We have established earlier a cell line from the human limbal area to study cell growth and response to the toxic effects of antibiotics used in ophthalmology. In the recent work, the effect of multi-walled carbon nanotubes (MWCNTs) in cornea damage was investigated in vitro and in vivo in mice. In the in vitro experiments, the physiological effects of multi-walled carbon nano-tube (MWCNT) bundles on corneal wound healing were mimicked in vitro by a reepithelization limbal stem cell model. Murine in vivo experiments were performed with intact, non-functionalized MWCNTs to confirm the validity of in vitro tests. The MWCNTs of 10 -30 nm outer diameter at low concentration (5 µg/ml) did not interfere with the wound healing of the damaged limbal cell monolayer. Higher than 50 µg/ml concentrations: a) generated MWCNT aggregates, b) restrained the movement and prolonged the time of wound healing, c) increased the amplitudes of the oscillations of the cells, and d) resulted in scar formation affecting both cor-neal function and refraction. Chromatin condensation, a sensitive test of the viability of cells, including limbal stem cells revealed that the presence of a low concentration of nanotubes (5 µg/ml), did not significantly affect the viability of limbal cells. Chromatin condensation was completed and metaphase chromosomes were seen at higher MWCNT concentration proving that their aggregates did not affect the viability of limbal cells. This concentration of MWCNTs (5 µg/ml) did impact neither the reepithelization in vitro nor in vivo in the scratched eyes of mice. Scar formation took place at higher than 50 µg/ml concentrations and the healing of the cornea was prevented by the lack of movement of increasingly larger macroaggregates. In vivo murine experiments vali-dated in vitro monolayer regrowth followed by time-lapse microscopy portraying realistically the reepithelization of the damaged cornea that process was gradually slowed down by macro aggregate formation and caused the scarring of the cornea.

Since the past few decades, numerous modifications and innovations have been done to design the optimal corneal biomatrix for corneal epithelial cells (CECs) or limbal epithelial stem cells (LESCs) carriers. However, researchers have yet to discover the ideal optimization strategies in the development of corneal biomatrix design and its effects on cultured CECs or LESCs. This review further discusses and summarizes recent optimization strategies to develop an ideal collagen biomatrix and its interaction with CECs and LESCs. Using PRISMA guidelines, the articles published from June 2012 to June 2022 were systematically searched using Web of Science (WoS), Scopus, PubMed, Wiley, and EBSCOhost databases. The literature search identified 444 potential relevant published articles, with 29 relevant articles selected based on the inclusion and exclusion criteria after the screening and appraising processes. The current paper highlights the physicochemical and biocompatibility (in vitro and in vivo) characterization methods, which were inconsistent throughout the different studies. Despite the variability in the methodology approach, the reviewer postulated that the modification of the collagen biomatrix improves its mechanical and biocompatibility properties toward CECs and LESCs. All findings were discussed in this review; thus, it provides a general view of up-to-date trends in this field.