Nanofiber light technology achieves breakthrough in sorting chiral nanoparticles by handedness

Scientists use ultra-thin fibers and polarized light to sort chiral nanoparticles. This breakthrough could revolutionize drug development and molecular research.

By: AXL Media

Published: Apr 25, 2026, 7:59 AM EDT

Source: Information for this report was sourced from EurekAlert!

The Challenge of Nanoscale Chirality

Chirality, or handedness, is a fundamental property where an object cannot be superimposed on its mirror image, much like a human hand or a screw. This characteristic is vital in biological systems, as the effectiveness of drugs often depends on the specific handedness of their constituent molecules. While scientists have long used circularly polarized light to separate micro-sized particles, applying these forces to nanoparticles has proven difficult. At the nanoscale, the interaction between light and matter weakens, and the resulting forces are typically overwhelmed by the chaotic random motion of particles in a fluid.

Concentrating Light with Optical Nanofibers

To combat the limitations of standard light beams, a collaborative research team led by Professor Mark Sadgrove utilized ultra-thin optical fibers to concentrate electromagnetic energy. By tapering fibers to sub-wavelength diameters, the researchers created a high-intensity region near the fiber surface known as an evanescent field. This field tightly confines the light, drastically enhancing the momentum transfer between photons and any nearby objects. This concentration is the key technical advancement that allows the system to exert enough force to influence particles 1,000 times smaller than a human hair.

Selective Transport via Circular Polarization

The experiment employed metallic nanocubes with twisted faces, providing them with a clear geometric chirality. When these twisted particles were introduced to the evanescent field of the nanofiber, they began to move along its length. Crucially, the researchers observed that the speed and direction of this movement were dictated by a combination of the particle's own handedness and the rotation of the light's circular polarization. By switching the polarization from clockwise to anticlockwise, the team could selectively reverse the transport direction of specific particles, effectively acting as a microscopic sorting machine.