# New Bacterial Detection Technology Directly Grows Plasmonic Nanostructures on and Around Bacteria, Overcoming Structural Limitations of Conventional SERS
# Separation, Enrichment, and Signal Amplification Integrated on a Single Substrate Enable Detection of Trace Bacteria Within One Hour and Assessment of Antibiotic Response Within Two Hours, Laying the Foundation for Rapid Sepsis Diagnosis
□ CHANGWON, South Korea —
A research team led by Senior Researcher Minyoung Lee and Principal Researcher Sunggyu Park of the Advanced Bio and Healthcare Materials Research Division at the Korea Institute of Materials Science (KIMS), headed by President Chul-jin Choi, has developed a label-free surface-enhanced Raman scattering (SERS) analysis technology that rapidly detects extremely low concentrations of viable bacteria by directly growing plasmonic metal nanostructures on and around bacterial cells. The technology enables trace levels of bacteria to be detected within one hour without conventional culture-based amplification and could also assess bacterial responses to antibiotics within two hours. It is expected to provide a foundation for rapid diagnosis of severe infectious diseases such as sepsis and for more precise selection of antibiotic treatments.
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Sepsis is a life-threatening condition in which the body’s dysregulated response to infection leads to organ dysfunction. Rapid identification of the causative pathogen and timely administration of an effective antibiotic are therefore critical.
During the early stages of infection, however, bacterial concentrations in the bloodstream can be extremely low, making direct detection difficult. Conventional blood culture testing requires bacteria in a blood sample to be grown before the causative organism and an appropriate antibiotic can be identified, meaning that final results may take tens of hours or several days.
This has created strong demand for technologies capable of rapidly detecting viable pathogens and determining which antibiotics are effective.
□ KIMS previously developed highly sensitive biosensor technologies that use three-dimensional plasmonic nanostructures to detect protein biomarkers associated with sepsis in blood.
The new research goes a step further by directly detecting viable causative bacteria themselves rather than disease-associated biomarkers and by rapidly evaluating their response to antibiotics.
□ To achieve this,
the research team developed a SERS analysis approach in which bacterial cells themselves serve as nucleation sites for nanostructure growth. Plasmonic metal nanostructures are formed directly on and around bacterial cells, creating highly localized electromagnetic enhancement and amplifying the bacteria’s intrinsic Raman signals. The researchers progressively advanced the technology through three stages: growing nanostructures around bacteria in solution, directly depositing metal nanostructures onto bacterial surfaces, and finally integrating bacterial separation and enrichment with additional in situ nanostructure growth. This stepwise development substantially improved the ability to detect bacteria at extremely low concentrations.
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SERS is an analytical technique that amplifies the weak Raman signals characteristic of a material by using intense electromagnetic fields known as plasmonic hot spots, which form in nanoscale gaps between metallic nanostructures such as gold or silver. Conventional SERS approaches face an inherent structural mismatch: plasmonic hot spots are typically only a few to tens of nanometers in size, whereas bacterial cells are approximately one micrometer in scale. As a result, only a small portion of a bacterial surface may come into contact with the signal-enhancing region. Rather than attempting to position a bacterium precisely within pre-existing nanoscale hot spots, the KIMS team reversed the approach. By directly forming plasmonic hot spots where the bacteria are located, the researchers significantly amplified the intrinsic Raman signals of bacterial cells without requiring separate labeling agents.
□ The team first developed a method for growing metal nanostructures around bacteria suspended in solution and then advanced the approach by using electrochemical deposition to form metal nanostructures directly on bacterial surfaces. By combining the resulting SERS spectra with artificial intelligence-based analysis, the researchers were able to distinguish among eight different bacterial species. The electrochemically engineered platform directly creates plasmonic hot spots on captured bacterial surfaces, addressing the spatial mismatch between bacterial cells and conventional SERS-active nanogaps. The researchers subsequently developed a filtration-integrated SERS substrate that captures and concentrates bacteria in a localized area and then grows plasmonic nanostructures around them to amplify their signals. By integrating separation, enrichment, and detection on a single substrate, the platform successfully detected bacteria at concentrations as low as approximately 1–10 colony-forming units per milliliter (CFU/mL). The latest platform also demonstrated the potential for rapid antimicrobial susceptibility assessment based on changes in SERS signal intensity associated with bacterial viability.
□ The team further confirmed
bacterial detection performance in bacteria-spiked serum and urine samples. By analyzing changes in SERS signals after exposing the bacteria to antibiotics, the researchers also demonstrated the
potential to evaluate antibiotic response within two hours. Going forward,
the team plans to conduct clinical validation using blood samples from patients with bloodstream infections and sepsis. The ultimate goal is to develop an integrated rapid precision-diagnostic platform that combines direct pathogen detection with antimicrobial susceptibility testing.
□ “The key to this research is that we directly grow nanostructures where the bacteria are located and combine this approach with separation and enrichment technologies to overcome the limitations of detecting extremely low bacterial concentrations,” said Minyoung Lee, Senior Researcher and project leader at KIMS. “Our next goal is to rapidly identify causative pathogens directly in blood samples from patients with infections and evaluate their response to antibiotics, ultimately helping clinicians make faster treatment decisions for sepsis,” she added. “The central achievement of this work is that we directly formed the signal-enhancing plasmonic nanostructures on and around bacterial surfaces, thereby overcoming a fundamental structural limitation of conventional SERS,” said Sunggyu Park, Principal Researcher at KIMS. “We plan to further develop the technology into an ultrasensitive infectious-disease diagnostic platform that can ultimately be used in real clinical environments,” he added.
□ “This achievement is particularly meaningful because it demonstrates how advanced materials technologies can help address a major clinical challenge: the rapid diagnosis of infectious diseases,” said KIMS President Chul-jin Choi. “KIMS will continue to actively support the convergence of materials and biotechnology so that our research can contribute both to public health and to strengthening the competitiveness of Korea’s bio and medical-device industries,” he added.
□ The research was supported by the Materials and Components Technology Development Program of the Ministry of Trade, Industry and Resources (MOTIR) and the KIMS Institutional Research Program. The research team is currently securing related intellectual property rights. The ministry’s current official English name is Ministry of Trade, Industry and Resources (MOTIR). Related findings were published throughout 2026 in three international journals in the fields of biosensors and nanomaterials: Chemical Engineering Journal (Impact Factor: 12.5), online on February 8; Biosensors and Bioelectronics (Impact Factor: 11.8), online on March 2; and Small Methods (Impact Factor: 9.46), online on August 16. KIMS lists the three corresponding DOIs as 10.1016/j.cej.2026.173940, 10.1016/j.bios.2026.118577, and 10.1002/smtd.70972, respectively. The three studies are titled
“Sensitive Label-Free Bacterial Detection and Rapid Antibiotic Susceptibility Testing via Gold Nanolayer Coating on Bacterial Surfaces in Multi-Well SERS Plates,” “Electrochemically Engineered Plasmonic Nanostructuring on Universally Captured Bacterial Surfaces for Label-Free and Ultrasensitive SERS Pathogen Detection,” and
“Filtration-Based SERS With In Situ Gold Growth in Bacterial Microenvironment for Rapid Detection of Low-Level Bacteria.”
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About Korea Institute of Materials Science(KIMS)
KIMS is a non-profit government-funded research institute under the Ministry of Science and ICT of the Republic of Korea. As the only institute specializing in comprehensive materials technologies in Korea, KIMS has contributed to Korean industry by carrying out a wide range of activities related to materials science including R&D, inspection, testing&evaluation, and technology support.