Image created by Dr. Michael J. Miller
Bacterial infections remain a global health crisis, responsible for millions of deaths each year. Current identification methods, such as culture-based techniques, often take days to yield results, delaying critical treatment. The need for rapid, accurate, and accessible diagnostic tools has never been more urgent. While SERS has long been recognized for its high sensitivity and molecular specificity in pathogen detection, inconsistent signal reproducibility and limited detection at low analyte concentrations have hindered clinical adoption. Addressing these challenges, researchers have devised an innovative approach that integrates portability, ease of use, and high-precision detection into a single device.
Published in Microsystems & Nanoengineering, the study, conducted by researchers at the Ulsan National Institute of Science and Technology (UNIST) and the Institute for Basic Science (IBS) in South Korea, introduces the plasmonic fidget spinner (P-FS) as a hand-powered, scalable, and cost-effective solution for bacterial detection. The device combines a nitrocellulose membrane with nanoplasmonic arrays, allowing SERS to detect unique Raman signatures of bacteria with unprecedented accuracy. The research demonstrates the P-FS’s ability to identify bacterial species at low concentrations, making it particularly valuable for on-site diagnostics in clinical and field settings.
At the core of the P-FS is a nanoplasmonic-enhanced filtration system, where a nitrocellulose membrane captures bacteria while nanoplasmonic hotspots amplify Raman signals. Using photolithography and metal sputtering, researchers engineered precise nanostructures to maximize signal intensity, transforming bacterial identification into a rapid and highly sensitive process. The device was tested on E. coli and S. aureus, successfully distinguishing them based on their unique vibrational fingerprints. Additionally, the P-FS demonstrated exceptional performance in real-world samples, including urine, where it detected multiple bacterial species simultaneously. Notably, its hand-powered operation eliminates the need for electricity, making it an ideal solution for remote and resource-constrained areas.
"This innovative approach fuses the simplicity of a fidget spinner with the precision of nanoplasmonic technology, creating a powerful tool for rapid bacterial detection," said Dr. Yoon-Kyoung Cho, a lead researcher on the project. "The P-FS has the potential to transform infection diagnostics, especially in settings where time and resources are scarce."
The potential applications of the P-FS extend far beyond bacterial detection. Its rapid and precise identification capabilities could significantly improve infection management, antibiotic stewardship, and disease surveillance. The device’s scalability and adaptability open possibilities for detecting other pathogens and biomolecules, expanding its role in global health monitoring. As researchers push forward with clinical trials and real-world deployment, the P-FS could become a cornerstone technology in rapid diagnostics, ultimately saving lives and reducing healthcare costs worldwide.
Reference
Karmacharya, M., Michael, I., Han, J. et al. Nanoplasmonic SERS on fidget spinner for digital bacterial identification. Microsyst Nanoeng 11, 38 (2025). https://doi.org/10.1038/s41378-025-00870-1
Abstract
Raman spectroscopy offers non-destructive and highly sensitive molecular insights into bacterial species, making it a valuable tool for detection, identification, and antibiotic susceptibility testing. However, achieving clinically relevant accuracy, quantitative data, and reproducibility remains challenging due to the dominance of bulk signals and the uncontrollable heterogeneity of analytes. In this study, we introduce an innovative diagnostic tool: a plasmonic fidget spinner (P-FS) incorporating a nitrocellulose membrane integrated with a metallic feature, referred to as a nanoplasmonic-enhanced matrix, designed for simultaneous bacterial filtration and detection. We developed a method to fabricate a plasmonic array patterned nitrocellulose membrane using photolithography, which is then integrated with a customized fidget spinner. Testing the P-FS device with various bacterial species (E. coli 25922, S. aureus 25923, E. coli MG1655, Lactobacillus brevis, and S. mutans 3065) demonstrated successful identification based on their unique Raman fingerprints. The bacterial interface with regions within the plasmonic array, where the electromagnetic field is most intensely concentrated—called nanoplasmonic hotspots—on the P-FS significantly enhances sensitivity, enabling more precise detection. SERS intensity mappings from the Raman spectrometer are transformed into digital signals using a threshold-based approach to identify and quantify bacterial distribution. Given the P-FS’s ability to enhance vibrational signatures and its scalable fabrication under routine conditions, we anticipate that nanoplasmonic-enhanced Raman spectroscopy—utilizing nanostructures made from metals (specifically gold and silver) deposited onto a nitrocellulose membrane to amplify Raman scattering signals—will become the preferred technology for reliable and ultrasensitive detection of various analytes, including those crucial to human health, with strong potential for transitioning from laboratory research to clinical applications.