Rapid biofabrication of cell-free, anisotropic collagen tissues using a novel horizontal shear flow technique

Ultrastructure and organisation of collagen fibres is essential to tissue function, due to the loadbearing properties of collagen. Current techniques used to create aligned collagen tissue equivalents use the contractile ability of cells to remodel and align collagen fibres or utilise highly specialised pieces of equipment. The aim of this study is to develop a novel and rapid method to produce acellular aligned collagen sheets by combining horizontal shear flow (HSFlow) and the established RAFT method to remove excess fluid from a hydrogel.

Force applied to the gel during the HSFlow process was measured to allow replication of the method. Quantification of fibres and cellular alignment revealed a significant difference between HSFlow and control samples, where both cells and collagen fibres showed alignment in the direction of shear flow, compared to the randomly aligned RAFT controls. Mechanical properties were also measured and revealed that HSFlow does not appear to improve the strength of the constructs despite the improved alignment, therefore further optimisation is needed to strengthen the constructs.

In conclusion, we developed a novel and rapid technique to generate flat sheets of aligned collagen without relying on the contractile ability of cells to rearrange collagen fibres. This rapid method has potential to be used in the fabrication of a scaffold to mimic anisotropic tissues for regenerative medicine.