Single-molecule microfluidic assay for prostate-specific antigen based on magnetic beads and upconversion...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Early diagnosis of prostate cancer is crucial for effective treatment and improved patient prognosis.
• Prostate-specific antigen (PSA) is the standard biomarker for non-invasive diagnosis, requiring ultrasensitive detection methods.
• Current methods for PSA detection need enhancement for improved sensitivity in diagnostics and recurrence monitoring.

Purpose of the Study:

• To develop a highly sensitive microfluidic device for single-molecule analysis of PSA.
• To utilize photon-upconversion nanoparticles (UCNPs) and magnetic microparticles (MBs) for enhanced PSA detection.
• To establish a digital readout assay for precise quantification of PSA at low concentrations.

Main Methods:

• Optimization of magnetic microparticles (MBs) for PSA capture and preconcentration.
• Implementation of a bead-based upconversion-linked immunoassay (ULISA) within a microfluidic device.
• Single-molecule analysis using UCNPs as detection labels and a digital counting readout.

Main Results:

• Achieved an ultrasensitive PSA detection limit of 1.04 pg mL-1 (36 fM) in 50% fetal bovine serum.
• Demonstrated an 11-fold improvement in sensitivity compared to analog MB-based ULISA.
• Validated the microfluidic setup's suitability for clinical samples with high recovery rates (97-105%) against a reference assay.

Conclusions:

• The developed microfluidic device offers exceptional sensitivity for PSA detection, crucial for early prostate cancer diagnosis.
• The bead-based ULISA in a microfluidic format provides a robust platform for ultrasensitive biomarker quantification.
• This technology holds potential for high-throughput analysis and improved clinical diagnostics of prostate cancer.