W13 - Development of a novel dielectrophoretic-surface enhanced Raman spectroscopy-based platform for the concentration and detection of methicillin-resistant Staphylococcus aureus

In fifteen words or less, explain the significance of this contribution (Novel Aspect).: Integration of DEP and SERS for rapid, amplification-free MRSA detection in point-of-care diagnostics.

Abstract Text:

The misuse of antimicrobials has led to the emergence of antimicrobial resistance (AMR) in many important pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA).[1] As the threat of AMR increases, the early detection of resistant pathogens is critical for the provision of appropriate and effective treatments.[2] Point-of-care (POC) platforms are proving to be a portable and inexpensive alternative to traditional methods for detecting bacterial infections. POC tests are straightforward and typically require no professional training, offering quick and affordable results. Hence, POC tests are necessary for various global healthcare programs, especially in cases where rapid medical decisions are needed.

Recent advancements in nanotechnology, microfluidics, and device fabrication have made it possible for various sensing methods, including nanopore sensing and field-effect transistor-based biosensors, to be incorporated into POC devices.[3] However, in all these devices, the limit of detection is restricted by the diffusion-limited transport of the analyte to the sensor.[4] This makes detection of low concentrations analyte difficult, without employing lengthy reagent-intensive analyte preconcentration.

The aim of this work is to address these challenges by developing a next generation POC device that incorporates a dielectrophoresis (DEP)-based sample concentration and surface-enhanced Raman spectroscopy (SERS)-based sensing. DEP is an electrokinetic method that has been widely employed for concentration and separation of target analytes by engineering the field gradient.[5] Here, we have developed a DEP device capable of shuttling MRSA from a very dilute solution to a region of interest, following by detection, via the addition of gold shell isolated nanoparticles conjugated with a Raman reporter molecule, using SERS. Initial results have shown rapid detection of MRSA from concentrations as low as 10³ cfu/ml. Utilising this approach in POC devices will enable easy detection of analytes and could significantly reduce hospital wait times.

1. Hutchings, M. et al. Curr Opin Microbiol 2019, 51, 72-80.

2. Li, Z. et al. Infect Dis 2019, 6 (10).

3. Hakim, K. S. et al.. Electrophoresis 2021, 42 (5), 588-604.

4. Xuan, X. C. Electrophoresis 2019, 40 (18-19), 2484-2513.

5. Kim, D. et al. Analytical Chemistry 2019, 91 (1), 277-295.