Development of porous scaffolds based on the in situ synthesis of biphasic calcium phosphate in a gelatin-polyvinyl alcohol matrix for bone tissue engineering

Abstract

3D porous scaffolds are the preferred scaffold for tissue engineering applications that require good biocompatibility and mechanical properties. However, those scaffolds, based on gelatin and calcium phosphate, have been shown to be elusive due to the difficulty of reconciling excellent biological properties, long-term degradation, and desirable mechanical properties of scaffolds. Here, we designed porous scaffolds based on biphasic calcium phosphate (BCP: a mixture of hydroxyapatite (HAp) and β-tricalcium phosphate (TCP)) and polymer (gelatin and polyvinyl alcohol (PVA)) composite hydrogel using a lyophilization technique. BCP was prepared in situ in gelatin and PVA at polymer/BCP ratios equal to 0. 2, 0. 4, and 0. 6. The composition and structure of the scaffolds were investigated using a variety of techniques: XRD, FTIR, TGA-DTA, and SEM. The mechanical properties and in vitro swelling-degradation studies of the scaffolds were investigated. The results showed the formation of well-dispersed BCP in scaffolds with different HAp/TCP ratios. Scaffolds with lower content of BCP showed higher porosity and somewhat lower mechanical properties, lower diffusion of ceramic particles into fine pores and reduced pore size shrinkage compared to those with higher content of BCP. The scaffolds had good mechanical compressive strength in the range of 40–70 kPa, porosity of 10–90% and pore size of 10–310 μm. They exhibited high permeability, high swelling capacity of up to 800%, long-term swelling and degradation behavior of up to 42 days. These porous scaffolds could be potential biomaterials for damaged bones in orthopedic tissue engineering.