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Highly sensitive label-free biomolecular detection using Au-WS2 nanohybrid based SERS substrates
Om Prakash1, Abhijith T2,3, Priya Nagpal4
1Nanostech Laboratory, Department of Physics, Indian Institute of Technology Delhi New Delhi 110016 India santanu1@physics.iitd.ac.in.
Nanoscale Advances
|October 7, 2024
Summary
New gold-tungsten disulfide nanohybrids enable ultra-sensitive, label-free detection using surface-enhanced Raman spectroscopy (SERS). These advanced nanomaterials offer a low-cost, rapid platform for identifying molecular analytes and bacteria, enhancing biosensor capabilities.
Area of Science:
- Nanotechnology
- Spectroscopy
- Materials Science
Background:
- Surface-enhanced Raman spectroscopy (SERS) offers rapid, low-cost, and ultra-sensitive detection of molecular analytes.
- Nanomaterials are crucial for enhancing SERS performance through synergistic plasmonic and chemical effects.
Purpose of the Study:
- To develop novel gold-tungsten disulfide (Au-WS2) nanohybrids for enhanced SERS detection.
- To investigate the synergistic plasmonic and chemical enhancement effects in Au-WS2 nanohybrids.
- To demonstrate the application of these nanohybrids in detecting bacterial strains.
Main Methods:
- Chemical synthesis of monodispersed gold nanoparticles (Au NPs) with varying diameters.
- Liquid-phase exfoliation of tungsten disulfide (WS2) nano-flakes.
- Fabrication of Au-WS2 nanohybrids by blending Au NPs and WS2 nano-flakes.
- Finite-difference time-domain (FDTD) simulations to analyze plasmonic enhancement.
- SERS measurements using R6G as an analyte and detection of E. coli bacterial strain.
Main Results:
- Au-WS2 nanohybrids achieved a maximum enhancement factor (EF) of approximately 1.80 × 10^9 for R6G.
- FDTD simulations revealed field-intensity enhancement exceeding 1000 at plasmonic hotspots due to coupled plasmon oscillations.
- Synergistic electromagnetic and chemical enhancement effects significantly boosted Raman signals.
- Successful detection of E. coli ATCC 35218 at concentrations as low as 10^4 CFU mL^-1.
Conclusions:
- Au-WS2 nanohybrids exhibit significant synergistic enhancement for SERS, driven by plasmonic and chemical effects.
- These nanohybrids demonstrate high sensitivity and potential for label-free detection of analytes and pathogens.
- The developed nanomaterials offer a promising platform for innovative biosensors to address public health concerns.
