Fabrication of porous collagen/chitosan scaffolds with controlling microstructure for dermal equivalent

Two sets of homemade apparatus have been utilized to fabricate collagen/chitosan porous membranes by quenching its acetic solution and subsequently extracting the solvent with ethanol. The influence of chitosan concentration on the surface morphology of the collagen/chitosan membranes was studied using a quenching cold plate (apparatus 1). The pore size was enlarged along with an increase in the chitosan content, accompanied with the emergence of a sheet‐like microstructure. Due to the large thermal conductivity of the membrane‐forming platform (stainless steel), collagen/chitosan membranes prepared using apparatus 1 at freezing temperature between −60 to −20 °C present similar pore size (2–4 nm) and surface morphology. However, a large difference in pore size is generated using apparatus 2 (membrane preparation in a cold ethanol bath) and using a membrane‐forming platform of poor thermal conductivity (polymethylmethacrylate), e.g. ∼10 to 20 μm at freezing temperature of −60 to −40 °C, and 265 μm at −20 °C accompanied with the transformation from fiber‐ to sheet‐dominated morphology. The spongy collagen/chitosan membranes with pore sizes ranging from tens to hundreds of micrometers and porosity higher than 95%, which could be used as dermal regeneration template, have thus been fabricated.