Biophysical Society Thematic Meeting | Ascona 2026

Mechanobiology of Infection

Poster Abstracts

8-POS Board 8 DRIVING THE BACTERIAL FLAGELLAR MOTOR WITH LIGHT Giacomo Donini 1 ; Silvio Bianchi 2 ; Nicola Pellicciotta 2 ; Giacomo Frangipane 1 ; Maria Cannarsa 1 ; Ojus Bagal 1 ; Roberto Di Leonardo 1 ; 1 ‘Sapienza’ University of Rome, Department of Physics, Rome, Italy 2 NANOTEC-CNR, Institute of Nanotechnology, Soft and Living Matter Laboratory, Rome, Italy The bacterial flagellar motor is a rotary molecular machine powered by ion flow and capable of kilohertz rotation. While it enables cellular motility and chemotaxis, the mechanochemical principles underlying its operation remain incompletely understood. Here we show that combining advanced optical techniques, including two-photon polymerization, optical tweezers, and optogenetics, provides an all-optical platform for simultaneous mechanical and energetic control of the motor. We engineered 3D chiral microstructures that exchange orbital angular momentum with a trapping beam, providing a controllable mechanical torque source. When selectively coupled to individual flagellar motors, these “light mills” function as tunable torque clamps, resisting motor torque to slow, stop, or reverse rotation while measuring the motor’s speed–torque relation [1]. By expressing the light-driven proton pump proteorhodopsin, light can also dynamically tune the proton motive force that powers flagellar motors [2]. This combination of optical tools enables a broad range of experimental protocols to investigate the motor’s temporal response to both external and internal modulations.[1]Donini, Giacomo, et al. Microsystems & Nanoengineering 12.1 (2026): 48.[2]Bianchi, Silvio, et al. Biophysical Reports (2026).

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