Ultrafast Plasmonic Nanocavity Thermocycler for Direct Real-Time Reverse Transcription PCR at a Point-of-Care Level.

Area of Science:

• Nanotechnology
• Molecular Diagnostics
• Biomedical Engineering

Background:

• Current molecular diagnostics face limitations in nucleic acid extraction and thermocycling speed.
• These bottlenecks hinder true point-of-care deployment for rapid testing.

Purpose of the Study:

• To develop an ultrafast plasmonic nanocavity thermocycler (PNT) for direct real-time reverse transcription PCR (DRT-qPCR).
• To enable rapid molecular diagnostics at the point-of-care.

Main Methods:

• Utilized a plasmonic nanocavity with clustered Au, SiO2, and Au thin film, incorporating a Pt resistance temperature detector and WLED.
• Integrated the PNT with a microlens array fluorescence camera and disposable PCR cartridge into a palm-sized system.
• Achieved rapid heating (20.4 °C/s) and cooling (7.5 °C/s) for 40 thermocycles in 269 seconds.

Main Results:

• Completed DRT-qPCR, including sample prep, reverse transcription, and amplification, in under 15 minutes.
• Demonstrated amplification efficiency comparable to commercial benchtop PCR machines.
• Clinical validation with 60 SARS-CoV-2 samples showed 87.1% sensitivity, 100% specificity, and 93.3% accuracy.

Conclusions:

• The PNT-based DRT-qPCR offers a precise and scalable solution for rapid molecular diagnostics.
• This technology is suitable for decentralized and time-sensitive settings for various infectious diseases.
• All false negatives were detected upon retesting, indicating high reliability.