Scanning surface confocal microscopy for simultaneous topographical and fluorescence imaging: application to single virus-like particle entry into a cell.

We have developed a method for simultaneous recording of high-resolution topography and cell surface fluorescence in a single scan which we call scanning surface confocal microscopy. The resolution of the system allows imaging of individual fluorescent particles in the nanometer range on fixed or live cells. We used this technique to record the interaction of single virus-like particles with the cell surface and demonstrated that single particles sink into the membrane in invaginations reminiscent of caveolae or pinocytic vesicles. This method provides a technique for elucidating the interaction of individual viruses and other nanoparticles, such as gene therapy vectors, with target cells. Furthermore, this technique should find widespread application for studying the relationship of fluorescently tagged molecules with components of the cell plasma membrane.