Construction Of Biology Functionalized Magnetic Nanoparticles For Capturing Endothelial Progenitor Cells

Currently coronary heart disease treatment methods mainly comprise medications, surgery and interventional treatment. Duing simple operation, quick results and less trauma advantages, interventional treatment has become the most important means, in which percutaneous coronary interventional therapy (PTCA) is one of the most effective technique. However, stents can cause vascular endothelial injury, thrombosis and restenosis. The study found that accelerated re-endothelialization of the stent fastly will inhibit restenosis and late thrombosis. Therefore capturing and homing progenitor cells (EPCs) to vascular endothelial injury sites is an effective regulating means to physiologic repair endothelial damage. Now EPCs can be captured by magnetic nanoparticles.This paper used gallic acid (GA) to modify Fe3O4 then combined with CD34 antibody, obtained magnetic nanoparticles of good magnetic response and specific recognition EPCs(MNP@GA-CD34); Fourier transform infrared spectroscopy(FT-IR), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) results showed that GA and CD34 antibodies successfully modified MNP. Particle size analysis (DLS), field emission scanning electron microscope (SEM) and vibrating sample magnetometer (VSM) respectively characterized hydrated particle size, morphology and magnetic saturation of before and after the modification nanoparticles. DLS results showed that particle size of bare Fe3O4 nanoparticles larger than the modified nanoparticles, because of the dispersion of the surfactant GA; SEM results also showed that Fe3O4 nanoparticles had severe agglomeration and larger particle size, MNP@GA and MNP@GA-CD34 had clear particle outline and decreasing particle size. But MNP@GA-CD34 were less dispersed uniformly than MNP@GA. Because it was difficult to ensure each antibody bind to nanoparticles. VSM displayed saturation magnetization of three samples decrease gradually.Secondly, evaluating the influence of biology functionalized magnetic nanoparticles on EPCs adhesion, proliferation, apoptosis and label effect in vitro; The results showed:five group concentration 12,24,48,96,120μg/ml of MNP@GA-CD34 labeled cells by binding on the cell surface. Labeled effect showed cells in high concentrations of MNP@GA-CD34 spreading well. When MNP@GA-CD34 concentration increased, the cells appeared to fall off. Proliferation and adhesion results displayed when concentration higher than 24μg/ml, cells proliferation and normal adhesion had been significantly inhibited.24μg/ml of MNP@GA-CD34 cell group hadn’t significant apoptosis phenomenon. Therefore, the optimum concentration of MNP@GA-CD34 to capture EPCs was 24μg/ml.To study MNP@GA-CD34 attracted EPCs to targeted site under short and long-term external magnetic field action. The results showed that the number of cells of MNP@GA-CD34 group than MNP@GA group as well as control group, the number of capturing cells in long-term magnetic field significantly increased than short-term. Peristaltic pump circulation systems, combining with stent, comparing the presence or absence of external magnetic field, MNP@GA-CD34 showed captured effect and the number of adherent cells in the stent surface more than non-magnetic field group. Preliminary indication was MNP@GA-CD34 had captured effect on the EPCs.