A new technology can detect the metabolome of individual cells. With a detection limit in the zeptomolar range, the nanopost arrays (NAPA) technology also allows detection of contaminants in the environment at very low levels. The NAPA technology takes advantage of the interactions between silicon nanoposts and laser light, creating a ionization platform. NAPA was developed in the past years by Professor Akos Vertes’ team at George Washington University in collaboration with Oak Ridge National Laboratory. The discoveries were published in the journals Angewandte Chemie International Edition, Analytical Chemistry and Physical Chemistry Chemical Physics. The technology was eventually licensed by Protea Biosciences Group and in June 2015 it was commercialized as REDIchip™.
Cells respond to the changes in environmental conditions by adjusting their metabolism, that is, they change the amount and type of metabolites consumed or produced. Researchers are restricted to observe these changes at cellular population level due to technical limitations. Matrix-assisted laser desorption ionization (MALDI) MS techniques need to embed the sample in a matrix that hinders observation of small molecules in individual cells. But Dr. Vertes and colleagues solved the matrix background problem by getting rid of the matrix. In NAPA-MS, a cell is place on an array of silicon nanoposts, which are irradiated with laser pulses, in a process that ionizes the molecules inside the cell. So far, the scientists have observed the individual cell response to oxidative stress, and they have analyzed the biomolecules and xenobiotics in many samples.
The NAPA technique permits reusing current scientific platforms to measure trace levels of small molecules without background effects from the matrix.