Intra-fibrillar citric acid crosslinking of marine collagen electrospun nanofibres.

The physical strength of the collagen fibre network in the extracellular matrix is due to the covalent crosslinks between the molecules within the fibres (intra-fibrillar crosslinks). Citric acid was investigated as an agent to introduce crosslinks within marine collagen electrospun fibres. We used collagen films to understand the ideal conditions for citric acid crosslinking. This information was used to develop an optimised method for intra-fibrillar crosslinking in electrospun marine collagen fibres, which increased the stability of these fibres in aqueous environments. The optimised method included a spinning solution containing collagen and citric acid at pH3.5 at high concentrations (260:1 citric acid:collagen molar ratio) coupled with high temperature annealing (165°C), which resulted in the highest intra-fibrillar crosslinking density in electrospun fibres.