Nanogéis termorresponsivos à base de amido de manga e sua aplicabilidade como carreador de moléculas hidrofóbicas

Abstract

Brazil is a major mango producer. In particular, the Brazilian Northeast, which in 2019 produced more than 1 million tons of the fruit. Mango seed is a rich source of starch, but it is currently discarded as agro-industrial waste. Given this scenario, producing copolymers based on mango starch, which is currently discarded as organic waste, in the form of thermoresponsive nanogels for drug incorporation is an economically viable solution. In addition, a problem faced in the pharmacological area is that most hydrophobic drugs have low absorption in the human body, due to their low solubility and stability in aqueous media. Consequently, the use of specific carriers for the delivery of hydrophobic drugs can increase their efficiency of action. Therefore, in this work the proposal is the production of biodegradable and thermoresponsive nanovehicles that are effective in the transport of hydrophobic drugs. For this, first, the starch was crosslinked with glutaraldehyde, followed by carboxymethylation with monocloacetic acid and, finally, by grafting of poly(N-isopropylacrylamide) chains (PNIPAM). The results obtained in the elemental analysis, hydrogen NMR and infrared with Fourier transform revealed the structural aspects and composition of the materials, evidencing the success in the production of carboxymethylamido-g-poly(N-isopropylacrylamide) (CMA-g-PNIPAM). Through SEM and DLS it was found that the nanoparticles showed high swelling power. The transmittance of the copolymers in aqueous media abruptly decreased above 33 °C. The nanogels showed no toxicity to human adipose tissue-derived stem cells (ADSCs) and red blood cells (RBCs). Likewise, the products proved to be non-hemolytic in the LDH, alamarBlue and hemolysis assays. In view of the results obtained, the potential of polymeric matrices based on CMA-gPNIPAM as carriers of hydrophobic drugs was evaluated, using curcumin as a model drug. The curcumin incorporation kinetics data showed that in 8 hours the polymer matrix was able to absorb approximately 25% of the available free curcumin, fitting the pseudo-second order sorption model. Based on the results obtained, it is concluded that the synthesized copolymers present interesting functional characteristics for application in hydrophobic drug delivery systems.