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Boychev N, Lee S, Yeung V, Ross AE, Kuang L, Chen L, Dana R, Ciolino JB. Contact lenses as novel tear fluid sampling vehicles for total RNA isolation, precipitation, and amplification. Sci Rep 2024; 14:11727. [PMID: 38778161 PMCID: PMC11111455 DOI: 10.1038/s41598-024-62215-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 05/14/2024] [Indexed: 05/25/2024] Open
Abstract
The tear fluid is a readily accessible, potential source for biomarkers of disease and could be used to monitor the ocular response to contact lens (CL) wear or ophthalmic pathologies treated by therapeutic CLs. However, the tear fluid remains largely unexplored as a biomarker source for RNA-based molecular analyses. Using a rabbit model, this study sought to determine whether RNA could be collected from commercial CLs and whether the duration of CL wear would impact RNA recovery. The results were referenced to standardized strips of filtered paper (e.g., Shirmer Strips) placed in the inferior fornix. By performing total RNA isolation, precipitation, and amplification with commercial kits and RT-PCR methods, CLs were found to have no significant differences in RNA concentration and purity compared to Schirmer Strips. The study also identified genes that could be used to normalize RNA levels between tear samples. Of the potential control genes or housekeeping genes, GAPDH was the most stable. This study, which to our knowledge has never been done before, provides a methodology for the detection of RNA and gene expression changes from tear fluid that could be used to monitor or study eye diseases.
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Affiliation(s)
- Nikolay Boychev
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, and Harvard Medical School, Boston, USA.
| | - Seokjoo Lee
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, and Harvard Medical School, Boston, USA
| | - Vincent Yeung
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, and Harvard Medical School, Boston, USA
| | - Amy E Ross
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, and Harvard Medical School, Boston, USA
| | - Liangju Kuang
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, and Harvard Medical School, Boston, USA
| | - Lin Chen
- Department of Optometry and Visual Science, West China Hospital, Sichuan University, Chengdu, Sichuan, China
- Department of Ophthalmology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
| | - Reza Dana
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, and Harvard Medical School, Boston, USA
| | - Joseph B Ciolino
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear, and Harvard Medical School, Boston, USA
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Yamasaki K, Dantam J, Sasanuma K, Hisamura R, Mizuno Y, Hui A, Jones L. Impact of in vitro lens deposition and removal on bacterial adhesion to orthokeratology contact lenses. Cont Lens Anterior Eye 2024; 47:102104. [PMID: 38161140 DOI: 10.1016/j.clae.2023.102104] [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: 09/14/2023] [Revised: 11/22/2023] [Accepted: 12/11/2023] [Indexed: 01/03/2024]
Abstract
PURPOSE The purpose of this study was to explore the impact of several contact lens (CL) care solutions on the removal of proteins and lipids, and how deposit removal impacts bacterial adhesion and solution disinfection. METHODS Lysozyme and lipid deposition on three ortho-k (rigid) and two soft CL materials were evaluated using an ELISA kit and gas chromatography respectively. Bacterial adhesion to a fluorosilicone acrylate material using Pseudomonas aeruginosa with various compositions of artificial tear solutions (ATS), including with denatured proteins, was also investigated. The impact of deposition of the different formulations of ATS on biofilm formation was explored using cover slips. Finally, the lysozyme and lipid cleaning efficacy and disinfection efficacy against P. aeruginosa and Staphylococcus aureus of four different contact lens care solutions were studied using qualitative analysis. RESULTS While maximum lysozyme deposition was observed with the fluorosilicone acrylate material (327.25 ± 54.25 µg/lens), the highest amount of lipid deposition was recorded with a fluoro-siloxanyl styrene material (134.71 ± 19.87 µg/lens). Adhesion of P. aeruginosa to fluorosilicone acrylate lenses and biofilm formation on cover slips were significantly greater with the addition of denatured proteins and lipids. Of the four contact lens care solutions investigated, the solution based on povidone-iodine removed both denatured lysozyme and lipid deposits and could effectively disinfect against P. aeruginosa and S. aureus when contaminated with denatured proteins and lipids. In contrast, the peroxide-based solution was able to inhibit P. aeruginosa growth only, while the two multipurpose solutions were unable to disinfect lenses contaminated with denatured proteins and lipids. CONCLUSION Bacterial adhesion and biofilm formation is influenced by components within artificial tear solutions depositing on lenses, including denatured proteins and lipids, which also affects disinfection. The ability of different solutions to remove these deposits should be considered when selecting systems to clean and disinfect ortho-k lenses.
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Affiliation(s)
| | - Jaya Dantam
- Centre for Ocular Research & Education (CORE), School of Optometry and Vision Science, University of Waterloo, Ontario, Canada
| | | | | | - Yohei Mizuno
- Kobe Research Center, OPHTECS Corporation, Kobe, Japan
| | - Alex Hui
- Centre for Ocular Research & Education (CORE), School of Optometry and Vision Science, University of Waterloo, Ontario, Canada; School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW Sydney, Australia.
| | - Lyndon Jones
- Centre for Ocular Research & Education (CORE), School of Optometry and Vision Science, University of Waterloo, Ontario, Canada; Centre for Eye and Vision Research (CEVR), Hong Kong Special Administrative Region, Hong Kong
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Su CY, Yeh LK, Huang PH, Lin WP, Huang HF, Lai CC, Fang HW. Long-term effects of tear film component deposition on the surface and optical properties of two different orthokeratology lenses. Cont Lens Anterior Eye 2023; 46:101852. [PMID: 37150645 DOI: 10.1016/j.clae.2023.101852] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 03/08/2023] [Accepted: 04/28/2023] [Indexed: 05/09/2023]
Abstract
PURPOSE To understand the effects of long-term deposition of tear film components on the surface and optical properties of orthokeratology (ortho-k) lenses, two different lenses, Brighten 22 and Optimum Extra, were tested here. METHODS Ortho-k lenses were immersed in artificial tears and cleaned with a commercial care solution repeatedly for up to 90 days. Both the daily and accumulated lysozyme deposition amounts using an Enzyme-Linked ImmunoSorbent Assay were then analyzed. The base curve, central thickness, power, and transmission of visible light, ultraviolet A, and ultraviolet B were analyzed before and after repeated tear film component deposition procedures. The surface roughness using atomic force microscopy was observed and an energy dispersive spectrometer was used to analyze the composition of the deposits. RESULTS The highest levels of lysozyme were adsorbed on both lens materials during the first four days of the procedure and became saturated by day 6. For both lens materials, contamination on the lenses was easily observed by day 30, and the degree of surface roughness was higher. The transmission levels of different light spectrums were reduced showing that the optical characteristics of both lenses were also affected. CONCLUSIONS The results provide in vitro evidence that lysozyme could not be completely removed from orthokeratology lenses. Both surface and optical properties were affected by the deposition of tear film components. However, only one commercial multipurpose care solution was used to clean the lens in this study when the main ingredient was a surfactant, and the results might be different when other care regimens with other key ingredients are used. In addition, whether tear film component deposition might result in increased risks of infection or corneal abrasion will require further investigation.
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Affiliation(s)
- Chen-Ying Su
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
| | - Lung-Kun Yeh
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou, No. 5, Fuxing St., Taoyuan 333, Taiwan; College of Medicine, Chang Gung University, No. 259, Wenhua 1st Rd., Taoyuan 333, Taiwan
| | - Pin-Hsuan Huang
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan
| | - Wen-Pin Lin
- Research and Development Center, Brighten Optix Co., 6F-1, No. 150, Sec.4, Chengde Rd., Shilin Dist., Taipei 111, Taiwan; Department of Optometry, University of Kang Ning, No. 137, Alley 75, Sec. 3, Kang Ning Road, Neihu District, Taipei 11485, Taiwan
| | - Hsueh-Fang Huang
- Research and Development Center, Brighten Optix Co., 6F-1, No. 150, Sec.4, Chengde Rd., Shilin Dist., Taipei 111, Taiwan
| | - Chi-Chun Lai
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou, No. 5, Fuxing St., Taoyuan 333, Taiwan; College of Medicine, Chang Gung University, No. 259, Wenhua 1st Rd., Taoyuan 333, Taiwan
| | - Hsu-Wei Fang
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology. 1, Sec. 3, Zhongxiao E. Rd., Taipei 10608, Taiwan; Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, No. 35, Keyan Road, Zhunan Town, Miaoli County 35053, Taiwan.
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Contact Lens Wear Induces Alterations of Lactoferrin Functionality in Human Tears. Pharmaceutics 2022; 14:pharmaceutics14102188. [PMID: 36297623 PMCID: PMC9612143 DOI: 10.3390/pharmaceutics14102188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/10/2022] [Accepted: 10/12/2022] [Indexed: 11/06/2022] Open
Abstract
The tear film is a complex matrix composed of several molecular classes, from small metal ions to macromolecules. Contact lens (CL) wear can affect the protein homeostasis of the tear film, by accumulating deposits on the CL surface and/or altering their structural and functional properties. This work investigates the effect of CL wear on lactoferrin (Lf), one of the most abundant tear proteins, known as an unspecific biomarker of inflammation. Tears from eight volunteers were collected and analyzed after alternated periods of CL wear and without CL. The experimental approach is to probe Lf into unprocessed human tears by the peculiar fluorescence emission originating from complex formation of Lf with terbium (Tb3+) at the iron-binding sites. The experimental data indicate that CL wear does not significantly affect the total amount of Lf. On the other hand, Lf affinity for Tb3+ is reduced upon CL wear, suggesting relevant changes in Lf structure and possible alterations of protein functionality. Future studies based on this approach will help define CL features (material, lens-care solution, wearing time, etc.) with minimal effects on tear protein activity, in order to obtain more biocompatible and comfortable devices.
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Xue Y, Gao Q, Zhang L. Extended ocular delivery of latanoprost from niosome-laden contact lenses: In vitro characterization and in vivo studies. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2021.103044] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Masoudi S, Willcox M. Development of an enzymatic method for the evaluation of protein deposition on contact lenses. BIOFOULING 2022; 38:84-99. [PMID: 35016572 DOI: 10.1080/08927014.2021.2019225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 12/09/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023]
Abstract
The aim of this study was to evaluate a new digestion method to quantify protein deposition on contact lenses. Four silicone hydrogel and one hydrogel contact lens material were incubated in lactoferrin, lysozyme, immunoglobulin A, and bovine serum albumin solutions at approximate physiological concentrations and temperature. Immobilized trypsin was used to digest the protein deposits from the contact lens surfaces. The total protein absorbed to lenses was extracted and digested using sequencing grade trypsin. The tryptic peptides were quantified using selected reaction monitoring mass spectrometry. The concentration of surface protein deposits was either lower than or the same as the total protein for all lens types and proteins. Immobilised trypsin can digest protein deposits from the surface of contact lenses. This ability to analyse the amount of protein at a contact lens surface may help in elucidating the effect of surface deposition on clinical outcomes during lens wear.
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Affiliation(s)
- Simin Masoudi
- School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia
| | - Mark Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia
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Walsh K, Jones L, Moody K. Addressing common myths and misconceptions in soft contact lens practice. Clin Exp Optom 2021; 105:459-473. [PMID: 34886744 DOI: 10.1080/08164622.2021.2003693] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Advances in contact lens technology over the past 50 years since the commercialisation of the first soft lenses in 1971 have been incredible, with significant changes in contact lens materials, frequency of replacement, care systems and lens designs occurring. However, despite the widespread availability of contact lenses, penetration rates for those who need vision correction remain in the low single digits and many practitioners seem to hold on to concepts around the potential value of contact lenses that appear based in the dim and distant past and are certainly no longer valid today. This review addresses 10 common 'myths and misconceptions' around soft contact lenses using an evidence-based approach that can hopefully dispel some of these incorrect assumptions.
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Affiliation(s)
- Karen Walsh
- Centre for Ocular Research & Education (CORE), School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
| | - Lyndon Jones
- Centre for Ocular Research & Education (CORE), School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada.,Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Shatin, Hong Kong
| | - Kurt Moody
- Johnson & Johnson Vision, Jacksonville, Florida, USA
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8
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Chan VWY, Phan CM, Ngo W, Jones L. Lysozyme Deposition on Contact Lenses in an In Vitro Blink-Simulation Eye Model Versus a Static Vial Deposition Model. Eye Contact Lens 2021; 47:388-393. [PMID: 33840748 DOI: 10.1097/icl.0000000000000784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/07/2021] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate active lysozyme deposition on daily disposable (DD) contact lenses (CL) using a novel in vitro blink model. METHODS Three conventional hydrogel DD CL materials (etafilcon A, omafilcon A, nelfilcon A) and three silicone hydrogel DD CL materials (delefilcon A, senofilcon A, somofilcon A) were tested. The device blink rate was set to 6 blinks/min with a tear flow rate of 1 μL/min using an artificial tear solution (ATS) containing lysozyme and other typical tear film components. After incubation at 2, 4, or 8 hr, lenses were removed, and lysozyme activity was measured. A separate experiment was conducted with lenses incubated in a static vial containing 480 μL of ATS. RESULTS Etafilcon A deposited significantly higher amounts of active lysozyme (402±102 μg/lens) than other lens materials after 8 hr (P<0.0001). Etafilcon A had a higher amount of active lysozyme using the blink model compared with the static vial (P=0.0435), whereas somofilcon A (P=0.0076) and senofilcon A (P=0.0019) had a higher amount of lysozyme activity in the vial compared with the blink model. CONCLUSION The blink model can be tuned to provide quantitative data that closely mimics ex vivo studies and can be used to model deposition of lysozyme on CL materials.
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Affiliation(s)
- Vivian W Y Chan
- Centre for Ocular Research and Education (CORE) (V.W.Y.C., C.-M.P., W.N., L.J.), School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada ; and Centre for Eye and Vision Research (CEVR) (C.-M.P., W.N., L.J.), Hong Kong, China
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9
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Walther H, Lorentz H, Heynen M, Kay L, Jones LW. The Impact of Incubation Conditions on In Vitro Phosphatidylcholine Deposition on Contact Lens Materials. Optom Vis Sci 2021; 98:341-349. [PMID: 33828039 DOI: 10.1097/opx.0000000000001680] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
SIGNIFICANCE Previous in vitro measurements of contact lenses commonly investigate the impact of nonpolar tear film lipids (i.e., sterols). Polar lipids, however, are equally important stabilizing components of the tear film. This research explores and presents further knowledge about various aspects of polar lipid uptake that may impact contact lens performance. PURPOSE This study evaluated the impact of incubation time, lipid concentration, and replenishment of an artificial tear solution (ATS) on the uptake of phosphatidylcholine (PC) onto conventional hydrogel (CH) and silicone hydrogel (SH) contact lens materials. METHODS Four SHs and two CH lens materials (n = 4) were soaked in a complex ATS containing radioactive 14C-PC as a probe molecule. Phosphatidylcholine uptake was monitored at various incubation time points (1, 3, 7, 14, and 28 days), with different ATS lipid concentrations (0.5×, 1×, 2×) and with and without regular replenishment of the ATS. Phosphatidylcholine was extracted from the lenses, processed, and counted by a β counter, and accumulated PC (μg/lens) was extrapolated from standard lipid calibration curves. RESULTS All materials exhibited increasing PC deposition over time. Conventional hydrogel materials showed significantly lower PC uptake rates (P < .001) than any of the SH materials. Increasing lipid concentration in the ATS resulted in increased PC binding onto the contact lens materials (P < .001). Replenishing the ATS every other day, however, impacted the PC deposition differently, showing increased binding (P < .001) on CHs and reduced PC deposition for SH materials (P < .001). CONCLUSIONS Length of incubation, lipid concentration in the ATS, and renewal of the incubation solution all influenced the amount of PC that sorbed onto various lens materials and therefore need to be considered when conducting future in vitro deposition studies.
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Affiliation(s)
| | | | - Miriam Heynen
- Centre for Ocular Research & Education, School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
| | - Lise Kay
- Centre for Ocular Research & Education, School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
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10
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Therapeutic Hydrogel Lenses and the Antibacterial and Antibiotic Drugs Release. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11041931] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The aim of this research was to evaluate the effects of different lens types on the availability and efficacy of anti-inflammatory and antibiotic drugs. Three lens types were examined: (1) nonionic hydrogel lenses; (2) ionic hydrogel lenses; and (3) silicone hydrogel lenses. The lenses were incubated with (a) dexamethasone; (b) betamethasone; (c) bromophenacyl bromide; and (d) chloramphenicol. Drug availability was quantified by gradient HPLC, and chloramphenicol antibacterial activity was quantified by testing the inhibition of Salmonella typhimurium growth on agar. The lens allowing the most abundant passage of betamethasone was the ionic hydrogel lens, followed by the silicone hydrogel lens and nonionic hydrogel lens. The lens allowing the most abundant passage of dexamethasone was the ionic hydrogel lens, but only at 0.5 h and 1 h. Regarding chloramphenicol, the ionic hydrogel lens and silicone hydrogel lens allowed more abundant passage than the nonionic hydrogel lens. These results highlight the relevance of adapting lenses to anti-inflammatory therapy, thus allowing a personalized medical approach.
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11
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Antifouling silicone hydrogel contact lenses via densely grafted phosphorylcholine polymers. Biointerphases 2020; 15:041013. [PMID: 32867505 DOI: 10.1116/6.0000366] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Silicone hydrogel contact lenses (CLs) permit increased oxygen permeability through their incorporation of siloxane functional groups. However, contact lens biofouling can be problematic with these materials; surface modification to increase lens compatibility is necessary for acceptable properties. This work focuses on the creation of an antifouling CL surface through a novel grafting method. A polymer incorporating 2-methacryloyloxyethyl phosphorylcholine (MPC), well known for its antifouling and biomimetic properties, was grafted to the model lens surfaces using surface-initiated atom transfer radical polymerization (SI-ATRP). The SI-ATRP modification generated a unique double-grafted polymeric architecture designed to resist protein adsorption through the presence of a surrounding hydration layer due to the PC groups and steric repulsion due to the density of the grafted chains. The polymer was grafted from model silicone hydrogel CL using a four-step SI-ATRP process. Attenuated total reflectance-Fourier transform infrared spectroscopy and XPS were used to confirm the surface chemical composition at each step of the synthesis. Both the surface wettability and equilibrium water content of the materials increased significantly upon polyMPC modification. The surface water contact angle was as low as 16.04 ± 2.37° for polyMPC-50 surfaces; complete wetting (∼0°) was observed for polyMPC-100 surfaces. A decrease in the protein adsorption by as much as 83% (p < 0.000 36) for lysozyme and 73% (p < 0.0076) for bovine serum albumin was observed, with no significant difference between different polyMPC chain lengths. The data demonstrate the potential of this novel modification process for the creation of extremely wettable and superior antifouling surfaces, useful for silicone hydrogel CL surfaces.
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Ballard Z, Bazargan S, Jung D, Sathianathan S, Clemens A, Shir D, Al-Hashimi S, Ozcan A. Contact lens-based lysozyme detection in tear using a mobile sensor. LAB ON A CHIP 2020; 20:1493-1502. [PMID: 32227027 PMCID: PMC7189769 DOI: 10.1039/c9lc01039d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We report a method for sensing analytes in tear-fluid using commercial contact lenses (CLs) as sample collectors for subsequent analysis with a cost-effective and field-portable reader. In this study we quantify lysozyme, the most prevalent protein in tear fluid, non-specifically bound to CLs worn by human participants. Our mobile reader uses time-lapse imaging to capture an increasing fluorescent signal in a standard well-plate, the rate-of-change of which is used to indirectly infer lysozyme concentration through the use of a standard curve. We empirically determined the best-suited CL material for our sampling procedure and assay, and subsequently monitored the lysozyme levels of nine healthy human participants over a two-week period. Of these participants who were regular CL wearers (6 out of 9), we observed an increase in lysozyme levels from 6.89 ± 2.02 μg mL-1 to 10.72 ± 3.22 μg mL-1 (mean ± SD) when inducing an instance of digital eye-strain by asking them to play a game on their mobile-phones during the CL wear-duration. We also observed a lower mean lysozyme concentration (2.43 ± 1.66 μg mL-1) in a patient cohort with dry eye disease (DED) as compared to the average monitoring level of healthy (no DED) human participants (6.89 ± 2.02 μg mL-1). Taken together, this study demonstrates tear-fluid analysis with simple and non-invasive sampling steps along with a rapid, easy-to-use, and cost-effective measurement system, ultimately indicating physiological differences in human participants. We believe this method could be used in future tear-fluid studies, even supporting multiplexed detection of a panel of tear biomarkers toward improved diagnostics and prognostics as well as personalized mobile-health applications.
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Affiliation(s)
- Zachary Ballard
- Department of Electrical and Computer Engineering, University of California, Los Angeles, USA.
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13
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Efron N, Brennan NA, Chalmers RL, Jones L, Lau C, Morgan PB, Nichols JJ, Szczotka-Flynn LB, Willcox MD. Thirty years of 'quiet eye' with etafilcon A contact lenses. Cont Lens Anterior Eye 2020; 43:285-297. [PMID: 32278644 DOI: 10.1016/j.clae.2020.03.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/27/2020] [Accepted: 03/28/2020] [Indexed: 11/17/2022]
Abstract
Frequent replacement contact lenses made from the etafilcon A hydrogel lens material were introduced onto the market over 30 years ago, and etafilcon A remains the most widely used hydrogel lens material today. Although the prescribing of silicone hydrogel lenses is increasing, millions of lens wearers globally have been wearing hydrogel lenses for many years and exhibit a physiologically-stable 'quiet eye', with a low profile of adverse events. Hydrogel lenses are demonstrated to maintain a low inflammatory response and infection risk profile during daily wear, which in the case of etafilcon A, may be related to its low modulus, and the naturally-protective, anti-microbial, non-denatured lysozyme absorbed into the lens from the tear fluid. Although improved corneal physiology from decreased hypoxia with silicone hydrogel lenses is well accepted, equivalent levels of corneal oxygenation are maintained during daily wear of low to medium powered hydrogel lenses, which do not impede the daily corneal de-swelling process, and do not induce clinically significant changes in ocular health. Therefore, hydrogel lenses remain an important alternative for daily wear in modern contact lens practice.
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Affiliation(s)
- Nathan Efron
- Institute of Health and Biomedical Innovation, School of Optometry and Vision Science, Queensland University of Technology, Australia.
| | | | | | - Lyndon Jones
- Centre for Ocular Research & Education (CORE), School of Optometry & Vision Science, University of Waterloo, Waterloo, ON, Canada
| | - Charis Lau
- Johnson & Johnson Vision, Inc, Jacksonville, FL, USA
| | - Philip B Morgan
- Eurolens Research, Division of Pharmacy and Optometry, The University of Manchester, UK
| | - Jason J Nichols
- The University of Alabama at Birmingham, School of Optometry, Birmingham, AL, USA
| | - Loretta B Szczotka-Flynn
- University Hospitals Eye Institute, University Hospitals Cleveland Medical Center, Department of Ophthalmology & Visual Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Mark D Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney, Australia
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Su CY, Yeh LK, Lai CC, Li KY, Tseng CL, Fang HW. Effects of lysosomal deposition on the friction coefficient of hydrogel contact lenses. Cont Lens Anterior Eye 2019; 43:144-148. [PMID: 31623924 DOI: 10.1016/j.clae.2019.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 07/22/2019] [Accepted: 09/22/2019] [Indexed: 10/25/2022]
Abstract
When a contact lens is in contact with the eyelid and the cornea, tear proteins start to be accumulated on the lens and may subsequently undergo conformational changes. Protein adsorption or conformational changes on the lens may lead to discomfort, red eye, or even inflammatory reactions. Although measuring the friction coefficient of contact lens has been linked to comfort degree in vivo, there is not much research about the effects of tear protein deposition on the friction coefficient of the contact lens. Therefore, we investigated the friction coefficient of three distinct materials of contact lenses in two different lysosomal concentrations. We also studied lysozyme deposition on the lens without the influence of friction. The results demonstrated that although the amount of lysozyme deposition was high on all the materials we tested, it was not corresponded to higher friction coefficient. In addition, we investigated the effect of the contact lens care solution we developed on friction coefficient and lysozyme deposition of three different materials of contact lenses. The results showed that the care solution could reduce the increased friction coefficient caused by high lysosomal concentration. Therefore, we proposed a potential mechanism of why lysosomal deposition may result in high friction coefficient for certain types of hydrogel contact lenses.
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Affiliation(s)
- Chen-Ying Su
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology. 1, Sec. 3, Zhongxiao E. Rd., Taipei, 10608, Taiwan
| | - Lung-Kun Yeh
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou. No. 5, Fuxing St., Taoyuan, 333, Taiwan; College of Medicine, Chang Gung University, No.259, Wenhua 1st Rd., Taoyuan, 333, Taiwan
| | - Chi-Chun Lai
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou. No. 5, Fuxing St., Taoyuan, 333, Taiwan; College of Medicine, Chang Gung University, No.259, Wenhua 1st Rd., Taoyuan, 333, Taiwan
| | - Kuan-Yi Li
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology. 1, Sec. 3, Zhongxiao E. Rd., Taipei, 10608, Taiwan
| | - Ching-Li Tseng
- Graduate Institute of Biomedical Materials and Tissue Engineering, College of Biomedical Engineering, Taipei Medical University, No. 250, Wu-Hsing St., Taipei 110, Taiwan
| | - Hsu-Wei Fang
- Department of Chemical Engineering and Biotechnology, National Taipei University of Technology. 1, Sec. 3, Zhongxiao E. Rd., Taipei, 10608, Taiwan; Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, No. 35, Keyan Road, Zhunan Town, Miaoli County, 35053, Taiwan.
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Cheung S, Subbaraman LN, Ngo W, Jay GD, Schmidt TA, Jones L. Localization of full-length recombinant human proteoglycan-4 in commercial contact lenses using confocal microscopy. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2019; 31:110-122. [PMID: 31594478 DOI: 10.1080/09205063.2019.1678454] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The aim of this study was to determine the sorption location of full-length recombinant human proteoglycan 4 (rhPRG4) tagged with fluorescein isothiocyanate (FITC) to four silicone hydrogel contact lenses [balafilcon A (PureVision, Bausch + Lomb), senofilcon A (Acuvue Oasys, Johnson & Johnson), comfilcon A (Biofinity, CooperVision), lotrafilcon B (Air Optix, Alcon)] and one conventional hydrogel lens [etafilcon A (Acuvue 2, Johnson & Johnson)], using confocal laser scanning microscopy (CLSM). Lenses (n = 3 each) were incubated under two conditions: (1) FITC-rhPRG4 solution at 300 μg/mL and (2) phosphate-buffered saline, for 1 h at 37 °C in darkness with gentle shaking. The central 4 mm of each lens was removed and viewed with the Zeiss 510 CLSM using an argon laser at 488 nm (FITC excitation 495 nm, emission 521 nm). Depth scans were taken at 1 μm intervals to a maximum depth of 100 μm. All lens materials demonstrated sorption of rhPRG4. Both senofilcon A and balafilcon A revealed FITC-rhPRG4 penetration into the bulk of the lens, generally favoring the surface. rhPRG4 was observed exclusively on the surface of lotrafilcon B, with no presence within the bulk of the lens. rhPRG4 was evenly distributed throughout the bulk of the lens, as well as on the surface, for comfilcon A and etafilcon A. The sorption profile of FITC-rhPRG4 was successfully visualized using CLSM in various contact lens materials. The polymer composition, surface treatment and pore size of the material can influence the sorption of rhPRG4.
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Affiliation(s)
- Steven Cheung
- Centre for Ocular Research & Education (CORE), School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
| | - Lakshman N Subbaraman
- Centre for Ocular Research & Education (CORE), School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
| | - William Ngo
- Centre for Ocular Research & Education (CORE), School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
| | - Gregory D Jay
- Department of Emergency Medicine, Alpert Medical School & School of Engineering, Brown University, Providence, Rhode Island, USA
| | - Tannin A Schmidt
- Faculty of Kinesiology & Schulich School of Engineering, University of Calgary, Calgary, Alberta, Canada.,Biomedical Engineering Department, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - Lyndon Jones
- Centre for Ocular Research & Education (CORE), School of Optometry and Vision Science, University of Waterloo, Waterloo, Ontario, Canada
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The influence of protein deposition on contact lens tear film stability. Colloids Surf B Biointerfaces 2019; 180:229-236. [DOI: 10.1016/j.colsurfb.2019.04.051] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/18/2019] [Accepted: 04/24/2019] [Indexed: 11/22/2022]
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Depth Profile Assessment of the Early Phase Deposition of Lysozyme on Soft Contact Lens Materials Using a Novel In Vitro Eye Model. Eye Contact Lens 2018; 44 Suppl 2:S11-S18. [DOI: 10.1097/icl.0000000000000397] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Omali NB, Subbaraman LN, Heynen M, Ng A, Coles-Brennan C, Fadli Z, Jones L. Surface versus bulk activity of lysozyme deposited on hydrogel contact lens materials in vitro. Cont Lens Anterior Eye 2018; 41:329-334. [DOI: 10.1016/j.clae.2018.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 12/15/2017] [Accepted: 03/18/2018] [Indexed: 01/12/2023]
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Inner layer-embedded contact lenses for ion-triggered controlled drug delivery. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2018; 93:36-48. [PMID: 30274068 DOI: 10.1016/j.msec.2018.07.065] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 06/26/2018] [Accepted: 07/23/2018] [Indexed: 11/22/2022]
Abstract
Drug leakage during manufacturing and storage process is the main obstacle hindering the application of contact lenses as the carrier for extended ocular drug delivery. In this study, we have designed a novel inner layer-embedded contact lens capable of ion-triggered drug release for extended ocular drug delivery. Using betaxolol hydrochloride as a drug model, drug-ion exchange resin complex dispersed polymer film was used as an inner layer, and silicone hydrogel was used as an outer layer to fabricate inner layer-embedded contact lens. Influence of composition of the inner film and crosslinking degree of the outer hydrogel on drug release profile was studied and optimized for weekly use. The ion-triggered drug eluting property enables the inner layer-embedded contact lens being stable when stored in distilled water at 5 °C for at least 30 days with ignorable drug loss and negligible changes in drug release kinetics. In vivo pharmacokinetic study in rabbits showed sustained drug release for over 168 h in tear fluid, indicating significant improvement in drug corneal residence time. A level A IVIVC was established between in vitro drug release and in vivo drug concentration in tear fluid. In conclusion, this inner layer embedded contact lens design could be used as a platform for extended ocular drug delivery with translational potential for both anterior and posterior ocular disease therapy.
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Heynen M, Babaei Omali N, Fadli Z, Coles-Brennan C, Subbaraman LN, Jones L. Selectivity and localization of lysozyme uptake in contemporary hydrogel contact lens materials. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2017; 28:1351-1364. [DOI: 10.1080/09205063.2017.1327751] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Miriam Heynen
- Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
| | - Negar Babaei Omali
- Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
| | - Zohra Fadli
- Johnson & Johnson Vision Care Inc., Jacksonville, FL, USA
| | | | - Lakshman N. Subbaraman
- Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
| | - Lyndon Jones
- Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Waterloo, Canada
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A Review of Techniques to Measure Protein Sorption to Soft Contact Lenses. Eye Contact Lens 2017; 43:276-286. [PMID: 28198731 DOI: 10.1097/icl.0000000000000366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To compare and critically evaluate a variety of techniques to measure the quantity and biological activity of protein sorption to contact lenses over short time periods. METHODS A literature review was undertaken investigating the major techniques to measure protein sorption to soft contact lens materials, with specific reference to measuring protein directly on lenses using in situ, ex situ, protein structural, and biological activity techniques. RESULTS The use of in situ techniques to measure protein quantity provides excellent sensitivity, but many are not directly applicable to contact lenses. Many ex situ techniques struggle to measure all sorbed proteins, and these measurements can have significant signal interference from the lens materials themselves. Techniques measuring the secondary and tertiary structures of sorbed proteins have exhibited only limited success. CONCLUSIONS There are a wide variety of techniques to measure both the amount of protein and the biological activity of protein sorbed to soft contact lens materials. To measure the mass of protein sorbed to soft contact lenses (not just thin films) over short time periods, the method of choice should be I radiolabeling. This technique is sensitive enough to measure small amounts of deposited protein, provided steps are taken to limit and measure any interaction of the iodine tracer with the materials. To measure the protein activity over short time periods, the method of choice should be to measure the biological function of sorbed proteins. This may require new methods or adaptations of existing ones.
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Omali NB, Subbaraman LN, Coles-Brennan C, Fadli Z, Jones LW. Biological and Clinical Implications of Lysozyme Deposition on Soft Contact Lenses. Optom Vis Sci 2015; 92:750-7. [PMID: 26002002 PMCID: PMC5638422 DOI: 10.1097/opx.0000000000000615] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 02/17/2015] [Indexed: 12/28/2022] Open
Abstract
Within a few minutes of wear, contact lenses become rapidly coated with a variety of tear film components, including proteins, lipids, and mucins. Tears have a rich and complex composition, allowing a wide range of interactions and competitive processes, with the first event observed at the interface between a contact lens and tear fluid being protein adsorption. Protein adsorption on hydrogel contact lenses is a complex process involving a variety of factors relating to both the protein in question and the lens material. Among tear proteins, lysozyme is a major protein that has both antibacterial and anti-inflammatory functions. Contact lens materials that have high ionicity and high water content have an increased affinity to accumulate lysozyme during wear, when compared with other soft lens materials, notably silicone hydrogel lenses. This review provides an overview of tear film proteins, with a specific focus on lysozyme, and examines various factors that influence protein deposition on contact lenses. In addition, the impact of lysozyme deposition on various ocular physiological responses and bacterial adhesion to lenses and the interaction of lysozyme with other tear proteins are reviewed. This comprehensive review suggests that deposition of lysozyme on contact lens materials may provide a number of beneficial effects during contact lens wear.
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Kruh JN, Kruh-Garcia NA, Foster CS. Evaluation of the Effect ofN-Acetylcysteine on Protein Deposition on Contact Lenses in Patients with the Boston Keratoprosthesis Type I. J Ocul Pharmacol Ther 2015; 31:314-22. [DOI: 10.1089/jop.2015.0010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jonathan N. Kruh
- Massachusetts Eye Research and Surgery Institution, Cambridge, Massachusetts
- Ocular Immunology and Uveitis Foundation, Cambridge, Massachusetts
| | - Nicole A. Kruh-Garcia
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado
| | - C. Stephen Foster
- Massachusetts Eye Research and Surgery Institution, Cambridge, Massachusetts
- Ocular Immunology and Uveitis Foundation, Cambridge, Massachusetts
- Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
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Hall B, Heynen M, Jones LW, Forrest JA. Analysis of Using I125Radiolabeling for Quantifying Protein on Contact Lenses. Curr Eye Res 2015; 41:456-65. [DOI: 10.3109/02713683.2015.1031350] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Hall B, Jones L, Forrest JA. Kinetics of Competitive Adsorption between Lysozyme and Lactoferrin on Silicone Hydrogel Contact Lenses and the Effect on Lysozyme Activity. Curr Eye Res 2014; 40:622-31. [PMID: 25251834 DOI: 10.3109/02713683.2014.946518] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To determine the effect of competitive adsorption between lysozyme and lactoferrin on silicone hydrogel contact lenses and the effect on lysozyme activity. METHODS Three commercially available silicone hydrogel contact lens materials (senofilcon A, lotrafilcon B and balafilcon A) were examined, for time points ranging from 10 s to 2 h. Total protein deposition was determined by I(125) radiolabeling of lysozyme and lactoferrin, while the activity of lysozyme was determined by a micrococcal activity assay. RESULTS Senofilcon A and balafilcon A did not show any relevant competitive adsorption between lysozyme and lactoferrin. Lotrafilcon B showed reduced protein deposition due to competitive adsorption for lactoferrin at all time points and lysozyme after 7.5 min. Co-adsorption of lactoferrin and lysozyme decreased the activity of lysozyme in solution for senofilcon A and lotrafilcon B, but co-adsorption had no effect on the surface activity of lysozyme for all lens types investigated. CONCLUSIONS Competition between lysozyme and lactoferrin is material specific. Co-adsorption of lysozyme and lactoferrin does not affect the activity of surface-bound lysozyme but can reduce the activity of subsequently desorbed lysozyme.
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Affiliation(s)
- Brad Hall
- Centre for Contact Lens Research, School of Optometry and Vision Science , Waterloo, Ontario , Canada and
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Hall B, Phan CM, Subbaraman L, Jones LW, Forrest J. Extraction versus In Situ Techniques for Measuring Surface-Adsorbed Lysozyme. Optom Vis Sci 2014; 91:1062-70. [DOI: 10.1097/opx.0000000000000354] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Elkins CM, Qi QM, Fuller GG. Corneal cell adhesion to contact lens hydrogel materials enhanced via tear film protein deposition. PLoS One 2014; 9:e105512. [PMID: 25144576 PMCID: PMC4140805 DOI: 10.1371/journal.pone.0105512] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/21/2014] [Indexed: 12/03/2022] Open
Abstract
Tear film protein deposition on contact lens hydrogels has been well characterized from the perspective of bacterial adhesion and viability. However, the effect of protein deposition on lens interactions with the corneal epithelium remains largely unexplored. The current study employs a live cell rheometer to quantify human corneal epithelial cell adhesion to soft contact lenses fouled with the tear film protein lysozyme. PureVision balafilcon A and AirOptix lotrafilcon B lenses were soaked for five days in either phosphate buffered saline (PBS), borate buffered saline (BBS), or Sensitive Eyes Plus Saline Solution (Sensitive Eyes), either pure or in the presence of lysozyme. Treated contact lenses were then contacted to a live monolayer of corneal epithelial cells for two hours, after which the contact lens was sheared laterally. The apparent cell monolayer relaxation modulus was then used to quantify the extent of cell adhesion to the contact lens surface. For both lens types, lysozyme increased corneal cell adhesion to the contact lens, with the apparent cell monolayer relaxation modulus increasing up to an order of magnitude in the presence of protein. The magnitude of this increase depended on the identity of the soaking solution: lenses soaked in borate-buffered solutions (BBS, Sensitive Eyes) exhibited a much greater increase in cell attachment upon protein addition than those soaked in PBS. Significantly, all measurements were conducted while subjecting the cells to moderate surface pressures and shear rates, similar to those experienced by corneal cells in vivo.
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Affiliation(s)
- Claire M. Elkins
- Department of Chemical Engineering, Stanford University, Stanford, California, United States of America
- * E-mail:
| | - Qin M. Qi
- Department of Chemical Engineering, Stanford University, Stanford, California, United States of America
| | - Gerald G. Fuller
- Department of Chemical Engineering, Stanford University, Stanford, California, United States of America
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Abstract
PURPOSE To analyze the impact of intermittent air exposure on the in vitro deposition of two radioactive lipids on various contact lens (CL) materials, using a custom-designed model blink cell. METHODS Six different CL materials (balafilcon A, lotrafilcon B, comfilcon A, senofilcon A, etafilcon A, and omafilcon A) were mounted on the model blink cell pistons, which cycled the lenses in and out of a complex artificial tear solution (ATS) that contained a trace amount of C-cholesterol or C-phosphatidylcholine. For the short-term experiment, air-exposed lenses were continuously cycled in and out of the ATS for 10 h. Longer term incubations for 6 days were tested with lotrafilcon B and balafilcon A materials incubated in C-cholesterol ATS. The air-exposed CLs were cycled for 14 h then submerged for 10 h each day. For both experiments, the control lenses were submerged for the entire test period. After incubation, lenses were processed, and deposited masses were quantified. RESULTS Exposure to air resulted in increased amounts of cholesterol deposited by 1.6 to 4.3 fold on omafilcon A, balafilcon A, comfilcon A, and senofilcon A (p ≤ 0.03) compared with submerged lenses. No differences in deposition were observed for etafilcon A and lotrafilcon B (p > 0.05). The longer term incubation of lotrafilcon B and balafilcon A showed statistically significant increases in cholesterol deposition for both air-exposed lens materials (p < 0.02) with the increase in deposition 1.8× and 2.8×, respectively. For phosphatidylcholine, all air-exposed lenses had increased masses of deposition. These deposits were statistically greater by 1.1 to 1.6 times for omafilcon A, comfilcon A, lotrafilcon B, and senofilcon A (p < 0.04), but not statistically different for etafilcon A or balafilcon A (p > 0.05). CONCLUSIONS This study found that lipid deposition profiles are CL material dependent and that intermittent air exposure can influence the mass of lipid deposited.
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Ng A, Heynen M, Luensmann D, Subbaraman LN, Jones L. Impact of tear film components on the conformational state of lysozyme deposited on contact lenses. J Biomed Mater Res B Appl Biomater 2013; 101:1172-81. [PMID: 23564739 DOI: 10.1002/jbm.b.32927] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 12/06/2012] [Accepted: 01/30/2013] [Indexed: 11/07/2022]
Affiliation(s)
- Alan Ng
- Centre for Contact Lens Research; School of Optometry and Vision Science; University of Waterloo; 200 University Avenue West Waterloo Ontario N2L 3G1 Canada
| | - Miriam Heynen
- Centre for Contact Lens Research; School of Optometry and Vision Science; University of Waterloo; 200 University Avenue West Waterloo Ontario N2L 3G1 Canada
| | - Doerte Luensmann
- Centre for Contact Lens Research; School of Optometry and Vision Science; University of Waterloo; 200 University Avenue West Waterloo Ontario N2L 3G1 Canada
| | - Lakshman N. Subbaraman
- Centre for Contact Lens Research; School of Optometry and Vision Science; University of Waterloo; 200 University Avenue West Waterloo Ontario N2L 3G1 Canada
| | - Lyndon Jones
- Centre for Contact Lens Research; School of Optometry and Vision Science; University of Waterloo; 200 University Avenue West Waterloo Ontario N2L 3G1 Canada
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Ng A, Heynen M, Luensmann D, Subbaraman LN, Jones L. Optimization of a fluorescence-based lysozyme activity assay for contact lens studies. Curr Eye Res 2013; 38:252-9. [PMID: 23373676 DOI: 10.3109/02713683.2012.757324] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To optimize a fluorescence-based lysozyme activity assay to investigate the conformational state of lysozyme in solution and to determine the impact of extraction and evaporation procedures and the possible interference of contact lens materials on lysozyme activity. METHODS The fluorescence-based lysozyme activity assay, Enzchek (Molecular Probes Inc, Eugene, OR) which utilizes fluorescently quenched Micrococcus lysodeikticus, was compared to the gold standard, classical lysozyme turbidity assay, using four differently concentrated lysozyme samples (20, 10, 5.0 and 2.0 ng/µL). Furthermore, six differently concentrated lysozyme samples (2.0, 1.0, 0.5, 0.25, 0.125 and 0.01 µg/µL) were quantified using the fluorescence-based assay in the presence of extraction solvents consisting of 0.2% and 0.02% trifluroacetic acid/acetonitrile and following evaporation procedures. RESULTS A standard curve was generated by the fluorescence-based assay ranging from 2 to 150 ng. The total active lysozyme quantified in the four lysozyme samples was not significantly different between the two assays (p > 0.05) and the concordance correlation coefficient was determined to be 0.995. However an average discrepancy between the two assays was found to be 0.474 ng, with the turbidity assay typically reporting higher active lysozyme measurements. The sensitivity of the fluorescence-based assay was higher than the classical turbidity assay when quantifying 20 ng or less active lysozyme. Following the extraction and evaporation procedures and the addition of lens extracts, the total active lysozyme recovered was 95% or greater. CONCLUSIONS In comparison to the classical turbidity assay, the fluorescence-based assay is a very sensitive method, making it a favorable technique, particularly when studying contact lens materials that deposit relatively low levels of lysozyme.
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Affiliation(s)
- Alan Ng
- Centre for Contact Lens Research, School of Optometry and Vision Science, University of Waterloo, Waterloo, ON, Canada.
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Hall B, Jones L, Forrest JA. Measuring the kinetics and activity of adsorbed proteins:In vitrolysozyme deposited onto hydrogel contact lenses over short time periods. J Biomed Mater Res A 2012; 101:755-64. [DOI: 10.1002/jbm.a.34357] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 06/05/2012] [Accepted: 06/20/2012] [Indexed: 11/11/2022]
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Lorentz H, Heynen M, Tran H, Jones L. Using anIn VitroModel of Lipid Deposition to Assess the Efficiency of Hydrogen Peroxide Solutions to Remove Lipid from Various Contact Lens Materials. Curr Eye Res 2012; 37:777-86. [DOI: 10.3109/02713683.2012.682636] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Weeks A, Boone A, Luensmann D, Jones L, Sheardown H. The effects of hyaluronic acid incorporated as a wetting agent on lysozyme denaturation in model contact lens materials. J Biomater Appl 2012; 28:323-33. [PMID: 22561981 DOI: 10.1177/0885328212446936] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Conventional and silicone hydrogels as models for contact lenses were prepared to determine the effect of the presence of hyaluronic acid on lysozyme sorption and denaturation. Hyaluronic acid was loaded into poly(2-hydroxyethyl methacrylate) and poly(2-hydroxyethyl methacrylate)/TRIS--methacryloxypropyltris (trimethylsiloxy silane) hydrogels, which served as models for conventional and silicone hydrogel contact lens materials. The hyaluronic acid was cross-linked using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide in the presence of dendrimers. Active lysozyme was quantified using a Micrococcus lysodeikticus assay while total lysozyme was determined using 125-I radiolabeled protein. To examine the location of hyaluronic acid in the gels, 6-aminofluorescein labeled hyaluronic acid was incorporated into the gels using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide chemistry and the gels were examined using confocal laser scanning microscopy. Hyaluronic acid incorporation significantly reduced lysozyme sorption in poly(2-hydroxyethyl methacrylate) (p < 0.00001) and poly(2-hydroxyethyl methacrylate)/TRIS--methacryloxypropyltris (trimethylsiloxy silane) (p < 0.001) hydrogels, with the modified materials sorbing only 20% and 16% that of the control, respectively. More importantly, hyaluronic acid also decreased lysozyme denaturation in poly(2-hydroxyethyl methacrylate) (p < 0.005) and poly(2-hydroxyethyl methacrylate)/TRIS--methacryloxypropyltris (trimethylsiloxy silane) (p < 0.02) hydrogels. The confocal laser scanning microscopy results showed that the hyaluronic acid distribution was dependent on both the material type and the molecular weight of hyaluronic acid. This study demonstrates that hyaluronic acid incorporated as a wetting agent has the potential to reduce lysozyme sorption and denaturation in contact lens applications. The distribution of hyaluronic acid within hydrogels appears to affect denaturation, with more surface mobile, lower molecular weight hyaluronic acid being more effective in preventing denaturation.
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Affiliation(s)
- Andrea Weeks
- School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada
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Weeks A, Subbaraman LN, Jones L, Sheardown H. The Competing Effects of Hyaluronic and Methacrylic Acid in Model Contact Lenses. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 23:1021-38. [DOI: 10.1163/092050611x569060] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Andrea Weeks
- a School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada L8S 4L7
| | | | - Lyndon Jones
- c School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada L8S 4L7; Department of Chemical Engineering, McMaster University, Hamilton, ON, Canada L8S 4L7; Centre for Contact Lens Research, University of Waterloo, Waterloo, ON, Canada
| | - Heather Sheardown
- d School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada L8S 4L7; Department of Chemical Engineering, McMaster University, Hamilton, ON, Canada L8S 4L7; Centre for Contact Lens Research, University of Waterloo, Waterloo, ON, Canada.
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Chow LM, Subbaraman LN, Sheardown H, Jones L. Kinetics of in Vitro Lactoferrin Deposition on Silicone Hydrogel and FDA Group II and Group IV Hydrogel Contact Lens Materials. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 20:71-82. [PMID: 19105901 DOI: 10.1163/156856208x393509] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Lisa M. Chow
- a Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Lakshman N. Subbaraman
- b Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
| | - Heather Sheardown
- c Department of Chemical Engineering, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4L8
| | - Lyndon Jones
- d Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
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van Beek M, Weeks A, Jones L, Sheardown H. Immobilized hyaluronic acid containing model silicone hydrogels reduce protein adsorption. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 19:1425-36. [PMID: 18973721 DOI: 10.1163/156856208786140364] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Mark van Beek
- a Department of Chemical Engineering, McMaster University, 1280 Main St. West, Hamilton, ON, Canada L8S 4L7
| | - Andrea Weeks
- b School of Biomedical Engineering, McMaster University, 1280 Main St. West, Hamilton, ON, Canada L8S 4L7
| | - Lyndon Jones
- c Department of Chemical Engineering, McMaster University, 1280 Main St. West, Hamilton, ON, Canada L8S 4L7; Centre for Contact Lens Research, University of Waterloo, Waterloo, ON, Canada
| | - Heather Sheardown
- d Department of Chemical Engineering, McMaster University, 1280 Main St. West, Hamilton, ON, Canada L8S 4L7; School of Biomedical Engineering, McMaster University, 1280 Main St. West, Hamilton, ON, Canada L8S 4L7; Centre for Contact Lens Research, University of Waterloo, Waterloo, ON, Canada
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Subbaraman LN, Jones L. Kinetics of Lysozyme Activity Recovered from Conventional and Silicone Hydrogel Contact Lens Materials. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 21:343-58. [DOI: 10.1163/156856209x415873] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Lakshman N. Subbaraman
- a Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
| | - Lyndon Jones
- b Centre for Contact Lens Research, School of Optometry, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
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