Bio-mineralisation on the composites of silicon-based polymer and nanodiamond particles by a species of Serratia Bacteria

Serratia sp. NCIMB 40259 is a non-pathogenic Gram-negative bacterium that is able to produce hydroxyapatite by a mechanism involving enzymic cleavage of organic phosphates. Serratia bacteria can attach and form a biofilm on glass, plastics, ceramics and metals and the method can be used to form three dimensional porous scaffolds and for coating 3D structures with hydroxyapatite. The production of calcium phosphate is driven by an acid phosphatase enzyme located in the bacterial cell wall, on fimbriae and within the bacterial extracellular polymeric matrix. Calcium phosphate ceramic may be obtained by two methods: In the first, crystals of calcium phosphate are formed extracellularly within the pre-formed bacterial biofilm grown on the substrata. In the second method, planktonic bacteria catalyse the formation of CaP in suspension and on solid substrata placed in the same container. Composite thin layer of silicon-based polymer and detonated nanodiamond (DND) particles was used as substrate for the process of biomineralization by a species of Serratia. The plasma polymerization (PP) method was chosen to obtain composites of silicon-based polymer, in which DND particles were incorporated. Over the past decades carbon-based nanostructures have been the focus of intense research due to their unique chemical and physical properties. Recently it was shown that the incorporation of the DND particles in a polymer matrix (an organosilicon polymer) changes their physico-chemical properties. The composite films are homogeneous, chemically resistant, thermally and mechanically stable, thus allowing a large amount of biological components to be loaded onto their surface and to be used in tissue engineering, regenerative medicine, implants, stents, biosensors and other medical and biological devices. The aim of this study was to investigate the process of biomineralisation by Serratia bacteria on various composites of silicon-based polymer and detonated nanodiamond particles, and to determine the effect of composite surface on the process of biomineralisation