The use of transglutaminase in the modification of collagen for the development of biomaterials

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Chau, D.Y.S., 2007. The use of transglutaminase in the modification of collagen for the development of biomaterials. PhD, Nottingham Trent University.

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Abstract

Collagen, type I, is a highly abundant natural protein material which has been cross- linked by a variety of methods Including chemical agents, physical heating and UV Irradiation with the aim of enhancing its physical characteristics such as mechanical strength, thermal stability, resistance to proteolytic breakdown, thus increasing its overall biocompatibility. However, in view of the toxicity of residual cross-linking agents, or Impracticability at large scales, it would be more useful if the collagen could be cross-linked by a milder, efficient and more practical means by using enzymes as biological catalysts. We demonstrate that on treating native collagen type I with both tissue transglutaminase (TG2; tTG; guinea pig liver) and microbial transglutaminase (mTG; Streptoverticilllium mobaraense) leads to an enhancement in cell attachment, spreading and proliferation of human osteoblasts (HOB) and human foreskin dermal fibroblasts (HFDF) when compared to culture on native collagen. The transglutaminase-treated collagen substrates also showed a greater resistance to cell-mediated endogenous protease degradation than the native collagen. Moreover, the HOB cells were shown to differentiate at a faster rate than on native collagen when assessed by measurement of alkaline phosphatase activity and osteopontin expression. It has also been demonstrated that it is possible to further enhance biocompatibility of the novel biomaterial by incorporating additional growth/attachment peptides and proteins (i.e. fibronectin) via a transglutaminase- mediated reaction. Furthermore, analyses including atomic force microscopy (AFM) confirm distinct differences; not only between the gross macro-structure of the matrix but, also, changes to the molecular formation of the fibrils of the native compared to the transglutaminase-crosslinked collagen. The results suggest that the modified collagen experiences physical conformational changes that expose new (or more) cryptic sites (consistent with a quasi-collagen-gelatin material) that leads to increased cellular characteristics brought about by enhancement of outside-in Integrin mediated signaling pathways. As such, it has been demonstrated the transglutaminase enzyme can be used as a biocatalyst to modify collagen to develop novel biomaterials that are conducive to both soft and hard tissue repair applications.

Item Type:

Thesis

Creators:

Chau, D.Y.S.

Date:

2007

ISBN:

9781369314793

Identifiers: