Preparation And Antibacterial And Antitumor Activity Of Quercetin-Polydopamine(PDA)encapsulated In Cell Membrane

Polydopamine?PDA?,as a synthetic melanin,has the same physical and chemical properties as natural melanin?Melanin?,and has anti-tumor and antibacterial activity.However,because PDA has low water solubility,it cannot be effectively used.Therefore,this experiment mainly studies the PDA surface modification and carrier loading to improve the use efficiency of PDA.In this experiment,the PDA chemical synthesis method is optimized.A PDA with uniform particle size and uniform shape is synthesized under the condition of avoiding light.At the same time,the natural drug quercetin?Q?is modified by?-?interaction and covalent bond interaction.On the surface of PDA,quercetin-melanin?PDA-Q?was obtained,and the PDA and PDA-Q were characterized by infrared absorption spectrum,ultraviolet absorption spectrum,scanning electron microscope SEM analysis,transmission electron microscope TEM analysis and Zeta potential particle size analysis.Q has natural anti-tumor and antibacterial activity.Under acidic or neutral conditions,the PDA shell falls off,which can effectively release quercetin to achieve antibacterial effect.The MIC test,CFU test,LIVE/DEAD test and ultra-thin section test were used to verify the antibacterial effect of PDA-Q.The results of this experiment are as follows:PDA and PDA-Q are in the form of black spheres with a diameter of about 100 nm,uniform particle size,and uniform shape.The release rate of PDA-Q under acidic conditions is higher than that under neutral conditions.The antibacterial test screened out the target bacteria of drug-resistant Escherichia coli.The MIC value was 10.6±0.34?g/m L.CFU and LIVE/DEAD tests showed that PDA-Q with the same drug concentration had stronger antibacterial activity,and the antibacterial effect increased with the increase of drug concentration.The ultrathin section test further analyzed the potential antibacterial mechanism:PDA-Q can enter the cell,thereby destroying the integrity of the bacteria and causing bacterial death.Also due to the low water solubility of PDA-Q,it is not targeted in tumor treatment,and its bioavailability is greatly limited.Inspired by natural cells,this paper aims at the problem of clear immunity and non-targeted transportation encountered in the in vivo transport of nanocarriers,and studies how to use the homogenous targeting characteristics of tumor cells in vivo to extract the cell membrane of small intestine cancer?HIC?cells,Encapsulated PDA-Q,obtained quercetin-melanin?C@PDA-Q?wrapped in cell membrane,and verified the resistance of C@PDA-Q by MTT test,LIVE/DEAD test and cell flow cytometry technology Tumor effect.The results of this experiment are as follows:C@PDA-Q has a spherical shape with a diameter of about 120 nm and a film-like structure on the outside.In the MTT test,HIC cells were selected as the target object.The IC₅₀ value of C@PDA-Q treated HIC cells was 12.3±0.7?g/m L.In the LIVE/DEAD test results,at the same concentration,C@PDA-Q Has the best anti-tumor effect.In the analysis results of cell flow cytometry,as the concentration of C@PDA-Q increased,the anti-tumor effect gradually increased,showing a concentration-dependent.