Self-Assembling Peptides as Biomimetic Scaffolds for Mineralised Tissue Repair

Objectives: To investigate the ability of a range of SAPs to nucleate and support the growth of hydroxyapatite in vitro.

Methods: Quantitation of mineral deposited in self-supporting SAP gels compared with poly-GLU controls was carried out over 7d using a modification of the steady state system described by Hunter and Goldberg (Proceedings of the National Academy of Sciences, 1993). Further characterisation of crystalline deposits within the gels was made using SEM.

Results: All of the SAPs used were able to nucleate hydroxyapatite. However, the extent to which each SAP had accumulated mineral over the 7d period differed significantly. SEM revealed that crystal morphologies also differed, ranging from needle-like crystals to large flattened plates.

Conclusions: The results suggest that SAPs are able to nucleate and foster mineral growth under the in vitro conditions used here. The relationship between SAP structure and amount of mineral present within the gels is complex and not yet clear, though gel rheology, SAP chemistry and scaffold structure could all potentially contribute towards the differences observed. Further work using systematically designed SAPs will answer these questions and identify best candidate SAPs for skeletal tissue engineering.

(Supported by the Charitable Foundation of Leeds Hospitals Trust, the Royal Society (AA is a Royal Society University Research Fellow) and an EPSRC CASE award).