Coating Magnetic Nanospheres with PEG To Reduce Nonspecific Adsorption on Cells

With the rapid advancement of nanobioscience, the interaction between nanomaterials and cells has become increasingly important, among which, understanding the nonspecific adsorption (NSA) between nanomaterials and cells is beneficial to the comprehension of nano-bio interactions. Herein, magnetic nanospheres (MNs) modified with different types of poly(ethylene glycol) (MNs-PEG) were used as models to systematically study the NSA between nanomaterials and cells. By exploring different surface properties of MNs modified with PEG, we found that the NSA between MNs and cells was greatly reduced after the modification of MNs-COOH with a long-chain (MW: 10 000), brush-conformational PEG, the extremely low NSA rate of which (less than 5%) was nearly one-fifth that of unmodified ones. Additionally, PEG modification improved the colloidal stability and adsorption uniformity of MNs to cells and remarkably reduced the number of adsorbed white blood cells (WBCs) in circulating tumor cell detection from complex blood samples. Surprisingly, the number of adsorbed WBCs by immunomagnetic nanospheres (IMNs) was 17 times more than that of PEGylated IMNs (IMNs-PEG). In a word, this work provides some perspective for the study on nanobio interactions and will be helpful to the construction and surface modification of low-adsorption nanomaterials.