Synthesis Thiolated Chitosan

Chitosan-cysteine
conjugates synthesized by the addition of 50 mM EDAC has the highest content of thiol
groups of 265,169 μmol per 50 mg of conjugates.

Synthesis of chitosan-cysteine conjugates
Chitosan-cysteine conjugates are made by: prepared beaker glass capacity 500 mL of
4 pieces. Made of 1% acetic acid solution of 250 mL in each beaker. Then into each beaker
glass was dissolved 5 g of chitosan. After all the soluble chitosan, into each beaker glass is
added 2,5 g of cysteine until dissolved. Then added with a concentration 0 mM EDAC, 30
mM, 40 mM, and 50 mM in each solution. pH value adjusted to 5 with the addition of NaOH
1 N. The mixture was incubated for 3 hours with continous stirring. The solution was
dialyzed twice in a dialysis tubing (MW cut-off 12-14 kDa) protected from light at 100C with
1 mM HCl containing 1% NaCl for 1 day and then with 1 mM HCl for 2 days to eliminate
EDAC and cysteine of the conjugate solution. The solution is lyophilized and conjugates (dry
conditions) maintained at 4oC until ready for use (Roldo et al., 2004).