Optical Manipulation of Nanoparticles and Biomolecules

Optical manipulation exploits the momentum transfer between light and matter to trap, transport and sort particles ranging from tens of nanometres to micrometres in size. By shaping light fields in the far-field (through tightly focused beams) or the near-field (via evanescent waves or plasmonic resonances), researchers can exert piconewton-scale forces to overcome Brownian motion and viscous drag. Techniques span classical optical tweezers, which rely on intensity gradients, to advanced schemes employing holographic beam shaping, optothermal effects and tailored surface-wave geometries. These methods offer non-invasive, contact-free control of synthetic nanoparticles, functionalised biomolecules and living cells, enabling applications in single-molecule biophysics, point-of-care diagnostics, self-assembly of nanomaterials and in vivo micromanipulation. Recent innovations have focused on enhancing throughput, reducing photothermal damage and extending manipulation capabilities to complex composite objects and biological specimens in their native environments.

Research from Nature Portfolio

Recent studies have advanced near-field and in vivo manipulation. One report demonstrated that composite Janus nanoparticles half-coated with gold can be tightly localised and propelled along the evanescent field of an optical nanofibre, achieving higher speeds and positional stability than homogeneous counterparts. Another study configured an opto-fluidic lattice to sculpt nanoparticle trajectories, enabling single-bacteria-level screening and direct measurement of binding efficiencies in a dynamic optical potential. A further work introduced an indirect trapping platform in which optically actuated micro-rotors generate sculpted hydrodynamic flows, permitting contact-free control of absorbing particles and live cells, thus broadening material compatibility and reducing photothermal damage.

Optical Manipulation of Nanoparticles and Biomolecules publication trend

The graph below shows the total number of articles in optical manipulation of nanoparticles and biomolecules across all publications each year (not limited to Nature Index journals).

Technical terms

Optical tweezers: A technique using a tightly focused laser beam to generate gradient forces that trap and manipulate microscopic particles.

Evanescent field: A decaying electromagnetic field that forms at the interface of two media, enabling near-surface trapping and propulsion of particles.

Plasmonic tweezers: Nanostructure-assisted traps that exploit surface plasmon resonances to confine light below the diffraction limit for enhanced precision.

Optothermal nanotweezers: A method combining photothermal excitation and fluid flows to capture and enrich nanoparticles via diffusiophoresis and thermo-osmotic forces.

Holographic optical tweezers: An arrangement of multiple traps generated by spatial light modulation, allowing simultaneous and dynamic control of many particles.

Janus particles: Composite colloidal objects with two distinct surface properties, often half-coated, yielding asymmetric optical interactions.

References

1. Evanescent field trapping and propulsion of Janus particles along optical nanofibers. Nature Communications (2023).
2. Sculpting nanoparticle dynamics for single-bacteria-level screening and direct binding-efficiency measurement. Nature Communications (2018).
3. Indirect optical trapping using light driven micro-rotors for reconfigurable hydrodynamic manipulation. Nature Communications (2019).
4. Artificial potential field-empowered dynamic holographic optical tweezers for particle-array assembly and transformation. PhotoniX (2024).
5. CRISPR-powered optothermal nanotweezers: Diverse bio-nanoparticle manipulation and single nucleotide identification. Light: Science & Applications (2023).
6. Plasmonic tweezers: for nanoscale optical trapping and beyond. Light: Science & Applications (2021).