Microstructural and mechanical properties of porous biocomposite scaffolds based on polyvinyl alcohol, nano-hydroxyapatite and cellulose nanocrystals

In this study, in situ synthesis of polyvinyl alcohol (PVA)/nano-hydroxyapatite (n-HA)/cellulose nanocrystals (CNC) organic-inorganic biocomposite porous scaffolds is reported. The effect of the CNC content on the properties of the biocomposite scaffold was investigated and characterized using field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, porosity and compressive strength measurements, thermal studies, and in vitro biomineralization and degradation studies. The morphological study showed highly porous structures with good pore interconnectivity in which n-HA was homogeneously dispersed. XRD analysis showed a decrease in the crystalline fraction and crystallite size of nano-hydroxyapatite with introduction of PVA and with increasing content of CNC. It was observed that the porosity decreased to some extent with increasing CNC content, while increases in the compressive strength (from 0.85 to 2.09 MPa) and elastic modulus (from 4.68 to 16.01 MPa) were found as the CNC content was increased. In vitro biomineralization study revealed the formation of apatite on PVA/n-HA/CNC biocomposite scaffolds when soaked for 7 and 14 days in simulated body fluid (SBF) solution. The obtained porous scaffolds offering good mechanical performance may provide a promising alternative scaffolding matrix for use in the field of bone tissue engineering.