Construction and operation of a light-driven gold nanorod rotary motor system
Artikel i vetenskaplig tidskrift, 2018

The possibility to generate and measure rotation and torque at the nanoscale is of fundamental interest to the study and application of biological and artificial nanomotors and may provide new routes towards single cell analysis, studies of non-equilibrium thermodynamics, and mechanical actuation of nanoscale systems. A facile way to drive rotation is to use focused circularly polarized laser light in optical tweezers. Using this approach, metallic nanoparticles can be operated as highly efficient scattering-driven rotary motors spinning at unprecedented rotation frequencies in water. In this protocol, we outline the construction and operation of circularly-polarized optical tweezers for nanoparticle rotation and describe the instrumentation needed for recording the Brownian dynamics and Rayleigh scattering of the trapped particle. The rotational motion and the scattering spectra provides independent information on the properties of the nanoparticle and its immediate environment. The experimental platform has proven useful as a nanoscopic gauge of viscosity and local temperature, for tracking morphological changes of nanorods and molecular coatings, and as a transducer and probe of photothermal and thermodynamic processes.

Brownian motion


Optical tweezers

Photothermal effects



Optical rotation

LSPR spectroscopy


Daniel Andrén

Chalmers, Fysik, Bionanofotonik

Pawel Karpinski

Chalmers, Fysik, Bionanofotonik

Mikael Käll

Chalmers, Fysik, Bionanofotonik

Journal of Visualized Experiments

1940-087X (ISSN)

Vol. 2018 136 e57947


Nanovetenskap och nanoteknik


Atom- och molekylfysik och optik

Annan fysik

Den kondenserade materiens fysik



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