Water-stability and biological behavior of electrospun collagen/PEO fibers by environmental friendly crosslinking

Electronspun collagen fibers have to be crosslinked to improve their mechanical properties and water stability. But, the toxicity of some crosslinkers like glutaraldehyde have been fiercely debated. Others like genipin have been proved to affect the morphology of electrospinning fibers. Citric acid (CA) as a crosslinking agent has the advantages of simple, cheap and nontoxicity. In this paper, the effects of CA crosslinking on the physical and biological properties of electrospun collagen/polyethylene oxide (PEO) nanofibrous membranes were investigated and compared with dehydrothermal (DHT) crosslinking. Collagen/PEO fibers crosslinked by 10 wt% CA had at least 80 % higher crosslinking degree (p<0.05) and better water stability compared with DHT crosslinking (p<0.05). The stress of fibers crosslinked by CA (7.11±0.05 MPa) has been improved compared with non-crosslinked fibers (5.86±0.02 MPa). At the same time, the strain of non-crosslinked fibers was highest (10.90 %). The results of enzymatic (ED) and hydrolytic degradation (HD) of fibers showed crosslinking could improve the resistance of collagen/PEO nanofibers against ED and HD. The hemolytic percentages of fibers after crosslinking was below 5 %, which proved that CA could protect red cells from destroying. The results of cytotoxicity test showed fibers before and after crosslinking both had no cytotoxicity and that of animal acute test indicated membranes treated with DHT and CA had no apparent toxicity.