- Fig. 1: Images of the copper (left) and cobalt (right) doped bioactive glasses. (Courtesy of Dr Richard Martin)
Making stained glass is an ancient skill, known to the artisans of Ancient Rome and Egypt. Stained glass as an art form reached its zenith in medieval Europe, with magnificent windows crafted for great cathedrals. In the 12th century, the German monk Theophilus studied glaziers and glass painters and recorded their methods, and it’s clear that the basic methods, at least, have changed little. But while Theophilus might recognise the glass-making that goes on in Dr Martin’s lab, he would be astonished by the resulting glass, and its purpose.
Bioactive phosphate glasses are of considerable
interest for a range of soft and hard tissue engineering
applications, because they are degradable and can release
biologically-important ions in a controlled manner. Including calcium and phosphate in a bioactive glass, for example, can help with bone regeneration. The body’s natural remodelling processes reabsorbs these minerals and then deposits them to form new bone, which can be quite a slow process. Bioactive glasses are quicker to dissolve, providing minerals that can be used to form bone more rapidly.
Recent work has investigated adding cobalt to bioactive glasses to increase blood flow, which can be critical for healing, and studies have shown that glasses can be tailored to release cobalt ions at biologically effective concentrations, with no risk of toxicity. Dr Martin and his team wanted to investigate whether cobalt-doped bioactive glasses could also be manufactured with antimicrobial activity.
Dr Martin and his team use X-ray Powder Diffraction to investigate the bioactive glasses they make, and are frequent visitors to the I15 beamline (and also to ISIS
, where they conduct complementary neutron studies). Whist investigating the structure of several other bioactive glasses the team took the opportunity to confirm that their cobalt doped glasses were indeed glassy, and had not crystallised, which can cause reduced bioactivity. The samples needed to be ground into a powder for analysis, but that is the way they would be used in the body, where they would be used as a filling agent for small defects or incorporated into coatings.