Kinetics of Competitive Adsorption between Lysozyme and Lactoferrin on Silicone Hydrogel Contact Lenses and the Effect on Lysozyme Activity.

PURPOSE

To determine the effect of competitive adsorption between lysozyme and lactoferrin on silicone hydrogel contact lenses and the effect on lysozyme activity.

METHODS

Three commercially available silicone hydrogel contact lens materials (senofilcon A, lotrafilcon B and balafilcon A) were examined, for time points ranging from 10 s to 2 h. Total protein deposition was determined by I(125) radiolabeling of lysozyme and lactoferrin, while the activity of lysozyme was determined by a micrococcal activity assay.

RESULTS

Senofilcon A and balafilcon A did not show any relevant competitive adsorption between lysozyme and lactoferrin. Lotrafilcon B showed reduced protein deposition due to competitive adsorption for lactoferrin at all time points and lysozyme after 7.5 min. Co-adsorption of lactoferrin and lysozyme decreased the activity of lysozyme in solution for senofilcon A and lotrafilcon B, but co-adsorption had no effect on the surface activity of lysozyme for all lens types investigated.

CONCLUSIONS

Competition between lysozyme and lactoferrin is material specific. Co-adsorption of lysozyme and lactoferrin does not affect the activity of surface-bound lysozyme but can reduce the activity of subsequently desorbed lysozyme.