Fellow researcher, Institute of Chemistry Advanced of Catalonia, Spain. Superior Council of the Scientific Investigations

Speech Title: SOFT CONTACT LENSES EXHIBITING ANTIBACTERIAL ACTIVITY
Abstract:In this work, commercial soft contact lenses were chemically modified to incorporate antibacterial properties. Soft contact lenses are hydrogel materials recently receiving great attention due to their high potential for ophthalmic medical applications [1]. One of the most common problems related to contact lenses is associated with the risk of eye microbial infection. Indeed, the presence of bacteria and fungi in contact lenses may cause severe corneal infections that eventually lead to vision loss. This is a significant health issue given the large population of contact lenses wearers worldwide [2]. Previous studies demonstrated that Pseudomonas aeruginosa (P. ae.) and Klebsiella pneumonia were identified as the most common pathogens [3]. In order to introduce bactericidal activity in hydrogel contact lenses, two short antimicrobial peptides (AMP1 and AMP2) specifically effective against the aforementioned bacteria were selected. The hydrogel chemical modification was performed under very mild conditions (room temperature, pH=7.4) following two approaches: physisorption by weak interactions and covalent binding (Figure 1A). Both methods proved to be effective for incorporating the desired peptides at different concentrations. However, stability studies demonstrated that covalently bound peptides show a much higher stability at the hydrogel material in PBS solution (Figure 1B). The physical, chemical and optical properties of the modified contact lenses were investigated through several analytical techniques including wettability, Raman confocal microscopy, fluorescence studies, refractometry and spectrophotometry. Bacterial culture studies show that modified contact lenses can drastically reduce the bacterial adhesion when exposed to Pseudomonas aeruginosa. These systems offer the potential to minimise corneal bacterial infection and represent a suitable platform for future ophthalmic devices. All these aspects will be herein discussed within the frame of product development.



Figure 1. A) Schematic representation of AMP-modified soft contact lenses. B) Fluorescence stability studies on the AMP-modified contact lenses. C1) Microscopy images of P. ae. adherent bacteria on unmodified lenses (control) and AMPs modified contact lenses under white light and C2) fluorescence microscopy of adhered P. ae after staining with LIVE (green)/DEAD (red) BacLight Bacterial ViabilityKit (scale bar = 10µm).

Acknowledgements : We would like to acknowledge the TECNIOspring programme for funding.
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