Optical disassembly of cellular clusters by tunable 'tug-of-war' tweezers.
Bacterial biofilms underlie many persistent infections, posing major hurdles in antibiotic treatment. Here we design and demonstrate 'tug-of-war' optical tweezers that can facilitate the assessment of cell-cell adhesion-a key contributing factor to biofilm development, thanks to the combined actions of optical scattering and gradient forces. With a customized optical landscape distinct from that of conventional tweezers, not only can such 'tug-of-war' tweezers stably trap and stretch a rod-shaped bacterium in the observing plane, but, more importantly, they can also impose a tunable lateral force that pulls apart cellular clusters without any tethering or mechanical movement. As a proof of principle, we examined aSinorhizobium melilotistrain that forms robust biofilms and found that the strength of intercellular adhesion depends on the growth medium. This technique may herald new photonic tools for optical manipulation and biofilm study, as well as other biological applications.
Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132, USA.
Anna S
AS
Bezryadina
School of Mathematics and Physics, The University of Queensland, Brisbane, QLD 4072, Australia; Department of NanoEngineering, University of California, San Diego, La Jolla, CA 92093, USA.
Daryl C
DC
Preece
Department of Biology, San Francisco State University, San Francisco, CA 94132, USA.
Joseph C
JC
Chen
Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132, USA; The MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physical Institute and School of Physics, Nankai University, Tianjin 300457, China.
Zhigang
Z
Chen
bacterial adhesion; biofilm; optical forces; optical manipulation; tug-of-war optical tweezers