Effective Capture And Release Of Circulating Tumor Cells Using Core-shell Fe₃O₄@MnO₂ Nanoparticles

Under the influence of tumorigenic factors such as physical,chemical and biological factors,some of the cells lose the control in the genetic level of its growth and differentiation and grow unlimitedly to destroy normal tissue and organs.Not only that,tumor cells will be transferred to other organs to form metastases,studies have shown that most of cancer-related death were caused by tumor metastasis.Current means of cancer detection often the result in terminal cancer which means greatly increased difficulties of treatment.Circulating Tumor Cells?CTCs?refers to the cells that come from the primary tumor tissue or metastases and travel in the peripheral blood of patients,studies have shown that circulating tumor cells already exists in the peripheral blood in the early stage of tumor formation.Therefore,CTCs have very important clinical value for the early diagnosis of the tumor.Because circulating tumor cells in the blood content is very low,usually one milliliter of blood in cancer patients contains only a few to several hundred circulating tumor cells but there are hundreds of millions of normal blood cells as interfering cells,so capture and release of circulating tumor cells is still a huge technical challenge.Immune magnetic beads,is a new immunological technology developed in recent years.Using immunomagnetic beads to separate cells is based on the fact that the cell surface antigen can be connected with a specific monoclonal antibody linked to the magnetic bead.In the external magnetic field,cells connected with immunomagnetic beads were adsorbed and retained in the magnetic field,and other cells cannot be separated because they cannot connect to the specific monoclonal antibody that binds to the magnetic beads and without magneticity they cannot stay in the magnetic field,so the target cells can be separated.However,the immune magnetic beads are still attached to the surface of the cell separated from blood which will has a negative impact on the follow-up biomolecules analysis.Because manganese dioxide has good biocompatibility,the surface is rich in hydroxyl and easy for functional modification,so manganese dioxide has a very good application prospects in biomedical studies.Not only that,manganese dioxide can be dissolved by low concentrations of oxalic acid.In this paper,we will give a brief review of the background of CTCs as well as the means to capture them.Then in order to overcome the shortcomings of the magnetic beads after the capture of the tumor cells in the subsequent biochemical analysis,the core-shell Fe₃O₄@MnO₂ magnetic nanoparticles were prepared.The surface of the particles was functionalized and Anti-EpCAM was grafted on the surface of the particles to achieve the capture of tumor cells.And the release of the cells is achieved by dissolving the manganese dioxide in the shell by the treatment of low-concentration oxalic acid.In the end,we will give a brief summary of our research and a perspective of the future work.