University College London
My main research field, supported by Royal Society and EPSRC funding, currently concerns the simulation of glass materials for biomedical applications: namely, bioactive glasses for hard and soft tissue replacement and glass vectors for in-situ radiotherapy of cancer (further details below). In the past few years I have devised and developed new methods and computational/statistical tools to model structural and dynamical properties of these complex materials, and used them to expose hidden features which contribute to explain the biological behaviour of bioglasses: see for instance my recent perspective published in Phys. Chem. Chem. Phys. 16, 3874 (2014).
We have introduced new structural descriptors of the dissolution behaviour of the glass, beyond the network connectivity, and our simulations have been the first to explore from an atomistic point of view the structure and reactivity at the bioglass surface, the migration mechanism of sodium and calcium in the bioglass, and the effect of nanosize dimensions on the above features.These original ideas and approaches are now inspiring new computational work in this exciting field using similar approaches and tools.
Certain compositions of phosphosilicate glasses containing Na and Ca network modifiers can bond directly to bone - and in some cases to muscles - shortly upon implant in the human body. The bioactivity of these materials reflects the special response that they induce upon contact with the physiological environment, with a series of chemical and biological processes occurring at their surface, leading to the formation of a strong and stable bonding interface connecting the glass to the living tissues. This bond in turn enables stable integration of bioglass implants in the human host, and supports many successful biomedical applications as bone or soft-tissue replacements. Our approach involves using state-of-the-art simulation techniques to provide a new picture of these materials with atomistic resolution, which represents a step beyond conventional trial-and-error approaches, towards more rational progress in developing new bioactive compositions.
Glasses for in-situ radiotherapy of cancer
Radiotherapy for treatment of cancer is generally performed irradiating the tumour from an external source: the need to avoid unnecessary exposure to radiation and consequent damage to healthy surrounding tissues can result in ineffective treatment when irradiating some deep seated tumours, such as liver or kidney. In-situ radiotherapy, on the other hand, is performed by directly injecting the radionuclides in the blood vessels supplying the tumour, thus delivering a high, localized dose of radiation, which does not affect the surrounding tissues. A suitable vector is needed to transport the radionuclide to the tumour target site and lock it there; in addition to other specific properties, this "carrier" should have long enough durability in the physiological environment, to avoid releasing the active ions in the blood flow before their radiation decay. We are currently focusing on yttrium-doped alumino-silicate and bioactive glasses, and use computer simulations to investigate their structure, dynamics and surface reactivity, in order to probe and understand their potential as carriers for radiotherapeutic applications.