Biomimetic composite scaffolds based mineralization of hydroxyapatite on electrospun calcium-containing poly(vinyl alcohol) nanofibers

Abstract

Nanocomposite materials consisting of polymer matrix and inorganic salts in the form of nanocrystals of hydroxyapatite (HA) are regarded as superior candidates for bone treatment. A biomimetic nanocomposite scaffold with HA formation on the electrospun poly(vinyl alcohol) (PVA) nanofibrous structure by employing a Ca–P alternate soaking method was developed in this work. The calcium-containing PVA nanofibers were prepared by adding calcium nitrate to the starting solution prior to electrospinning, and then mineralized by Ca–P treatment in incubation solution. With this rapid and effective procedure, a continuous biomimetic crystalline HA layer could be formed successfully without the need of a prior chemical modification of the substrate surface under very mild reaction conditions. Moreover, the HA formed with a relatively accelerated growth had a carbonated and poor crystalline structure, resembling biological apatite in the bone mineral. The introduction of calcium ions in nanofibers by electrospinning was a favorable approach to induce the deposition of calcium phosphate and improve the distribution, nucleation, and growth of crystalline HA layer on nanofibrous scaffolds. Bioactivity tests revealed that these mineralized PVA/HA composite scaffolds improved the biocompatibility. The porous polymer/HA composite scaffolds produced in the present study might have potential applications in bone tissue engineering.