Combining Molecular Measurement Techniques on a Single Chip
Many people likely associate the image of a table covered with beakers, flasks, burners, and at least one microscope with a chemistry laboratory, but that is likely to change in the future. Many groups around the world are working on creating lab-on-a-chip systems that will condense chemical testing equipment onto something the size of a computer chip. Researchers at the University of California, Santa Cruz have recently created a chip with the ability to identify single molecules by combining electrical and optical measurement techniques.
The chip utilizes a nanopore that acts as a smart gate, to control the flow of molecules into a channel. The nanopore also allows the researchers to make electrical measurements as the molecules crosses it. For DNA passing through the nanopore, the electrical measurements would actually be able to determine the genetic sequence of the DNA, by fluctuations of the current. Once in the channel, the molecule is also exposed to a beam of light, and changes to the light's intensity indicates the size and optical properties of the molecule, as well as the flow speed through the channel.
When the researchers tested their chip with a mixture of influenza viruses and nanobeads of similar diameter, tagged with fluorescent labels, they found that they were able to distinguish between the two particle types using their electrical and flow properties with perfect accuracy. They were even able to count the number of virus particles, which would be very useful for analyzing samples.