Figure 1.

Schematic of single-virus content-mixing assay. Influenza A virions are tethered to a passivated (gray), DNA-functionalized glass coverslip in a microfluidic device through DNA hybridization (green). Target vesicles containing a self-quenched concentration of SRB content buffer (red) and GD1a glycolipids (purple) bind to HA (blue) of influenza A virions. For vesicles composed of 10 mol% cholesterol, vesicles also displayed a small number of DNA-lipids that were orthogonal to the surface-tethering sequences (Fig. S1). Once vesicles are bound, low pH buffer is exchanged to trigger fusion, and fluorescence dequenching occurs as the contents between target vesicle and virus mix. To see this figure in color, go online.