Researchers from MIT have developed a technique that allows scientists to measure the growth of individual cells simultaneously. Their findings could lead to faster testing of new drugs and the ability to track the growth of cells in dynamic environments. The details are in a paper just published in the journal Nature Biotechnology.
A research team began development of the new measurement technique in 2007, refining it over the years. Cells in suspension flow through a tiny microfluidic channel with 10 to 12 resonant mass sensors. The sensors weigh individual cells as they pass through, allowing researchers to accurately measure cell growth rates. The team was able to measure over 60 mammalian cells, or 150 bacterial cells, in one hour.
The team is already using their device to conduct research. Antibiotic testing is normally a long process that first requires growing a culture. Using their new technique, the research team was able to test the effects of an antibiotic called kanamycin on Escherichia coli bacteria. The test, which would take at least a day using traditional methods, was completed in under an hour.
The research team also tested an antimicrobial peptide called CM15. CM15 pokes microscopic holes in the cell walls of bacteria, causing the contents to leak out. This kills the bacteria but the size of the cell doesn’t change, making it difficult to measure with standard microscopy methods. The team’s new measurement technique measures mass, not size, and could be used to analyze the effectiveness of CM15. As expected, the bacterial cells lost mass after being exposed to the CM15 peptide.
The ability to quickly measure the susceptibility of bacteria to antibiotics can allow for better testing of new medications. It can also be used to treat patients who quickly need the proper antibiotic for an infection. The team is already working with the Dana Farber Cancer Institute to conduct a new study. The authors are hopeful that their device could be used to measure the effectiveness of anticancer drugs by recording the mass of individual tumor cells after drug exposure.
Nathan Cermak et al. High-throughput measurement of single-cell growth rates using serial microfluidic mass sensor arrays. Nature Biotechnology (2016).