Multiplexed biosensors based on interference of surface plasmons in multimode nanoslits

Area of Science:

• Nanotechnology
• Biosensing
• Optics

Background:

• Multiplexed biosensors are vital for simultaneous detection of multiple analytes in environmental monitoring, food safety, and medical diagnostics.
• Surface plasmon resonance (SPR) biosensors offer high sensitivity but are often bulky, expensive, and not easily integrated into lab-on-a-chip systems.
• Current limitations hinder the widespread adoption of multiplexed SPR biosensors in point-of-care diagnostics.

Purpose of the Study:

• To propose and demonstrate a novel, scalable, and integrated multiplexed biosensor array.
• To overcome the limitations of existing multiplexed SPR biosensors, focusing on miniaturization and cost-effectiveness.
• To enable simultaneous, high-accuracy detection of multiple biomarkers for improved diagnostics.

Main Methods:

• A periodic array of plasmonic biosensor unit cells, each featuring a plasmonic interferometer.
• Excitation via grating couplers, with surface plasmons converging to a multimode nanoslit for signal output.
• Integration of microfluidic channels for defining sensing regions and absorbing shadow elements to minimize crosstalk.

Main Results:

• Electromagnetic simulations demonstrate the feasibility of the proposed multiplexed biosensor array concept.
• Predicted resolutions of R_b=6.3×10^-6 RIU for bulk sensing and R_s=10 pm for surface sensing.
• The array design allows for lithographic scaling and interrogation by a single Gaussian beam and camera.

Conclusions:

• The proposed multiplexed biosensor array offers a scalable and integrated solution for simultaneous multi-analyte detection.
• This technology has the potential to significantly advance medical diagnostics, environmental monitoring, and food safety applications.
• The design overcomes key limitations of current SPR-based biosensors, paving the way for lab-on-a-chip integration.