High-resolution, long-term characterization of bacterial motility using optical tweezers

• Published in: Nature methods Vol. 6; no. 11; pp. 831 - 835
• Main Authors: Min, Taejin L, Mears, Patrick J, Chubiz, Lon M, Rao, Christopher V, Golding, Ido, Chemla, Yann R
• Format: Journal Article
• Language: English
• Published: New York Nature Publishing Group US 01.11.2009; Nature Publishing Group
• Subjects: Bacteria; Bioinformatics; Biological Microscopy; Biological Techniques; Biomedical and Life Sciences; Biomedical Engineering/Biotechnology; Cellular biology; E coli; Escherichia coli; Escherichia coli - physiology; Flagella - physiology; Fluorescence; Fluorescence microscopy; Life Sciences; Locomotion - physiology; Microfluidic Analytical Techniques; Microfluidics; Microscopy; Microscopy, Fluorescence - instrumentation; Molecular Motor Proteins - physiology; Optical Tweezers; Proteomics; Research methodology; Rotation; Swimming; Time series
• ISSN: 1548-7091; 1548-7105; 1548-7105
• DOI: 10.1038/nmeth.1380

Optically trapping an individual E. coli cell allows the long-term quantification of bacterial swimming phenotype: the stochastic transitions between 'running' and 'tumbling' as well as changes in swimming speed and direction. We present a single-cell motility assay, which allows the quantification of bacterial swimming in a well-controlled environment, for durations of up to an hour and with a temporal resolution greater than the flagellar rotation rates of ∼100 Hz. The assay is based on an instrument combining optical tweezers, light and fluorescence microscopy, and a microfluidic chamber. Using this device we characterized the long-term statistics of the run-tumble time series in individual Escherichia coli cells. We also quantified higher-order features of bacterial swimming, such as changes in velocity and reversals of swimming direction.