SYNTHESIS AND CHARACTERIZATION OF THERMORESPONSIVE NANOGELS BASED ON MANGO STARCH
Nanogel; Starch; Coupling Reaction; Poly(N-isopropylacrylamide)
Thermoresponsive copolymers have broad biomedical applications, including encapsulation and cell transplantation, wound healing, and controlled drug release. In this scenario, the presence of polysaccharide as a polymer matrix is advantageous, since it combines its renewable origin, abundance, biocompatibility and biodegradability, with a rapid response to the temperature of thermoresponsive polymers, such as poly (N-isopropylacrylamide) (PNIPAM). Thus, in this work, the starch, obtained from mango kernel, was crosslinked with glutaraldehyde and then carboxymethylated with monocloacetic acid, producing carboxymethylstarch nanoparticles. These nanoparticles were then grafted with amino-terminated poly(N-isopropylacrylamide) chains (PNIPAM-NH2) via coupling reaction, using the reactants 1-ethyl-3-[3- (dimethylamino)propyl] carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). Elemental analysis together with the results of the spectroscopic techniques 1H NMR and Fourier transform infrared revealed the structural aspects and composition of the materials, evidencing the success in the production of the carboxymethyl starch particles grafted with PNIPAM. Thermogravimetric analysis showed that grafting of PNIPAM chains made the products thermally more stable than the unmodified starch. Through the techniques of SEM and DLS it was observed that the nanoparticles presented high swelling ability which, together with thermoresponsive properties, make of these materials promising candidates for use in controlled drug release systems.