Original title: Nanoporous Copper Films as Platform for UV-SERS: Sensitivity and Ability to Perform Chiral Discrimination
Huaizhou Jin, Anastasiia Sapunova, Yanqiu Zou, Ali Douaki +7 · September 2026
Detecting small biological molecules usually requires expensive tools, and glowing background light often blurs the signals. Surface-enhanced Raman spectroscopy, or SERSA technique where a rough metal surface dramatically boosts the faint signals from molecules when light scatters off them., uses laser light bouncing off rough metal surfaces to identify molecules by their unique vibrations. Doing this with ultraviolet light helps reduce unwanted glow, but finding cheap, stable surfaces that work has been difficult. To solve this, researchers used a dry process to create nanoporousHaving extremely tiny holes (nanometer-sized) that increase the surface area. copper and copper oxide films with microscopic holes on silicon. When ultraviolet light at 325 nm shines on the copper, it triggers an electric charge transfer with attached molecules. This boost allowed the researchers to detect adenine down to 10 microM, whereas green light produced no signal. The copper films also gathered signals from a protein called streptavidin. Crucially, the metal told apart left- and right-handed forms of tryptophan without adding extra chemical selectors, simply by altering how the film was rotated during manufacturing.
You are trying to tell two nearly identical keys apart by the sound they make when tapped on a table. The sound is too faint to notice any difference. In this paper, the copper surface with microscopic holes works like a powerful amplifier for light signals; when ultraviolet light hits the molecules on that surface, the scattered light becomes strong enough to reveal a tiny difference in brightness between left- and right-handed versions of the same molecule, without any extra chemical markers.
Detecting which handedness a molecule has—left or right—is crucial in drug development, because one version heals and the other can harm. Existing methods often need expensive chemical additives or complex surfaces. This work shows that a plain copper film with tiny pores can tell them apart using ultraviolet light alone, opening a simpler path to chiral biosensing.
The experiments only tested a few molecules (adenine and tryptophan), so it is unclear if the method works for many others. The chiral discrimination relies on intensity differences, not complete separation of peaks, so it may fail for mixtures or low concentrations. The charge-transfer mechanism is inferred from a single control experiment (lack of 532 nm signal), not proven directly, so the underlying physics remains speculative.
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Nanoporous Copper Films as Platform for UV-SERS: Sensitivity and Ability to Perform Chiral Discrimination — Huaizhou Jin, Anastasiia Sapunova, Yanqiu Zou et al.
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.