Coating Magnetic Nanospheres With PEG To Reduce Non-Specific Adsorption On Cells

Enrichment of circulating tumor cells(CTCs)from blood is a necessary step for their detection and analysis,where immuno-magnetic separation is the most commonly strategy for CTCs enrichment due to the high operability,efficiency and specificity.However,the non-specific adsorption(NSA)between magnetic nanomaterials and cells is inevitable in immuno-magnetic separation-based CTCs enrichment,which reduces the purity of enriched CTCs and the sensitivity in biosensing.On the other hand,with the rapid advances of nanobioscience,the interaction between nanomaterials(NMs)and cells has become increasingly important,among which,understanding the NSA between NMs and cells is beneficial to the comprehension of nano-bio interaction and the biological applications of NMs,but the study on which is still urgent.Herein,magnetic nanospheres(MNs)modified with different types of PEG(MNs-PEG)were used as models to 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 long-chain(MW:10000),hydrophilic PEG chains with brush conformation.The extremely low NSA rate of MNs-PEG(less than 5%)was nearly one-fifth that of unmodified ones.Additionally,PEG modification improved the colloidal stability of MNs and adsorption uniformity of different batches of MNs to cells.Surprisingly,the number of adsorbed white blood cells(WBCs)by immunomagnetic nanospheres(IMNs)in CTC detection from complex blood samples was 17 times more than that of PEGylated IMNs(IMNs-PEG).In a word,this work provides some perspectives for the study on nano-bio interaction,and will be helpful to the biomedical applications of nanomaterials.