Universal Cell Surface Imaging for Mammalian, Fungal, and Bacterial Cells

Because of the distinct surface structures of different cells (mammalian cells, fungi, and bacteria), surface labeling for these cells requires a variety of fluorescent dyes. Besides, fluorescent dyes (especially the commercial ones) for staining Gram-negative bacterial cell walls are still lacking. Herein, a conformation-adjustable glycol chitosan (GC) derivative (GC-PEG cholesterol-FITC) with "all-in-one" property was developed to realize universal imaging for plasma membranes of mammalian cells (via hydrophobic interaction) and cell walls of fungal and bacterial cells (via electrostatic interaction). By comparing the different staining behaviors of GC-PEG cholesterol-FITC and three other analogs (GC-PEG-FITC, GC-FITC, and cholesterol-PEG-FITC), we have elucidated the different roles the hydrophobic and electrostatic interactions play in the staining performance of these different cells. Such a simple, noncytotoxic, economic, and universal cell surface staining reagent will be very useful for investigating cell surface-related biological events and advancing cell surface engineering of various types of cells.