Constrution Of Red Blood Cell Membrane Coated Black Phosphorus Quantum Dots And Appication In Biological Analysis

Black phosphorus quantum dots(BPQDs)as a new form of black phosphorus(BP)nanomaterials,have excellent physicochemical properties such as broad absorption in spectral region,high photothermal conversion efficiency and h igh singlet oxygen yield.It has broad prospect in biomedicine field such as biosensors,drug delivery and cancer therapy.Under the conditions of water and oxidative stress,BPQDs degrade to produce phosphate which is a substrate in biological reaction an d metabolite in the body.But transient rise of phosphate in the cytoplasm may break the balance of the cell microenvironment,inhibit ing its proliferation and leading to cell death.Moreover,due to the strong intracellular oxidative stress and accelerate d energy metabolism in tumor cells,the degradation behavior of BPQDs in tumor cells is different from that in normal cells,which makes BPQD s capable of becoming a kind of bioactive nanomaterials that selectively kills tumor cells.At present,the application of BPQDs in biomedicine still faces some problems,such as poor biological stability,short blood circulation time and strong immune repulsion.Therefore,it is crucial to improve the stability of BPQD s in biological system,prolong its circulation time in vivo,and increase the enrichment degree of BPQDs in tumor sites.Nano vehicles have the characteristics of long circulation time and high drug delivery rate.Using nano vehicles to encapsulate BPQDs is the most effective way to improve its stability.Amon g them,natural red cell membrane vehicles have the merits of easy extraction and purification,long circulation time in vivo and low immune repulsion.These vehicles with unique properties are of great help to improve the stability of BPQDs in biological system,and are expected to become the best nanocarrier for BPQDs.In order to further study the biological behavior of BPQDs,we designed the red blood cell membrane coated black phosphorus quantum dots(BPQDs@RBCM).On the one hand,we studied the degrada bility,stability and other properties of BPQDs@RBCM,On the other hand,we analyzed the biological behavior of BPQDs@RBCM based on these properties.The specific contents are as follows:(1)In order to prolong the circulation time of BPQDs in vivo,the BPQDs@RBCM was constructed by coating BPQDs with RBCM in this chapter,and its stability and degradation were also analyzed.Firstly,we synthesized 2-3 nm ultra-small BPQDs.Then,RBCM and BPQDS were mixed and extruded to realize the encapsulation of BPQDS by RBCM.The results of morphology,particle size and surface charge(Zeta)show that we have successfully synthesized BPQDs@RBCM with spherical appearance,size of 40-50 nm and Zeta potential of about-12 m A.Secondly,the results of gel electrophoresis showed that the surface membrane protein of BPQDs@RBCM was basically not lost,and UV absorption detection also comfirmed that the stability of BPQDs @RBCM was higher than that of bare BPQDs,which played an important role in maintaining long-term stable circulation of BPQDs in the body.Finally,the unpar allel degradation of BPQDs@RBCM occurred in different solution condition mimicking the normal physiological environment and tumor microenvironment.Moreover,the degradation rate of BPQDs@RBCM in the simulated tumor environment was higher than that in norm al environment,which indicated that the stability of BPQDs@RBCM was improved while the degradability was retained,and the degradation of BPQDs @RBCM was also environmentally selective.Based on the results of the above studies,BPQDs@RBCM is expected to be used as a bioactive nanomaterial for the specific treatment of cancer.(2)In order to evaluate the biological behavior of BPQDs@RBCM in tumor cell and its therapeutic potential,this chapter explores the mechanism of biological toxicity of BPQDs@RBCM at the cellular level.Firstly,we used mouse osteoblasts(MC3T3)and oral squamous cancer cells(SCC7)as the models to investigate the degradation behavior and the toxic effect of BPQDs@RBCM in different ce lls.The results of Raman scattering characterization and toxicity experiment showed that the degradation rate of BPQDs@RBCM in SCC7 cells is higher than that in MC3T3 cells,and it has a greater toxic effect on SCC7 cells.In order to explore the toxicity mechanism of BPQDs@RBCM to tumor cells,we observ ed the effects of BPQDs@RBCM on intracellular reactive oxygen species concentration and organelle structure by transmission electron microscope,and used Western blot to explore the expression of proteins related to the apoptosis pathway.The results showe d that BPQDs@RBCM can increase intracellular autophagy vesicles through the reactive oxygen species pathway,promote autophagy levels and cell apoptosis.The evaluation of the biological toxicity mechanism of BPQDs@RBCM in SCC7 cells,paves the way for anti-tumor properties of BPQDs in vivo.