Glass - Back to the Future!

Presenting Author:
Md Towhidul Islam

article posted 4 April 2016

Md Towhidul Islam is currently undertaking his PhD studies at the University of Nottingham (UK), working in the area of novel resorbable glasses and glass fibres under the supervision of Dr Ifty Ahmed.

In vitro bioactivity and degradation studies of novel phosphate based glasses for biomedical applications

Md Towhidul Islama*, Kazi M. Zakir Hossaina, Nusrat Sharminb, Andrew J. Parsonsa & Ifty Ahmeda
a Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UK
b Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, 199 Taikang East Road, university park, Ningbo, 315100, China

In the era of advanced biomedical science, interests in phosphate based glass (PBG) as potential bio-implant materials for application in bone tissue engineering have grown significantly due to their fully degradable and ion releasing properties. As the use of PBG for implant applications depends on the optimisation of their composition, this work aimed to develop an optimise PBG compositions in a quaternary/quinternary system. More specifically, this work aimed to investigate the effect of reducing Mg content on in vitro bioactivity, degradation rate and ion release properties in a glass series 40P2O5.(24-x)MgO.(16+x)CaO.(20-y)Na2O.yTiO2 (where 0<x<22 and 0<y<1). Five different types of glass formulations in the above mentioned glass series were prepared by melt-quenching using the following precursors sodium dihydrogen phosphate (NaH2PO4), calcium hydrogen phosphate (CaHPO4), magnesium hydrogen phosphate trihydrate (MgHPO4.3H2O), titanium dioxide (TiO2) and phosphorous pentoxide (P2O5) (Simga Aldrich, UK). The melt temperatures ranged from between 11501250C for 152 hours, depending on the titanium content in glass composition. The glass compositions produced were confirmed by energy-dispersive X-ray spectroscopy (EDX) and X-ray Diffraction (XRD) analysis, respectively. Thermal analysis was conducted using differential thermal analysis (DTA) and it was seen that the glass transition (Tg) temperature decreased from 450C for 24 mol% MgO to 412C for 8 mol% MgO. In vitro bioactivity studies were conducted using glass discs in simulated body fluid (SBF) at 37C up to 28 days. The surface morphology of the glass discs were analysed using a D8 Advanced Diffractometer and scanning electron microscopy (SEM) and compositions were also confirmed by EDX. Degradation studies were also performed in phosphate buffer solution (PBS) at 37C. The degradation rate was seen to be higher for the lower magnesium containing glass samples and a 31% wt loss up to 21 days was observed for the sample containing 8 mol% MgO. Ion release studies were also conducted via ion chromatography analysis.