Monitoring bacterial growth using tunable resistive pulse sensing with a pore-based technique
- 1.3k Downloads
A novel bacterial growth monitoring method using a tunable resistive pulse sensor (TRPS) system is introduced in this study for accurate and sensitive measurement of cell size and cell concentration simultaneously. Two model bacterial strains, Bacillus subtilis str.168 (BSU168) and Escherichia coli str.DH5α (DH5α), were chosen for benchmarking the growth-monitoring performance of the system. Results showed that the technique of TRPS is sensitive and accurate relative to widely used methods, with a lower detection limit of cell concentration measurement of 5 × 105 cells/ml; at the same time, the mean coefficient of variation from TRPS was within 2 %. The growth of BSU168 and DH5α in liquid cultures was studied by TRPS, optical density (OD), and colony plating. Compared to OD measurement, TRPS-measured concentration correlates better with colony plating (R = 0.85 vs. R = 0.72), which is often regarded as the gold standard of cell concentration determination. General agreement was also observed by comparing TRPS-derived cell volume measurements and those determined from microscopy. We have demonstrated that TRPS is a reliable method for bacterial growth monitoring, where the study of both cell volume and cell concentration are needed to provide further details about the physical aspects of cell dynamics in real time.
KeywordsTunable resistive pulse sensing Bacterial growth monitoring Cell volume Cell concentration
This work is supported by the Hong Kong RGC Collaborative Research Fund (CUHK3/CRF/11G), the Lo Kwee-Seong Biomedical Research Fund, and the Lee Hysan Foundation.
- Henriques AO, Glaser P, Piggot PJ, Moran CP Jr (1998) Control of cell shape and elongation by the rodA gene in Bacillus subtilis. Mol Microbiol 28(2):235–247Google Scholar
- Kubitschek HE (1990) Cell volume increase in Escherichia coli after shifts to richer media. J Bacteriol 172(1):94–101Google Scholar
- Matlock BC, Beringer RW, Ash DL, Page AF (2011) Differences in bacterial optical density measurements between spectrophotometers. Thermo Fisher Scientific. http://www.thermoscientific.de/eThermo/CMA/PDFs/Product/productPDF_58468.PDF
- Rolfe MD, Rice CJ, Lucchini S, Pin C, Thompson A, Cameron AD, Alston M, Stringer MF, Betts RP, Baranyi J, Peck MW, Hinton JCD (2012) Lag phase is a distinct growth phase that prepares bacteria for exponential growth and involves transient metal accumulation. J Bacteriol 194(3):686–701PubMedCentralPubMedCrossRefGoogle Scholar
- Volkmer B, Heinemann M (2011) Condition-dependent cell volume and concentration of Escherichia coli to facilitate data conversion for systems biology modeling. PLoS ONE 6(7):e23126Google Scholar