Esmaiel Jabbari - Laboratory of Biomaterials and Controlled Delivery Systems for Bioactive Agents, School of Biomedical Engineering, Amirkabir University of Technology.

At adsorption of lysozyme on an anionic and a neutral hydrophilic soft contat lens based on hydroxy ethyl methacrylate was measured as a function o protein concentration, time, and solution pH using ultra-violet spectroscopy. The amount of adsorbed proteion reduced significantly form pH 8 to 11. This was consistent with the fat that the isoelectric point of lysozme is 11. Between pH values of 5 to 8, Lysozyme has the highest positive charge density and its interaction with the negatively charged anionic lens is highest and therefore the amount of protein adsorbed highest. As the pH is increased from 8 to 11, the density of positive charge on lysozyme decreases as it approaches its isoelectric point, its above 11, lysozyme has a net negative charge, its interaction with the negatively charged lens is low and therefore the amount of adsorbed is lowest.

anionic, neutral, hydrophilic, softlens, protein, lysozyme, adsorption