June 9, 2008 Bone growth and joint replacement is a painful process, but British scientists claim that one possible solution for a glass jaw is, well, a jaw made from glass. New research into a porous "bioactive" glass substance that activates the genes responsible for stimulating bone growth has the potential to replace the need for bone transplants. .

Originally developed at Imperial College, the glass dissolves completely after entering the body, leaving no trace of itself or any toxic chemicals. While dissolving, it releases specific concentrations of soluble silica and calcium ions into adjacent body fluids. When the timing sequence of the cell cycle is matched by the controlled release of the ions and the glass surface reactions, gene activation occurs. This results in the encoding of proteins to form bone matrix and the rapid mineralization of bone nodules.

The research at the Science and Technology Facilities Council’s ISIS neutron source is revealing how the calcium is suspended in the glass, and how it is disseminated through the body. When the ISIS Second Target Station opens later this year, scientists will investigate glass/polymer hybrids, and attempt to develop mechanically stronger versions of the glass. If the glass substance is made strong enough it could be used for joint replacement. Researchers hope to conduct clinical trials within the next five years.

Professor Bob Newport at the University of Kent states “Although variants of these bioactive materials are already in clinical use, and the role of calcium in these materials was already understood as being critical in terms of both the stability of the glass and its bioactivity, no direct and quantitative study of the calcium atoms within the glass network had been undertaken. Using ISIS to study the relationship between these atoms and the host silicate glass via techniques unique to neutron diffraction has enabled us to move forward with the programme. The key outcome of our experiments has been a full understanding, at the level of atomic arrangements, of why it is that calcium is able so easily to leave the glass at the rate required to generate the desired response.”