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Scientific Presentations
2023
Chan V, Drolle E, Phan CM, Hui A, Shi C, Subbaraman L, Wu J, Jones L. Evaluating the activity of lysozyme deposited on contemporary reusable silicone hydrogel contact lenses using an in vitro eye model The Association for Research in Vision and Ophthalmology, New Orleans, LA, USA, 2023 [ Show Abstract ][ PDF ]
Purpose: To evaluate lysozyme activity (LA) on five contemporary reusable silicone hydrogel contact lens (CL)materials over their proposed wear period using an advanced in vitro blink model.
Methods: Five CL materials (lotrafilcon B, samfilcon A, comfilcon A, senofilcon A, and serafilcon A) were cycled daily for 16h on an eye model, followed by 8h of soaking in OPTI-FREE PureMoist, to mimic a typical wear cycle. An artificial tear solution containing physiologically representative proteins and lipids was delivered to the model at a rate of 1.2-2.1μl/min. The model includes an artificial eyelid that blinks at a rate of 6blinks/min, which was kept at room temperature and humidity above 50%. Serafilcon A and senofilcon A were tested over 14 days, whereas the other CLs were evaluated for 30 days. At specified time intervals, including after 1, 7, 14 and 30 days, CLs were removed from the model and lysozyme extracted using a solvent containing acetonitrile and trifluoroacetic acid. The LA from the extracts were then evaluated using a micrococcal absorbance assay.
Results: Overall, LA decreased over time, reaching non-detectable levels by day 30 (p<0.05). Serafilcon A (13.9 ± 7.8μg/lens), and samfilcon A (9.6 ± 2.3μg/lens), had the highest LA after 1 day, followed by comfilcon A (4.7 ± 1.8μg/lens), lotrafilcon B (3.3 ± 1.6μg/lens), and senofilcon A (2.2 ± 3.7μg/lens). By day 7, LA for the weekly replacement lens, serafilcon A, decreased to 0.5 ± 0.6μg/lens. By day 14, LA for the biweekly replacement lens, senofilcon A, decreased to 0.6 ± 0.7μg/lens. Lotrafilcon B, samfilcon A, and comfilcon A, all monthly replacement lenses, decreased in activity by day 30 (0.1 ± 0.2μg/lens, 0.5 ± 0.7μg/lens, 0.0 ±0.0μg/lens respectively).
Conclusions: Deposition of biologically active lysozyme has been proposed to be an important factor for biocompatible CL wear. A decline in activity over time as the deposited protein becomes denatured may impact overall CL performance and has been linked to reduced comfort. LA decreases over time and reaches near zero for all lens types by the end of their proposed wearing period, confirming that they should be replaced within their specified replacement intervals. Compared to simple in vitro vial models, using an advanced blink model for CL deposition testing aims to provide more physiologically relevant results prior to clinical testing.
Ho B, Phan CM, Ramasamy M, Hui A, Jones L. PDMS microfluidic devices fabricated from commercial 3D printers support growth of viable HCECs and enable cell biological assays for low-cost high-throughput screening The Association for Research in Vision and Ophthalmology, New Orleans, LA, USA, April, 2023 [ Show Abstract ]
Purpose: To integrate human corneal epithelial cells (HCECs) into a PDMS microfluidic chip fabricated from a novel 3D printing method to perform cell biological assays.
Introduction: The advent of microfluidic devices has enabled tight control over the physical and chemical cellular environment in vitro, while allowing for large-scale imaging and biochemical reactions at single-cell resolution. These devices are capable of miniaturizing assays to the microliter and nanoliter range, thereby increasing assay throughput with high sensitivity, a feature that is highly advantageous in high-throughput cell-based screens. Polydimethylsiloxane (PDMS) has been widely used in microfluidics devices due to its optical clarity and non-toxicity to cells, among other desirable features. However, the fabrication of PDMS devices traditionally requires specialized facilities and instruments. Additionally, PDMS itself is highly hydrophobic and does not support mammalian cellular viability and growth.
Methods: PDMS devices were cured in 3D-printed moulds generated using the FormLabs stereolithography (SLA) printer (FormLabs 3B+, FormLabs, Somerville, MA). These devices were sterilized by autoclaving, and coated with 0.01% polydopamine (PDA) and 20μg/mL collagen. HCECs were seeded onto the device, and allowed to grow for 18-36 hours in DMEM/F12 media at 37oC. HCECs were imaged by light microscopy, and viability was assessed by alamarBlue assays.
Results: Here, we present a novel and simple method of generating PDMS microfluidic devices suitable for mammalian cell biology assays using commercial 3D printing. We show that PDMS devices coated with polydopamine (PDA) support the growth of human corneal epithelial cells (HCECs) that are metabolically active (~60-90% viability) and are comparable to HCECs cultured in standard tissue culture plastic consumables. Finally, HCECs cultured in our devices are capable of growth with fluid flow rates of up to 1mm/s.
Conclusion: Our study shows that PDMS devices manufactured through the aid of a novel 3D printing pipeline support the growth of HCECs. We aim to utilize these microfluidic devices as a tool to screen different compounds and formulations while assessing cellular viability and acquiring high resolution microscopic and fluorescence images of HCECs.
Hui A. Commercialized Ocular Drug Delivery Devices XXV Biennial Meeting of the International Society for Eye Research, Feb 21, 2023 [ Show Abstract ]
The goal of creating a sustained drug delivery device for the anterior or posterior segment has been approached from numerous avenues, from inserts to contact lenses and punctal plugs. The utility of a device which can sustain drug release allows for the potential to increase patient compliance as well as improve clinical outcomes, as agents are able to be maintained at appropriate concentrations for desired periods with less administration. This presentation will discuss drug releasing devices for the eye which have reached commercialization. The indications for these devices, their reported effectiveness and known adverse reactions will be discussed. The experience on the use of the devices after they have been released on to the market will also be discussed, as well as their current clinical usage in contemporary eye care management.
Hui A, Heynen M, Chan V, Mirzapour P, Enstone D, Saad M, George M, Ngo W, Jones L. The impact of RGP care solutions on ISO measured lens parameters and the protein deposition on RGP lenses when managed with a hydrogen peroxide care solution Global Specialty Lens Symposium, Las Vegas, Jan 20, 2023 [ PDF ]
Phan CM, Ramasamy M, Ho B, Hui A, Jones L. Fabrication of a microfluidic chip using 3D printing for evaluating ocular cytotoxicity The Association for Research in Vision and Ophthalmology, New Orleans, LA, USA, April, 2023 [ Show Abstract ][ PDF ]
Purpose: To develop a PDMS (polydimethyl siloxane) microfluidic chip to evaluate ocular cytotoxicity with ophthalmic formulations and materials.
Methods: The microfluidic chip was designed using CAD software (FreeCAD), and the moulds of the chips were printed using (1) a stereolithography (SLA) and (2) digital light processing (DLP) 3D printer. The printed moulds were washed with isopropyl alcohol (IPA), UV-cured for 1-hour at 60oC, followed by heating in an oven at 120oC for 2 hours to remove any unreacted polymers. The surface of the chips was smoothed with sandpaper with increasing grit, followed by an application of nail polish. The moulds were then cast with PDMS, a gas-permeable and clear polymer commonly used for the fabrication of microfluidic chips. The moulds and chips were imaged using SEM (scanning electron microscopy). The light transmittance of the chips was also measured. The PDMS top half of the chip was adhered to a microscope slide using medical-grade double-sided tape. For a pilot study, the PDMS chips were sterilized via autoclaving, coated with 0.1% polydopamine to improve their surface wettability, and then seeded with immortalized human corneal epithelial cells (HCEC). After 2 days of incubation in a nutrient media broth (no flow), cell adhesion and growth were evaluated using light microscopy.
Results: Both 3D printers were able to print moulds with high resolution, with channel dimensions as low as 50 µm, and with faster print times for the DLP printer. SEM images revealed that moulds that were both sanded and had a nail coating were significantly smoother than the original 3D-printed moulds. The chips cast from the polished moulds were transparent, with >85% transmittance from 450-700 nm, and could be used to image cells through a microscope. The microfluidic chips were able to handle flow rates up to 1 mL/min for 24 hours without any signs of leakage. HCEC cells were able to adhere and grow on the coated PDMS microfluidic chip after 2 days.
Conclusion: This study showed that SLA and DLP printers could be used to fabricate PDMS microfluidic chips as a low-cost rapid prototyping approach. The fabricated chips were clear and could be used to incorporate HCEC cells. Future work will examine the viability of cells under different flow rates and shear stress conditions on these chips.
2014
Hui A, Jones L. Uptake and release of atropine and pirenzepine from commercial hydrogel and silicone hydrogel contact lens materials Optom Vis Sci 2014;91: E-abstract 140059
Hui A, Jones L. Material Properties of Antibiotic Releasing Contact Lenses Invest Ophthalmol Vis Sci 2014;55: E-abstract 4642 [ PDF ]
Hui A, Willcox M, Jones L. Material properties and antimicrobial efficacy of novel antibacterial silicone hydrogel contact lenses BCLA Clinical Conference and Exhibition, 2014 [ PDF ]
2013
Hui A, Jones L. Uptake and release of ciprofloxacin and dexamethasone from commercial contact lens materials Invest Ophthalmol Vis Sci 2013;54: E-Abstract 1086
Hui A, Jones L. Release of ciprofloxacin and dexamethasone from commercial contact lens materials Canadian Optometry Schools Research Conference, Waterloo, Canada, 2013
Hui A, Willcox M, Jones L. In vitro evaluation of antimicrobial activity of novel ciprofloxacin releasing silicone hydrogels Optom Vis Sci 2013;90: E-Abstract130748
Hui A, Willcox M, Jones L. In vitro evaluation of the antimicrobial properties of a novel silicone hydrogel material designed for the sustained release of the antibiotic ciprofloxacin NSERC 20/20 Meeting, 2013
Hui A, Willcox M, Jones L. In vitro evaluation of the antimicrobial properties of a novel silicone hydrogel material designed for the sustained release of the antibiotic ciprofloxacin ISCLR conference, Kyoto, Japan, 2013
Jones L, Hui A. Release of ciprofloxacin and dexamethasone from commercial contact lens materials Contact Lens & Anterior Eye 2013;36, S2:e38
Jones L, Hui A. Antibiotic drug delivery via contact lenses 20/20 NSERC ophthalmic materials conference, Niagara Falls, Canada, 2013
2012
Soluri A, Hui A, Jones L. Ocular Delivery Of Ketotifen Fumarate By Silicone Hydrogel And Conventional Hydrogel Contact Lens Materials Invest Ophthalmol Vis Sci 2012;53:ARVO E-Abstract 6101
2011
Hui A, Boone A, Jones L. Uptake and Release of Ciprofloxacin and Dexamethasone from Commercially Available Conventional and Silicone Hydrogel Materials 15th Symposium on the Material Science and Chemistry of Contact Lenses (New Orleans, USA), 2011
Hui A, Sheardown H, Jones L. Molecular imprinted silicone hydrogel materials for ciprofloxacin drug delivery Optom Vis Sci 2011;88: E-abstract 110429
Hui A, Sheardown H, Jones LW. Molecular Imprinted Silicone Hydrogels for Ciprofloxacin Drug Delivery International Society for Contact Lens Research (ISCLR) Meeting (Napa Valley, California), 2011
Hui A, Weeks A, Sheardown H, Jones L. Novel silicone hydrogel contact lens materials for ciprofloxacin drug delivery Invest Ophthalmol Vis Sci 2011;52:E-Abstract 6531
2010
Hui A, Weeks AK, Sheardown H, Jones L. Novel contact lens materials for ciprofloxacin drug delivery 7th Canadian University Conference in Optometry (Montreal, Canada), 2010
Hui A, Weeks AK, Sheardown H, Jones L. Novel contact lens materials for ciprofloxacin drug delivery 20:20 National Science and Engineering Council Network Meeting (Horseshoe Valley, Ontario, Canada), 2010
2009
Dalton K, Hui A, Jones L, Simpson T. Diurnal variation in tear film osmolality, stability, ocular surface redness and ocular comfort Contact Lens & Anterior Eye 2009;32, 5:220
2008
Hui A, Boone A, Jones L. Uptake and release of Ciprofloxacin-HCl from conventional and silicone hydrogel contact lens materials Rising Stars of Research Conference (Alberta, Canada), 2008
Continuing Education Presentations
2023
Hui A. Sustained Drug Delivery Devices for the Eye American Academy of Optometry, New Orleans, October 14, 2023 [ Show Abstract ]
This presentation will detail the barriers to effective pharmacokinetics for drug delivery to the eye with currently available therapies such as eye drops, and provide supportive evidence for the need for sustained drug delivery in appropriate instances. Commercially available, drug releasing devices will be presented, and their indications and experience when used clinically will be discussed. How ocular sustained drug delivery devices may be incorporated into the practice of today as well as the practice of the future will also be presented and discussed within the context of currently available and developing devices.
2022
Hui A. Evaluation of novel contact lens materials 10th Canadian Optometry School Research Conference, Montréal, Canada, Dec 4, 2022
Hui A. Help Satisfy the Ocular Allergy Contact Lens Wearer Canadian Association of Optometrists Congress, St John's, Newfoundland, Jul 8, 2022
Professional Publications
2023
Hui A. Recent Strategies to Manage CLD Contact Lens Spectrum 2023;38, July: 10-11
2022
Hui A. CL drug delivery for dry eye treatment Contact Lens Spectrum 2022;37, July: 12-13
2012
Hui A. Contact lenses for drug delivery – overview and recent developments ContactLensUpdate.com 2012
Hui A. Complications when you least expect them Contact Lens Spectrum 2012;27, Sept: 30-55
Nguyen D, Hui A, Weeks A, Heynen M, Martell E, Sheardown H, Jones L. Release of Ciprofloxacin-HCl and Dexamethasone phosphate by soft contact lens materials loaded with Hyaluronic Acid Materials 2012;5684-698
2011
Hui A.. The Future of Fitting: Predictions and contact lens innovations right around the corner Optometric Management 2011, August:
2010
Hui A, Jones L. Contact lenses offer effective drug delivery Optometry Pharma 2010, Sept: 26-27
