Engineering Cell Surfaces via Liposome Fusion

In this study, we have rewired cell surfaces with ketone and oxyamine molecules based on liposome fusion for applications in cell-surface engineering. Lipid vesicles, functionalized with ketone and oxyamine molecules, display complementary chemistry and undergo recognition, docking, and subsequent fusion upon covalent oxime bond formation. Liposome fusion was characterized by several techniques including matrix-assisted laser-desorption/ionization mass spectrometry (MALDI-MS), light scattering, fluorescence resonance energy transfer (FRET), and transmission electron microscopy (TEM). When cultured with cells, ketone- and oxyamine-containing liposomes undergo spontaneous membrane fusion to present the respective molecules from cell surfaces. Ketone-functionalized cell surfaces serve as sites for chemoselective ligation with oxyamine-conjugated molecules. We tailored and fluorescently labeled cell surfaces with an oxyamine-conjugated rhodamine dye. As an application of this cell-surface engineering strategy, ketone- and oxyamine-functionalized cells were patterned on oxyamine- and ketone-presenting surfaces, respectively. Cells adhered, spread, and proliferated in the patterned regions via interfacial oxime linkage. The number of ketone molecules on the cell surface was also quantified by flow cytometry.