Red Blood Cell Membrane Based Biomimetic Modification Of Particles And Their Application In Cell Imaging And Construction Of Artificial Cell

Biomimetic membrane is an artificial membrane prepared from the extracted biological materials or synthetic functional material through the method of self-assembly, chemical crosslinking, surface adsorption to mimic the biological special structure and properties of biological membrane, which is the important content in the research of bionic technology. Red blood cells (RBCs) are nature's long-circulating delivery vehicles and rich in content in the blood. The structure of mammal mature red blood cell is simple and does not contain the nucleus and other organelles, so the cell membrane is easy to obtain. Here, we use the extracted red blood cell membrane phospholipids to encapsulate the hydrophobic quantum dots (QDs) and mediate them for cell membrane imaging. Meanwhile, red blood cell membrane phospholipids were also exploit to encapsulate the coacervate for the construction of artificial cells. Two works have been performed as following:1. Red blood cell membrane-mediated fusion of hydrophobic QDs with living cell membranes for cell imaging. RBCs membrane lipids were extracted by low osmotic hemolysis and they act as efficient surfactant to phase transfer the hydrophobic QDs. The resulting RBC-encapsulated QDs (RBC-QDs) maintained the single particle dispersion. Their zeta potential was -21.3±5,3 mV and they still preserved strong fluorescent properties. The RBC-QDs were applied to cell imaging. Fluorescence colocalization technique, time dynamic imaging, laser confocal scanning all confirmed that the RBC membrane mediated the fusion of RBC-QDs in cell membrane phospholipids, and the endocytosis of RBC-QDs will not occur even incubation more than 24 h. The cell membrane fusion mechanism is dependent on the size and the fluorescence emission wavelength of hydrophobic QDs. The fluorescence emission of 520 nm and 585 nm of QDs fused with the cell membrane, and 630nm fluorescence emission of the QDs were internalized into the cytoplasm. Single particle tracking imaging technique is used to distinguish the different diffusion behaviors of QDs. When the QDs were fused in the cell membrane, the diffusion coefficient was significantly reduced. The approach that red blood cell membrane was utilized to phase transfer and mediate the membrane fusion into cell membrane, provides a new tool for the cell membrane imaging of the QDs.2. Red blood cell membrane lipids encapsulated coacervate for the construction of artificial cell. Firstly, mixture of anionic polymer DNA and cationic polymer DEAE-Dextran precursor resulted in the formation of coacervate with average size of 8.8±2.5?m. The zeta potential of coacervate is determined from the their molar ratio of polymer precursors, and the zeta potential was close to the isoelectric point at the molar ratio of 2.05:1. The addition of extracted red blood cell membrane phospholipids into coacervate lead to the complete surface coating of coacervate. Fluorescence imaging showed that the red blood cell membrane covered on the surface of the coacervate, and a cell compartmentation formed. The biocompatibility of the red blood cell membrane-coacervate (RBC-coacervate) was investigated, and the resulted showed that the membrane coated coacervate can coexist with living cells. Meanwhile, the hemolytic ability of coacervate was found to be significantly decreased after coated the red blood cell membrane. Besides, RBC-coacervates have a high internalization and the loading capacity of the dye molecules such as doxorubicin. Therefore, a preliminary model of artificial cells was constructed based on the red blood cell membrane encapsulated coacervate, which provides an important reference for the application of artificial cells in the biological catalysis, cell imaging and drug loading.