Characterization of 3D scaffold based on carboxymethyl chitosan and PVP

Abstract

Carboxymethyl chitosan (CMCh) is a water-soluble chitosan derivative with excellent biocompatibility and biodegradability, making it a promising material for tissue engineering and controlled drug delivery. In this study, three-dimensional (3D) scaffolds based on a 50/50 CMCh/poly(N-vinylpyrrolidone) (PVP) mixture were modified with tannic acid (TA) or citric acid (CA) as cross-linking agents and fabricated by freeze-drying. The effects of these cross-linking agents on scaffold morphology, physicochemical properties, and cytocompatibility were evaluated using infrared spectroscopy (IR), microscopy, swelling tests, thermogravimetric analysis (TGA), mechanical testing, and in vitro cytotoxicity assays. Both cross-linking agents altered the scaffold morphology, swelling behaviour, and mechanical properties. The swelling capacity reached 1280 ± 37% for 50/50/TA and 1345 ± 145% for 50/50/CA, while the compressive modulus decreased from 505 ± 103 kPa for the unmodified scaffold to 188 ± 31 kPa for the 50/50/CA scaffold. TA promoted the formation of smaller pores (<130 μm), whereas CA produced smoother scaffold surfaces. Cross-linking slightly improved the thermal stability of the scaffolds, and IR analysis confirmed intermolecular interactions between the polymer matrix and the TA or CA molecules. The modified scaffolds exhibited high porosity (approximately 90%) and supported cell proliferation without cytotoxic effects, demonstrating their potential as biomaterials for tissue engineering and other biomedical applications.