Accelerated Digital Biodetection Using Magneto-plasmonic Nanoparticle-Coupled Photonic Resonator Absorption...

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Molecular Diagnostics

Background:

• Ultrasensitive quantification of circulating microRNA (miRNA) biomarkers is crucial for early cancer diagnosis and monitoring.
• Existing nanoparticle-based assays face limitations in response time due to diffusion-limited analyte transport.
• Enzymatic amplification is often required, adding complexity and time to biomarker detection.

Purpose of the Study:

• To develop a rapid and ultrasensitive method for circulating miRNA quantification using magnetic nanoparticles.
• To overcome the diffusion-limited transport bottleneck in current biosensing assays.
• To enable faster and more efficient biomarker detection for potential point-of-care applications.

Main Methods:

• Magnetic activate capture and digital counting (mAC+DC) approach utilizing magneto-plasmonic nanoparticles (MPNPs).
• MPNPs with target-specific probes bind to miRNA, are magnetically transported to capture probes on a photonic crystal (PC).
• Detection via spectral matching of MPNP plasmon resonance to PC resonance, enabling digital counting of captured MPNPs.

Main Results:

• Demonstrated quantification of miR-375 cancer biomarker in unprocessed human serum.
• Achieved a rapid 1-minute response time and a low detection limit of 61.9 aM.
• Exhibited a broad dynamic range (100 aM to 10 pM) and single-base mismatch selectivity.

Conclusions:

• The mAC+DC approach accelerates single-molecule sensing for miRNA detection.
• This method offers a rapid, ultrasensitive, and selective platform for biomarker quantification.
• The technology is suitable for minimally invasive diagnostics and point-of-care testing with short turnaround times.