332, USA
- School of Electrical & Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Corresponding author,
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Zhu YI, Yoon H, Zhao AX, Emelianov SY. Leveraging the Imaging Transmit Pulse to Manipulate Phase-Change Nanodroplets for Contrast-Enhanced Ultrasound. IEEE Trans Ultrason Ferroelectr Freq Control 2019; 66:692-700. [PMID: 30703017 PMCID: PMC6545583 DOI: 10.1109/tuffc.2019.2895248] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Phase-change perfluorohexane nanodroplets (PFHnDs) are a new class of recondensable submicrometer-sized contrast agents that have potential for contrast-enhanced and super-resolution ultrasound imaging with an ability to reach extravascular targets. The PFHnDs can be optically triggered to undergo vaporization, resulting in spatially stationary, temporally transient microbubbles. The vaporized PFHnDs are hyperechoic in ultrasound imaging for several to hundreds of milliseconds before recondensing to their native, hypoechoic, liquid nanodroplet state. The decay of echogenicity, i.e., the dynamic behavior of the ultrasound signal from optically triggered PFHnDs in ultrasound imaging, can be captured using high-frame-rate ultrasound imaging. We explore the possibility to manipulate the echogenicity dynamics of optically triggered PFHnDs in ultrasound imaging by changing the phase of the ultrasound imaging pulse. Specifically, the ultrasound imaging system was programmed to transmit two imaging pulses with inverse polarities. We show that the imaging pulse phase can affect the amplitude and the temporal behavior of PFHnD echogenicity in ultrasound imaging. The results of this study demonstrate that the ultrasound echogenicity is significantly increased (about 78% improvement) and the hyperechoic timespan of optically triggered PFHnDs is significantly longer (about four times) if the nanodroplets are imaged by an ultrasound pulse starting with rarefactional pressure versus a pulse starting with compressional pressure. Our finding has direct and significant implications for contrast-enhanced ultrasound imaging of droplets in applications such as super-resolution imaging and molecular imaging where detection of individual or low-concentration PFHnDs is required.
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Hood ZD, Kubelick KP, Gilroy KD, Vanderlaan D, Yang X, Yang M, Chi M, Emelianov SY, Xia Y. Photothermal transformation of Au-Ag nanocages under pulsed laser irradiation. Nanoscale 2019; 11:3013-3020. [PMID: 30698179 DOI: 10.1039/c8nr10002k] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Pulsed laser irradiation has emerged as an effective means to photothermally transform plasmonic nanostructures after their use in different biomedical applications. However, the ability to predict the products after photothermal transformation requires extensive ex situ studies. Here, we report a systematic study of the photothermal transformation of Au-Ag nanocages with a localized surface plasmon resonance at ca. 750 nm under pulsed laser irradiation at different fluences and a pulse duration of 5 ns. At biologically relevant laser energies, the pulsed laser transforms Au-Ag nanocages into pseudo-spherical, solid nanoparticles. The solid nanoparticles contained similar numbers of Au and Ag atoms to the parent Au-Ag nanocages. At increased laser fluences (>16 mJ cm-2) and number of pulses (>150), the average diameter of the resulting pseudo-spherical particles increased due to the involvement of Ostwald ripening and/or attachment-based growth. The changes in optical properties as a result of the transformation were validated using simulations based on the discrete dipole approximation method, where the spectral profiles and peak positions of the initial and final states matched well with the experimentally derived data. The results may have implications for the future use of Au-Ag nanocages in biomedicine, catalysis, and sensing.
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Affiliation(s)
- Zachary D Hood
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
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Hartman RK, Hallam KA, Donnelly EM, Emelianov SY. Photoacoustic imaging of gold nanorods in the brain delivered via microbubble-assisted focused ultrasound: a tool for in vivo molecular neuroimaging. Laser Phys Lett 2019; 16:025603. [PMID: 30800031 PMCID: PMC6380671 DOI: 10.1088/1612-202x/aaf89e] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The protective barriers of the CNS present challenges during the treatment and monitoring of diseases. In particular, the blood brain barrier is a major hindrance to the delivery of imaging contrast agents and therapeutics to the brain. In this work, we use gas microbubble-assisted focused ultrasound to transiently open the blood brain barrier and locally deliver silica coated gold nanorods across the barrier. This particular nanoagent possesses a strong optical absorption which enables in vivo and ex vivo visualization of the delivered particles using ultrasound-guided photoacoustic imaging. The results of these studies demonstrate the potential of ultrasound-guided photoacoustics to image contrast agents delivered via microbubble-assisted focused ultrasound for longitudinal diagnostic imaging and for therapeutic monitoring of neurological diseases.
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Affiliation(s)
- Robin K. Hartman
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Kristina A. Hallam
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
| | - Eleanor M. Donnelly
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Stanislav Y. Emelianov
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
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Yoon H, Luke GP, Emelianov SY. Impact of depth-dependent optical attenuation on wavelength selection for spectroscopic photoacoustic imaging. Photoacoustics 2018; 12:46-54. [PMID: 30364441 PMCID: PMC6197329 DOI: 10.1016/j.pacs.2018.10.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 10/02/2018] [Accepted: 10/05/2018] [Indexed: 05/02/2023]
Abstract
An optical wavelength selection method based on the stability of the absorption cross-section matrix to improve spectroscopic photoacoustic (sPA) imaging was recently introduced. However, spatially-varying chromophore concentrations cause the wavelength- and depth-dependent variations of the optical fluence, which degrades the accuracy of quantitative sPA imaging. This study introduces a depth-optimized method that determines an optimal wavelength set minimizing an inverse of the multiplication of absorption cross-section matrix and fluence matrix to minimize the errors in concentration estimation. This method assumes that the optical fluence distribution is known or can be attained otherwise. We used a Monte Carlo simulation of light propagation in tissue with various depths and concentrations of deoxy-/oxy-hemoglobin. We quantitatively compared the developed and current approaches, indicating that the choice of wavelength is critical and our approach is effective especially when quantifying deeper imaging targets.
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Affiliation(s)
- Heechul Yoon
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, United States
| | - Geoffrey P. Luke
- Thayer School of Engineering, Dartmouth College, Hanover, NH, 03755, United States
| | - Stanislav Y. Emelianov
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, United States
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, 30332, United States
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Yoon H, Hallam KA, Yoon C, Emelianov SY. Super-Resolution Imaging With Ultrafast Ultrasound Imaging of Optically Triggered Perfluorohexane Nanodroplets. IEEE Trans Ultrason Ferroelectr Freq Control 2018; 65:2277-2285. [PMID: 29993686 PMCID: PMC6325306 DOI: 10.1109/tuffc.2018.2829740] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Super-resolution imaging with moving microbubbles has shown potential in identifying fine details of deep-lying vascular compartments. To image the extravascular targets, this paper has employed nanometer-sized, optically triggered perfluorohexane nanodroplets (PFHnDs). In response to pulsed laser irradiation, the PFHnDs repeatedly vaporize and stochastically recondense, resulting in random changes of ultrasound signals. Our previous study has shown that the stochastic recondensation of the PFHnDs can be used to isolate individual PFHnDs for super-resolution imaging. This paper introduces an improved method for super-resolution imaging with ultrafast ultrasound imaging of PFHnDs. The previous method was based on subtraction of two consecutive ultrasound images to detect signals from recondensed, isolated droplets, whereas our current method compounds respective multiple pre- and post-recondensation ultrafast ultrasound images prior to subtraction to improve the spatial resolution further. To evaluate the axial and lateral resolutions of our method, we repeatedly imaged a phantom containing PFHnDs using a programmable ultrasound system synchronized with a pulsed laser system. As a result, our method improved the lateral and axial resolutions by 54% and 68%, respectively, over the previous super-resolution imaging approach, indicating that it can be used for localizing extravascular molecular targets with superior accuracy.
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Affiliation(s)
- Heechul Yoon
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332 USA ()
| | - Kristina A. Hallam
- Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332 USA
| | - Changhan Yoon
- Department of Biomedical Engineering, Inje University, Gimhae, Gyeongsangnam-do 50834 Republic of Korea
| | - Stanislav Y. Emelianov
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332 USA, and with Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332 USA ()
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Donnelly EM, Kubelick KP, Dumani DS, Emelianov SY. Photoacoustic Image-Guided Delivery of Plasmonic-Nanoparticle-Labeled Mesenchymal Stem Cells to the Spinal Cord. Nano Lett 2018; 18:6625-6632. [PMID: 30160124 DOI: 10.1021/acs.nanolett.8b03305] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Regenerative therapies using stem cells have great potential for treating neurodegenerative diseases and traumatic injuries in the spinal cord. In spite of significant research efforts, many therapies fail at the clinical phase. As stem cell technologies advance toward clinical use, there is a need for a minimally invasive, safe, affordable, and real-time imaging technique that allows for the accurate and safe monitoring of stem cell delivery in the operating room. In this work, we present a combined ultrasound and photoacoustic imaging tool to provide image-guided needle placement and monitoring of nanoparticle-labeled stem cell delivery into the spinal cord. We successfully tagged stem cells using gold nanospheres and provided image-guided delivery of stem cells into the spinal cord in real-time, detecting as few as 1000 cells. Ultrasound and photoacoustic imaging was used to guide needle placement for direct stem cell injection to minimize the risk of needle shear and accidental injury and to improve therapeutic outcomes with accurate, localized stem cell delivery. Following injections of various volumes of cells, three-dimensional ultrasound and photoacoustic images allowed the visualization of stem cell distribution along the spinal cord, showing the potential to monitor the migration of the cells in the future. The feasibility of quantitative imaging was also shown by correlating the total photoacoustic signal over the imaging volume to the volume of cells injected. Overall, the presented method may allow clinicians to utilize imaged-guided delivery for more accurate and safer stem cell delivery to the spinal cord.
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Affiliation(s)
- Eleanor M Donnelly
- School of Electrical and Computer Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
| | - Kelsey P Kubelick
- Wallace H. Coulter Department of Biomedical Engineering , Georgia Institute of Technology and Emory University School of Medicine , Atlanta , Georgia 30332 , United States
| | - Diego S Dumani
- School of Electrical and Computer Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
- Wallace H. Coulter Department of Biomedical Engineering , Georgia Institute of Technology and Emory University School of Medicine , Atlanta , Georgia 30332 , United States
| | - Stanislav Y Emelianov
- School of Electrical and Computer Engineering , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
- Wallace H. Coulter Department of Biomedical Engineering , Georgia Institute of Technology and Emory University School of Medicine , Atlanta , Georgia 30332 , United States
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Karpiouk AB, VanderLaan DJ, Larin KV, Emelianov SY. Integrated optical coherence tomography and multielement ultrasound transducer probe for shear wave elasticity imaging of moving tissues. J Biomed Opt 2018; 23:1-7. [PMID: 30369107 PMCID: PMC6210783 DOI: 10.1117/1.jbo.23.10.105006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 09/25/2018] [Indexed: 05/18/2023]
Abstract
Accurate measurements of microelastic properties of soft tissues in-vivo using optical coherence elastography can be affected by motion artifacts caused by cardiac and respiratory cycles. This problem can be overcome using a multielement ultrasound transducer probe where each ultrasound transducer is capable of generating acoustic radiation force (ARF) and, therefore, creating shear waves in tissue. These shear waves, produced during the phase of cardiac and respiratory cycles when tissues are effectively stationary, are detected at the same observation point using phase-sensitive optical coherence tomography (psOCT). Given the known distance between the ultrasound transducers, the speed of shear wave propagation can be calculated by measuring the difference between arrival times of shear waves. The combined multitransducer ARF/psOCT probe has been designed and tested in phantoms and ex-vivo studies using fresh rabbit heart. The measured values of shear moduli are in good agreement with those reported in literature. Our results suggest that the developed multitransducer ARF/psOCT probe can be useful for many in-vivo applications, including quantifying the microelasticity of cardiac muscle.
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Affiliation(s)
- Andrei B. Karpiouk
- Georgia Institute of Technology, Electrical and Computer Engineering Department, Atlanta, Georgia, United States
| | - Donald J. VanderLaan
- Georgia Institute of Technology, Electrical and Computer Engineering Department, Atlanta, Georgia, United States
| | - Kirill V. Larin
- University of Houston, Biomedical Engineering Department, Houston, Texas, United States
- Tomsk State University, Interdisciplinary Laboratory of Biophotonics, Tomsk, Russia
| | - Stanislav Y. Emelianov
- Georgia Institute of Technology, Electrical and Computer Engineering Department, Atlanta, Georgia, United States
- Georgia Institute of Technology and Emory University, School of Medicine, Wallace H. Coulter Department of Biomedical Engineering, Atlanta, Georgia, United States
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Hallam KA, Donnelly EM, Karpiouk AB, Hartman RK, Emelianov SY. Laser-activated perfluorocarbon nanodroplets: a new tool for blood brain barrier opening. Biomed Opt Express 2018; 9:4527-4538. [PMID: 30615730 PMCID: PMC6157760 DOI: 10.1364/boe.9.004527] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/08/2018] [Accepted: 08/20/2018] [Indexed: 05/03/2023]
Abstract
A major obstacle in the monitoring and treatment of neurological diseases is the blood brain barrier (BBB), a semipermeable barrier that prevents the delivery of many therapeutics and imaging contrast agents to the brain. In this work, we explored the possibility of laser-activated perfluorocarbon nanodroplets (PFCnDs) to open the BBB and deliver agents to the brain tissue. Specifically, near infrared (NIR) dye-loaded PFCnDs comprised of a perfluorocarbon (PFC) core with a boiling point above physiological temperature were repeatedly vaporized and recondensed from liquid droplet to gas bubble under pulsed laser excitation. As a result, this pulse-to-pulse repeated behavior enabled the recurring interaction of PFCnDs with the endothelial lining of the BBB, allowing for a BBB opening and extravasation of dye into the brain tissue. The blood brain barrier opening and delivery of agents to tissue was confirmed on the macro and the molecular level by evaluating Evans Blue staining, ultrasound-guided photoacoustic (USPA) imaging, and histological tissue analysis. The demonstrated PFCnD-assisted pulsed laser method for BBB opening, therefore, represents a tool that has the potential to enable non-invasive, cost-effective, and efficient image-guided delivery of contrast and therapeutic agents to the brain.
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Affiliation(s)
- Kristina A. Hallam
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Eleanor M. Donnelly
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Andrei B. Karpiouk
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Robin K. Hartman
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Stanislav Y. Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA
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Yoon H, Emelianov SY. Combined Multiwavelength Photoacoustic and Plane-Wave Ultrasound Imaging for Probing Dynamic Phase-Change Contrast Agents. IEEE Trans Biomed Eng 2018; 66:595-598. [PMID: 29993455 DOI: 10.1109/tbme.2018.2849077] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE The purpose of this study was to introduce combined multiwavelength photoacoustic (PA) and plane-wave ultrasound (US) imaging referred to as mwPA/pwUS imaging capable of probing the rapid dynamic behavior of optically activated phase-change contrast agents. METHODS A dedicated mwPA/pwUS imaging sequence was developed based on a programmable US system synchronized with a tunable laser to irradiate tissue with laser pulses at desired optical wavelengths and to acquire post laser pulse PA images followed by ultrafast plane-wave US images. To evaluate the mwPA/pwUS imaging, a capillary filled with optically responsive perfluorohexane nanodroplets (PFHnDs) containing a dye with the peak absorption at 760 nm was imaged with optical wavelengths ranging from 700 to 940 nm. The differences between post-laser ultrafast US images [i.e., differential US (ΔUS)] were taken to visualize the recondensation dynamics of PFHnDs at each wavelength. RESULTS The PA images of PFHnDs showed higher contrast near 760 nm wavelength, corresponding to the peak absorption of the dye encapsulated in the PFHnDs. Moreover, the ΔUS signals immediately after 760-nm pulsed laser irradiation were also high due to the increased US contrast associated with vaporized PFHnDs. CONCLUSION The mwPA/pwUS imaging allowed for the US-based optical spectroscopic characterization of PFHnDs and their dynamics. SIGNIFICANCE The introduced mwPA/pwUS imaging sequence can be used in various clinical applications where both spectroscopic PA imaging of endogenous and/or exogenous chromophores and ultrafast US imaging of phase-change nanodroplets are desired.
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Santiesteban DY, Dumani DS, Profili D, Emelianov SY. Copper Sulfide Perfluorocarbon Nanodroplets as Clinically Relevant Photoacoustic/Ultrasound Imaging Agents. Nano Lett 2017; 17:5984-5989. [PMID: 28926263 DOI: 10.1021/acs.nanolett.7b02105] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We have developed laser-activated perfluorocarbon nanodroplets containing copper sulfide nanoparticles (CuS NPs) for contrast-enhanced ultrasound and photoacoustic imaging. As potential clinical contrast agents, CuS NPs have favorable properties including biocompatibility, biodegradability, and enhance contrast in photoacoustic images at clinically relevant depths. However, CuS NPs are not efficient optical absorbers when compared to plasmonic nanoparticles and therefore, contrast enhancement with CuS NPs is limited, requiring high concentrations to generate images with sufficient signal-to-noise ratio. We have combined CuS NPs with laser-activated perfluorocarbon nanodroplets (PFCnDs) to achieve enhanced photoacoustic contrast and, more importantly, ultrasound contrast while retaining the favorable clinical characteristics of CuS NPs. The imaging characteristics of synthesized CuS-PFCnD constructs were first tested in tissue-mimicking phantoms and then in in vivo murine models. The results demonstrate that CuS-PFCnDs enhance contrast in photoacoustic (PA) and ultrasound (US) imaging. Upon systemic administration in vivo, CuS-PFCnDs remain stable and their unique vaporization provides sufficient PA/US contrast that can be further exploited for contrast-enhanced background-free imaging. The conducted studies provide a solid foundation for further development of CuS-PFCnDs as PA/US diagnostic and eventually therapeutic agents for clinical applications.
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Affiliation(s)
- Daniela Y Santiesteban
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine , Atlanta, Georgia 30332, United States
- School of Electrical and Computer Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Diego S Dumani
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine , Atlanta, Georgia 30332, United States
- School of Electrical and Computer Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
| | - Daniel Profili
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine , Atlanta, Georgia 30332, United States
| | - Stanislav Y Emelianov
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine , Atlanta, Georgia 30332, United States
- School of Electrical and Computer Engineering, Georgia Institute of Technology , Atlanta, Georgia 30332, United States
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Yoon H, Aglyamov SR, Emelianov SY. Dual-Phase Transmit Focusing for Multiangle Compound Shear-Wave Elasticity Imaging. IEEE Trans Ultrason Ferroelectr Freq Control 2017; 64:1439-1449. [PMID: 28708552 PMCID: PMC5668129 DOI: 10.1109/tuffc.2017.2725839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Shear-wave elasticity imaging (SWEI) enables the quantitative assessment of the mechanical properties of tissue. In SWEI, the effective generation of acoustic radiation force is of paramount importance. Consequently, several research groups have investigated various transmit beamforming and pulse-sequencing methods. To further improve the efficiency of the shear-wave generation, and therefore, to increase the quality of SWEI, we introduce a technique referred to as "multiangle compound SWEI" (MAC-SWEI), which uses simultaneous multiangular push beams created by dual-phase transmit focusing. By applying a constant phase offset on every other element of an array transducer, dual-phase transmit focusing creates both main and grating lobes (i.e., multiangular push beams for pushing) to simultaneously generate shear waves with several wavefront angles. The shear waves propagating at different angles are separated by multidirectional filtering in the frequency domain, leading to the reconstruction of multiple spatially co-registered shear-wave velocity maps. To form a single-elasticity image, these maps are combined, while regions associated with known artifacts created by the push beams are omitted. Overall, we developed and tested the MAC-SWEI method using Field II quantitative simulations and the experiments performed using a programmable ultrasound imaging system. Our results suggest that MAC-SWEI with dual-phase transmit focusing may improve the quality of elasticity maps.
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Yoon H, Yarmoska SK, Hannah AS, Yoon C, Hallam KA, Emelianov SY. Contrast-enhanced ultrasound imaging in vivo with laser-activated nanodroplets. Med Phys 2017; 44:3444-3449. [PMID: 28391597 DOI: 10.1002/mp.12269] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 04/04/2017] [Accepted: 04/04/2017] [Indexed: 12/16/2022] Open
Abstract
PURPOSE This study introduces a real-time contrast-enhanced ultrasound imaging method with recently developed laser-activated nanodroplets (LANDs), a new class of phase-change nanometer-scale contrast agents that provides perceptible, sustained high-contrast with ultrasound. METHODS In response to pulsed laser irradiation, the LANDs-, which contain liquid perfluorohexane and optical fuses-blink (vaporize and recondense). That is, they change their state from liquid nanodroplets to gas microbubbles, and then back to liquid nanodroplets. In their gaseous microbubble state, the LANDs provide high-contrast ultrasound, but the microbubbles formed in situ typically recondense in tens of milliseconds. As a result, LAND visualization by standard, real-time ultrasound is limited. However, the periodic optical triggering of LANDs allows us to observe corresponding transient, periodic changes in ultrasound contrast. This study formulates a probability function that measures how ultrasound temporal signals vary in periodicity. Then, the estimated probability is mapped onto a B-scan image to construct a LAND-localized, contrast-enhanced image. We verified our method through phantom and in vivo experiments using an ultrasound system (Vevo 2100, FUJIFILM VisualSonics, Inc., Toronto, ON, Canada) operating with a 40-MHz linear array and interfaced with a 10 Hz Nd:YAG laser (Phocus, Opotek Inc., Carlsbad, CA, USA) operating at the fundamental 1064 nm wavelength. RESULTS From the phantom study, the results showed improvements in the contrast-to-noise ratio of our approach over conventional ultrasound ranging from 129% to 267%, with corresponding execution times of 0.10 to 0.29 s, meaning that the developed method is computationally efficient while yielding high-contrast ultrasound. Furthermore, in vivo sentinel lymph node (SLN) imaging results demonstrated that our technique could accurately identify the SLN. CONCLUSIONS The results indicate that our approach enables efficient and robust LAND localization in real time with substantially improved contrast, which is essential for the successful translation of this contrast agent platform to clinical settings.
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Affiliation(s)
- Heechul Yoon
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA
| | - Steven K Yarmoska
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, 30332, USA
| | - Alexander S Hannah
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, 30332, USA
- Applied Physics Laboratory, Center for Industrial and Medical Ultrasound, University of Washington, Seattle, Washington, 98105, USA
| | - Changhan Yoon
- Department of Biomedical Engineering, Inje University, Gimhae, Gyeongnam, 621-749, Korea
| | - Kristina A Hallam
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, 30332, USA
| | - Stanislav Y Emelianov
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, USA
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, 30332, USA
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Bayer CL, Wlodarczyk BJ, Finnell RH, Emelianov SY. Ultrasound-guided spectral photoacoustic imaging of hemoglobin oxygenation during development. Biomed Opt Express 2017; 8:757-763. [PMID: 28270982 PMCID: PMC5330552 DOI: 10.1364/boe.8.000757] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/19/2016] [Accepted: 12/23/2016] [Indexed: 05/06/2023]
Abstract
Few technologies are capable of imaging in vivo function during development. In this study, we have implemented spectral photoacoustic imaging to estimate tissue oxygenation longitudinally in pregnant mice. We used the spectral photoacoustic signal to estimate hemoglobin oxygen saturation within intact, in vivo mouse concepti from developmental day (E) 8.5 to E16.5-a first step towards functional imaging of the maternal-fetal environment. Future work will apply these methods to compare longitudinal functional changes during normal vs abnormal development of embryos, fetuses, and placentas.
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Affiliation(s)
- Carolyn L. Bayer
- Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, Austin, TX 78712, USA
- Currently with the Department of Biomedical Engineering, Tulane University, 500 Lindy Boggs Center, New Orleans, LA 70118, USA
| | - Bogdan J. Wlodarczyk
- Dell Pediatric Research Institute, Department of Nutritional Sciences, The University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, TX 78723, USA
| | - Richard H. Finnell
- Dell Pediatric Research Institute, Department of Nutritional Sciences, The University of Texas at Austin, 1400 Barbara Jordan Blvd, Austin, TX 78723, USA
| | - Stanislav Y. Emelianov
- Department of Biomedical Engineering, The University of Texas at Austin, 1 University Station, Austin, TX 78712, USA
- Currently with the School of Electrical and Computer Engineering, Georgia Institute of Technology, 777 Atlantic Drive NW, Atlanta, GA 30332, USA
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Park S, Yoon H, Larin KV, Emelianov SY, Aglyamov SR. The impact of intraocular pressure on elastic wave velocity estimates in the crystalline lens. Phys Med Biol 2016; 62:N45-N57. [PMID: 27997379 DOI: 10.1088/1361-6560/aa54ef] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Intraocular pressure (IOP) is believed to influence the mechanical properties of ocular tissues including cornea and sclera. The elastic properties of the crystalline lens have been mainly investigated with regard to presbyopia, the age-related loss of accommodation power of the eye. However, the relationship between the elastic properties of the lens and IOP remains to be established. The objective of this study is to measure the elastic wave velocity, which represents the mechanical properties of tissue, in the crystalline lens ex vivo in response to changes in IOP. The elastic wave velocities in the cornea and lens from seven enucleated bovine globe samples were estimated using ultrasound shear wave elasticity imaging. To generate and then image the elastic wave propagation, an ultrasound imaging system was used to transmit a 600 µs pushing pulse at 4.5 MHz center frequency and to acquire ultrasound tracking frames at 6 kHz frame rate. The pushing beams were separately applied to the cornea and lens. IOP in the eyeballs was varied from 5 to 50 mmHg. The results indicate that while the elastic wave velocity in the cornea increased from 0.96 ± 0.30 m s-1 to 6.27 ± 0.75 m s-1 as IOP was elevated from 5 to 50 mmHg, there were insignificant changes in the elastic wave velocity in the crystalline lens with the minimum and the maximum speeds of 1.44 ± 0.27 m s-1 and 2.03 ± 0.46 m s-1, respectively. This study shows that ultrasound shear wave elasticity imaging can be used to assess the biomechanical properties of the crystalline lens noninvasively. Also, it was observed that the dependency of the crystalline lens stiffness on the IOP was significantly lower in comparison with that of cornea.
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Affiliation(s)
- Suhyun Park
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78712, USA
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Meiburger KM, Nam SY, Chung E, Suggs LJ, Emelianov SY, Molinari F. Skeletonization algorithm-based blood vessel quantification usingin vivo3D photoacoustic imaging. Phys Med Biol 2016; 61:7994-8009. [DOI: 10.1088/0031-9155/61/22/7994] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Bayer C, Luke GP, Cook JR, Emelianov SY. Abstract 131: Quantification of
in vivo
Placental Oxygenation Using Ultrasound-guided Spectral Photoacoustic Imaging. Hypertension 2016. [DOI: 10.1161/hyp.68.suppl_1.131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Preeclampsia, linked to abnormal placental development and ischemia, is a major cause of fetal and maternal death. Currently, the only cure is high-risk preterm delivery. Although clinical therapies to regulate the symptoms of preeclampsia—mean arterial pressure and proteinuria—it is unknown whether these therapeutics restore placental blood flow and reduce ischemia. We are developing ultrasound-guided spectral photoacoustic imaging to quantify placental ischemia and characterize therapeutic response. Ultrasound imaging is the preferred imaging modality to monitor pregnancy due to its safety, low cost, and mobility. Similar to ultrasound, photoacoustic imaging can provide co-registered images of tissue function. In these studies, pregnant SWV mice were imaged longitudinally from E12.5 to 18.5 using a Vevo LAZR small animal imaging system. Algorithms were developed to correlate the spectral photoacoustic data to a hemoglobin oxygenation (%sO
2
) calibration standard—a phantom containing blood at varying partial pressures of oxygen. The phantom calibration standard deviation was 7.9% (n=3). The resulting ultrasound images were used to segment the placenta (Figure 1). An overlay of the %sO
2
on the ultrasound image maps placental variation in %sO
2
during longitudinal development. We demonstrate that our imaging method is capable of quantifying %sO2 and monitoring placental function
in vivo
. Future work will use our preclinical %sO2 quantification methods to characterize placental function during treatment for preeclampsia.
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Hannah AS, Luke GP, Emelianov SY. Blinking Phase-Change Nanocapsules Enable Background-Free Ultrasound Imaging. Theranostics 2016; 6:1866-76. [PMID: 27570556 PMCID: PMC4997242 DOI: 10.7150/thno.14961] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 05/12/2016] [Indexed: 01/07/2023] Open
Abstract
Microbubbles are widely used as contrast agents to improve the diagnostic capability of conventional, highly speckled, low-contrast ultrasound imaging. However, while microbubbles can be used for molecular imaging, these agents are limited to the vascular space due to their large size (> 1 μm). Smaller microbubbles are desired but their ultrasound visualization is limited due to lower echogenicity or higher resonant frequencies. Here we present nanometer scale, phase changing, blinking nanocapsules (BLInCs), which can be repeatedly optically triggered to provide transient contrast and enable background-free ultrasound imaging. In response to irradiation by near-infrared laser pulses, the BLInCs undergo cycles of rapid vaporization followed by recondensation into their native liquid state at body temperature. High frame rate ultrasound imaging measures the dynamic echogenicity changes associated with these controllable, periodic phase transitions. Using a newly developed image processing algorithm, the blinking particles are distinguished from tissue, providing a background-free image of the BLInCs while the underlying B-mode ultrasound image is used as an anatomical reference of the tissue. We demonstrate the function of BLInCs and the associated imaging technique in a tissue-mimicking phantom and in vivo for the identification of the sentinel lymph node. Our studies indicate that BLInCs may become a powerful tool to identify biological targets using a conventional ultrasound imaging system.
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Abstract
We have developed a method for super-resolution ultrasound imaging, which relies on a new class of blinking nanometer-size contrast agents: laser-activated nanodroplets (LANDs). The LANDs can be repeatedly optically triggered to undergo vaporization; the resulting spatially stationary, temporally transient microbubbles provide high ultrasound contrast for several to hundreds of milliseconds before recondensing to their native liquid nanodroplet state. By capturing high frame rate ultrasound images of blinking LANDs, we demonstrate the ability to detect individual recondensation events. Then we apply a newly developed super-resolution image processing algorithm to localize the LAND positions in vivo almost an order of magnitude better than conventional ultrasound imaging. These results pave the way for high resolution molecular imaging deep in tissue.
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Affiliation(s)
- Geoffrey P. Luke
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Alexander S. Hannah
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Stanislav Y. Emelianov
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712, United States
- Corresponding Author
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Aglyamov SR, Wang S, Emelianov SY, Larin KV. A three-dimensional solution for laser-induced thermoelastic deformation of the layered medium. ACTA ACUST UNITED AC 2016. [DOI: 10.1117/12.2213480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
| | - Shang Wang
- Baylor College of Medicine (United States)
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Nagao RJ, Ouyang Y, Keller R, Nam SY, Malik GR, Emelianov SY, Suggs LJ, Schmidt CE. Ultrasound-guided photoacoustic imaging-directed re-endothelialization of acellular vasculature leads to improved vascular performance. Acta Biomater 2016; 32:35-45. [PMID: 26708553 DOI: 10.1016/j.actbio.2015.12.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 12/09/2015] [Accepted: 12/16/2015] [Indexed: 10/22/2022]
Abstract
As increasing effort is dedicated to investigating the regenerative capacity of decellularized tissues, research has progressed to recellularizing these tissues prior to implantation. The delivery and support of cells seeded throughout acellular scaffolds are typically conducted through the vascular axis of the tissues. However, it is unclear how cell concentration and injection frequency can affect the distribution of cells throughout the scaffold. Furthermore, what effects re-endothelialization have on vascular patency and function are not well understood. We investigated the use of ultrasound-guided photoacoustic (US/PA) imaging as a technique to visualize the distribution of microvascular endothelial cells within an optimized acellular construct upon re-endothelialization and perfusion conditioning. We also evaluated the vascular performance of the re-endothelialized scaffold using quantitative vascular corrosion casting (qVCC) and whole-blood perfusion. We found US/PA imaging was an effective technique to visualize the distribution of cells. Cellular retention following perfusion conditioning was also detected with US/PA imaging. Finally, we demonstrated that a partial recovery of vascular performance is possible following re-endothelialization-confirmed by fewer extravasations in qVCC and improved blood clearance following whole-blood perfusion. STATEMENT OF SIGNIFICANCE Re-endothelialization is a method that enables decellularized tissue to become useful as a tissue engineering construct by creating a nutrient delivery and waste removal system for the entire construct. Our approach utilizes a decellularization method that retains the basement ECM of a highly vascularized tissue upon which endothelial cells can be injected to form an endothelium. The US/PA method allows for rapid visualization of cells within a construct several cm thick. This approach can be experimentally used to observe changes in cellular distribution over large intervals of time, to help optimize cell seeding parameters, and to verify cell retention within re-endothelialized constructs. This approach has temporal and depth advantages compared to section reconstruction and imaged fluorophores respectively.
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Abstract
PURPOSE To determine the ability of ultrasonography (US)-guided spectroscopic photoacoustic (sPA) imaging to depict changes in blood oxygen saturation (SO2) in metastatic lymph nodes of a mouse model of oral cancer. MATERIALS AND METHODS All studies were performed by following protocols approved by the institutional animal care and use committee at the University of Texas at Austin. Coregistered US and photoacoustic images were acquired spanning volumes containing a total of 31 lymph nodes in 17 female nu/nu mice. The mice were either healthy (three mice, five nodes) or bearing a primary tumor consisting of luciferase-labeled FaDu cells (14 mice, 26 nodes). Ten photoacoustic images acquired with optical wavelengths spanning from 680 to 860 nm were spectrally unmixed by using a linear least-squares method to obtain sPA images. After imaging, histologic analysis enabled confirmation of the presence of micrometastases. Generalized estimating equations were used to compare metastatic and normal lymph nodes, with a P value of .05 taken to indicate a significant difference. Sensitivity and specificity were determined with a receiver operator characteristic curve constructed from the background-subtracted SO2 values. RESULTS Metastatic lymph nodes (n = 7) exhibited a significantly (P = .018) lower spatially averaged background-subtracted SO2 (mean, 5.4% ± 3.5 [standard error]) when compared with lymph nodes without metastases (mean, 13.7% ± 1.3; n = 24). This effect was observed throughout the entire volume of the nodes rather than being limited to the metastatic foci. The change in SO2, which was inversely related to the size of the metastasis, was detectable in metastases as small as 2.6 × 10(-3) mm(3). CONCLUSION The results show that US-guided sPA imaging is capable of depicting changes in SO2 in lymph nodes that were correlated with metastatic invasion.
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Affiliation(s)
- Geoffrey P Luke
- From the Department of Biomedical Engineering, the University of Texas at Austin, 107 W Dean Keeton St, Austin, TX 78712; and Department of Imaging Physics, the University of Texas MD Anderson Cancer Center, Houston, Tex
| | - Stanislav Y Emelianov
- From the Department of Biomedical Engineering, the University of Texas at Austin, 107 W Dean Keeton St, Austin, TX 78712; and Department of Imaging Physics, the University of Texas MD Anderson Cancer Center, Houston, Tex
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Aglyamov SR, Wang S, Karpiouk AB, Li J, Twa M, Emelianov SY, Larin KV. The dynamic deformation of a layered viscoelastic medium under surface excitation. Phys Med Biol 2015; 60:4295-312. [PMID: 25974168 DOI: 10.1088/0031-9155/60/11/4295] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this study the dynamic behavior of a layered viscoelastic medium in response to the harmonic and impulsive acoustic radiation force applied to its surface was investigated both theoretically and experimentally. An analytical solution for a layered viscoelastic compressible medium in frequency and time domains was obtained using the Hankel transform. A special incompressible case was considered to model soft biological tissues. To verify our theoretical model, experiments were performed using tissue-like gel-based phantoms with varying mechanical properties. A 3.5 MHz single-element focused ultrasound transducer was used to apply the radiation force at the surface of the phantoms. A phase-sensitive optical coherence tomography system was used to track the displacements of the phantom surface. Theoretically predicted displacements were compared with experimental measurements. The role of the depth dependence of the elastic properties of a medium in its response to an acoustic pulse at the surface was studied. It was shown that the low-frequency vibrations at the surface are more sensitive to the deep layers than high-frequency ones. Therefore, the proposed model in combination with spectral analysis can be used to evaluate depth-dependent distribution of the mechanical properties based on the measurements of the surface deformation.
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Affiliation(s)
- Salavat R Aglyamov
- Biomedical Engineering, University of Texas at Austin, Austin, TX 78731, USA
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50
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Nam SY, Ricles LM, Suggs LJ, Emelianov SY. Imaging strategies for tissue engineering applications. Tissue Eng Part B Rev 2015; 21:88-102. [PMID: 25012069 PMCID: PMC4322020 DOI: 10.1089/ten.teb.2014.0180] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 07/08/2014] [Indexed: 12/18/2022]
Abstract
Tissue engineering has evolved with multifaceted research being conducted using advanced technologies, and it is progressing toward clinical applications. As tissue engineering technology significantly advances, it proceeds toward increasing sophistication, including nanoscale strategies for material construction and synergetic methods for combining with cells, growth factors, or other macromolecules. Therefore, to assess advanced tissue-engineered constructs, tissue engineers need versatile imaging methods capable of monitoring not only morphological but also functional and molecular information. However, there is no single imaging modality that is suitable for all tissue-engineered constructs. Each imaging method has its own range of applications and provides information based on the specific properties of the imaging technique. Therefore, according to the requirements of the tissue engineering studies, the most appropriate tool should be selected among a variety of imaging modalities. The goal of this review article is to describe available biomedical imaging methods to assess tissue engineering applications and to provide tissue engineers with criteria and insights for determining the best imaging strategies. Commonly used biomedical imaging modalities, including X-ray and computed tomography, positron emission tomography and single photon emission computed tomography, magnetic resonance imaging, ultrasound imaging, optical imaging, and emerging techniques and multimodal imaging, will be discussed, focusing on the latest trends of their applications in recent tissue engineering studies.
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Affiliation(s)
- Seung Yun Nam
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas
| | - Laura M. Ricles
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Laura J. Suggs
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
| | - Stanislav Y. Emelianov
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas
- Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas
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