The carboxymethyl dextran shell is an important modulator of magnetic nanoparticle uptake in human cells

In oncology and hematology the separation of tumor cells from healthy cells in peripheral blood is a vital problem. We could show previously, that enrichment of tumor cells from peripheral blood is possible by using magnetic nanoparticles with a carboxymethyl dextran (CMD) shell. Long-term storage of CMD nanoparticles eliminated the differential labeling of tumor cells and leukocytes which might be due to an alteration of the carboxymethyl dextran shell. Incubation of stored CMD nanoparticles with freshly prepared carboxymethyl dextran restored the differential labeling. In contrast, enzymatic degradation of the carboxymethyl dextran shell with dextranase abolished the cell-type specific labeling. Thus, an intact carboxymethyl dextran shell is crucial for the cell-type specific interaction of the CMD nanoparticles and living cells.