Glass Reflections
Cambridge 7th to 9th September

Presenting Author:
Uresha Patel

article posted 01 Apr 2015


Uresha Patel is a second year PhD student in the advanced materials group at the University of Nottingham, where she is involved in investigating formulations doped with varying modifier oxides in aim of providing tailored degradation and ion release profiles. Structural analysis on complex (quaternary and quinternary systems) is also examined in order to develop an understanding of the inter-relationship between composition, structure, durability and ion release rates. Her interests lie in orthopaedic materials and completed her MSc in Biomaterials at the University of Manchester in 2013.

Strontium enriched phosphate based glass microspheres for orthopaedic applications

Uresha Patel*, Andrew Kennedy, Alex Hannon, Emma Barney, Ifty Ahmed
University of Nottingham

The worldwide ageing population is placing ever greater demands on healthcare systems to provide effective treatments for bone related diseases such as osteoporosis. Strontium ranelate has been used as a drug treatment for osteoporosis which is known to reduce the risk of fragility fractures. Studies in the literature have shown that strontium ions act by promoting bone making cells (osteoblasts) and reducing the activity of cells which break down bone (osteoclasts), hence minimising bone weakening [1].

Therefore the aim of this research was to manufacture bioresorbable phosphate based glass (PBG) microspheres, tailoring the composition of these glasses to include therapeutic ions, such as strontium, to be released during resorption.

This study focused on two strands of research. The first part investigated the manufacturing process used to produce microspheres (Figure 1a) of varying sizes. This processing was vital as the spherical morphology potentially enables treatment via a minimally invasive delivery route. Furthermore, microspheres provide greater versatility when fitting defects of various sizes as they can pack more efficiently compared to scaffolds with a predetermined shape.

The second part of this study focussed on the compositional development of the glasses used to optimise the therapeutic effects of the microspheres. A series of quaternary PBGs were fabricated by substituting the CaO component with SrO in order to investigate effects on their structure, thermal properties and their degradation profiles. Addition of Sr2+ ions had little effect on the glasses thermal properties (Figure 1b) suggesting degradation rates may also not be significantly different between compositions.

Substituting Ca2+ (1 A.U.) for Sr2+ (1.18 A.U) resulted in an increase in density (Figure 1c) and a marginal increase in molar volume suggesting that addition of slightly larger ions minimally increases the free volume of the network, with no unexpected changes in the local environment of the glass when substituting the therapeutic ion Sr2+ in place of Ca2+


[1] Kyllonen, L., et al., Local drug delivery for enhancing fracture healing in osteoporotic bone. Acta Biomaterialia, 2015. 11: p. 412-434.