1
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Stepp H, Sroka R. Simple Characterization of Cylindrical Diffuser Fibers With a Fluorescent Layer. Lasers Surg Med 2024; 56:597-605. [PMID: 38923545 DOI: 10.1002/lsm.23821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 05/27/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024]
Abstract
OBJECTIVES A fast, simple, versatile, and reliable method to record light emission intensity profiles of cylindrical light diffusers (CDFs) in air and transparent liquids has been developed. METHODS A fluorescent color glass filter (RG695) converts red light emitted by a cylindrical diffuser fiber into near-infrared light in an emission angle-independent manner. The red light was provided from a diode laser system at 635 nm. Near-infrared fluorescence from the RG695 was imaged with a camera. Images from this camera were processed to obtain emission intensity profiles. Cylindrical diffuser fiber profiles of four different manufacturers were compared. RESULTS The proposed method provides angle-independent intensity profiles of cylindrical diffuser fibers with a single camera shot. It could be demonstrated that dependent on the underlying principle of how the diffuser fiber tips emit light, the emission profile can change significantly in media with different refractive indices. CONCLUSIONS By converting the light emitted by a diffuser fiber tip into fluorescence light one can eliminate the dependence of the recorded profile on the emission angle from the diffusor. This approach allows for easily taking into account refraction-index (mis)matching by placing the equipment into a suitable liquid. The proposed measurement principle bears potential for quality assurance measurements of CDFs used for interstitial laser thermotherapy or photodynamic therapy.
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Affiliation(s)
- Herbert Stepp
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Planegg, Germany
| | - Ronald Sroka
- Laser-Forschungslabor, LIFE Center, University Hospital, LMU Munich, Planegg, Germany
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2
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Mestre-Torà B, Duocastella M. Enhanced light focusing inside scattering media with shaped ultrasound. Sci Rep 2023; 13:11511. [PMID: 37460784 DOI: 10.1038/s41598-023-38598-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 07/11/2023] [Indexed: 07/20/2023] Open
Abstract
Light focusing is the primary enabler of various scientific and industrial processes including laser materials processing and microscopy. However, the scattering of light limits the depth at which current methods can operate inside heterogeneous media such as biological tissue, liquid emulsions, and composite materials. Several approaches have been developed to address this issue, but they typically come at the cost of losing spatial or temporal resolution, or increased invasiveness. Here, we show that ultrasound waves featuring a Bessel-like profile can locally modulate the optical properties of a turbid medium to facilitate light guiding. Supported by wave optics and Monte Carlo simulations, we demonstrate how ultrasound enhances light focusing a factor of 7 compared to conventional methods based on placing optical elements outside the complex medium. Combined with point-by-point scanning, images of samples immersed in turbid media with an optical density up to 15, similar to that of weakly scattering biological tissue, can be reconstructed. The quasi-instantaneous generation of the shaped-ultrasound waves, together with the possibility to use transmission and reflection architectures, can pave the way for the real-time control of light inside living tissue.
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Affiliation(s)
- Blanca Mestre-Torà
- Department of Applied Physics, Universitat de Barcelona, C/Martí i Franquès 1, 08028, Barcelona, Spain
| | - Martí Duocastella
- Department of Applied Physics, Universitat de Barcelona, C/Martí i Franquès 1, 08028, Barcelona, Spain.
- Institut de Nanociència i Nanotecnologia (In2UB), Universitat de Barcelona, 08028, Barcelona, Spain.
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3
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Microneedle arrays for cutaneous and transcutaneous drug delivery, disease diagnosis, and cosmetic aid. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2022.104058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
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4
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Shan W, Mao X, Wang X, Hogan RE, Wang Q. Potential surgical therapies for drug-resistant focal epilepsy. CNS Neurosci Ther 2021; 27:994-1011. [PMID: 34101365 PMCID: PMC8339538 DOI: 10.1111/cns.13690] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/07/2021] [Accepted: 05/18/2021] [Indexed: 12/19/2022] Open
Abstract
Drug-resistant focal epilepsy (DRFE), defined by failure of two antiepileptic drugs, affects 30% of epileptic patients. Epilepsy surgeries are alternative options for this population. Preoperative evaluation is critical to include potential candidates, and to choose the most appropriate procedure to maximize efficacy and simultaneously minimize side effects. Traditional procedures involve open skull surgeries and epileptic focus resection. Alternatively, neuromodulation surgeries use peripheral nerve or deep brain stimulation to reduce the activities of epileptogenic focus. With the advanced improvement of laser-induced thermal therapy (LITT) technique and its utilization in neurosurgery, magnetic resonance-guided LITT (MRgLITT) emerges as a minimal invasive approach for drug-resistant focal epilepsy. In the present review, we first introduce drug-resistant focal epilepsy and summarize the indications, pros and cons of traditional surgical procedures and neuromodulation procedures. And then, focusing on MRgLITT, we thoroughly discuss its history, its technical details, its safety issues, and current evidence on its clinical applications. A case report on MRgLITT is also included to illustrate the preoperational evaluation. We believe that MRgLITT is a promising approach in selected patients with drug-resistant focal epilepsy, although large prospective studies are required to evaluate its efficacy and side effects, as well as to implement a standardized protocol for its application.
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Affiliation(s)
- Wei Shan
- Department of NeurologyBeijing Tiantan HospitalCapital Medical UniversityBeijingChina
- National Center for Clinical Medicine of Neurological DiseasesBeijingChina
- Beijing Institute for Brain DisordersBeijingChina
- Beijing Key Laboratory of Neuro‐modulationBeijingChina
| | - Xuewei Mao
- Shandong Key Laboratory of Industrial Control TechnologySchool of AutomationQingdao UniversityQingdaoChina
| | - Xiu Wang
- National Center for Clinical Medicine of Neurological DiseasesBeijingChina
| | - Robert E. Hogan
- Departments of Neurology and NeurosurgerySchool of MedicineWashington University in St. LouisSt. LouisMOUSA
| | - Qun Wang
- Department of NeurologyBeijing Tiantan HospitalCapital Medical UniversityBeijingChina
- National Center for Clinical Medicine of Neurological DiseasesBeijingChina
- Beijing Institute for Brain DisordersBeijingChina
- Beijing Key Laboratory of Neuro‐modulationBeijingChina
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5
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Li M, Vu T, Sankin G, Winship B, Boydston K, Terry R, Zhong P, Yao J. Internal-Illumination Photoacoustic Tomography Enhanced by a Graded-Scattering Fiber Diffuser. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:346-356. [PMID: 32986546 PMCID: PMC7772228 DOI: 10.1109/tmi.2020.3027199] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The penetration depth of photoacoustic imaging in biological tissues has been fundamentally limited by the strong optical attenuation when light is delivered externally through the tissue surface. To address this issue, we previously reported internal-illumination photoacoustic imaging using a customized radial-emission optical fiber diffuser, which, however, has complex fabrication, high cost, and non-uniform light emission. To overcome these shortcomings, we have developed a new type of low-cost fiber diffusers based on a graded-scattering method in which the optical scattering of the fiber diffuser is gradually increased as the light travels. The graded scattering can compensate for the optical attenuation and provide relatively uniform light emission along the diffuser. We performed Monte Carlo numerical simulations to optimize several key design parameters, including the number of scattering segments, scattering anisotropy factor, divergence angle of the optical fiber, and reflective index of the surrounding medium. These optimized parameters collectively result in uniform light emission along the fiber diffuser and can be flexibly adjusted to accommodate different applications. We fabricated and characterized the prototype fiber diffuser made of agarose gel and intralipid. Equipped with the new fiber diffuser, we performed thorough proof-of-concept studies on ex vivo tissue phantoms and an in vivo swine model to demonstrate the deep-imaging capability (~10 cm achieved ex vivo) of photoacoustic tomography. We believe that the internal light delivery via the optimized fiber diffuser is an effective strategy to image deep targets (e.g., kidney) in large animals or humans.
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6
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Li M, Nyayapathi N, Kilian HI, Xia J, Lovell JF, Yao J. Sound Out the Deep Colors: Photoacoustic Molecular Imaging at New Depths. Mol Imaging 2020; 19:1536012120981518. [PMID: 33336621 PMCID: PMC7750763 DOI: 10.1177/1536012120981518] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Photoacoustic tomography (PAT) has become increasingly popular for molecular imaging due to its unique optical absorption contrast, high spatial resolution, deep imaging depth, and high imaging speed. Yet, the strong optical attenuation of biological tissues has traditionally prevented PAT from penetrating more than a few centimeters and limited its application for studying deeply seated targets. A variety of PAT technologies have been developed to extend the imaging depth, including employing deep-penetrating microwaves and X-ray photons as excitation sources, delivering the light to the inside of the organ, reshaping the light wavefront to better focus into scattering medium, as well as improving the sensitivity of ultrasonic transducers. At the same time, novel optical fluence mapping algorithms and image reconstruction methods have been developed to improve the quantitative accuracy of PAT, which is crucial to recover weak molecular signals at larger depths. The development of highly-absorbing near-infrared PA molecular probes has also flourished to provide high sensitivity and specificity in studying cellular processes. This review aims to introduce the recent developments in deep PA molecular imaging, including novel imaging systems, image processing methods and molecular probes, as well as their representative biomedical applications. Existing challenges and future directions are also discussed.
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Affiliation(s)
- Mucong Li
- Department of Biomedical Engineering, 3065Duke University, Durham, NC, USA
| | - Nikhila Nyayapathi
- Department of Biomedical Engineering, 12292University of Buffalo, NY, USA
| | - Hailey I Kilian
- Department of Biomedical Engineering, 12292University of Buffalo, NY, USA
| | - Jun Xia
- Department of Biomedical Engineering, 12292University of Buffalo, NY, USA
| | - Jonathan F Lovell
- Department of Biomedical Engineering, 12292University of Buffalo, NY, USA
| | - Junjie Yao
- Department of Biomedical Engineering, 3065Duke University, Durham, NC, USA
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7
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Akhter F, Bascos GNW, Canelas M, Griffin B, Hood RL. Mechanical characterization of a fiberoptic microneedle device for controlled delivery of fluids and photothermal excitation. J Mech Behav Biomed Mater 2020; 112:104042. [PMID: 32927279 DOI: 10.1016/j.jmbbm.2020.104042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 06/17/2020] [Accepted: 08/14/2020] [Indexed: 01/18/2023]
Abstract
Current clinical approaches for treating pancreatic cancer have been demonstrated as ineffective at improving midterm survival. A primary obstacle to local drug delivery is the desmoplastic nature of the peritumoral environment, which acts as a significant barrier to circulating macromolecules. To address this need, our group presents a sharp fiberoptic microcatheter capable of accessing the pancreas through transduodenal endoscope and penetrating a tumor to locally co-deliver photothermal and fluid-based therapies. Experiments sought to characterize the mechanical penetration capabilities and fluid mechanics of the fiberoptic microneedle design. A refined off-center fusion splicing technique was developed for joining a multimode fiber to the annular core of a light-guiding capillary, allowing light transmission with minimal optical loss. A novel and frugal technique for assessing the penetration force of the microneedle was conducted in a bovine gelatin tissue phantom with a Young's modulus stiffer than the high range for pancratic tissue or tumor. Buckling forces for different microneedle lengths were measured and compared against theoretical values obtained from Euler's Critical Load equation under fixed-pinned column conditions. Hydraulic resistance of different capillary lengths was evaluated and compared against the theoretical values from Hagen-Poiseuille's law, allowing assessment of contributions from different segments of the device. The results demonstrated that the microcatheter can robustly and repeatably penetrate a soft tissue phantom chosen to be a conservative model of pancreatic tissue for penetration properties. Experiments showed that a 1.5 N insertion force was required for phantom penetration with a 45° beveled needle at a 5 mm unsupported length, while the critical buckling load was measured to be approximately 4 N. In addition, the design was demonstrated to efficiently transport 1064 nm light and aqueous fluids with a 70-75% light coupling efficiency and 12,200 Pa.s/μl hydraulic resistance, respectively. These findings motivate the FMD's further development as a treatment platform for pancreatic cancer.
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Affiliation(s)
- Forhad Akhter
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX, USA
| | - Gregg Neal W Bascos
- Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX, USA
| | - Max Canelas
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX, USA
| | - Bradley Griffin
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX, USA
| | - R Lyle Hood
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX, USA; Graduate School of Biomedical Sciences, UT Health San Antonio, San Antonio, TX, USA.
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8
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Ai M, Youn JI, Salcudean SE, Rohling R, Abolmaesumi P, Tang S. Photoacoustic tomography for imaging the prostate: a transurethral illumination probe design and application. BIOMEDICAL OPTICS EXPRESS 2019; 10:2588-2605. [PMID: 31143504 PMCID: PMC6524588 DOI: 10.1364/boe.10.002588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/09/2019] [Accepted: 04/10/2019] [Indexed: 05/05/2023]
Abstract
In vivo imaging of prostate cancer with photoacoustic tomography is currently limited by the lack of sufficient local fluence for deep tissue penetration and the risk of over-irradiation near the laser-tissue contact surface. We propose the design of a transurethral illumination probe that addresses those limitations. A high energy of 50 mJ/pulse is coupled into a 1000-µm-core diameter multimode fiber. A 2 cm diffusing end is fabricated, which delivers light in radial illumination. The radial illumination is then reflected and reshaped by a parabolic cylindrical mirror to obtain nearly parallel side illumination with a doubled fluence. The fiber assembly is housed in a 25 Fr cystoscope sheath to provide protection of the fiber and maintain a minimal laser-tissue contact distance of 5 mm. A large laser-tissue contact surface area of 4 cm2 is obtained and the fluence on the tissue surface is kept below the maximum permissible exposure. By imaging a prostate mimicking phantom, a penetration depth of 3.5 cm at 10 mJ/cm2 fluence and 700 nm wavelength is demonstrated. The results indicate that photoacoustic tomography with the proposed transurethral probe has the potential to image the entire prostate while satisfying the fluence maximum permissible exposure and delivering a high power to the tissue.
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Affiliation(s)
- Min Ai
- University of British Columbia, Faculty of Applied Science, Department of Electrical and Computer Engineering, 2332 Main Mall, Vancouver, V6T 1Z4, Canada
| | - Jong-in Youn
- Daegu Catholic University, College of Bio and Medical Sciences, Department of Biomedical Engineering, Gyeongsan-si, Gyeongbuk, 712702, South Korea
| | - Septimiu E. Salcudean
- University of British Columbia, Faculty of Applied Science, Department of Electrical and Computer Engineering, 2332 Main Mall, Vancouver, V6T 1Z4, Canada
| | - Robert Rohling
- University of British Columbia, Faculty of Applied Science, Department of Electrical and Computer Engineering, 2332 Main Mall, Vancouver, V6T 1Z4, Canada
| | - Purang Abolmaesumi
- University of British Columbia, Faculty of Applied Science, Department of Electrical and Computer Engineering, 2332 Main Mall, Vancouver, V6T 1Z4, Canada
| | - Shuo Tang
- University of British Columbia, Faculty of Applied Science, Department of Electrical and Computer Engineering, 2332 Main Mall, Vancouver, V6T 1Z4, Canada
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9
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Shabahang S, Forward S, Yun SH. Polyethersulfone optical fibers with thermally induced microbubbles for custom side-scattering profiles. OPTICS EXPRESS 2019; 27:7560-7567. [PMID: 30876318 PMCID: PMC6825622 DOI: 10.1364/oe.27.007560] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 02/04/2019] [Accepted: 02/08/2019] [Indexed: 05/24/2023]
Abstract
Polyethersulfone (PES) optical fibers are drawn and thermally processed in order to generate variable side-illumination profiles. The thermal treatment allows microbubbles to be formed in an outer layer of the PES fiber, providing light scattering with controllable amplitudes (0.25-2.5 cm-1). Several fibers with different scattering profiles, such as uniform axial irradiation and multiple irradiation spots, are demonstrated. A small microbubble-induced scattering spot on the surface may be used for side-coupling of ambient light into the fiber. These mechanically flexible all-PES fibers with custom-designable scattering profiles may be useful for spatially tuned delivery of light for various applications, including phototherapy.
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Affiliation(s)
- Soroush Shabahang
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts, USA, 02114
| | - Sarah Forward
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts, USA, 02114
| | - Seok-Hyun Yun
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, 50 Blossom Street, Boston, Massachusetts, USA, 02114
- Harvard-MIT Health Sciences and Technology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts, USA, 02139
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10
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Truong VG, Park S, Tran VN, Kang HW. Spatial effect of conical angle on optical-thermal distribution for circumferential photocoagulation. BIOMEDICAL OPTICS EXPRESS 2017; 8:5663-5674. [PMID: 29296495 PMCID: PMC5745110 DOI: 10.1364/boe.8.005663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/13/2017] [Accepted: 11/13/2017] [Indexed: 05/06/2023]
Abstract
A uniformly diffusing applicator can be advantageous for laser treatment of tubular tissue. The current study investigated various conical angles for diffuser tips as a critical factor for achieving radially uniform light emission. A customized goniometer was employed to characterize the spatial uniformity of the light propagation. An ex vivo model was developed to quantitatively compare the temperature development and irreversible tissue coagulation. The 10-mm diffuser tip with angle at 25° achieved a uniform longitudinal intensity profile (i.e., 0.90 ± 0.07) as well as a consistent thermal denaturation on the tissue. The proposed conical angle can be instrumental in determining the uniformity of light distribution for the photothermal treatment of tubular tissue.
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Affiliation(s)
- Van Gia Truong
- Interdisciplinary Program of Marine-Bio, Electrical & Mechanical Engineering, Pukyong National University, Busan, South Korea
- These authors contributed equally to this work
| | - Suhyun Park
- School of Electrical and Electronics Engineering, Chung-Ang University, Seoul, South Korea
- These authors contributed equally to this work
| | - Van Nam Tran
- Interdisciplinary Program of Marine-Bio, Electrical & Mechanical Engineering, Pukyong National University, Busan, South Korea
| | - Hyun Wook Kang
- Center for Marine-Integrated Biomedical Technology (BK21 Plus), Pukyong National University, Busan, South Korea
- Department of Biomedical Engineering, Pukyong National University, Busan, South Korea
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11
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Wang Y, Wang Y, Wang Y, Murray CK, Hamblin MR, Hooper DC, Dai T. Antimicrobial blue light inactivation of pathogenic microbes: State of the art. Drug Resist Updat 2017; 33-35:1-22. [PMID: 29145971 DOI: 10.1016/j.drup.2017.10.002] [Citation(s) in RCA: 162] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 06/28/2017] [Accepted: 10/02/2017] [Indexed: 12/20/2022]
Abstract
As an innovative non-antibiotic approach, antimicrobial blue light in the spectrum of 400-470nm has demonstrated its intrinsic antimicrobial properties resulting from the presence of endogenous photosensitizing chromophores in pathogenic microbes and, subsequently, its promise as a counteracter of antibiotic resistance. Since we published our last review of antimicrobial blue light in 2012, there have been a substantial number of new studies reported in this area. Here we provide an updated overview of the findings from the new studies over the past 5 years, including the efficacy of antimicrobial blue light inactivation of different microbes, its mechanism of action, synergism of antimicrobial blue light with other angents, its effect on host cells and tissues, the potential development of resistance to antimicrobial blue light by microbes, and a novel interstitial delivery approach of antimicrobial blue light. The potential new applications of antimicrobial blue light are also discussed.
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Affiliation(s)
- Yucheng Wang
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Cancer Center, Aviation General Hospital, Beijing, China; Department of Medical Oncology, Beijing Institute of Translational Medicine, Chinese Academy of Sciences, Beijing, China
| | - Ying Wang
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Department of Laser Medicine, Chinese PLA General Hospital, Beijing, China
| | - Yuguang Wang
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Center of Digital Dentistry, School and Hospital of Stomatology, Peking University, Beijing, China
| | - Clinton K Murray
- Infectious Disease Service, San Antonio Military Medical Center, JBSA-Fort Sam Houston, TX, USA
| | - Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - David C Hooper
- Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Tianhong Dai
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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12
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Kim M, An J, Kim KS, Choi M, Humar M, Kwok SJJ, Dai T, Yun SH. Optical lens-microneedle array for percutaneous light delivery. BIOMEDICAL OPTICS EXPRESS 2016; 7:4220-4227. [PMID: 27867727 PMCID: PMC5102534 DOI: 10.1364/boe.7.004220] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 09/09/2016] [Accepted: 09/14/2016] [Indexed: 05/08/2023]
Abstract
The limited penetration depth of light in skin tissues is a practical bottleneck in dermatologic applications of light-induced therapies, including anti-microbial blue light therapy and photodynamic skin cancer therapy. Here, we demonstrate a novel device, termed optical microneedle array (OMNA), for percutaneous light delivery. A prototype device with a 11 by 11 array of needles at a spacing of 1 mm and a length of 1.6 mm was fabricated by press-molding poly-(lactic acid) (PLA) polymers. The device also incorporates a matched microlens array that focuses the light through the needle tips at specific points to achieve an optimal intensity profile in the tissue. In experiments done with bovine tissues, the OMNA enabled us to deliver a total of 7.5% of the input photons at a wavelength of 491 nm, compared to only 0.85% without the device. This 9-fold enhancement of light delivery was close to the prediction of 10.8 dB by ray-tracing simulation and is expected to increase the effective treatment depth of anti-microbial blue light therapy significantly from 1.3 to 2.5 mm in human skin.
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Affiliation(s)
- Moonseok Kim
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Cambridge, MA 02139, USA
- Department of Physics, Korea University, Seoul 136-701, South Korea
- These authors contributed equally
| | - Jeesoo An
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Cambridge, MA 02139, USA
- These authors contributed equally
| | - Ki Su Kim
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Cambridge, MA 02139, USA
- These authors contributed equally
| | - Myunghwan Choi
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Cambridge, MA 02139, USA
- Department of Biomedical Engineering, Sungkyunkwan University; Center for Neuroscience and Imaging Research, Institute for Basic Science, Suwon, South Korea
| | - Matjaž Humar
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Cambridge, MA 02139, USA
- Condensed Matter Department, J. Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000, Ljubljana, Slovenia
| | - Sheldon J. J. Kwok
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Cambridge, MA 02139, USA
- Harvard-MIT Health Sciences and Technology, Cambridge, MA 02139, USA
| | - Tianhong Dai
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Cambridge, MA 02139, USA
| | - Seok Hyun Yun
- Harvard Medical School and Wellman Center for Photomedicine, Massachusetts General Hospital, Cambridge, MA 02139, USA
- Harvard-MIT Health Sciences and Technology, Cambridge, MA 02139, USA
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13
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Chang CH, Fried NM. Diffusing, Side-Firing, and Radial Delivery Laser Balloon Catheters for Creating Subsurface Thermal Lesions in Tissue. PROCEEDINGS OF SPIE--THE INTERNATIONAL SOCIETY FOR OPTICAL ENGINEERING 2016; 9689. [PMID: 30774179 DOI: 10.1117/12.2208132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Infrared lasers have been used in combination with applied cooling methods to preserve superficial skin layers during cosmetic surgery. Similarly, combined laser irradiation and tissue cooling may also allow development of minimally invasive laser therapies beyond dermatology. This study compares diffusing, side-firing, and radial delivery laser balloon catheter designs for creation of subsurface lesions in tissue, ex vivo, using a near-IR laser and applied contact cooling. An Ytterbium fiber laser with 1075 nm wavelength delivered energy through custom built 18 Fr (6-mm-OD) balloon catheters incorporating either 10-mm-long diffusing fiber tip, 90 degree side-firing fiber, or radial delivery cone mirror, through a central lumen. A chilled solution was flowed through a separate lumen into 9-mm-diameter balloon to keep probe cooled at 7°C. Porcine liver tissue samples were used as preliminary tissue model for immediate observation of thermal lesion creation. The diffusing fiber produced subsurface thermal lesions measuring 49.3 ± 10.0 mm2 and preserved 0.8 ± 0.1 mm of surface tissue. The side-firing fiber produced subsurface thermal lesions of 2.4 ± 0.9 mm2 diameter and preserved 0.5 ± 0.1 mm of surface tissue. The radial delivery probe assembly failed to produce subsurface thermal lesions, presumably due to the small effective spot diameter at the tissue surface, which limited optical penetration depth. Optimal laser power and irradiation time measured 15 W and 100 s for diffusing fiber and 1.4 W and 20 s, for side-firing fiber, respectively. Diffusing and side-firing laser balloon catheter designs provided subsurface thermal lesions in tissue. However, the divergent laser beam in both designs limited the ability to preserve a thicker layer of tissue surface. Further optimization of laser and cooling parameters may be necessary to preserve thicker surface tissue layers.
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Affiliation(s)
- Chun-Hung Chang
- Department of Physics and Optical Science, University of North Carolina at Charlotte
| | - Nathaniel M Fried
- Department of Physics and Optical Science, University of North Carolina at Charlotte
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14
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Nguyen TH, Rhee YH, Ahn JC, Kang HW. Circumferential irradiation for interstitial coagulation of urethral stricture. OPTICS EXPRESS 2015; 23:20829-40. [PMID: 26367936 DOI: 10.1364/oe.23.020829] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
An optical diffuser was developed to achieve radially uniform light irradiation by micro-machining helical patterns on the fiber surface for endoscopically treating urethral stricture. Spatial emission from the diffuser was evaluated by goniometric measurements. A computational model was developed to predict spatio-temporal heat distribution during the interstitial coagulation. The fabricated diffuser yielded circumferential light distribution with slightly concentrated energy at the proximal end. Both simulation and tissue testing demonstrated approximately 1-mm coagulation thickness at 6 W for 10 sec with 1470 nm. The proposed optical diffuser may be a feasible tool to treat the urethral stricture in a uniform manner.
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15
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McCrudden MTC, McAlister E, Courtenay AJ, González-Vázquez P, Singh TRR, Donnelly RF. Microneedle applications in improving skin appearance. Exp Dermatol 2015; 24:561-6. [PMID: 25865925 DOI: 10.1111/exd.12723] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2015] [Indexed: 02/06/2023]
Abstract
Microneedles (MNs) are micron-sized, minimally invasive devices that breach the outermost layer of the skin, the stratum corneum (SC), creating transient, aqueous pores in the skin and facilitating the transport of therapeutic molecules into the epidermis. Following many years of extensive research in the area of MN-mediated trans- and intra-dermal drug delivery, MNs are now being exploited in the cosmeceutical industry as a means of disrupting skin cell architecture, inducing elastin and collagen expression and deposition. They are also being used as vehicles to deliver cosmeceutic molecules across the skin, in addition to their use in combinatorial treatments with topical agents or light sources. This review explores the chronology of microneedling methodologies, which has led to the emergence of MN devices, now extensively used in cosmeceutical applications. Recent developments in therapeutic molecule and peptide delivery to the skin via MN platforms are addressed and some commercially available MN devices are described. Important safety and regulatory considerations relating to MN usage are addressed, as are studies relating to public perception of MN, as these will undoubtedly influence the acceptance of MN products as they progress towards commercialisation.
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Affiliation(s)
| | - Emma McAlister
- School of Pharmacy, Queen's University Belfast, Belfast, UK
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Butt H, Knowles KM, Montelongo Y, Amaratunga GAJ, Wilkinson TD. Devitrite-based optical diffusers. ACS NANO 2014; 8:2929-2935. [PMID: 24559189 DOI: 10.1021/nn500155e] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Devitrite is a novel material produced by heat treatment of commercial soda-lime-silica glass. It consists of fans of needle-like crystals which can extend up to several millimeters and have interspacings of up to a few hundred nanometers. To date, only the material properties of devitrite have been reported, and there has been a distinct lack of research on using it for optical applications. In this study, we demonstrate that randomly oriented fans of devitrite crystals can act as highly efficient diffusers for visible light. Devitrite crystals produce phase modulation of light because of their relatively high anisotropy. The nanoscale spacings between these needles enable light to be diffused to large scattering angles. Experimentally measured results suggest that light diffusion patterns with beam widths of up to 120° are produced. Since devitrite is an inexpensive material to produce, it has the potential to be used in a variety of commercial applications.
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Affiliation(s)
- Haider Butt
- School of Mechanical Engineering, University of Birmingham , Edgbaston, Birmingham B15 2TT, United Kingdom
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Hood RL, Andriani RT, Emch S, Robertson JL, Rylander CG, Rossmeisl JH. Fiberoptic microneedle device facilitates volumetric infusate dispersion during convection-enhanced delivery in the brain. Lasers Surg Med 2013; 45:418-26. [PMID: 23861185 DOI: 10.1002/lsm.22156] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2013] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND OBJECTIVES A fiberoptic microneedle device (FMD) was designed and fabricated for the purpose of enhancing the volumetric dispersal of macromolecules delivered to the brain through convection-enhanced delivery (CED) by concurrent delivery of sub-lethal photothermal hyperthermia. This study's objective was to demonstrate enhanced dispersal of fluid tracer molecules through co-delivery of 1,064 nm laser energy in an in vivo rodent model. MATERIALS AND METHODS FMDs capable of co-delivering fluids and laser energy through a single light-guiding capillary tube were fabricated. FMDs were stereotactically inserted symmetrically into both cerebral hemispheres of 16 anesthetized rats to a depth of 1.5 mm. Laser irradiation (1,064 nm) at 0 (control), 100, and 200 mW was administered concurrently with CED infusions of liposomal rhodamine (LR) or gadolinium-Evans blue-serum albumin conjugated complex (Gd-EBA) at a flow rate of 0.1 µl/min for 1 hour. Line pressures were monitored during the infusions. Rodents were sacrificed immediately following infusion and their brains were harvested, frozen, and serially cryosectioned for histopathologic and volumetric analyses. RESULTS Analysis by ANOVA methods demonstrated that co-delivery enhanced volumetric dispersal significantly, with measured volumes of 15.8 ± 0.6 mm(3) for 100 mW compared to 10.0 ± 0.4 mm(3) for its fluid only control and 18.0 ± 0.3 mm(3) for 200 mW compared to 10.3 ± 0.7 mm(3) for its fluid only control. Brains treated with 200 mW co-delivery exhibited thermal lesions, while 100 mW co-deliveries were associated with preservation of brain cytoarchitecture. CONCLUSION Both lethal and sub-lethal photothermal hyperthermia substantially increase the rate of volumetric dispersal in a 1 hour CED infusion. This suggests that the FMD co-delivery method could reduce infusion times and the number of catheter insertions into the brain during CED procedures.
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Affiliation(s)
- R Lyle Hood
- School of Biomedical Engineering and Sciences, Virginia Tech, Blacksburg, Virginia, 24061
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Kim C, Park H, Lee H. Comparison of laser-induced damage with forward-firing and diffusing optical fiber during laser-assisted lipoplasty. Lasers Surg Med 2013; 45:437-49. [PMID: 23852719 DOI: 10.1002/lsm.22155] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/03/2013] [Indexed: 11/06/2022]
Abstract
BACKGROUND AND OBJECTIVES Laser-assisted lipoplasty is made possible by using an optical fiber that delivers light endoscopically to subcutaneous fat tissue. Most optical fibers for laser-assisted lipoplasty are designed to be irradiated in a forward direction. In this study, we compared forward-firing fiber and diffusing fiber for use in laser-assisted lipoplasty. The effective parameters of the ablation pattern which resulted from the laser-induced damage are discussed for both systems. In particular, we note the effect resulting from the different beam emission patterns and the contours of laser fluence. METHODS We used two different laser delivery systems (a forward-firing fiber and a diffusing fiber) to examine how the beam emission pattern affects the laser-assisted coagulation and damage pattern of in vitro fat tissues. A porcine liver tissue (water-rich tissue) was used as a secondary laser target to investigate how the laser-assisted coagulation pattern depends on both the type of tissue (water-rich and lipid-rich tissue) as well as the delivery system. An evaluation using a digital camera and a thermal camera was conducted for the tissue ablation processes in order to observe the generated heat transfer in fat and liver. RESULTS The overall shape of the laser-assisted coagulation zone was different from the beam emission pattern in the case where a forward-firing fiber was used within fat tissue. The center of the laser-affected zone is characterized by the formation of a reservoir of melted fat. In the thermal image analysis, there existed a discrepancy between the temperature distribution of the fat tissue and the liver tissue during the forward-firing fiber irradiation. In the liver tissue ablation process, the temperature distribution during the laser ablation also demonstrated an elongated ellipse that matches well with the laser-induced damage zone. The temperature distribution in fat tissue adhered to a more discoid pattern that corresponded to the laser-induced damage zone. CONCLUSIONS Based on our findings, we have proposed mechanisms that can explain the laser-induced damage in both tissues when a forward firing fiber is employed as the delivery system. In the case of fat tissue, the ablation mechanism can be characterized by the reservoir formation of melted lipids while the ablation is characterized as the well-known drilling effect for liver tissue.
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Affiliation(s)
- Changhwan Kim
- School of Mechanical Engineering, Kyungpook National University, Daegu, 702-701, Korea
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Ultraviolet C light for Acinetobacter baumannii wound infections in mice: potential use for battlefield wound decontamination? J Trauma Acute Care Surg 2012; 73:661-7. [PMID: 22929495 DOI: 10.1097/ta.0b013e31825c149c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Since the beginning of the conflicts in the Middle East, US Army physicians have noted a high rate of multidrug-resistant Acinetobacter baumannii infections among US soldiers wounded and initially treated in Iraq. In this study, we investigated the use of ultraviolet C (UVC) light for prevention of multidrug-resistant A. baumannii wound infections using mouse models. METHODS Partial-thickness skin abrasions and full-thickness burns in mice were infected with a multidrug-resistant A. baumannii isolate recovered from a wounded US soldier deployed to Iraq. The luxCDABE operon, which was contained in plasmid pMF 385, was cloned into the A. baumannii strain. This allowed real-time monitoring of the extent of infection in mice using bioluminescence imaging. UVC light was delivered to the mouse wounds at 30 minutes after the inoculation of A. baumannii. Groups of infected mouse wounds without being exposed to UVC served as the controls. RESULTS In vitro studies demonstrated that A. baumannii cells were inactivated at UVC exposures much lower than those needed for a similar effect on mammalian cells. It was observed in animal studies that UVC (3.24 J/cm(2) for abrasions and 2.59 J/cm(2) for burns) significantly reduced the bacterial burdens in UVC-treated wounds by approximately 10-fold compared with nontreated controls (p = 0.004 for abrasions, p = 0.019 for burns). DNA lesions were observed by immunofluorescence in mouse skin abrasions immediately after a UVC exposure of 3.24 J/cm(2); however, the lesions were extensively repaired within 72 hours. CONCLUSION These results suggested that UVC may be useful in preventing combat-related wound infections.
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Kosoglu MA, Hood RL, Rylander CG. Mechanical strengthening of fiberoptic microneedles using an elastomeric support. Lasers Surg Med 2012; 44:421-8. [DOI: 10.1002/lsm.22026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2012] [Indexed: 11/06/2022]
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