Label-free integrated microfluidic plasmonic biosensor from vertical-cavity surface-emitting lasers for SARS-CoV-2...

Area of Science:

• Plasmonics and Nanophotonics
• Biomedical Engineering
• Laser Technology

Background:

• Nanoplasmonic sensors offer label-free, rapid biological detection capabilities.
• Integrating nanograting arrays with vertical-cavity surface-emitting lasers (VCSELs) provides on-chip light sources for biosensing.
• Existing methods require improvements in sensitivity and integration for point-of-care diagnostics.

Purpose of the Study:

• To develop a highly sensitive, label-free biosensor for detecting COVID-19 specific receptor binding domain (RBD) protein.
• To integrate a gold nanograting array with a VCSEL platform for on-chip biosensing.
• To demonstrate the feasibility of a compact, portable biosensing solution.

Main Methods:

• Fabrication of a gold nanograting array integrated onto an 850 nm VCSEL.
• Utilizing the localized surface plasmon resonance (LSPR) effect excited by the VCSEL for detection.
• Modification of the nanograting surface with RBD aptamers for specific protein capture.

Main Results:

• Achieved a refractive index sensitivity of 2.99 × 10^6 nW/RIU.
• Successfully detected RBD protein with high sensitivity and a wide dynamic range (0.50 ng/mL - 50 µg/mL).
• Demonstrated the effectiveness of the integrated VCSELs biosensor for specific biomarker detection.

Conclusions:

• The integrated VCSELs biosensor is a powerful, label-free technique for RBD protein detection.
• This technology offers a compact, portable, and miniaturized platform for biomarker analysis.
• The developed biosensor shows significant potential for advancing rapid diagnostics and on-chip sensing applications.