A Novel Injectable pH/Temperature Sensitive CS-HLC/β-GP Hydrogel: The Gelation Mechanism and Its Properties

摘要

The chitosan-human-like collagen/β-sodium glycerophosphate (CS-HLC/β-GP) hydrogel, is sensitive to pH and temperature changes and has proved to be a potential candidate as an injectable filling biomaterial in plastic and reconstruction surgery. The formation and pH/temperature-sensitivity mechanism of the novel CS-HLC/β-GP hydrogel were explored by Fourier transform infrared spectroscopy (FTIR) and swelling tests. Our results showed that an amide bond (-CONH) is formed between the carbonyl (CO) of HLC and the amino of CS and -NRH_2~+ is formed between the amide bond and β-GP; the temperature sensitivity depended on the hydrophobic-hydrophilic interaction of molecular chains, and the pH sensitivity depended on the electrostatic interaction of ionic groups (-NRH_2~+ and -OPO_3~(2-)). The properties of the novel CS-HLC/β-GP hydrogel were also examined using the tube inverting method, the swelling test, the liquid displacement method, and mechanical testing. The gelling time before and after addition of HLC is 30 min and 8 min, respectively, at 37℃. Compared with conventional CS/β-GP hydrogels, such as CS-AC (animal-derived collagen)/β-GP hydrogel, the CS-HLC/β-GP hydrogel showed a desirable porosity level, swelling ratio, pH/temperature sensitivity, a smooth surface, regular porous networks, and adequate mechanical strength and cross-linking densities. Therefore, the CS-HLC/β-GP hydrogels are excellent candidates for use in biomedical fields, such as in soft tissue defect filling and drug delivery.