Computer modelling of bio-material interfaces
Lead Research Organisation:
University College London
Department Name: Chemistry
Abstract
The project will employ computational techniques to investigate key aspects of the solid state chemistry of the major mammalian bone and teeth enamel constituent hydroxy-apatite, and its interactions with biological molecules and ceramic supports. As apatite is a possible candidate in the manufacture of artificial bones, we first need to understand the structure and formation of natural bone, which is grown on an organic matrix, in an aqueous solution containing a host of solvated ions. Another application, which may be important for the acceptance by the body of ceramic implants, is to use ceramics as a support for the crystallisation and layer growth of apatite, which can then bond to living bone. The aim of the research is to use state-of-the-art computer simulation techniques to advance generally our knowledge of the solid state chemistry of apatite minerals, but with a strong emphasis on the investigation of the major factors determining apatite crystal growth and its interfacial behaviour: first the formation of pure apatite in aqueous environment and the nature of solid solutions of fluor- and hydroxy-apatite, secondly interactions with impurities and implant materials, such as silicates and titania, and finally the adsorption of organics (e.g. RCOOH, RCP04H2, R3COH) and solvated ions (e.g. OH-, Cat+, C032-) onto the growing mineral surface.
Organisations
People |
ORCID iD |
| Nora De Leeuw (Principal Investigator) |
Publications
Liu F.
(2009)
A computer simulation study of the effects of anions on nickel carbonate crystallization process
in Chinese Journal of Inorganic Chemistry
Rabone J
(2007)
Potential routes to carbon inclusion in apatite minerals: a DFT study
in Physics and Chemistry of Minerals
Rabone JA
(2006)
Interatomic potential models for natural apatite crystals: incorporating strontium and the lanthanides.
in Journal of computational chemistry
Ruiz Hernandez SE
(2015)
The effect of water on the binding of glycosaminoglycan saccharides to hydroxyapatite surfaces: a molecular dynamics study.
in Physical chemistry chemical physics : PCCP
Tang E
(2010)
An Ab Initio Molecular Dynamics Study of Bioactive Phosphate Glasses
in Advanced Engineering Materials
Tilocca A
(2006)
Ab initio molecular dynamics study of 45S5 bioactive silicate glass.
in The journal of physical chemistry. B
| Description | The Fellowship project addressed the fundamentals of the structure, defect behaviour and surface and interface properties of the hydroxyapatite mineral, and biomaterials in general. Significant progress has been made in each of the five specific objectives, as follows: • Development of accurate models for the bulk and surface structures of apatite materials Density Functional Theory (DFT) calculations have been used to determine the structure of hydroxy-apatite, followed the derivation of interatomic potential models for all known natural apatite minerals, which accurately reproduced experimental properties. Next, these potential parameters were used to determine surface structures and stabilities of the apatite mineral in an aqueous environment and to calculate the crystal morphologies. • Investigation of solid solutions and determination of the role of impurities in phosphates A combination of DFT and interatomic potential techniques were used to investigate hydroxy-fluorapatite and fluor-chlorapatite solid solutions, as well as the uptake of a number of known impurity cations in the lattice and the incorporation of a range of carbon defects, especially carbonate groups which are of particular interest in biological hydroxyapatite. • Investigation of the mechanisms of crystal growth of apatites We have determined that fluoride ions strengthen the hydroxy-apatite mineral by ion exchanging from solution with the hydroxy groups and anchoring the surface calcium ions, which helps to explain the efficacy of fluoride in dental enamel in the prevention of caries. • Modelling the effects of organic adsorbates on crystal growth and morphology The adsorption of a number of important organic molecules to the apatite surfaces has been investigated and their strength of binding to the surface compared to that of water in order to evaluate their effectiveness as growth inhibitors. As the organics adsorb preferentially to certain surfaces, their presence during apatite crystal growth will have a marked effect on the eventual morphology of the apatite grain. • Investigation of apatite/ceramic interfaces and its relation to the role of apatites as bio-materials Real progress has been made in the modelling of apatite adhesion to a number of quartz and titania surfaces. We have investigated the effect of surface hydration on the binding of the apatite thin films to the quartz surfaces as well as the effect of surface topology on the growth of apatite nano-particles on the titania surfaces. A comprehensive final report was submitted to EPSRC on completion of the fellowship. |
| Exploitation Route | May be taken up by tissue engineers to help develop biomaterials that better mimic natural tissue |
| Sectors | Healthcare |
| Description | Published in peer-reviewed scientific journals, presented at international conferences, used as a basis for further funding applications, formed the basis of new research collaborations abroad |
| First Year Of Impact | 2002 |
| Sector | Healthcare |
| Impact Types | Societal |
| Description | Royal Society Wolfson Research Merit Award |
| Amount | £87,500 (GBP) |
| Organisation | The Royal Society |
| Sector | Charity/Non Profit |
| Country | United Kingdom |
| Start | 07/2009 |
| End | 07/2014 |