Surface modification of poly(dl-lactide-co-glycolide) copolymer with covalently immobilized collagen for esophageal tissue engineering

Synthetic polyester and the extracellular matrix molecules such as collagen are among the most widely-utilized amterials in tissue engineering. However, it is still difficult that collagen can be integrated onto polyester scaffolds without losing its biological function. In this paper, collagen is investigated to be covalently immobilized onto poly(lactide-co-glycolide) (PLGA) membrane surface via the bridge of 1,8-diaminooctane and with glutaraldehyde as cross-linking agent. It involved aminolysis of the PLGA using 1,8-diaminooctane to introduce free surface amino groups. Spectroscopy absorbance using ninyhdrin-labeling showed ultralow concentrations of free amino groups on the PLGA surfaces. To obtain the collagen modified PLGA surface, the free surface amino groups were further treated with glutaraldehyde, rinsed and incubated in collagen solutions. X-ray photoelectron spectroscopy (XPS) and fluorescence measurement have confirmed the existence of the bonded collagen. The effect of collagen-modified PLGA was compared with unmodified PLGA sample and tissue culture polystyrene (TCPS) plates using porcine esophageal smooth muscle cells (ESMC). DNA analysis showed that collagen-modified PLGA improved the overall proliferation of the ESMCs compared against unmodified PLGA and TCPS plates. Cells seeded on collagen-modified PLGA also showed a more extended morphology. The collagen-modified PLGA showed good potential for be used as a scaffold material for tissue engineering of the esophagus.