Preparation Of Black Phosphorus Nanosheets Drug Delivery System And Its Effect On Ischemic Brain Injury

Objective:To study the drug carrying capacity of black phosphorus and its protective effect on cerebral ischemia /reperfusion injury.Methods:Part I: black phosphorus was prepared by ordinary liquid phase method,res was loaded on BP nano tablets by PEG,the drug loading rate of black phosphorus was determined by UV spectrophotometry,the morphological changes of black phosphorus after drug loading were determined by stem and TEM,and the changes of particle size and zeta potential after drug loading were determined by Malvin particle sizer.Dialysis method was used to investigate the changes of drug release capacity of black phosphorus under nearinfrared light irradiation.Part II: the hemolysis of black phosphorus was studied by erythrocyte hemolysis test,the biocompatibility of black phosphorus was studied by HE staining test,and the brain targeting and bloodbrain barrier permeability of black phosphorus nanoparticles were investigated by fluorescent protein labeling method.Part III: TTC staining,Neurobehavioral Evaluation and brain edema were used to study the effect of black phosphorus on cerebral ischemia / reperfusion injury.Western blot was used to explore the molecular mechanism of resveratrol against ischemic brain injury.Results:Part I: according to the imaging results of scanning and transmission microscope,the nano flake structure is well preserved without obvious change after drug loading.The results of drug release experiment showed that black phosphorus had excellent drug loading capacity and stable drug release curve.According to the test results of Malvin particle sizer,the stability after drug loading is slightly worse than that before drug loading,and some black phosphorus nano tablets overlap.Photothermal experiments show that black phosphorus nanoparticles have excellent photothermal effect.Part II: investigation of hemolysis experiment of red blood cells by black phosphorus no hemolysis phenomenon occurred for black phosphorus and its drug loading.In vivo toxicity study of black phosphorus showed that black phosphorus and its drug loading had no obvious toxicity and high safety according to the results of H & E experiments.Through the analytical contrast of fluorescence intensity,black phosphorus nanosheets exhibited certain brain targeting and blood-brain barrier permeability under NIR light assisted irradiation conditions.Part III: the alignment of behavioral studies among different groups of mice by longa’s method showed that the black phosphorus drug loaded system could obviously improve the postoperative behavioral ability of mice.By contrasting the results of TTC staining in the infarct area,black phosphorus loaded drug administration group,the infarct size can be significantly reduced.Compared with the results of brain edema degree,black phosphorus loading could obviously reduce the degree of brain edema in the model mice.Western blot assay demonstrated that resveratrol may exert anti ischemic brain injury effects by activating the expression of antioxidant signaling pathway proteins Nrf2,HO-1.Conclusion:1.Black phosphorus has good drug loading capacity,excellent photothermal ability,efficient drug release ability under near-infrared conditions.2.Black phosphorus does not produce hemolytic effect at therapeutic concentrations and has good biocompatibility with low toxicity3.Under NIR conditions,black phosphorus has a certain brain targeting ability.4.Black phosphorus can improve the therapeutic effect of resveratrol in the brain.