Plasmonic split-ring resonators as dichroic nanophotonic DNA biosensors

Area of Science:

• Nanotechnology
• Spectroscopy
• Molecular Diagnostics

Background:

• Surface-enhanced resonance Raman spectroscopy (SERRS) is a sensitive molecular detection technique.
• Current SERRS methods can be limited by sensor specificity and multiplexing capabilities.

Purpose of the Study:

• To engineer silver split-ring resonators with tunable plasmonic properties for multimodal SERRS sensing.
• To demonstrate the use of these resonators as discriminating sensors for multiple DNA analytes simultaneously.

Main Methods:

• Electron beam lithography was used to fabricate silver split-ring resonators with controlled nanoscale geometry.
• The optical properties of the resonators were tuned to achieve two independently addressable high-frequency plasmon resonance modes.
• The resonators were functionalized and tested as SERRS sensors for different DNA targets using distinct Raman reporter molecules and laser excitation wavelengths.

Main Results:

• The fabricated silver split-ring resonators exhibited two independently addressable plasmon resonance modes.
• Each resonance mode was successfully tuned to specific Raman reporter molecules and laser wavelengths, enabling multiwavelength sensing.
• The sensors demonstrated the ability to independently detect low concentrations of specific DNA types within a mixed DNA sample.
• The influence of the split-ring's dichroic response on SERRS signal and detection limits was investigated.

Conclusions:

• Tailored nanoscale geometry of silver split-ring resonators enables multimodal SERRS sensing.
• Independently addressable resonance modes allow for simultaneous, specific detection of multiple analytes.
• This approach enhances the capabilities of SERRS for molecular diagnostics and multiplexed sensing applications.