Preparation Of Near-infrared Light-responsive Injectable Hydrogel And Study On Photo-controlled Drug Releast

The light-controlled release type hydrogel has the ability to release the entrapped drug molecules on time and space under internal or external stimulation,and has outstanding advantages in many aspects such as drug utilization rate,treatment mode,toxic side effects,etc.Tumors offer new strategies.In this paper,a photo-controlled drug delivery system of disulfide-crosslinked polyaspartic acid hydrogel(PASP-SS)encapsulating proteinase K(PtNPs-ProK)adsorbing platinum nanoparticles was designed.The sulfhydryl group on the cysteamine is grafted onto the polyaspartic acid backbone and oxidized in the air to form PASP-SS.Characterization of chemical structure was showed by spectroscopic methods.The rheological properties of the spine showed the redox-induced reversible sol-gel transition of thiol-modified polyaspartic acid(PASP-SH).Platinum nanoparticles(PtNPs)are coated with a hydrophilic polymer,which is combined with proteinase K(ProK)by physical adsorption,and the local heating ability of PtNPs under infrared light irradiation enhances the enzyme activity of ProK.The morphology was characterized by transmission electron microscopy and laser confocal microscopy.The preparation method of PtNPs-ProK was optimized according to the particle size distribution of PtNPs and the enzyme activity of ProK.Under the optimal conditions,the control blank group increased the enzyme activity by 10 times.Finally,the effects of ProK on the degradation of PASP-SS under time were investigated by the changes in mass and rheological properties.The results of in vitro drug release experiments showed that the release rate of macromolecular drug lentinan under the irradiation of infrared light was significantly higher than that of normal release.The results of cytotoxicity experiments showed that the carrier of photo-controlled release hydrogel PASP-SH and oxidant sodium bromate PtNPs-ProK and lentinan have no proliferation inhibition effect on mouse embryonic fibroblast NIH3T3,while the macromolecular drug lentinan has a significant inhibitory effect on the proliferation of human breast cancer cell MCF7.The inhibition rate is 1000μg/mL.Up to 43.22%.