Free radical scavenger activity of chitosan and its aminated derivative.

Antioxidants may have a positive effect on human health since they can protect the human body against deterioration by reactive oxygen species (ROS). Chitosan has many promising properties as nontoxic, biocompatible, biodegradable, antimicrobial and recently antioxidant properties. Most of the reports on the antioxidant activity of chitosan are based on the ability of amine and hydroxyl group to scavenge free radical to form stable macromolecular radical. In the current study, a new chitosan derivative with extra free amine groups was evaluated using two popular antioxidant evaluation methods (uninhibited/inhibited hyaluronan degradation and decolorization of ABTS method). The result obtained in our study show increase the activity of aminated chitosan for scavenging free radicals than chitosan itself.

Development of thermo-sensitive poly N-isopropyl acrylamide grafted chitosan derivatives.

In this study, the thermo-sensitive copolymers were synthesized by graft copolymerization of poly N isopropyl acrylamide (PNIPAm) onto chitosan (Ch) and aminated chitosan (AmCh) derivative. Free radical polymerization using potassium persulphate (KPS) as initiator was used for performing the grafting process. FTIR, TGA and DSC analysis were used to verify the structure of the resulting graft copolymers. The thermal sensitivity of the prepared copolymers was determined by monitoring the phase transition temperature at 550nm using a UV–VIS spectrophotometer. The results show that the transition of the PNIPAm-g-Ch is sharper than that of the PNIPAm-g-AmCh and the tr-ansition, in both cases, became sharper as increase the PNIPAm grating percentage.