Year: 2009
Type: dissertation
Abstract: Purpose: \nTo locate protein sorption on the surface and inside the matrix of soft contact lens materials and intraocular lenses (IOL). \n \nMethods: \nThe proteins albumin and lysozyme were investigated as they are highly abundant in blood serum and tears, respectively. Proteins were conjugated with organic fluorescent probes and using confocal laser scanning microscopy (CLSM) the sorption profile to contact lenses and IOL could be determined. Radiolabeled protein was used for quantification purposes. \n•\tAlbumin sorption to etafilcon A and lotrafilcon B was determined (Chapter 3) \n•\tDifferent fluorescent probes were used for conjugation and the impact on albumin sorption behaviour was investigated (Chapter 4) \n•\tLysozyme sorption to nine different pHEMA-based and silicone hydrogel contact lenses was determined using two fluorescent probes (Chapter 5) \n•\tThe efficiency of protein removal from contact lenses using contact lens care regimens was investigated (Chapter 6) \n•\tAlbumin sorption to IOL materials was quantified and imaged using a modified CLSM technique (Chapter 7) \n \n \nResults: \nAlbumin and lysozyme sorption profiles differed between materials, and were influenced by the fluorescent probes used for conjugation. After one day of incubation, both proteins could be located within all contact lens materials, except for lotrafilcon A and lotrafilcon B, which primarily allowed deposition on the lens surface. An increase in protein accumulation was found for most materials over the maximum investigated period of 14 days, using CLSM and radiolabel techniques. The efficiency of contact lens care regimens to remove lysozyme and albumin depended on the lens material, care regimen and protein type investigated. \nPMMA and silicone IOLs showed protein exclusively on the surface, while a hydrophilic acrylic IOL allowed penetration into the lens matrix over time. Despite the albumin penetration depth into hydrophilic acrylic, the highest albumin levels were determined for the silicone IOL. \n\t \nConclusions: \nCLSM provides detailed information that can describe the protein distribution in transparent biomaterials, with scanning depths up to a few hundred microns. However, the CLSM data are primarily of qualitative value, which necessitates a quantitative technique (e.g. radiolabeling) to determine the total protein content.
Source: UWSpace (University of Waterloo)
Author: Doerte Luensmann
Language: English
Subfield: Ophthalmology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2550817213