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Wang S, Hossack JA, Klibanov AL. Targeting of microbubbles: contrast agents for ultrasound molecular imaging. J Drug Target 2018; 26:420-434. [PMID: 29258335 DOI: 10.1080/1061186x.2017.1419362] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
For contrast ultrasound imaging, the most efficient contrast agents comprise highly compressible gas-filled microbubbles. These micrometer-sized particles are typically filled with low-solubility perfluorocarbon gases, and coated with a thin shell, often a lipid monolayer. These particles circulate in the bloodstream for several minutes; they demonstrate good safety and are already in widespread clinical use as blood pool agents with very low dosage necessary (sub-mg per injection). As ultrasound is an ubiquitous medical imaging modality, with tens of millions of exams conducted annually, its use for molecular/targeted imaging of biomarkers of disease may enable wider implementation of personalised medicine applications, precision medicine, non-invasive quantification of biomarkers, targeted guidance of biopsy and therapy in real time. To achieve this capability, microbubbles are decorated with targeting ligands, possessing specific affinity towards vascular biomarkers of disease, such as tumour neovasculature or areas of inflammation, ischaemia-reperfusion injury or ischaemic memory. Once bound to the target, microbubbles can be selectively visualised to delineate disease location by ultrasound imaging. This review discusses the general design trends and approaches for such molecular ultrasound imaging agents, which are currently at the advanced stages of development, and are evolving towards widespread clinical trials.
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Affiliation(s)
- Shiying Wang
- a Department of Biomedical Engineering , University of Virginia , Charlottesville , VA , USA
| | - John A Hossack
- a Department of Biomedical Engineering , University of Virginia , Charlottesville , VA , USA
| | - Alexander L Klibanov
- a Department of Biomedical Engineering , University of Virginia , Charlottesville , VA , USA.,b Cardiovascular Division (Department of Medicine), Robert M Berne Cardiovascular Research Center , University of Virginia , Charlottesville , VA , USA
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Yu FTH, Chen X, Wang J, Qin B, Villanueva FS. Low Intensity Ultrasound Mediated Liposomal Doxorubicin Delivery Using Polymer Microbubbles. Mol Pharm 2015; 13:55-64. [PMID: 26567985 DOI: 10.1021/acs.molpharmaceut.5b00421] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cardiotoxicity is the major dose-limiting factor in the chemotherapeutic use of doxorubicin (Dox). A delivery vehicle that can be triggered to release its payload in the tumoral microvasculature but not in healthy tissue would help improve the therapeutic window of the drug. Delivery strategies combining liposomal encapsulated Dox (LDox), microbubbles (MBs), and ultrasound (US) have been shown to improve therapeutic efficacy of LDox, but much remains to be known about the mechanisms and the US conditions that maximize cytotoxicity using this approach. In this study, we compared different US pulses in terms of drug release and acute toxicity. Drug uptake and proliferation rates using low-intensity US were measured in squamous cell carcinoma cells exposed to LDox conjugated to or coinjected with polymer MBs. The aims of this study were: (1) to compare the effects of low- and high-pressure US on Dox release kinetics; (2) to evaluate whether conjugating the liposome to the MB surface (DoxLPX) is an important factor for drug release and cytotoxicity; and (3) to determine which US parameters most inhibit cell proliferation and whether this inhibition is mediated by drug release or the MB/US interaction with cells. Low-pressure US (170 kPa) at high duty cycle (stable cavitation) released up to ∼ 70% of the encapsulated Dox from the DoxLPX, thus improving Dox bioavailability and cellular uptake and leading to a significant reduction in cell proliferation at 48 h. Flow cytometry showed that US generating stable oscillations of DoxLPX significantly increased cellular Dox uptake at 4 h after US exposure compared to LDox. Drug uptake was correlated with cytotoxicity at 48 h. Our results demonstrate that Dox-containing liposomes conjugated to polymer MBs can be triggered to release ∼ 70% of their payload using noninertial US. Following release, Dox became bioavailable to the cells and induced significantly higher cytotoxicity compared to nonreleased encapsulated drug. Our findings show promise for targeted drug delivery using this theranostic delivery platform at low US intensities.
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Affiliation(s)
- Francois T H Yu
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States
| | - Xucai Chen
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States
| | - Jianjun Wang
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States
| | - Bin Qin
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States
| | - Flordeliza S Villanueva
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States
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Gauthier M, Yin Q, Cheng J, O'Brien WD. Design of Albumin-Coated Microbubbles Loaded With Polylactide Nanoparticles. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2015; 34:1363-72. [PMID: 26206822 PMCID: PMC4536807 DOI: 10.7863/ultra.34.8.1363] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 11/19/2014] [Indexed: 03/24/2024]
Abstract
OBJECTIVES A protocol was designed to produce albumin-coated microbubbles (MBs) loaded with functionalized polylactide (PLA) nanoparticles (NPs) for future drug delivery studies. METHODS Microbubbles resulted from the sonication of 5% bovine serum albumin and 15% dextrose solution. Functionalized NPs were produced by mixing fluorescent PLA and PLA-polyethylene glycol-carboxylate conjugates. Nanoparticle-loaded MBs resulted from the covalent conjugation of functionalized NPs and MBs. Three NP/MB volume ratios (1/1, 1/10, and 1/100) and unloaded MBs were produced and compared. Statistical evaluations were based on quantitative analysis of 3 parameters at 4 time points (1, 4, 5, and 6 days post MB fabrication): MB diameter using a circle detection routine based on the Hough transform, MB number density using a hemocytometer, and NP-loading yield based on MB counts from fluorescence and light microscopic images. Loading capacity of the albumin-coated MBs was evaluated by fluorescence. RESULTS Loaded MB sizes were stable over 6 days after production and were not significantly different from that of time-matched unloaded MBs. Number density evaluation showed that only 1/1 NP/MB volume ratio and unloaded MB number densities were stable over time, and that the 1/1 MB number density evaluated at each time point was not significantly different from that of unloaded MBs. The 1/10 and 1/100 NP/MB volume ratios had unstable number densities that were significantly different from that of unloaded MBs (P < .05). Fluorescence evaluation suggested that 1/1 MBs had a higher NP-loading yield than 1/10 and 1/100 MBs. Quantitative loading evaluation suggested that the 1/1 MBs had a loading capacity of 3700 NPs/MB. CONCLUSIONS A protocol was developed to load albumin MBs with functionalized PLA NPs for further drug delivery studies. The 1/1 NP/MB volume ratio appeared to be the most efficient to produce stable loaded MBs with a loading capacity of 3700 NPs/MB.
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Affiliation(s)
- Marianne Gauthier
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (M.G., W.D.O.), and Department of Materials Science and Engineering (Q.Y., J.C.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA.
| | - Qian Yin
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (M.G., W.D.O.), and Department of Materials Science and Engineering (Q.Y., J.C.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA
| | - Jianjun Cheng
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (M.G., W.D.O.), and Department of Materials Science and Engineering (Q.Y., J.C.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA
| | - William D O'Brien
- Bioacoustics Research Laboratory, Department of Electrical and Computer Engineering (M.G., W.D.O.), and Department of Materials Science and Engineering (Q.Y., J.C.), University of Illinois at Urbana-Champaign, Urbana, Illinois USA
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van Rooij T, Daeichin V, Skachkov I, de Jong N, Kooiman K. Targeted ultrasound contrast agents for ultrasound molecular imaging and therapy. Int J Hyperthermia 2015; 31:90-106. [PMID: 25707815 DOI: 10.3109/02656736.2014.997809] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ultrasound contrast agents (UCAs) are used routinely in the clinic to enhance contrast in ultrasonography. More recently, UCAs have been functionalised by conjugating ligands to their surface to target specific biomarkers of a disease or a disease process. These targeted UCAs (tUCAs) are used for a wide range of pre-clinical applications including diagnosis, monitoring of drug treatment, and therapy. In this review, recent achievements with tUCAs in the field of molecular imaging, evaluation of therapy, drug delivery, and therapeutic applications are discussed. We present the different coating materials and aspects that have to be considered when manufacturing tUCAs. Next to tUCA design and the choice of ligands for specific biomarkers, additional techniques are discussed that are applied to improve binding of the tUCAs to their target and to quantify the strength of this bond. As imaging techniques rely on the specific behaviour of tUCAs in an ultrasound field, it is crucial to understand the characteristics of both free and adhered tUCAs. To image and quantify the adhered tUCAs, the state-of-the-art techniques used for ultrasound molecular imaging and quantification are presented. This review concludes with the potential of tUCAs for drug delivery and therapeutic applications.
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Affiliation(s)
- Tom van Rooij
- Department of Biomedical Engineering, Thoraxcenter , Erasmus MC, Rotterdam , the Netherlands
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Leng X, Wang J, Carson A, Chen X, Fu H, Ottoboni S, Wagner WR, Villanueva FS. Ultrasound Detection of Myocardial Ischemic Memory Using an E-Selectin Targeting Peptide Amenable to Human Application. Mol Imaging 2014. [DOI: 10.2310/7290.2014.00006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Xiaoping Leng
- From the Department of Ultrasound, the Second Affiliated Hospital of Harbin Medical University, the Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Center for Ultrasound Molecular Imaging and Therapeutics and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA; and Depomed, Inc., Newark, CA
| | - Jianjun Wang
- From the Department of Ultrasound, the Second Affiliated Hospital of Harbin Medical University, the Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Center for Ultrasound Molecular Imaging and Therapeutics and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA; and Depomed, Inc., Newark, CA
| | - Andrew Carson
- From the Department of Ultrasound, the Second Affiliated Hospital of Harbin Medical University, the Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Center for Ultrasound Molecular Imaging and Therapeutics and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA; and Depomed, Inc., Newark, CA
| | - Xucai Chen
- From the Department of Ultrasound, the Second Affiliated Hospital of Harbin Medical University, the Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Center for Ultrasound Molecular Imaging and Therapeutics and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA; and Depomed, Inc., Newark, CA
| | - Huili Fu
- From the Department of Ultrasound, the Second Affiliated Hospital of Harbin Medical University, the Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Center for Ultrasound Molecular Imaging and Therapeutics and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA; and Depomed, Inc., Newark, CA
| | - Susanne Ottoboni
- From the Department of Ultrasound, the Second Affiliated Hospital of Harbin Medical University, the Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Center for Ultrasound Molecular Imaging and Therapeutics and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA; and Depomed, Inc., Newark, CA
| | - William R. Wagner
- From the Department of Ultrasound, the Second Affiliated Hospital of Harbin Medical University, the Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Center for Ultrasound Molecular Imaging and Therapeutics and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA; and Depomed, Inc., Newark, CA
| | - Flordeliza S. Villanueva
- From the Department of Ultrasound, the Second Affiliated Hospital of Harbin Medical University, the Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Center for Ultrasound Molecular Imaging and Therapeutics and McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA; and Depomed, Inc., Newark, CA
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Chen X, Wang J, Versluis M, de Jong N, Villanueva FS. Ultra-fast bright field and fluorescence imaging of the dynamics of micrometer-sized objects. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:063701. [PMID: 23822346 PMCID: PMC4108723 DOI: 10.1063/1.4809168] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 05/20/2013] [Indexed: 05/05/2023]
Abstract
High speed imaging has application in a wide area of industry and scientific research. In medical research, high speed imaging has the potential to reveal insight into mechanisms of action of various therapeutic interventions. Examples include ultrasound assisted thrombolysis, drug delivery, and gene therapy. Visual observation of the ultrasound, microbubble, and biological cell interaction may help the understanding of the dynamic behavior of microbubbles and may eventually lead to better design of such delivery systems. We present the development of a high speed bright field and fluorescence imaging system that incorporates external mechanical waves such as ultrasound. Through collaborative design and contract manufacturing, a high speed imaging system has been successfully developed at the University of Pittsburgh Medical Center. We named the system "UPMC Cam," to refer to the integrated imaging system that includes the multi-frame camera and its unique software control, the customized modular microscope, the customized laser delivery system, its auxiliary ultrasound generator, and the combined ultrasound and optical imaging chamber for in vitro and in vivo observations. This system is capable of imaging microscopic bright field and fluorescence movies at 25 × 10(6) frames per second for 128 frames, with a frame size of 920 × 616 pixels. Example images of microbubble under ultrasound are shown to demonstrate the potential application of the system.
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Affiliation(s)
- Xucai Chen
- Center for Ultrasound Molecular Imaging and Therapeutics, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania 15213, USA
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Duncanson WJ, Oum K, Eisenbrey JR, Cleveland RO, Wheatley MA, Wong JY. Targeted binding of PEG-lipid modified polymer ultrasound contrast agents with tiered surface architecture. Biotechnol Bioeng 2010; 106:501-6. [PMID: 20091738 PMCID: PMC2980833 DOI: 10.1002/bit.22678] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In order for site-directed polymer ultrasound contrast agents (UCAs) to provide acoustic enhancement at disease sites to distinguish normal tissue from diseased tissue, the surface of these agents must be functionalized with mixtures of grafted polymers. Here a combination of longer liganded polyethylene glycol (PEG)-lipids and shorter unliganded PEG-lipids were introduced into the oil phase of a modified solvent evaporation double emulsion method for preparing UCAs. UCAs with different lengths of both liganded and unliganded lipids were imaged under 7.5 MHz ultrasound. The B-mode image brightness of the mixed PEG-lipid UCAs was within 1 dB the brightness of the unliganded surface. After 15 min of continuous insonation, 70% of the contrast signal remained. The peptide arginine-glycine-aspartic acid (RGD) was added to the surface of these UCAs through a biotin-avidin linkage and binding was assessed under static and shear conditions. Binding was significant after 30 min of static incubation and the adherence of the UCA increased under shear flow from 3 UCA/cell (static) to 5 UCA/cell (shear).
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Affiliation(s)
| | - Kelleny Oum
- School of Biomedical Engineering, Science and Health Systems, Drexel University
| | - John R. Eisenbrey
- School of Biomedical Engineering, Science and Health Systems, Drexel University
| | | | | | - Joyce Y. Wong
- Department of Biomedical Engineering, Boston University
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Abstract
Ultrasound is a very effective modality for drug delivery and gene therapy because energy that is non-invasively transmitted through the skin can be focused deeply into the human body in a specific location and employed to release drugs at that site. Ultrasound cavitation, enhanced by injected microbubbles, perturbs cell membrane structures to cause sonoporation and increases the permeability to bioactive materials. Cavitation events also increase the rate of drug transport in general by augmenting the slow diffusion process with convective transport processes. Drugs and genes can be incorporated into microbubbles, which in turn can target a specific disease site using ligands such as the antibody. Drugs can be released ultrasonically from microbubbles that are sufficiently robust to circulate in the blood and retain their cargo of drugs until they enter an insonated volume of tissue. Local drug delivery ensures sufficient drug concentration at the diseased region while limiting toxicity for healthy tissues. Ultrasound-mediated gene delivery has been applied to heart, blood vessel, lung, kidney, muscle, brain, and tumour with enhanced gene transfection efficiency, which depends on the ultrasonic parameters such as acoustic pressure, pulse length, duty cycle, repetition rate, and exposure duration, as well as microbubble properties such as size, gas species, shell material, interfacial tension, and surface rigidity. Microbubble-augmented sonothrombolysis can be enhanced further by using targeting microbubbles.
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Affiliation(s)
- H-D Liang
- School of Engineering, Cardiff University, Cardiff, UK.
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Wang H, Chen X. Applications for site-directed molecular imaging agents coupled with drug delivery potential. Expert Opin Drug Deliv 2009; 6:745-68. [DOI: 10.1517/17425240902889751] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Klibanov AL. Preparation of targeted microbubbles: ultrasound contrast agents for molecular imaging. Med Biol Eng Comput 2009; 47:875-82. [PMID: 19517153 DOI: 10.1007/s11517-009-0498-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2008] [Accepted: 05/22/2009] [Indexed: 01/29/2023]
Abstract
Targeted ultrasound contrast agents can be prepared by attaching targeting ligands to the lipid, protein or polymer shell coating of gas-filled microbubbles. These materials are stable on storage, fully biocompatible and can be administered parenterally. Detection of microbubble contrast agents by ultrasound is very efficient (single particles with picogram mass can be visualized). Covalent or noncovalent binding techniques can be used to attach targeting ligands. Ligand-carrying microbubbles adhere to the respective molecular targets in vitro and in vivo. Several biomechanical methods are available to improve targeting efficacy, such as the use of a flexible tether spacer arm between the ligand and the bubble, and the use of folds on the microbubble shell, that project out, enhancing the contact area and increasing the length of the lever arm.
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Affiliation(s)
- Alexander L Klibanov
- Cardiovascular Division, University of Virginia, Charlottesville, VA, 22908-0158, USA.
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Kerby MB, Urban JC, Mouallem L, Tripathi A. Circulating IgSF Proteins Inhibit Adhesion of Antibody Targeted Microspheres to Endothelial Inflammatory Ligands. Appl Biochem Biotechnol 2009; 159:208-20. [DOI: 10.1007/s12010-008-8474-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2008] [Accepted: 12/03/2008] [Indexed: 02/07/2023]
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Schmidt BJ, Sousa I, van Beek AA, Böhmer MR. Adhesion and ultrasound-induced delivery from monodisperse microbubbles in a parallel plate flow cell. J Control Release 2008; 131:19-26. [DOI: 10.1016/j.jconrel.2008.06.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2008] [Revised: 06/20/2008] [Accepted: 06/25/2008] [Indexed: 10/21/2022]
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Rothlisberger M. First impact factor for Contrast Media & Molecular Imaging. CONTRAST MEDIA & MOLECULAR IMAGING 2008; 3:135. [DOI: 10.1002/cmmi.242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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