Successful Selective Transport of Chiral Nanoparticles by Evanescent Circularly Polarized Light ~A Significant Step Towards Establishing Non-Contact Optical Separation Technology for Chiral Molecules~
A joint research group including Tokyo University of Science has successfully developed a technology for selectively transporting chiral nanoparticles using evanescent circularly polarized light. This marks a significant step towards establishing non-contact optical separation technology for chiral molecules, with anticipated applications in drug discovery.
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- 📰 Published: April 24, 2026 at 19:00
- 🔍 Collected: April 24, 2026 at 10:31
- 🤖 AI Analyzed: April 24, 2026 at 13:28 (2h 56m after Collected)
## Press Release Information
Title: Successful Selective Transport of Chiral Nanoparticles by Evanescent Circularly Polarized Light ~A Significant Step Towards Establishing Non-Contact Optical Separation Technology for Chiral Molecules~
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Body (First 8000 characters): 【Research Summary and Key Points】
We have successfully achieved selective transport of chiral nanoparticles on a nanofiber using evanescent circularly polarized light.
By counter-propagating two light beams to cancel out non-chiral force components and extracting only pure chiral optical pressure, we demonstrated that the transport direction of nanoparticles can be controlled simply by switching the circular polarization.
We confirmed the effectiveness of this method even in particle populations with variations in size and shape, and it is expected to be applied in the future to technologies for optically separating chiral molecules such as drugs.
【Research Overview】
A joint research group comprising Professor Mark Sadgrove, Assistant Professor Georgiy Tkachenko, Assistant Professor Yining Xuan of the Department of Physics, Faculty of Science, Tokyo University of Science; Mr. Akifusa Suda (completed Master's program in 2022), Mr. Hiroto Iida (completed Master's program in 2024), Mr. Ichiro Kurihara (1st year Master's program in 2025), Mr. Koki Saito (1st year Master's program in 2025) of the Graduate School of Science, Department of Physics, Tokyo University of Science; Professor Hiromi Okamoto (at the time of research, now Emeritus Professor), Specially Appointed Assistant Professor Hyo-Yong Ahn of the Mesoscopic Measurement Research Center, Institute for Molecular Science; and Professor Ki Tae Nam, Mr. In Han Ha of the Department of Materials Science and Engineering, Seoul National University, has successfully achieved selective transport of chiral nanoparticles (*2) on a nanofiber based on their chirality (*3) using evanescent light (*1).
In pharmaceuticals, only one enantiomer (mirror image isomer, *4) may have medicinal effects, while the other can cause side effects. Therefore, accurately separating the two is a major challenge in manufacturing. In recent years, methods for non-contact separation of substances with different optical properties using optical pressure (*5) have attracted attention. However, for minute objects like nanoparticles, optical pressure becomes remarkably weak and is overwhelmed by thermal noise (*6). Consequently, experimental demonstrations at the nanoscale have been limited, and a practical method has not yet been established.
In this study, we utilized evanescent light leaking from the surface of a nanofiber and demonstrated that the transport speed of chiral nanoparticles changes simply by switching the handedness of the circular polarization. Furthermore, by using a "counter-propagating mode" where two light beams are incident from opposite directions, we completely canceled out the force components independent of chirality, successfully achieving selective forward and backward transport of nanoparticles solely by pure chiral optical pressure. Moreover, the effectiveness of this method was confirmed even in particle populations with variations in size and shape, demonstrating enantiomer separation at the 100 nm scale. These experimental results are also consistent with simulation results, indicating the validity and universality of this method.
By further developing this research, a wide range of applications are expected in drug discovery and chemical synthesis fields, such as the realization of non-contact enantio-separation for selecting chiral molecules like drugs using light.
These research results were published online in the international academic journal "Nature Communications" on April 16, 2026.
Figure: Transport experiment of nanoparticles on a nanofiber by evanescent light. (Left) Change in position and velocity of nanoparticles when circularly polarized light is incident from one side of the fiber. (Right) Change in position and velocity of nanoparticles when linearly polarized light and circularly polarized light are incident from both sides of the fiber.
【Research Background】
In the fields of drug discovery and chemical synthesis, accurately separating enantiomers (mirror image isomers) has been a long-standing challenge. Enantiomers are substances whose structures are mirror images of each other, like a right hand and a left hand. While their chemical properties are identical, their behavior in living organisms can differ significantly; some may exhibit medicinal effects, while others may show side effects or toxicity. Therefore, there is a strong demand for establishing reliable separation methods at the manufacturing stage.
The idea of non-contact separation of enantiomers using only light has gained attention in recent years, and theoretical proposals have been made. This method utilizes "optical pressure" generated when light and matter interact. Optical pressure contains chirality-dependent components, which are key to enantiomer separation. However, this chirality-dependent force is inherently very weak, and for minute objects like molecules and nanoparticles, it is overwhelmed by thermal noise. Consequently, experimental demonstrations have been difficult compared to theoretical advancements, with only a few reports of nanoscale realization.
Therefore, our research group focused on evanescent light leaking from the surface of a nanofiber. Since evanescent light exists locally very close to the nanofiber surface, the movement of particles on the nanofiber becomes a one-dimensional system restricted to the fiber axis direction, allowing the weak effect of optical pressure to efficiently act on nanoparticles. Also, particles
Keywords:
Title: Successful Selective Transport of Chiral Nanoparticles by Evanescent Circularly Polarized Light ~A Significant Step Towards Establishing Non-Contact Optical Separation Technology for Chiral Molecules~
Subtitle:
Company Name:
Industry:
Body (First 8000 characters): 【Research Summary and Key Points】
We have successfully achieved selective transport of chiral nanoparticles on a nanofiber using evanescent circularly polarized light.
By counter-propagating two light beams to cancel out non-chiral force components and extracting only pure chiral optical pressure, we demonstrated that the transport direction of nanoparticles can be controlled simply by switching the circular polarization.
We confirmed the effectiveness of this method even in particle populations with variations in size and shape, and it is expected to be applied in the future to technologies for optically separating chiral molecules such as drugs.
【Research Overview】
A joint research group comprising Professor Mark Sadgrove, Assistant Professor Georgiy Tkachenko, Assistant Professor Yining Xuan of the Department of Physics, Faculty of Science, Tokyo University of Science; Mr. Akifusa Suda (completed Master's program in 2022), Mr. Hiroto Iida (completed Master's program in 2024), Mr. Ichiro Kurihara (1st year Master's program in 2025), Mr. Koki Saito (1st year Master's program in 2025) of the Graduate School of Science, Department of Physics, Tokyo University of Science; Professor Hiromi Okamoto (at the time of research, now Emeritus Professor), Specially Appointed Assistant Professor Hyo-Yong Ahn of the Mesoscopic Measurement Research Center, Institute for Molecular Science; and Professor Ki Tae Nam, Mr. In Han Ha of the Department of Materials Science and Engineering, Seoul National University, has successfully achieved selective transport of chiral nanoparticles (*2) on a nanofiber based on their chirality (*3) using evanescent light (*1).
In pharmaceuticals, only one enantiomer (mirror image isomer, *4) may have medicinal effects, while the other can cause side effects. Therefore, accurately separating the two is a major challenge in manufacturing. In recent years, methods for non-contact separation of substances with different optical properties using optical pressure (*5) have attracted attention. However, for minute objects like nanoparticles, optical pressure becomes remarkably weak and is overwhelmed by thermal noise (*6). Consequently, experimental demonstrations at the nanoscale have been limited, and a practical method has not yet been established.
In this study, we utilized evanescent light leaking from the surface of a nanofiber and demonstrated that the transport speed of chiral nanoparticles changes simply by switching the handedness of the circular polarization. Furthermore, by using a "counter-propagating mode" where two light beams are incident from opposite directions, we completely canceled out the force components independent of chirality, successfully achieving selective forward and backward transport of nanoparticles solely by pure chiral optical pressure. Moreover, the effectiveness of this method was confirmed even in particle populations with variations in size and shape, demonstrating enantiomer separation at the 100 nm scale. These experimental results are also consistent with simulation results, indicating the validity and universality of this method.
By further developing this research, a wide range of applications are expected in drug discovery and chemical synthesis fields, such as the realization of non-contact enantio-separation for selecting chiral molecules like drugs using light.
These research results were published online in the international academic journal "Nature Communications" on April 16, 2026.
Figure: Transport experiment of nanoparticles on a nanofiber by evanescent light. (Left) Change in position and velocity of nanoparticles when circularly polarized light is incident from one side of the fiber. (Right) Change in position and velocity of nanoparticles when linearly polarized light and circularly polarized light are incident from both sides of the fiber.
【Research Background】
In the fields of drug discovery and chemical synthesis, accurately separating enantiomers (mirror image isomers) has been a long-standing challenge. Enantiomers are substances whose structures are mirror images of each other, like a right hand and a left hand. While their chemical properties are identical, their behavior in living organisms can differ significantly; some may exhibit medicinal effects, while others may show side effects or toxicity. Therefore, there is a strong demand for establishing reliable separation methods at the manufacturing stage.
The idea of non-contact separation of enantiomers using only light has gained attention in recent years, and theoretical proposals have been made. This method utilizes "optical pressure" generated when light and matter interact. Optical pressure contains chirality-dependent components, which are key to enantiomer separation. However, this chirality-dependent force is inherently very weak, and for minute objects like molecules and nanoparticles, it is overwhelmed by thermal noise. Consequently, experimental demonstrations have been difficult compared to theoretical advancements, with only a few reports of nanoscale realization.
Therefore, our research group focused on evanescent light leaking from the surface of a nanofiber. Since evanescent light exists locally very close to the nanofiber surface, the movement of particles on the nanofiber becomes a one-dimensional system restricted to the fiber axis direction, allowing the weak effect of optical pressure to efficiently act on nanoparticles. Also, particles
Keywords: