Dehydrothermal crosslinking of electrospun collagen

Electrospun collagen scaffolds must be crosslinked to improve stability. Chemical crosslinking methods are often associated with cytotoxicity and can require lengthy rinsing procedures to remove the crosslinker. Physical crosslinking using dehydrothermal (DHT) treatment is utilized to stabilize fibrous collagen sponges; however, little is known regarding the effect of DHT crosslinking on electrospun collagen. To investigate the efficacy of DHT crosslinking, soluble type I collagen was electrospun and exposed to DHT crosslinking, chemical crosslinking with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC; 5 mM), and DHT+EDC. DHT crosslinking produced no change in scaffold fiber diameter or interfiber distance and reduced scaffold degradation. Strength was significantly improved by DHT (139.0 ± 34.9 kPa) compared to control but was weaker than EDC or DHT+EDC (222.7 ± 58.4, 353.3 ± 19.0 kPa, respectively). Fourier transform infrared spectroscopy (FTIR) indicated increased amide bond formation with DHT compared to control but a lower amide bond density than EDC or DHT+EDC. After crosslinking, sterilization, and rinsing (a total of 50 h for DHT, 98 h for EDC, and 122 h for DHT+EDC), fibroblasts adhered and proliferated on all scaffolds; however, cell metabolism was 12% less on DHT scaffolds. These data indicate that DHT crosslinking can be utilized to stabilize electrospun collagen scaffolds; however, a tradeoff exists between scaffold stability/strength and rapid processing.