Synthesis and <I>In-Vitro</I> Analysis of Degradative Resistance of a Novel Bioactive Composite

Abstract

The biostability of the polymer is one of the critical parameter to use them for biomaterial application. Polyurethane being one of the most compliant polymer but there are concerns regarding its resistance to degradation, particularly from hydrolysis and oxidation. The aim of this study is to synthesise a novel bioactive composite by creating a covalent linkage between polyurethane and nano-apatites and to analyse the in-vitro hydrolytic degradation of a series of newly synthesised polyurethane (PU) and polyurethane/nano-hydroxyapatite (PU/n-HA) composites. Nanoapatite powder was produced through sol-gel technique. A novel polyurethane composite material was prepared by chemically bonding the n-HA to the diisocyanate component in the polyurethane backbone by utilising solvent polymerisation. The concentration of nano-apatite was 5, 10, 15 and 20% wt/wt in polyurethane. Hydrolytic degradation of the PU and PU/n-HA composites were carried out both in deionised water and in phosphate buffer solution (PBS) having (pH 7.4) at 37 C for a predetermined time interval of 90 days. The PU and PU/n-HA composites were physically and chemically characterised by using contact angle measurement, weight loss, Fourier Transform Infrared spectroscopy couples with Photoacoustic Sampling Cell (FTIR-PAS), Raman Spectroscopy, X-ray Diffraction (XRD) and Scanning electron microscopy (SEM). These characterisations showed that with the addition of n-HA the composite exhibits hydrophobic behaviour and degradation rate reduces due to covalent linkage between n-HA and PU. Hence it has been concluded that the degradation rate of the newly developed PU/n-HA composites can be controlled, which helps in tailor making the biomaterial for specific applications.

Structural, mechanical, and biocompatibility analyses of a novel dental restorative nanocomposite

“…The concept of creating mechanically/chemically homogenous units “ideal monoblocks” with root dentin is challenging. Our previous studies, confirmed the biostability of newly developed nanocomposite,15 the results of thermal properties, in vitro bioactivity, adhesion with root dentin were presented in subsequent studies 16,17. The incorporation of nHA in these composites enhanced the bioactive properties, thermal stability, and increased the resistance toward hydrolytical degradation.…”

“…The general concept of cell interaction demonstrates that cells attach much more readily to hydrophilic materials than to hydrophobic surface. The hydrophilic/hydrophobic nature of this novel material was previously analyzed by contact angle measurement 15. The degree of contact angle allows characterizing the surface wettability of a material, and can act as an indicator of its hydrophilicity/hydrophobicity.…”

A review of bioceramics-based dental restorative materials

“…However, it has been previously reported that by adding nano-HA as a filler, the material then becomes unsuitable for clinical performance and is hydrolytically unstable as compared to composites with microscopic particles 86,87) . The hydrophilicity of HA is due to the presence of the -OH group in its hexagonal structure that can easily attract surface moisture 153) , however it can be addressed with surface grafting during in situ synthesis 154) .…”

Effect of nano-bioceramics on monomer leaching and degree of conversion of resin-based composites

“…Fillers need silanization to immobilize them in the resinous matrix 5) . Previously, our group showed that addition of n-HA in the polymeric network and, on the other hand, the presence of hydrophobic matrices increased the degree of wetting and reduced water sorption 4,25,26) . In the current study, addition of n-HA improved the polymerization process.…”