Low level of residual monomer and specific surface properties affect intraocular lens material biocompatibility

Purpose Surface chemistry, roughness and adhesiveness properties of biomaterials can affect cell adhesion and protein mediation. Also release of inflammatory species from IOL material can promote foreign body reaction. Purpose of this study is of evaluating how the low quantity of residual monomer and specific surface properties of a hydrophilic IOL material can have efficacy in reducing release of species and controlling cell adhesion and protein mediation. Methods A co-polymer, material of a hydrophilic acrylic IOL (MIRA,SIFI Italy), was investigated by TG and TOF-SIMS analysis. Surface roughness and adhesiveness properties were evaluated by AFM. For protein adhesion QCM-D technique was employed. Cell Adherence (SIRC) and strength of interaction at the cell-surface contact area (McCoy) were also observed and measured. Results Thermal (TG) and chemical analysis (TOF-SIMS) showed that low level of residual monomer affects thermal stability. AFM analysis showed low surface roughness and adhesive force values. QCM-D analysis showed small values of thickness and mild viscoelastic behavior for protein layer. Cell adherence was not significant and strength of interaction did not show difference for bare and protein adsorbed substrate. Conclusion Properties of hydrophilic materials are variable and not directly related to the hydrophilicity of their surface. The hydrophilic acrylic IOL polymer tested, pure of residual monomer content and with the investigated specific surface properties cannot promote foreign body reaction and can control protein adsorption and inhibit cell reaction. Commercial interest