EPC Capture Magnetic Nanoparticles:Surface Modification And Evaluation

Applying vascular stents to treat cardiovascular diseases has been one of the most effective and rapidly adopted medical interventions.However,numerous reports have suggested the increasing incidences of in-stent restenosis（ISR）and late stent thrombosis（LST）after the implantation of stents.During the past decades,several generations of stents have been designed with a growing knowledge of the interaction among stent,blood and endothelium.Nowadays,bare metal stent,drug eluting stent,the endothelial progenitor cells（EPCs）capture stents,biodegradable metal stents,fully degradable stents and time sequence functional stents are currently in clinical evaluation.The outcomes of these studies are highly expected.Endothelial progenitor cells are a class of pluripotent stem cells with a characteristic of migration in the blood.It has a strong proliferative capacity and can differentiate into endothelial cells and repair damage in the vessel wall.Constructing endothelial progenitor cell capturing stents is currently hot field in cardiovascular diseases treatment.However,because of the weak specificity of binding between endothelial progenitor cells and biological molecules,the small number of progenitor blood cells and other factors,the number of endothelial progenitor cells and process of capturing the stent surface are limited.The use of magnetic nanoparticles capturing endothelial progenitor cells becomes more and more popular,but magnetic nanoparticles and magnetic field source function is relatively weak.This study introduced the iron stent as another source of the magnetic response to work together to improve the nanoparticles surface capture rates.In this study,magnetic nanoparticles modified with anti-CD34 antibody were constructed,which can specifically bind to endothelial progenitor cell and enriched in the surface of the stent under the guidance of a magnetic field.Fourier Transform Infrared Spectroscopy,nanoparticle size analysis,and other testing methods were used to detect the surface modified magnetic nanoparticles.The EPCs were cultured with the surface modified magnetic nanoparticles to evaluate cell compatibility and the combination effect of nanoparticles on EPCs in a short period of time.Directional guide of the surface modified magnetic nanoparticles to EPCs was evaluated under applied magnetic field and simulated dynamic flow condition.The results showed that the magnetic nanoparticles were successfully modified with CD34 antibody,which had good cell compatibility within a certain range of the nanoparticle concentrations.The surface modified nanoparticles can combine with EPCs effectively in a short time,and those nanoparticles combined EPCs can be directional guided under the magnetic field in the dynamic flow environment.The results of in vivo animal experiment exhibited that the Fe₃O₄-PEG@CD34 nanoparticles could specificity recognize and capture CD34+ cells.The Fe₃O₄-PEG@CD34 nanoparticles could rapidly home CD34+ cells to the surface of iron stents with the additional magnetic field.Thus,the CD34 antibody-modified magnetic nanoparticles might help to realize rapid endothelialization.