Preparation, structure and drug release behaviour of chitosan-based nanofibres.

Biomimetic polymeric nanofibres are of great interest in tissue engineering and wound repair because of their structural similarity to extracellular matrix. In this work, biomimetic chitosan-based nanofibres with various diameters were prepared by ionically cross-linking with tripolyphosphate (TPP) in adipic acid medium and characterised using transmission electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy. Using dexamethasone sodium phosphate (DMP) and bovine serum albumin (BSA) as low and high molecular-weight bioactive molecule models, respectively, drug loading and in vitro release behaviours of chitosan-TPP nanofibres were investigated. The drug-loaded chitosan-TPP nanofibres showed a prolonged release profile with three distinct stages in physiological conditions because of the complicated release mechanisms involving diffusion of the drug and degradation of the nanofibre, and BSA-loaded nanofibres showed a smaller release rate than DMP-loaded nanofibres. It is proposed that biomimetic chitosan-based nanofibres may be of use in tissue engineering for sustained release of bioactive agents.