Researchers have developed a novel nanoactuator system, where confirmation of a biomolecule can be tuned by the electric field and probed using optical properties of a gold nanoparticle.

Researchers at University of Jyväskylä (Finland) and University of Tampere (Finland) together with BioNavis Ltd (Finland) have developed a novel nanoactuator system, where the electric field can tune confirmation of a biomolecule and probed using optical properties of a gold nanoparticle.

Over the past decades, nanoactuators for detection or probing of different biomolecules have attracted vast interest for example in the fields of biomedical, food and environmental industry. To provide more versatile tools for active molecular control in nanometer scale.

Researchers have devised a nanoactuator scheme, where gold nanoparticle (AuNP) tethered on a conducting surface is moved reversibly using electric fields while monitoring its position optically via changes of its plasmon resonance.

Forces induced by the AuNP motion on the molecule anchoring the nanoparticle can be used to change and study its conformation. Related studies use either organic or inorganic interfaces or materials as probes. Our idea was to fuse these two domains together to achieve the best from both worlds.

More possibilities to study molecules

According to the current study, it was shown that AuNPs anchored via hairpin-DNA molecule experienced additional discretization in their motion due to opening and closing of the hairpin-loop compared to the plain, single-stranded DNA.


This finding will enable conformational studies of a variety of multiple interesting biomolecules, or even viruses. Besides studying the structure and behavior of molecules, this scheme can be extended to surface-enhanced spectroscopies like SERS, since the distance between the particle and the conducting surface and hence the plasmon resonance of the nanoparticle can be reversibly tuned.

Nanoparticle systems with post-fabrication tuneable optical properties have been developed in the past, but typically the tuning processes are irreversible. Our approach offers more customizability and possibilities when it comes to the detection wavelengths and molecules.