Influence of needle-like morphology on the bioactivity of nanocrystalline wollastonite--an in vitro study.

In the past 2 decades, wollastonite has been studied thoroughly for its application as a bone implant material due to its biocompatibility, high mechanical strength, and excellent bioactivity when compared to calcium phosphates bioceramics. Wollastonite was prepared through the low-temperature sol-gel combustion method using urea as the fuel, nitrate ions and nitric acid as the oxidizer. Calcium nitrate and tetraethyl orthosilicate were taken as the source of calcium and silica. The synthesized wollastonite were characterized by Fourier transform infrared spectroscopy for the identification of characteristic functional group and powder X-ray diffraction for the phase identification. Employing urea as a fuel resulted in needle-like morphology of the particles, which was confirmed by scanning electron microscopy and transmission electron microscopy. It was observed that the needle-like morphology enhances the mechanical properties such as elasticity and compressive strength and also increases the surface area of the material, which could help in a rapid deposition of hydroxyapatite layer. These properties of wollastonite warrant its application as a new artificial bone material in the field of hard tissue engineering.