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Stand-off trapping and manipulation of sub-10 nm objects and biomolecules using opto-thermo-electrohydrodynamic tweezers

A Publisher Correction to this article was published on 29 September 2020

This article has been updated


Optical tweezers have emerged as a powerful tool for the non-invasive trapping and manipulation of colloidal particles and biological cells1,2. However, the diffraction limit precludes the low-power trapping of nanometre-scale objects. Substantially increasing the laser power can provide enough trapping potential depth to trap nanoscale objects. Unfortunately, the substantial optical intensity required causes photo-toxicity and thermal stress in the trapped biological specimens3. Low-power near-field nano-optical tweezers comprising plasmonic nanoantennas and photonic crystal cavities have been explored for stable nanoscale object trapping4,5,6,7,8,9,10,11,12,13. However, the demonstrated approaches still require that the object is trapped at the high-light-intensity region. We report a new kind of optically controlled nanotweezers, called opto-thermo-electrohydrodynamic tweezers, that enable the trapping and dynamic manipulation of nanometre-scale objects at locations that are several micrometres away from the high-intensity laser focus. At the trapping locations, the nanoscale objects experience both negligible photothermal heating and light intensity. Opto-thermo-electrohydrodynamic tweezers employ a finite array of plasmonic nanoholes illuminated with light and an applied a.c. electric field to create the spatially varying electrohydrodynamic potential that can rapidly trap sub-10 nm biomolecules at femtomolar concentrations on demand. This non-invasive optical nanotweezing approach is expected to open new opportunities in nanoscience and life science by offering an unprecedented level of control of nano-sized objects, including photo-sensitive biological molecules.

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Fig. 2: Demonstration of transport, trapping and release of a single BSA protein molecule, as well as the stability of a trapped single BSA molecule.
Fig. 3: Frame-by-frame images showing a demonstration of dynamic manipulation of a single BSA protein molecule.
Fig. 4: Illustration of trapping stability and trapping position as a function of a.c. frequency.
Fig. 5: Frame-by-frame sequence showing the size-based sorting of dielectric polystyrene beads using OTET.

Data availability

The datasets generated and/or analysed during the current study are available in the Harvard Dataverse repository ( Source data are provided with this paper.

Change history

  • 29 September 2020

    An amendment to this paper has been published and can be accessed via a link at the top of the paper.


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The authors acknowledge financial support from the National Science Foundation (NSF ECCS-1933109) and Vanderbilt University. We thank A. Locke for providing the protein samples and K. Wang and C. Batista for help with the zeta potential measurements.

Author information

Authors and Affiliations



J.C.N. conceived and guided the project. C.H. fabricated the samples and performed the experiments and the numerical simulations. S.Y. contributed to the wave-optics simulations. J.C.N and C.H. discussed the results and wrote the manuscript.

Corresponding author

Correspondence to Justus C. Ndukaife.

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The authors declare no competing interests.

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Peer review information Nature Nanotechnology thanks Reuven Gordon and the other, anonymous, reviewer(s) for their contribution to the peer review of this work

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Supplementary information

Supplementary Information

Supplementary Figs. 1–2, discussion and refs. 1–5.

Supplementary Video 1

Fast transport, trapping and release of a single BSA protein molecule.

Supplementary Video 2

Dynamic manipulation of a single BSA protein molecule.

Supplementary Video 3

Frequency-dependent tuning of trapping position.

Supplementary Video 4

Sorting 20 nm polystyrene particles from a mixture of 100 nm and 20 nm polystyrene particles by changing the a.c. frequency.

Source data

Source Data Fig. 2

Excel data of particle positions for different a.c. frequencies.

Source Data Fig. 4

Excel data of particle displacements from the edge of the nanohole array for different a.c. frequencies; simulation data for the fluid’s radial velocity as a function of position for different a.c. frequencies; and Excel data of particle positions for different a.c. frequencies.

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Hong, C., Yang, S. & Ndukaife, J.C. Stand-off trapping and manipulation of sub-10 nm objects and biomolecules using opto-thermo-electrohydrodynamic tweezers. Nat. Nanotechnol. 15, 908–913 (2020).

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