光热敏感型羧甲基壳聚糖纳米微球的制备及光热性能

Carboxymethyl chitosan is widely used in biomedical field due to its good water solubility and biocompatibility. In this paper, N-isopropylacrylamide was grafted onto carboxymethyl chitosan by free radical combination method under the action of initiator potassium persulfate with natural degradable polymer carboxymethyl chitosan as carrier. Then, a new photo-thermal sensitive carboxymethyl chitosan microsphere loaded with photosensitizer indocyanine green (ICG) was prepared by emulsion crosslinking method under the crosslinking effect of vanillin. Fourier transform infrared (FT-IR), nuclear magnetic resonance (¹H-NMR) and scanning electron microscope (SEM) were used to characterize the structure of the copolymer and the morphology of the microspheres. The effects of oil-water ratio, rotation speed, vanillin and emulsification time on the drug loading rate of adriamycin in the nanospheres were investigated, and their photothermal properties were also studied. The experimental results shows that Fourier transform infrared (FTIR) and nuclear magnetic (¹H-NMR) analysis proved that N-isopropylacrylamide was successfully grafted onto carboxymethyl chitosan. Scanning electron microscopy showed that the appearance of the nanospheres was spherical, with uniform distribution and an average particle size of 143 nm. The drug loading rate of microspheres with oil-water ratio of 20:1, rotating speed of 600 r/min, vanillin content of 1 mL and emulsifying time of 3 h was the highest 19.32%. At the same time, the nano microspheres could slowly release drugs in a targeted manner and had good photothermal sensitivity. The nano microspheres had wide application prospects in the fields of drug controlled release, drug carriers and the like.