2 20 azobis 2 methylpropionitrile

Maleic anhydride, ethanolamine and acryloyl chloride were purchased from Alfa Aesar (UK). N-Vinyl pyrrolidone (NVP), triethylamine, N,N-methylenebis(acrylamide) (MBA), FITC-dextran (M W = 10 kDa), fluorescein sodium 2,2 0 -azobis(2-methylpropionamidine)hydrochloride (V-50), 2,2 0 -azobis(2-methylpropionitrile) (AIBN), 5,5-dithiobis(2-nitrobenzoic acid) (DTNB), chitosan (62 kDa, 70% deacetylation) and cysteine hydrochloride were purchased from Sigma-Aldrich (UK). All other reagents and solvents were of analytical grade and were used without further purification unless otherwise stated. Simulated tear fluid was composed of NaCl (0.67 g), NaHCO 3 (0.20 g), and CaCl 2 Á2H 2 O (0.008 g) dissolved in deionized water (100 mL). 1 Whole bovine eyeballs were sourced from a local abattoir on the day of slaughter, and transported in phosphate buffer (pH 7.4) maintained at 4-8 1C. The conjunctival tissues were removed and washed using phosphate buffer. All tissues were used within 24 h of retrieval.