SERS imaging of protein-specific glycan oxidation on living cells to quantitatively visualize pathogen-cell interactions.

Glycan oxidation on the cell surface occurs in many specific life processes including pathogen-cell interactions. This work develops a surface-enhanced Raman scattering (SERS) imaging strategy for quantitative monitoring of protein-specific glycan oxidation mediated pathogen-cell interactions by utilizing Raman reporter DTNB and aptamer co-assembled platinum shelled gold nanoparticles (Au@Pt-DTNB/Apt). Using () and MCF-7 cells as models, Au@Pt-DTNB/Apt can specifically bind to MUC1 protein on the cell surface containing heavy galactose (Gal) and -acetylgalactosamine (GalNAc) modification. When interacts with cells, the secreted galactose oxidase (GO) can oxidize Gal/GalNAc, and the generated reactive oxygen species (ROS) further oxidizes DTNB to produce TNB for greatly enhancing the SERS signal. This strategy can quantitatively visualize for the first time both the protein-specific glycan oxidation and the mediated pathogen-cell interactions, thus providing key quantitative information to distinguish and explore the pathogen-resistance and pharmacological mechanisms of different drugs.