Optical Sensor Detects Chirality

A University of Central Florida team has designed a nanostructured optical sensor that for the first time can efficiently detect molecular chirality. (Source: UCF, K. Norum)

A University of Central Florida team has designed a nano­structured optical sensor that for the first time can effi­ciently detect molecular chira­lity – a property of molecular spatial twist that defines its bio­chemical properties. Deter­mining chirality is critical for new drug develop­ment. Scientists have struggled to determine if molecules have unique left- or right-hand functions because their physical attributes such as length, weight, density, elasticity, etc. appear to be identical.

UCF’s Associate Professor Debashis Chanda and Ph.D. student Abraham Vazquez-Guardado have figured out a unique way to do it. The inter­action between light and the specially designed nano­structure they built creates a strong chiral light field – super­chiral light. Such a nano­structure does not have geo­metrical chira­lity yet it creates two opposite light chirality on demand. When light and matter’s chira­lity match, just as hand-shaking with our right hand, successful identi­fication happens. Therefore, this rotating light field has the ability to probe and identify any chiral molecule like drugs, proteins or DNAs. The light field lets scientist see the tiny hands, so to speak.

“Chirality detection is vital in the drug-develop­ment industry, where newly synthesized chiral drugs also have two-handed strands and always form with the same likeliness during the synthesis process,” Chanda said. “But while one chiral strand consti­tutes the active element in the drug, its opposite can turn out to be toxic or render detrimental side effects. Conse­quently, pharma­cological and toxi­cological charac­terization of chirality plays a crucial role in the pharma­ceutical drug industry and FDA approval process.”

By being able to detect chirality at this level, scientists will have a better way to identify what may be causing bad side effects or perhaps finding places to upload life-saving drugs. In this preli­minary study, the UCF team demon­strated chiral molecule-detection sensi­tivity that is four times higher compared to the conven­tional technique, but without the extensive and tedious sample prepa­ration and at much lower sample volume. The single optical element thin-film chira­lity sensor, when fabri­cated based on low cost and large-area nano­imprinting technique, will immensely benefit drug design and protein-confor­mation identi­fication, both of paramount impor­tance in treating and under­standing several diseases, Chanda added. (Source_ UCF)

Reference: A. Vázquez-Guardado et al.: Superchiral Light Generation on Degenerate Achiral Surfaces, Phys. Rev. Lett. 120, 137601 (2018); DOI: 10.1103/PhysRevLett.120.137601

Link: CREOL, College of Optics and Photonics, University of Central Florida, Orlando, USA

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