A Pipette-Tip-Based Point-of-Care Test Platform for Detection of MicroRNA at Subfemtomolar Concentrations Using Upconverting Nanoparticles on Microbeads.

Sadraeian, Mohammad; Zhou, Jiajia; Liao, Jiayan; Khan, Jawairia Umar; Maddahfar, Mahnaz; Cheng, Yuen Yee; Sabbagh, Milad; Jin, Dayong · Nano Lett · 2025

basic_science · Level V

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Abstract

MicroRNAs are potent early disease biomarkers, yet ultrasensitive assays suitable for point-of-care testing (POCT) remain scarce. We present a pipet-tip platform for quantitative detection of oncogenic miR-27a. This method employs a sandwich hybridization strategy utilizing biotinylated capture oligos on microbeads and upconversion nanoparticle (UCNP)-conjugated oligos as the reporting probe. Highly doped UCNPs were incorporated to enhance the detection sensitivity. The dynamic mobility of the bead-oligo complexes within the pipet tip fluid significantly improves the hybridization efficiency and signal detection specificity. The assay is linear from 128 attomolar (aM) to 2.05 fM, achieves a 158 aM limit of detection (LOD), and yields a 33-fold signal advantage over mismatched strands. Our platform offers a simplified, rapid, and cost-effective solution for detecting low-abundance miRNAs with the reusability of functionalized miRNA-beads. Its scalability and minimal instrumentation requirements make it a strong candidate for advanced molecular diagnostics and POCT applications.

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