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Xu C, Uahengo G, Rudnicki C, Hung C, Huang A, Xu Q, Chen Y, Halaney DL, Garay JE, Mangolini L, Aguilar G, Liu HH. Nanocrystalline Yttria-Stabilized Zirconia Ceramics for Cranial Window Applications. ACS Appl Bio Mater 2022; 5:2664-2675. [PMID: 35671525 DOI: 10.1021/acsabm.2c00119] [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] [Indexed: 11/29/2022]
Abstract
Transparent yttria-stabilized zirconia (YSZ) ceramics are promising for cranial window applications because of their good mechanical and optical properties as well as biocompatibility. YSZ discs with different yttria concentrations were either processed via current-activated pressure-assisted densification (CAPAD) using commercial nanoparticles or densified via spark plasma sintering (SPS) using pyrolysis-synthesized nanoparticles in-house. This study provided critical results to screen composition, processing, microstructure, and cytocompatibility of transparent YSZ discs for cranial window applications. CAPAD-processed YSZ discs with 6 or 8 mol % yttria (6YSZ and 8YSZ) and SPS-densified YSZ discs with 4 mol % yttria (4YSZ_P) showed 200-350 nm polycrystalline grains containing 20-30 nm crystallite domains. SPS-densified YSZ discs with 8 mol % yttria (8YSZ_P) showed larger polycrystalline grains of 819 ± 155 nm with 29 ± 5 nm crystallite domains. CAPAD-processed YSZ discs with 3 mol % yttria (3YSZ) showed 39 ± 9 nm grains. Bone-marrow-derived stem cells (BMSCs) on the polished YSZ discs showed statistically higher spreading areas than those on the unpolished YSZ discs of the same compositions. Generally, polished 8YSZ, 4YSZ_P, and 8YSZ_P discs and unpolished 8YSZ_R, 4YSZ_PR, and 8YSZ_PR discs had lower average cell adhesion densities than other YSZ discs under direct contact conditions. Under indirect contact conditions, all the YSZ disc groups showed similar average cell adhesion densities to the Cell-only control. The groups of polished 4YSZ_P and 8YSZ_P discs, unpolished 4YSZ_PR and 8YSZ_PR discs, and particle control of 8YSZ_Pnp showed higher Y3+ ion concentrations than other groups. No mineral deposition was detected on the polished YSZ discs after cell culture. Considering multiple factors such as cytocompatibility, cell adhesion density, Y3+ ion release, mineral deposition, and optical transparency collectively, 8YSZ may be the best candidate for the cranial window applications. Further studies are needed to evaluate the long-term transparency and biocompatibility of YSZ discs.
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Affiliation(s)
- Changlu Xu
- Materials Science and Engineering Program, University of California, Riverside, Riverside, California 92521, United States
| | - Gottlieb Uahengo
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093, United States
| | - Christopher Rudnicki
- Department of Mechanical Engineering, University of California, Riverside, Riverside, California 92521, United States
| | - Chengi Hung
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States
| | - Aaron Huang
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States
| | - Queenie Xu
- Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States
| | - Yiqing Chen
- Materials Science and Engineering Program, University of California, Riverside, Riverside, California 92521, United States
| | - David L Halaney
- Department of Mechanical Engineering, University of California, Riverside, Riverside, California 92521, United States
| | - Javier E Garay
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, California 92093, United States
| | - Lorenzo Mangolini
- Materials Science and Engineering Program, University of California, Riverside, Riverside, California 92521, United States.,Department of Mechanical Engineering, University of California, Riverside, Riverside, California 92521, United States
| | - Guillermo Aguilar
- Department of Mechanical Engineering, University of California, Riverside, Riverside, California 92521, United States
| | - Huinan Hannah Liu
- Materials Science and Engineering Program, University of California, Riverside, Riverside, California 92521, United States.,Department of Bioengineering, University of California, Riverside, Riverside, California 92521, United States.,Stem Cell Center, University of California, Riverside, Riverside, California 92521, United States
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Halaney DL, Katta N, Fallah H, Aguilar G, Milner TE. Group Refractive Index of Nanocrystalline Yttria-Stabilized Zirconia Transparent Cranial Implants. Front Bioeng Biotechnol 2021; 9:619686. [PMID: 33869149 PMCID: PMC8044953 DOI: 10.3389/fbioe.2021.619686] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 03/02/2021] [Indexed: 11/18/2022] Open
Abstract
Transparent “Window to the Brain” (WttB) cranial implants made from a biocompatible ceramic, nanocrystalline Yttria-Stabilized Zirconia (nc-YSZ), were recently reported. These reports demonstrated chronic brain imaging across the implants in mice using optical coherence tomography (OCT) and laser speckle imaging. However, optical properties of these transparent cranial implants are neither completely characterized nor completely understood. In this study, we measure optical properties of the implant using a swept source OCT system with a spectral range of 136 nm centered at 1,300 nm to characterize the group refractive index of the nc-YSZ window, over a narrow range of temperatures at which the implant may be used during imaging or therapy (20–43°C). Group refractive index was found to be 2.1–2.2 for OCT imaging over this temperature range. Chromatic dispersion for this spectral range was observed to vary over the sample, sometimes flipping signs between normal and anomalous dispersion. These properties of nc-YSZ should be considered when designing optical systems and procedures that propagate light through the window, and when interpreting OCT brain images acquired across the window.
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Affiliation(s)
- David L Halaney
- Laboratory of Guillermo Aguilar, Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Nitesh Katta
- Laboratory of Thomas Milner, Department of Biomedical Engineering, University of Texas, Austin, TX, United States
| | | | - Guillermo Aguilar
- Laboratory of Guillermo Aguilar, Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Thomas E Milner
- Laboratory of Thomas Milner, Department of Biomedical Engineering, University of Texas, Austin, TX, United States
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Halaney DL, Jonak CR, Liu J, Davoodzadeh N, Cano-Velázquez MS, Ehtiyatkar P, Park H, Binder DK, Aguilar G. Chronic Brain Imaging Across a Transparent Nanocrystalline Yttria-Stabilized-Zirconia Cranial Implant. Front Bioeng Biotechnol 2020; 8:659. [PMID: 32695757 PMCID: PMC7339873 DOI: 10.3389/fbioe.2020.00659] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 05/28/2020] [Indexed: 12/28/2022] Open
Abstract
Repeated non-diffuse optical imaging of the brain is difficult. This is due to the fact that the cranial bone is highly scattering and thus a strong optical barrier. Repeated craniotomies increase the risk of complications and may disrupt the biological systems being imaged. We previously introduced a potential solution in the form of a transparent ceramic cranial implant called the Window to the Brain (WttB) implant. This implant is made of nanocrystalline Yttria-Stabilized Zirconia (nc-YSZ), which possesses the requisite mechanical strength to serve as a permanent optical access window in human patients. In this present study, we demonstrate repeated brain imaging of n = 5 mice using both OCT and LSI across the WttB implant over 4 weeks. The main objectives are to determine if the WttB implant allows for chronic OCT imaging, and to shed further light on the question of whether optical access provided by the WttB implant remains stable over this duration in the body. The Window to the Brain implant allowed for stable repeated imaging of the mouse brain with Optical Coherence Tomography over 28 days, without loss of signal intensity. Repeated Laser Speckle Imaging was also possible over this timeframe, but signal to noise ratio and the sharpness of vessels in the images decreased with time. This can be partially explained by elevated blood flow during the first imaging session in response to trauma from the surgery, which was also detected by OCT flow imaging. These results are promising for long-term optical access through the WttB implant, making feasible chronic in vivo studies in multiple neurological models of brain disease.
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Affiliation(s)
- David L Halaney
- Laboratory of Guillermo Aguilar, Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Carrie R Jonak
- Laboratory of Devin Binder, Division of Biomedical Sciences, University of California, Riverside, Riverside, CA, United States
| | - Junze Liu
- Laboratory of Hyle Park, Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
| | - Nami Davoodzadeh
- Laboratory of Guillermo Aguilar, Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
| | - Mildred S Cano-Velázquez
- Laboratory of Juan Hernandez-Cordero, Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Pasha Ehtiyatkar
- Laboratory of Guillermo Aguilar, Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States.,Department of Neuroscience, University of California, Riverside, Riverside, CA, United States
| | - Hyle Park
- Laboratory of Hyle Park, Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
| | - Devin K Binder
- Laboratory of Devin Binder, Division of Biomedical Sciences, University of California, Riverside, Riverside, CA, United States
| | - Guillermo Aguilar
- Laboratory of Guillermo Aguilar, Department of Mechanical Engineering, University of California, Riverside, Riverside, CA, United States
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Davoodzadeh N, Cano-Velázquez MS, Halaney DL, Jonak CR, Binder DK, Aguilar G. Optical Access to Arteriovenous Cerebral Microcirculation Through a Transparent Cranial Implant. Lasers Surg Med 2019; 51:920-932. [PMID: 31236997 DOI: 10.1002/lsm.23127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2019] [Indexed: 01/20/2023]
Abstract
BACKGROUND AND OBJECTIVE Microcirculation plays a critical role in physiologic processes and several disease states. Laser speckle imaging (LSI) is a full-field, real-time imaging technique capable of mapping microvessel networks and providing relative flow velocity within the vessels. In this study, we demonstrate that LSI combine with multispectral reflectance imaging (MSRI), which allows for distinction between veins and arteries in the vascular flow maps produced by LSI. We apply this combined technique to mouse cerebral vascular network in vivo, comparing imaging through the skull, to the dura mater and brain directly through a craniectomy, and through a transparent cranial "Window to the Brain" (WttB) implant. STUDY DESIGN/MATERIALS AND METHODS The WttB implant used in this study is made of a nanocrystalline Yttria-Stabilized-Zirconia ceramic. MSRI was conducted using white-light illumination and filtering the reflected light for 560, 570, 580, 590, 600, and 610 nm. LSI was conducted using an 810 nm continuous wave near-infrared laser with incident power of 100 mW, and the reflected speckle pattern was captured by a complementary metal-oxide-semiconductor (CMOS) camera. RESULTS Seven vessel branches were analyzed and comparison was made between imaging through the skull, craniectomy, and WttB implant. Through the skull, MSRI did not detect any vessels, and LSI could not image microvessels. Imaging through the WttB implant, MSRI was able to identify veins versus arteries, and LSI was able to image microvessels with only slightly higher signal-to-noise ratio and lower sharpness than imaging the brain through a craniectomy. CONCLUSIONS This study demonstrates the ability to perform MSRI-LSI across a transparent cranial implant, to allow for cerebral vascular networks to be mapped, including microvessels. These images contain additional information such as vein-artery separation and relative blood flow velocities, information which is of value scientifically and medically. The WttB implant provides substantial improvements over imaging through the murine cranial bone, where microvessels are not visible and MSRI cannot be performed. Lasers Surg. Med. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Nami Davoodzadeh
- Department of Mechanical Engineering, University of California, Bourns Hall A342 900 University Ave., Riverside, California, 92521
| | - Mildred S Cano-Velázquez
- Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Ciudad Universitaria, Coyoacán, Mexico City, 04510, Mexico
| | - David L Halaney
- Department of Mechanical Engineering, University of California, Bourns Hall A342 900 University Ave., Riverside, California, 92521
| | - Carrie R Jonak
- Division of Biomedical Sciences, School of Medicine, University of California, 1126 Webber Hall 900 University Ave., Riverside, California, 92521
| | - Devin K Binder
- Division of Biomedical Sciences, School of Medicine, University of California, 1126 Webber Hall 900 University Ave., Riverside, California, 92521
| | - Guillermo Aguilar
- Department of Mechanical Engineering, University of California, Bourns Hall A342 900 University Ave., Riverside, California, 92521
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Davoodzadeh N, Cano-Velázquez MS, Halaney DL, Sabzeghabae A, Uahengo G, Garay JE, Aguilar G. Characterization of ageing resistant transparent nanocrystalline yttria-stabilized zirconia implants. J Biomed Mater Res B Appl Biomater 2019; 108:709-716. [PMID: 31172661 DOI: 10.1002/jbm.b.34425] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [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: 01/11/2019] [Revised: 05/01/2019] [Accepted: 05/17/2019] [Indexed: 12/14/2022]
Abstract
The "Window to the Brain" is a transparent cranial implant under development, based on nanocrystalline yttria-stabilized zirconia (nc-YSZ) transparent ceramic material. Previous work has demonstrated the feasibility of this material to facilitate brain imaging over time, but the long-term stability of the material over decades in the body is unknown. In this study, the low-temperature degradation (LTD) of nc-YSZ of 3, 6, and 8 mol % yttria is compared before and after accelerated ageing treatments following ISO standards for assessing the ageing resistance of zirconia ceramics. After 100 hr of accelerated ageing (equivalent to many decades of ageing in the body), the samples do not show any signs of phase transformation to monoclinic by X-ray diffraction and micro-Raman spectroscopy. Moreover, the mechanical hardness of the samples did not decrease, and changes in optical transmittance from 500 to 1000 nm due to ageing treatments was minimal (below 3% for all samples), and unlikely to be due to phase transformation of surface crystals to monoclinic. These results indicate the nc-YSZ has excellent ageing resistance and can withstand long-term implantation conditions without exhibiting LTD.
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Affiliation(s)
- Nami Davoodzadeh
- Department of Mechanical Engineering, University of California - Riverside, Riverside, California
| | - Mildred S Cano-Velázquez
- Instituto de Investigaciones en Materiales, Universidad Nacional Autónoma de México, México, Mexico
| | - David L Halaney
- Department of Mechanical Engineering, University of California - Riverside, Riverside, California
| | - Ariana Sabzeghabae
- Department of Mechanical Engineering, University of California - Riverside, Riverside, California
| | - Gottlieb Uahengo
- Department of Mechanical and Aerospace Engineering, University of California - San Diego, La Jolla, California
| | - Javier E Garay
- Department of Mechanical and Aerospace Engineering, University of California - San Diego, La Jolla, California
| | - Guillermo Aguilar
- Department of Mechanical Engineering, University of California - Riverside, Riverside, California
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Davoodzadeh N, Cano-Velázquez MS, Halaney DL, Jonak CR, Binder DK, Aguilar G. Evaluation of a transparent cranial implant as a permanent window for cerebral blood flow imaging. Biomed Opt Express 2018; 9:4879-4892. [PMID: 30319909 PMCID: PMC6179387 DOI: 10.1364/boe.9.004879] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/27/2018] [Accepted: 09/12/2018] [Indexed: 05/11/2023]
Abstract
Laser speckle imaging (LSI) of mouse cerebral blood flow was compared through a transparent nanocrystalline yttria-stabilized zirconia (nc-YSZ) cranial implant over time (at days 0, 14, and 28, n = 3 mice), and vs. LSI through native skull (at day 60, n = 1 mouse). The average sharpness of imaged vessels was found to remain stable, with relative change in sharpness under 7.69% ± 1.2% over 28 days. Through-implant images of vessels at day 60 appeared sharper and smaller on average, with microvessels clearly visible, compared to through-skull images where vessels appeared blurred and distorted. These results suggest that long-term imaging through this implant is feasible.
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Affiliation(s)
- Nami Davoodzadeh
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
| | | | - David L Halaney
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
| | - Carrie R Jonak
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Devin K Binder
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Guillermo Aguilar
- Department of Mechanical Engineering, University of California, Riverside, CA, USA
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Halaney DL, Sanyal A, Nafissi NA, Escobedo D, Goros M, Michalek J, Acevedo PJ, Pérez W, Patricia Escobar G, Feldman MD, Han HC. The Effect of Trabeculae Carneae on Left Ventricular Diastolic Compliance: Improvement in Compliance With Trabecular Cutting. J Biomech Eng 2017; 139:2595441. [PMID: 28024161 DOI: 10.1115/1.4035585] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Indexed: 12/25/2022]
Abstract
The role of trabeculae carneae in modulating left ventricular (LV) diastolic compliance remains unclear. The objective of this study was to determine the contribution of trabeculae carneae to the LV diastolic compliance. LV pressure-volume compliance curves were measured in six human heart explants from patients with LV hypertrophy at baseline and following trabecular cutting. The effect of trabecular cutting was also analyzed with finite-element model (FEM) simulations. Our results demonstrated that LV compliance improved after trabecular cutting (p < 0.001). Finite-element simulations further demonstrated that stiffer trabeculae reduce LV compliance further, and that the presence of trabeculae reduced the wall stress in the apex. In conclusion, we demonstrate that integrity of the LV and trabeculae is important to maintain LV stiffness and loss in trabeculae leads to more LV compliance.
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Affiliation(s)
- David L Halaney
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229;Department of Veterans Affairs, South Texas Veterans Health Care System, San Antonio, TX 78229
| | - Arnav Sanyal
- Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX 78249
| | - Navid A Nafissi
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Daniel Escobedo
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229;Department of Veterans Affairs, South Texas Veterans Health Care System, San Antonio, TX 78229
| | - Martin Goros
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Joel Michalek
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Pedro J Acevedo
- Department of Anatomy, University of Environmental and Applied Sciences U.D.C.A., Bogotá, Cundinamarca, Colombia
| | - William Pérez
- Department of Anatomy, Faculty of Veterinary Medicine, University of the Republic, Montevideo 11200, Uruguay
| | - G Patricia Escobar
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - Marc D Feldman
- Department of Medicine, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229;Department of Veterans Affairs, South Texas Veterans Health Care System, San Antonio, TX 78229 e-mail:
| | - Hai-Chao Han
- Fellow ASME Department of Mechanical Engineering, University of Texas at San Antonio, San Antonio, TX 78249
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Damestani Y, De Howitt N, Halaney DL, Garay JE, Aguilar G. Evaluation of laser bacterial anti-fouling of transparent nanocrystalline yttria-stabilized-zirconia cranial implant. Lasers Surg Med 2016; 48:782-789. [PMID: 27389389 DOI: 10.1002/lsm.22558] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/26/2016] [Indexed: 11/06/2022]
Abstract
BACKGROUND AND OBJECTIVE The development and feasibility of a novel nanocrystalline yttria-stabilized-zirconia (nc-YSZ) cranial implant has been recently established. The purpose of what we now call "window to the brain (WttB)" implant (or platform), is to improve patient care by providing a technique for delivery and/or collection of light into/from the brain, on demand, over large areas, and on a chronically recurring basis without the need for repeated craniotomies. WttB holds the transformative potential for enhancing light-based diagnosis and treatment of a wide variety of brain pathologies including cerebral edema, traumatic brain injury, stroke, glioma, and neurodegenerative diseases. However, bacterial adhesion to the cranial implant is the leading factor for biofilm formation (fouling), infection, and treatment failure. Escherichia coli (E. coli), in particular, is the most common isolate in gram-negative bacillary meningitis after cranial surgery or trauma. The transparency of our WttB implant may provide a unique opportunity for non-invasive treatment of bacterial infection under the implant using medical lasers. STUDY DESIGN/MATERIALS AND METHODS A drop of a diluted overnight culture of BL21-293 E. coli expressing luciferase was seeded between the nc-YSZ implant and the agar plate. This was followed by immediate irradiation with selected laser. After each laser treatment the nc-YSZ was removed, and cultures were incubated for 24 hours at 37 °C. The study examined continuous wave (CW) and pulsed wave (PW) modes of near-infrared (NIR) 810 nm laser wavelength with a power output ranging from 1 to 3 W. During irradiation, the temperature distribution of nc-YSZ surface was monitored using an infrared thermal camera. Relative luminescence unit (RLU) was used to evaluate the viability of bacteria after the NIR laser treatment. RESULTS Analysis of RLU suggests that the viability of E. coli biofilm formation was reduced with NIR laser treatment when compared to the control group (P < 0.01) and loss of viability depends on both laser fluence and operation mode (CW or PW). The results demonstrate that while CW laser reduces the biofilm formation more than PW laser with the same power, the higher surface temperature of the implant generated by CW laser limits its medical efficacy. In contrast, with the right parameters, PW laser produces a more moderate photothermal effect which can be equally effective at controlling bacterial growth. CONCLUSIONS Our results show that E. coli biofilm formation across the thickness of the nc-YSZ implant can be disrupted using NIR laser treatment. The results of this in vitro study suggest that using nc-YSZ as a cranial implant in vivo may also allow for locally selective, non-invasive, chronic treatment of bacterial layers (fouling) that might form under cranial implants, without causing adverse thermal damage to the underlying host tissue when appropriate laser parameters are used. Lasers Surg. Med. 48:782-789, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Yasaman Damestani
- Department of Bioengineering, University of California - Riverside, Riverside, California, 92521
| | - Natalie De Howitt
- Department of Bioengineering, University of California - Riverside, Riverside, California, 92521
| | - David L Halaney
- Department of Mechanical Engineering, University of California - Riverside, Riverside, California, 92521
| | - Javier E Garay
- Department of Mechanical and Aerospace Engineering, University of California - San Diego, La Jolla, California, 92093
| | - Guillermo Aguilar
- Department of Bioengineering, University of California - Riverside, Riverside, California, 92521. .,Department of Mechanical Engineering, University of California - Riverside, Riverside, California, 92521.
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Halaney DL, Zahedivash A, Phipps JE, Wang T, Dwelle J, Saux CJL, Asmis R, Milner TE, Feldman MD. Differences in forward angular light scattering distributions between M1 and M2 macrophages. J Biomed Opt 2015; 20:115002. [PMID: 26538329 PMCID: PMC4881287 DOI: 10.1117/1.jbo.20.11.115002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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: 03/31/2015] [Accepted: 10/09/2015] [Indexed: 05/11/2023]
Abstract
The ability to distinguish macrophage subtypes noninvasively could have diagnostic potential in cancer, atherosclerosis, and diabetes, where polarized M1 and M2 macrophages play critical and often opposing roles. Current methods to distinguish macrophage subtypes rely on tissue biopsy. Optical imaging techniques based on light scattering are of interest as they can be translated into biopsy-free strategies. Because mitochondria are relatively strong subcellular light scattering centers, and M2 macrophages are known to have enhanced mitochondrial biogenesis compared to M1, we hypothesized that M1 and M2 macrophages may have different angular light scattering profiles. To test this, we developed an in vitro angle-resolved forward light scattering measurement system. We found that M1 and M2 macrophage monolayers scatter relatively unequal amounts of light in the forward direction between 1.6 deg and 3.2 deg with M2 forward scattering significantly more light than M1 at increasing angles. The ratio of forward scattering can be used to identify the polarization state of macrophage populations in culture.
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Affiliation(s)
- David L. Halaney
- University of Texas Health Science Center at San Antonio, Division of Cardiology, Department of Medicine, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
- South Texas Veterans Health Care System, Department of Veterans Affairs, 7400 Merton Minter, San Antonio, Texas 78229, United States
| | - Aydin Zahedivash
- University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712, United States
| | - Jennifer E. Phipps
- University of Texas Health Science Center at San Antonio, Division of Cardiology, Department of Medicine, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
| | - Tianyi Wang
- University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712, United States
| | - Jordan Dwelle
- South Texas Veterans Health Care System, Department of Veterans Affairs, 7400 Merton Minter, San Antonio, Texas 78229, United States
- University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712, United States
| | - Claude Jourdan Le Saux
- University of Texas Health Science Center at San Antonio, Division of Cardiology, Department of Medicine, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
| | - Reto Asmis
- University of Texas Health Science Center at San Antonio, Departments of Clinical Laboratory Sciences and Biochemistry, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
| | - Thomas E. Milner
- University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712, United States
| | - Marc D. Feldman
- University of Texas Health Science Center at San Antonio, Division of Cardiology, Department of Medicine, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
- South Texas Veterans Health Care System, Department of Veterans Affairs, 7400 Merton Minter, San Antonio, Texas 78229, United States
- Address all correspondence to: Marc D. Feldman, E-mail:
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Mancuso JJ, Halaney DL, Elahi S, Ho D, Wang T, Ouyang Y, Dijkstra J, Milner TE, Feldman MD. Intravascular optical coherence tomography light scattering artifacts: merry-go-rounding, blooming, and ghost struts. J Biomed Opt 2014; 19:126017. [PMID: 25545341 PMCID: PMC4659478 DOI: 10.1117/1.jbo.19.12.126017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 08/29/2014] [Accepted: 12/04/2014] [Indexed: 06/04/2023]
Abstract
We sought to elucidate the mechanisms underlying two common intravascular optical coherence tomography (IV-OCT) artifacts that occur when imaging metallic stents: “merry-go-rounding” (MGR), which is an increase in strut arc length (SAL), and “blooming,” which is an increase in the strut reflection thickness (blooming thickness). Due to uncontrollable variables that occur in vivo, we performed an in vitro assessment of MGR and blooming in stented vessel phantoms. Using Xience V and Driver stents, we examined the effects of catheter offset, intimal strut coverage, and residual blood on SAL and blooming thickness in IV-OCT images. Catheter offset and strut coverage both caused minor MGR, while the greatest MGR effect resulted from light scattering by residual blood in the vessel lumen, with 1% hematocrit (Hct) causing a more than fourfold increase in SAL compared with saline (p<0.001 ). Residual blood also resulted in blooming, with blooming thickness more than doubling when imaged in 0.5% Hct compared with saline (p<0.001 ). We demonstrate that a previously undescribed mechanism, light scattering by residual blood in the imaging field, is the predominant cause of MGR. Light scattering also results in blooming, and a newly described artifact, three-dimensional-MGR, which results in “ghost struts” in B-scans.
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Affiliation(s)
- J. Jacob Mancuso
- The University of Texas Health Science Center at San Antonio, Division of Cardiology, Department of Medicine, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
- South Texas Veterans Health Care System, The Department of Veterans Affairs, San Antonio, Texas 78229, United States
| | - David L. Halaney
- The University of Texas Health Science Center at San Antonio, Division of Cardiology, Department of Medicine, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
- South Texas Veterans Health Care System, The Department of Veterans Affairs, San Antonio, Texas 78229, United States
| | - Sahar Elahi
- The University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712, United States
| | - Derek Ho
- The University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712, United States
| | - Tianyi Wang
- The University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712, United States
| | - Yongjian Ouyang
- The University of Texas Health Science Center at San Antonio, Division of Cardiology, Department of Medicine, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
| | - Jouke Dijkstra
- Leiden University Medical Center, Division of Image Processing, Department of Radiology, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Thomas E. Milner
- The University of Texas at Austin, Department of Biomedical Engineering, 1 University Station C0800, Austin, Texas 78712, United States
| | - Marc D. Feldman
- The University of Texas Health Science Center at San Antonio, Division of Cardiology, Department of Medicine, 7703 Floyd Curl Drive, San Antonio, Texas 78229, United States
- South Texas Veterans Health Care System, The Department of Veterans Affairs, San Antonio, Texas 78229, United States
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Phipps JE, Vela D, Hoyt T, Halaney DL, Mancuso JJ, Buja LM, Asmis R, Milner TE, Feldman MD. Macrophages and intravascular OCT bright spots: a quantitative study. JACC Cardiovasc Imaging 2014; 8:63-72. [PMID: 25499133 DOI: 10.1016/j.jcmg.2014.07.027] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 06/25/2014] [Accepted: 07/16/2014] [Indexed: 12/15/2022]
Abstract
OBJECTIVES This study hypothesized that bright spots in intravascular optical coherence tomography (IVOCT) images may originate by colocalization of plaque materials of differing indexes of refraction. To quantitatively identify bright spots, we developed an algorithm that accounts for factors including tissue depth, distance from light source, and signal-to-noise ratio. We used this algorithm to perform a bright spot analysis of IVOCT images and compared these results with histological examination of matching tissue sections. BACKGROUND Bright spots are thought to represent macrophages in IVOCT images, and studies of alternative etiologies have not been reported. METHODS Fresh human coronary arteries (n = 14 from 10 hearts) were imaged with IVOCT in a mock catheterization laboratory and then processed for histological analysis. The quantitative bright spot algorithm was applied to all images. RESULTS Results are reported for 1,599 IVOCT images co-registered with histology. Macrophages alone were responsible for only 23% of the bright spot-positive regions, although they were present in 57% of bright spot-positive regions (as determined by histology). Additional etiologies for bright spots included cellular fibrous tissue (8%), interfaces between calcium and fibrous tissue (10%), calcium and lipids (5%), and fibrous cap and lipid pool (3%). Additionally, we showed that large pools of macrophages in CD68(+) histology sections corresponded to dark regions in comparative IVOCT images; this is due to the fact that a pool of lipid-rich macrophages will have the same index of refraction as a pool of lipid and thus will not cause bright spots. CONCLUSIONS Bright spots in IVOCT images were correlated with a variety of plaque components that cause sharp changes in the index of refraction. Algorithms that incorporate these correlations may be developed to improve the identification of some types of vulnerable plaque and allow standardization of IVOCT image interpretation.
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Affiliation(s)
- Jennifer E Phipps
- University of Texas Health Science Center San Antonio, San Antonio, Texas
| | | | - Taylor Hoyt
- University of Texas Health Science Center San Antonio, San Antonio, Texas
| | - David L Halaney
- University of Texas Health Science Center San Antonio, San Antonio, Texas; Department of Veterans Affairs, South Texas Veterans Health Care System, San Antonio, Texas
| | - J Jacob Mancuso
- University of Texas Health Science Center San Antonio, San Antonio, Texas
| | | | - Reto Asmis
- University of Texas Health Science Center San Antonio, San Antonio, Texas
| | | | - Marc D Feldman
- University of Texas Health Science Center San Antonio, San Antonio, Texas; Department of Veterans Affairs, South Texas Veterans Health Care System, San Antonio, Texas.
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