Preparation, structure, drug release and bioinspired mineralization of chitosan-based nanocomplexes for bone tissue engineering

Chitosan-based nanocomplexes with various forms were prepared by ionically crosslinking with tripolyphosphate (TPP) in different acidic media under mild conditions. It was found that the self-assembly and ionic interactions of chitosan and TPP were greatly affected by reaction media, and chitosan-based nanofibers could be obtained in adipic acid medium while nanoparticles were formed in acetic acid medium. Using bovine serum albumin (BSA) as a macromolecular model-drug, in vitro drug release studies indicated that chitosan-based nanofibers and nanoparticles exhibited a similar prolonged release profile. In addition, the bioinspired mineralization of both chitosan-based nanofibers and nanoparticles was carried out by soaking them in synthetic body fluids (SBF). Transmission electron microscopy (TEM) and X-ray Diffraction (XRD) results indicated that chitosan-based nanofibers have better inductivity for nano-hydroxyapatite formation than chitosan-based nanoparticles. The results suggested that biomimetic chitosan-based nanofibers with controlled release capacity of bioactive factors may be of use in bone tissue engineering for enhancing the bioactivity and bone inductivity.