Atomic microscope spots viruses

Researchers from BioForce Nanosciences Inc., Iowa State University and Des Moines University have combined an atomic force microscope with a method of capturing virus particles to produce a tool that rapidly detects viruses.

The atomic force microscopy immunocapture assay consists of a chip, dubbed the ViriChip, that contains antibody molecules used to selectively capture viruses. An atomic force microscope is then used to analyze what has been trapped. Atomic force microscopes use nanoscale tips to trace the topography of surfaces and are capable of detecting individual atoms.

The method identifies a virus using an entire virus particle rather than viral components, can detect viruses in liquids, and does not need to destroy viruses during the identification process. This allows intact, identified viruses to be further analyzed, according to the researchers.

Standard virus detection methods destroy viruses by chemically extracting DNA or RNA in order to generate the many copies of the molecules need for genetic analysis.

Another way to make antibody-based virus detection devices is to use exceedingly small and thus very sensitive nanowires or nanotubes. Nanowires and nanotubes can be as narrow as the span of a few atoms. This approach is development in other research labs, but is likely to take longer to make practical than the atomic force microscope method, according to the researchers.

The researchers used their prototype assay to detect six related viruses and a pair of bacteriophages from a range of complex mixtures including serum, urine, and primary wastewater sludge inoculated with the viruses.

The immunosensor array could be ready for practical use within a year, according to the researchers. The work appeared in the January 19, 2004 issue of Nanotechnology.