Synthesis, characterization, and cytotoxicity of TMC-graft-poly(vinyl alcohol) copolymers

N-trimethyl chitosan-graft-poly(vinyl alcohol) (TMC-g-PVA) copolymers were prepared. The grafting reactions were conducted in water changing the feed ratios of poly(vinyl alcohol)/6-O-succinate-N-trimethyl chitosan (PVA/STMC). The structure of TMC-g-PVA copolymers was characterized through 1H NMR spectroscopy, thermogravimetric analysis (TGA/DTG), wide-angle X-ray scattering (WAXS) and scanning electron microscopy (SEM). The quaternization degree (DQ) and substitution degree (DS) of N-trimethyl chitosan (TMC) and 6-O-succinate-N-trimethyl chitosan (STMC) were determined by 1H NMR, being the spectroscopy 14.0 and 5.5 mol-% found, respectively. The viability of HCT-116 cancerous cells was investigated at different concentrations. The effect of PVA/STMC ratios on the cytotoxicity of the TMC-g-PVA copolymers was examined and the CC50 values determined for every case.

Graphical abstractPhysical structure of the new copolymers based on N-trimethyl chitosan/poly(vinyl alcohol) (TMC-g-PVA) depicting the major interactions that occur among the segments of polymers chains of 6-O-succinate-N-trimethyl chitosan (STMC) and PVA.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights• The high intensity of intermolecular interactions explained the elevated DG. • The copolymers presented low crystallinity in relation to pure PVA. • The copolymers showed lower cytotoxicity on the HCT-116 cells.