Bulletin of the American Physical Society
APS March Meeting 2023
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session GG04: V: Collective Dynamics and Network Theory in Complex Systems
12:30 PM–2:30 PM,
Monday, March 20, 2023
Room: Virtual Room 4
Sponsoring Unit: GSNP
Chair: Kunaal Joshi, Purdue University; Srividya Iyer-Biswas, Purdue University
Abstract: GG04.00010 : Low-Frequency Charge Noise of Bacteria as Indicator of Ion Concentration Regulation*
2:18 PM–2:30 PM
Kamil L Ekinci
membrane to power various cellular processes. These concentration gradients are regulated by
ion channels and ion pumps within the membrane. Due to the stochasticity of the transport and
the physical dimensions of a bacterium, intracellular ion concentrations are bound to fluctuate.
Thus, bacterial ion homeostasis is expected to be highly dynamic and dominated by strong charge
noise. By employing sensitive electrical measurement techniques in a microfluidic system, we
investigate the charge noise of several hundred nonmotile bacteria. The power spectral density
of these fluctuations displays 1/f2 behavior for frequencies 0.05 ≤ f ≤ 1 Hz. By fitting our
data to a simple noise model, we estimate the charge fluctuations of a single bacterium to be
±1.30 × 106e (e ≈ 1.60 × 10−19 C). The charge noise is directly related to the fluctuations in the
membrane potential. However, the limited understanding of intracellular concentration gradients
makes current predictions unreliable.
*Supported by NIH (1R21AI133264-01A1).
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