Multifunctional composite combining chitosan microspheres for drug delivery embedded in shape memory polyester-urethane matrix

Abstract Multifunctional composite biomaterials (3b-PU/CH_M) consisting of chitosan microspheres (CH-M) that provide drug release functionality and crosslinked polyester-urethane (3b-PU) matrix responsible for shape memory properties were designed. A series of 3b-PU/CH_M bio-composites with varying weight fraction of CH-M (2.5, 5, and 10 wt. %) embedded into 3b-PU matrix were synthesized. The ATR-FTIR confirmed the presence of covalent bonds between 3b-PU matrix and CH-M as well as enhanced hydrogen bonds interaction within bio-composites matrix in comparison to neat 3b-PU. It was found that CH-M had not impaired the shape memory properties of 3b-PU matrix and even slightly improved the shape recovery (Rr %). The Rr value increased to 100 % for 3b-PU/CH 2.5% M and 3b-PU/CH 5% M after the third thermo-mechanical cycle. Moreover, the transition temperature (Ttrans) of shape recovery tailored to 30oC by the chemical composition of the 3b-PU network was not affected by CH-M. Effectiveness of the application of the composites as a controlled drug delivery system at various pH conditions was confirmed in an in vitro release study of ciprofloxacin hydrochloride (Cpx-HCl) used as a model drug. In vitro biocompatibility studies revealed that the materials do not alter the cells’ ability to proliferate and differentiate.