Effect of crosslinking density on swelling and mechanical properties of PEGDA400/PCLTMA900 hydrogels.

A biodegradable polymer network hydrogel was fabricated and characterized for neural tissue engineering purposes. The proposed hydrogel contains both hydrophobic and hydrophilic components. The hydrophobic component is a three-arm poly(e-caprolactone) maleic acid with molecular weight of 900 (PCLTMA), and the hydrophilic component is poly(ethylene glycol) diacrylate macromer (PEGDA) with molecular weight of 400. A monolithic hard gel was generated by chemical photo-crosslinking. Three different networks, with varied ratios of PEGDA to PCLTMA including 25/75, 50/50 and 75/25, were characterized by compression testing, and the swelling properties were studied in phosphate-buffered saline (PBS, 7.4). The results of this study show that a wide-range of swelling data was obtained when the composition of PEGDA to PCLTMA was changed. The compressive modulus was measured for each composition, and the 75/25 gel was stiffer than the other compositions. These basic material properties will provide preliminary data for hydrogel development to be conducted in our laboratory.