The University of Michigan, Department of Chemistry, 930 N. University, Ann Arbor, MI 48109-1055, USA.
Biosens Bioelectron. 2011 Jan 15;26(5):2751-5. doi: 10.1016/j.bios.2010.10.010. Epub 2010 Oct 14.
Continuous growth of individual bacteria has been previously studied by direct observation using optical imaging. However, optical microscopy studies are inherently diffraction limited and limited in the number of individual cells that can be continuously monitored. Here we report on the use of the asynchronous magnetic bead rotation (AMBR) sensor, which is not diffraction limited. The AMBR sensor allows for the measurement of nanoscale growth dynamics of individual bacterial cells, over multiple generations. This torque-based magnetic bead sensor monitors variations in drag caused by the attachment and growth of a single bacterial cell. In this manner, we observed the growth and division of individual Escherichia coli, with 80-nm sensitivity to the cell length. Over the life cycle of a cell, we observed up to a 300% increase in the rotational period of the biosensor due to increased cell volume. In addition, we observed single bacterial cell growth response to antibiotics. This work demonstrates the non-microscopy limited AMBR biosensor for monitoring individual cell growth dynamics, including cell elongation, generation time, lag time, and division, as well as their sensitivity to antibiotics.
个体细菌的连续生长以前曾通过使用光学成像进行直接观察来研究。然而，光学显微镜研究本质上受到衍射限制，并且能够连续监测的单个细胞数量有限。在这里，我们报告了异步磁珠旋转（AMBR）传感器的使用情况，该传感器不受衍射限制。AMBR 传感器允许测量单个细菌细胞的纳米级生长动力学，跨越多个世代。这种基于扭矩的磁珠传感器监测由单个细菌细胞的附着和生长引起的阻力变化。通过这种方式，我们观察了单个大肠杆菌的生长和分裂，对细胞长度的灵敏度达到 80nm。在细胞的生命周期中，由于细胞体积的增加，我们观察到生物传感器的旋转周期增加了高达 300%。此外，我们还观察到单个细菌细胞对抗生素的生长反应。这项工作展示了非显微镜限制的 AMBR 生物传感器，用于监测单个细胞的生长动力学，包括细胞伸长、世代时间、滞后时间和分裂，以及它们对抗生素的敏感性。
