Abstract
Purpose:
To investigate the properties of chitosan, as a potential drug delivery system and adjuvant for conjunctival vaccines on human conjunctival epithelial (HCjE) and human corneal-limbal epithelial (HCLE) cells. Chitosan is a deacetylated form of chitin that has been show to have both mucoadhesive and permeation enhancing properties as well as being soluble in acidic solutions and biodegradable.
Methods:
Cytotoxicity was measured by quantifying lactate dehyrogenase production in both cell lines incubated with 0.1% chitosan dissolved in 100mM boric acid buffer for 5, 15, and 30 minutes, as well as 24h after 30 minutes of exposure. The 15 minute interaction between 0.1% chitosan-FITC and both HCjE and HCLE cells was examined with fluorescent microscopy and quantified with flow cytometry.
Results:
Both cell lines were shown to well tolerate incubation with chitosan for up to 30 minutes, whereas both showed elevated levels of toxicity 24 hours after the 30 minute incubation, HCLE cells more so (mean of 43.6%) than HCjE cells (mean of 23.6%). Uptake of the polymer by both cell lines was visualized by fluorescent microscopy and confirmed by flow cytometric quanitification, where uptake was shown to be higher in HCjE cells than HCLE cells.
Conclusions:
Chitosan shows low levels of cytotoxicity and high levels of uptake into HCjE and HCLE cells, thereby fulfilling the prerequisites needed for further investigation of its adjuvantic properties for a conjunctival vaccine.