Bacterial flagellar motor as a multimodal biosensor

Abstract

Bacterial Flagellar Motor is one of nature's rare rotary molecular machines. It enables bacterial swimming and it is the key part of the bacterial chemotactic network, one of the best studied chemical signalling networks in biology, which enables bacteria to direct its movement in accordance with the chemical environment. The network can sense down to nanomolar concentrations of specific chemicals on the time scale of seconds. Motor's rotational speed is linearly proportional to the electrochemical gradients of either proton or sodium driving ions, while its direction is regulated by the chemotactic network. Recently, it has been discovered that motor is also a mechanosensor. Given these properties, we discuss the motor's potential to serve as a multifunctional biosensor and a tool for characterising and studying the external environment, the bacterial physiology itself and single molecular motor biophysics.

Microbial stir bars: light-activated rotation of tethered bacterial cells to enhance mixing in stagnant fluids

“…We further demonstrated that cell rotation could be remotely activated using laser illumination, thus providing external control to switch on and off the rotation for mixing application. Besides the applications in mixing, bacterial motility could also be used to power micropumps (Dauparas et al, 2018), as a power generator (Tung & Kim, 2006), and for biosensors (Krasnopeeva et al, 2020). In future, various challenges such as specific tethering of cells, synchronized cell rotation, longer cell viability, and minimizing varying cell speed are necessary to be addressed to establish bacterial cell rotation as an efficient micro mixer.…”

“…The properties of bacterial motility and chemotactic sensing have been utilized to fabricate various microfluidics devices for mixing (M. J. Kim & Breuer, 2007), actuating the fluid flow (Al-Fandi et al, 2006), sensing pH (Krasnopeeva et al, 2020), and generating power (Tung & Kim, 2006).…”

Active Efflux Leads to Heterogeneous Dissipation of Proton Motive Force by Protonophores in Bacteria

“…It was cultured in lysogeny broth (LB) (10 g tryptone, 5 g yeast extract, 10 g NaCl per 1 liter) to an OD 600 of ∼2. Cells were sheared to truncate flagellar filaments, washed from LB to modified minimal medium (MM9; 50 mM Na 2 HPO 4 , 25 mM NaH 2 PO 4 , 8.5 mM NaCl, 18.7 mM NH 4 Cl, 0.1 mM CaCl 2 , 1 mM KCl, 2 mM MgSO 4 , pH 7.5) supplemented with 0.3% d -glucose and attached to the cover glass surface of a tunnel slide via poly- l- lysine ( 41 , 75 , 76 ). We have shown that the cytoplasmic pH of the cells in this medium is ∼7.8 ( 41 ).…”

Bioempowerment of Therapeutic Living Cells by Single‐Cell Surface Engineering

“…The concept of utilizing bacterial microswimmers has also garnered significant attention in recent years, owing to its potential applications in medicine and bioengineering, such as targeted delivery, biosensing, and cell transportation. [151][152][153] For in-stance, bacterial microswimmers were constructed by attaching microparticles to individual E. coli MG1655, in which the microparticles were fabricated by the LbL assembly of PAH/PSSbased PEM microstructures on PS particles with MNP embedment in the PEM nanoshells (Figure 7f). [154] The MNPs in the PEM nanoshells enabled magnetic steering control of bacteria-driven microswimmers, after electrostatic deposition of the PEM-MNP-decorated microparticles onto individual E. coli, forming E.coli@PEM-MNP.…”