TMC synthesis, we determined optimal reaction time and solvent
ratio for precipitation. O-methylation-free TMC was obtained using
the Eschweiler–Clarke reaction step. O-Carboxymethylation was
carried out using sufficiently strong base in isopropanol. Further
in vitro results indicated that CMTMC was devoid of toxicity on
humandermalfibroblasts withnonegative influence oncell growth
and morphology.
Taken together, these results provide a chitosan derivative platform
for drug delivery. The highly O-carboxymethylated chitosan
provides a materialfor subsequent derivatization with peptide, e.g.,
through carbodiimide coupling chemistry, proteins or targeting
moieties. The presence of charges enables formulation of nanoparticles,
gels, or dried sponges as carriers, allowing multiple delivery
modes for various biomedical applications.