Abstract
Human tears have over 60 different proteins that deposit on contact lenses. Protein deposits on contact lenses can cause conjunctival irritation and bacterial infection. The adhesion of albumin to omafilcon and hilafilcon soft contact lenses was examined. Lenses were incubated for 1 - 4 days in a 2.0 mg/dl albumin solution. The protein concentration in the incubation vials and protein deposition on the lenses was determined each day by bicinchoninic acid assay. Albumin deposited on the omafilcon lenses in a steadily increasing fashion, while the albumin concentration in the incubation solution decreased. Albumin deposited on the hilafilcon lenses in a steadily decreasing fashion as lenses were incubated, while the albumin concentration in the vials increased. However, much more albumin absorbed to the hilafilcon lenses than the omafilcon lenses. Human serum albumin is a negatively charged single peptide chain of 585 amino acids that binds and releases a variety of hydrophobic molecules. Hilafilcon is more negatively charged than omafilcon, therefore the large differences between the adhesion of the negatively-charged albumin to hilafilcon as compared to omafilcon must be due to differences in the hydrophobicity of the polymers. Omafilcon lenses are coated with phosphorylcholine which may reduce adhesion by the hydrophobic domains of albumin. Our results demonstrating that the negatively charged tear protein albumin absorbed in a linear fashion to the slightly negative omafilcon material is consistent with the findings of others that albumin deposits on contact lenses in a concentrationdependent way with a single timescale.
Faculty Sponsors
Dr. Edward O. Keith
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-13-2012 1:00 PM
End Date
4-13-2012 5:30 PM
Adhesion of Albumin to FDA Type II Soft Contact Lenses
Alvin Sherman Library
Human tears have over 60 different proteins that deposit on contact lenses. Protein deposits on contact lenses can cause conjunctival irritation and bacterial infection. The adhesion of albumin to omafilcon and hilafilcon soft contact lenses was examined. Lenses were incubated for 1 - 4 days in a 2.0 mg/dl albumin solution. The protein concentration in the incubation vials and protein deposition on the lenses was determined each day by bicinchoninic acid assay. Albumin deposited on the omafilcon lenses in a steadily increasing fashion, while the albumin concentration in the incubation solution decreased. Albumin deposited on the hilafilcon lenses in a steadily decreasing fashion as lenses were incubated, while the albumin concentration in the vials increased. However, much more albumin absorbed to the hilafilcon lenses than the omafilcon lenses. Human serum albumin is a negatively charged single peptide chain of 585 amino acids that binds and releases a variety of hydrophobic molecules. Hilafilcon is more negatively charged than omafilcon, therefore the large differences between the adhesion of the negatively-charged albumin to hilafilcon as compared to omafilcon must be due to differences in the hydrophobicity of the polymers. Omafilcon lenses are coated with phosphorylcholine which may reduce adhesion by the hydrophobic domains of albumin. Our results demonstrating that the negatively charged tear protein albumin absorbed in a linear fashion to the slightly negative omafilcon material is consistent with the findings of others that albumin deposits on contact lenses in a concentrationdependent way with a single timescale.
