Crosslinked carboxymethyl cellulose-SiO2 hidrogels fabrication: Composition and thermal stability towards biomedical applications

Abstract

Novel and innovative materials for biomedical and pharmaceutical applications have to consider several factors during their fabrication, such as the material composition and thermal stability, aiming to establish the promising physicochemical properties towards efficient and controlled drug release systems. In this study, carboxymethyl cellulose (CMC) hydrogels are prepared by incorporating silica dioxide (SiO2) nanoparticles previously modified with primary amine (-NH2) functional groups. The carbodiimide chemistry method is performed to promote the crosslinking of the CMC structure through the formation of amide bonds from the activation of carboxyl (C=O) groups and further covalent binding with -NH2 groups. The morphology information displays high dispersed SiO2 nanoparticles with a smooth surface, regular shape, and an average particle size of 104 nm. The material composition and thermal stability are evaluated using the Fourier transform infrared spectroscopy and thermogravimetric analysis to establish a preliminary overview of a functional hydrogel for biomedical and pharmaceutical applications. The formation of amide bonds is confirmed indicating the successful crosslinking of the CMC structure with SiO2-NH2 nanoparticles, which is attributed to the activation of the C=O groups and its strong affinity to the -NH2 groups. This interaction enhanced the thermal stability of the crosslinked CMC-SiO2 hydrogels up to 469°C which was the last decomposition event, outstanding the contribution of major content of SiO2-NH2 nanoparticles. These preliminary results suggest a suitable procedure for the fabrication of crosslinked CMC-SiO2 hydrogels as novel materials with promising physicochemical properties, allowing to proceed with further research works related to the controlled drug release and delivery.