Using buoyant mass to measure the growth of single cells

Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, USA.
Nature Methods (Impact Factor: 32.07). 04/2010; 7(5):387-90. DOI: 10.1038/nmeth.1452
Source: PubMed


We used a suspended microchannel resonator (SMR) combined with picoliter-scale microfluidic control to measure buoyant mass and determine the 'instantaneous' growth rates of individual cells. The SMR measures mass with femtogram precision, allowing rapid determination of the growth rate in a fraction of a complete cell cycle. We found that for individual cells of Bacillus subtilis, Escherichia coli, Saccharomyces cerevisiae and mouse lymphoblasts, heavier cells grew faster than lighter cells.

Download full-text


Available from: Alan D Grossman, Feb 03, 2014
  • Source
    • "We assume an exponential mode of growth for cell volume with a constant doubling time τ and a corresponding constant growth rate λ = ln 2/τ (Godin et al., 2010). From Equation (1) and the exponential mode of growth, durations between initiations are "
    [Show abstract] [Hide abstract]
    ABSTRACT: Bacteria are able to maintain a narrow distribution of cell sizes by regulating the timing of cell divisions. In rich nutrient conditions, cells divide much faster than their chromosomes replicate. This implies that cells maintain multiple rounds of chromosome replication per cell division by regulating the timing of chromosome replications. Here, we show that both cell size and chromosome replication may be simultaneously regulated by the long-standing initiator accumulation strategy. The strategy proposes that initiators are produced in proportion to the volume increase and is accumulated at each origin of replication, and chromosome replication is initiated when a critical amount per origin has accumulated. We show that this model maps to the incremental model of size control, which was previously shown to reproduce experimentally observed correlations between various events in the cell cycle and explains the exponential dependence of cell size on the growth rate of the cell. Furthermore, we show that this model also leads to the efficient regulation of the timing of initiation and the number of origins consistent with existing experimental results.
    Frontiers in Microbiology 07/2015; 6:662. DOI:10.3389/fmicb.2015.00662 · 3.99 Impact Factor
  • Source
    • "In dynamic mode, trampoline resonators can monitor mass changes during cell growth and division [3]; hollow cantilevers with embedded nanochannels can quantify cell growth by measuring the buoyant mass [4]. Toward developing very high frequency (VHF) resonators that are easy to fabricate yet high performance in biofluids, very limited types of devices have been explored, because the cell-living environment imposes not only significant mass loading (much lower frequency and smaller signal) and viscous damping (much lower quality (Q) factor), but also great challenges on choosing material (chemically inert and biocompatible), designing robust resonating structure, and finding actuation/detection scheme that is compatible with conductive biosolutions while reasonably minimizing structure complexity. "
    [Show abstract] [Hide abstract]
    ABSTRACT: This digest paper reports the first experimental exploration of directly culturing and measuring breast cancer cells at single-cell level, on the surfaces of silicon carbide (SiC) microdisk resonators. Enabled by the superior biocompatibility of SiC, individual breast cancer cells are observed to attach and spread on surfaces of SiC devices within only 3 hours of culturing. Multimode resonances at very high frequencies (up to ∼100MHz) of SiC microdisks (with diameter d∼20-30μm), and their responses to single attached MDA-MB-231 cells are characterized by taking advantage of the robust presence of multiple resonance modes in biological solutions. Such devices provide a useful biosensing platform for probing physical properties and behaviors of breast cancer cells in vitro, at single-cell level and in real time.
    The 28th IEEE International Conference on Micro Electro Mechanical Systems (MEMS 2015), Estoril, Portugal; 01/2015
  • Source
    • "However, the nature of any size-adjusting mechanism that would drive this size-asymmetry detection and correction mechanism remains elusive. It is not known whether, for example, it would relate to cell volume (Tzur et al., 2009), mass (Park et al., 2010; Sung et al., 2013), or density (Godin et al., 2010; Grover et al., 2011; Son et al., 2012). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Dividing cells almost always adopt a spherical shape. This is true of most eukaryotic cells lacking a rigid cell wall and is observed in tissue culture and single-celled organisms, as well as in cells dividing inside tissues. While the mechanisms underlying this shape change are now well described, the functional importance of the spherical mitotic cell for the success of cell division has been thus far scarcely addressed. Here we discuss how mitotic rounding contributes to spindle assembly and positioning, as well as the potential consequences of abnormal mitotic cell shape and size on chromosome segregation, tissue growth, and cancer.
    Developmental Cell 04/2014; 29(2):159-169. DOI:10.1016/j.devcel.2014.04.009 · 9.71 Impact Factor
Show more