| AVS 63rd International Symposium & Exhibition | |
| Applied Surface Science | Thursday Sessions |
| Session AS-ThA |
| Session: | Advances for Complicated Sample Preparation Strategies and Complex Systems |
| Presenter: | Katarzyna Wygladacz, Bausch + Lomb |
| Authors: | K.A. Wygladacz, Bausch + Lomb D.J. Hook, Bausch + Lomb |
| Correspondent: | Click to Email |
Background: Optimum surface wettability and high water content are both important factors that can influence successful contact lens wear. In the case of the silicone hydrogel contact lens, samfilcon A, polyvinylpyrrolidone (PVP) was engineered into the material to increase the water content and provide a wettable lens surface. As a compliment to high level of PVP in the lens chemistry another way to improve lens wettability is to take advantage of interactions between the lens material and the lens care solution. This study assessed the interaction of hyaluronate (HA), a natural humectant, present in Biotrue multi-purpose solution (MPS) with the high PVP-content samfilcon A lens, using multiple analytical techniques.
Method: X-ray Photoelectron Spectroscopy (XPS) characterization was used to confirm the presence of HA on the lens surface.The distribution of HA over the samfilcon A surface was assessed by quantitating lens surface roughness (RMS), before and after incubation with 0.1% (w/v) HA by atomic force microscopy (AFM) imaging. Confocal laser scanning (CLSM) and differential interference contrast (DIC) microscopies were used to characterize the association of HA to the surface of samfilcon A lenses after exposure to 0.1% (w/v) HA and HA present in Biotrue MPS.
Results: Differences in the XPS C1s spectra recorded for samfilcon A before and after exposure to 0.1% (w/v) HA were detected. Samfilcon A surface roughness (RMS) was 2.5 ± 0.4 nm before exposure to HA and was significantly decreased after incubation with 0.1% (w/v) HA, (RMS=0.6 ± 0.1nm; p<0.05). CLSM and DIC imaging illustrated a comparable confluent, stained HA network that extended across the entire surface with 0.1% (w/v) HA and commercial HA-containing MPS.
Conclusion: XPS analysis show evidence for samfilcon A surface modification with hyaluronate. CLSM and DIC imaging offered a comprehensive view of the lens surface and demonstrated an extensive coverage of HA on samfilcon A. AFM measurements confirmed that HA adsorption reduced roughness of the lens surface. Together, the combination of imaging techniques provided a unique picture of the interaction of HA and PVP containing silicone-hydrogel lenses.