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Hydrogel lens monomer constituents modulate protein sorption
Q Garrett1, B Laycock, R W Garrett
1Cooperative Research Centre for Eye Research and Technology, The University of New South Wales, Sydney, Australia. q.garrett@cclru.unsw.edu.au
Investigative Ophthalmology & Visual Science
|June 14, 2000
Summary
Hydrogel lens composition significantly impacts protein sorption. Methacrylic acid (MAA) influences lysozyme and albumin adsorption, while N-vinyl pyrrolidone (NVP) primarily increases overall protein uptake, with MAA dominating in mixed hydrogels.
Area of Science:
- Materials Science
- Biomaterials Engineering
- Ophthalmic Lens Technology
Background:
- Protein sorption onto contact lens materials is a critical factor influencing lens performance and wearer comfort.
- Understanding the influence of hydrogel monomer composition on protein adsorption is essential for developing advanced contact lenses.
Purpose of the Study:
- To investigate how specific monomer constituents within hydrogel lenses affect protein sorption.
- To elucidate the roles of methacrylic acid (MAA) and N-vinyl pyrrolidone (NVP) in protein adsorption and penetration.
Main Methods:
- Synthesis of hydroxyethylmethacrylate (HEMA)-based hydrogels with varying concentrations of MAA or NVP.
- Quantification of protein adsorption using a radiolabel tracer technique.
- Visualization of protein penetration into hydrogels via laser scanning confocal microscopy with fluorescence-labeled proteins (human serum albumin and hen egg lysozyme).
Main Results:
- Incorporating MAA or NVP increased hydrogel water content and significantly altered protein sorption.
- MAA enhanced lysozyme adsorption and penetration but reduced human serum albumin (HSA) adsorption.
- NVP increased adsorption of both HSA and lysozyme, with MAA demonstrating a dominant effect in poly(HEMA-co-MAA-co-NVP) hydrogels.
Conclusions:
- Monomer composition, particularly the charged carboxyl groups in MAA and lactam groups in NVP, dictates protein sorption.
- MAA influences lysozyme sorption via electrostatic attraction and enhanced penetration; NVP promotes protein attraction.
- Water content is not the primary determinant of protein adsorption; monomer constituents are the key factors.