# Evaluating Cytocompatibility of Corynebacterium glutamicum‐poly Vinyl Alcohol Living Biomaterials for Ocular Use

## TL;DR

This paper shows that a living biomaterial made of Corynebacterium glutamicum and polyvinyl alcohol is safe for use in the eye, with no harmful effects on corneal cells.

## Contribution

The study introduces an in vitro cornea model to evaluate the cytocompatibility of a living contact lens material for ophthalmic applications.

## Key findings

- The living biomaterial does not cause cytotoxicity or pro-inflammatory responses in corneal cells over 7 days.
- The material can be placed on the corneal epithelium without harmful effects.
- The in vitro model is effective for assessing living biomaterials for ocular use.

## Abstract

In ophthalmology, living biomaterials have appeared as promising drug delivery and biosensor devices to tackle dynamic sensing and delivery of compounds. Their living character complicates their assessment with the also dynamic ocular tissues. The use of animal experiments increases complexity, and most animal ocular models are anatomically different from humans. Thus, in vitro ocular systems applied specifically to living biomaterials are required to assess their safety, compatibility and efficacy. Here, we report on an in vitro cornea model for co‐cultures with Corynebacterium glutamicum‐polyvinyl alcohol living biomaterials, which are reported as suitable living contact lenses, to study their cytocompatibility to the eye. We co‐cultured this living biomaterial with human primary corneal cells (epithelial and fibroblasts) for 7 days, mimicking contact lens extended wear. We studied bacterial proliferation, biocontainment and biosafety. We investigated potential cytotoxicity and pro‐inflammatory responses of living biomaterials to corneal cells. Our results revealed that the living biomaterial does not trigger cytotoxicity or pro‐inflammatory phenotypes on corneal cells during the 7‐day co‐culture. We placed the living biomaterial on top of the corneal epithelium, observing no cytotoxic effects. Overall, these findings highlight the potential of in vitro investigations for living biomaterials and the applicability of these devices for ophthalmology purposes.

In ophthalmology, living biomaterials such as living contact lenses appear promising for sustained drug delivery or biosensing. The cytocompatibility of Cg‐PVA hydrogels, developed as a model living contact lens, is investigated with the ocular surface, showing their potential translation to the clinic.