3D nanofibrous structures formed of high content chitosan/PVA and chitosan/PLA blends using air-heated solution blow spinning (A-HSBS).

Polylactic acid/chitosan (PLA/CS) and poly(vinyl alcohol)/chitosan (PVA/CS) are considered potential blends for use in tissue engineering, since when obtained in the form of 3D fibers they can form structures with high porosity, biocompatibility, antimicrobial activity and morphology similar to tissues and organs. However, there is a scarce number of reports in the literature addressing the production of systems based on 3D fibrous mixtures of PVA or PLA with high chitosan amount because of the difficulty in spinning CS into stable structures using acidic solutions, and without further employment of cross-linking agents. Therefore, this work focused on a novel procedure to prepare 3D fibrous structures of PVA and PLA with high chitosan content, combining the solution blow spinning technique, a heated air environment and the use of eco-friendly solvents, without using crosslinking agents. The influence of CS incorporation on the as-prepared structures was assessed by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, contact angle measurement, porosity, swelling and degradation tests. Rheological tests evidenced that an increase in the CS content implies a greater viscosity of the spinning solutions, hindering the fibrillar structures formation. Fibers produced showed a randomly interconnected and highly porous fibrous cotton-wool-like structure, with fiber diameters ranging from 481 to 637 nm for PVA/CS systems, and from 1276 to 2050 nm for PLA/CS systems. A decrease in the thermal stability of the blend-based fibers and an increase in hydrophilicity, porosity, swelling and in vitro biodegradation were observed in the blend systems. Results indicate that the obtained fibrillar structures possess morphological and physical characteristics that may be interesting for application as 3D fibrous scaffolds in tissue engineering. [ABSTRACT FROM AUTHOR]