WHOLE PARTICLE MICROELECTROPHORESIS FOR SMALL VIRUSES

The surface-charge characteristics of viruses in water can strongly in fluence their behavior with respect to physicochemical processes like coagulation and filtration. In the past, characterization of this surf ace charge by whole-particle microelectrophoresis has been limited to relatively large viruses, primarily due to difficulties in visualizing the individual virus particles. Here, we demonstrate a new approach f or performing microelectrophoresis measurements which permits the surf ace characterization of even very small viruses. Our approach differs from conventional microelectrophoresis measurements in that virus part icles are visualized by light scattering, employing a green laser (wav elength = 544 nm) as the light source. We demonstrate this technique b y characterizing the electrophoretic mobilities and isoelectric points of two viruses-bacteriophage MS-2 and lambda (lambda strain cI47)-whi ch differ in their shape and size. (C) 1995 Academic Press, Inc.