Ultrasensitive DNA Detection Using Highly Fluorescent Bioconjugated Nanoparticles

TLDR

Sensitive DNA detection is critical for clinical diagnostics, gene therapy, and biomedical studies, and the highly fluorescent, photostable nanoparticles used here enable easy bioconjugation for bioanalysis. The study aims to develop a nanoparticle-based assay for reproducible, selective, and ultrasensitive DNA detection in biomedical applications. The assay uses organic dye silica nanoparticles synthesized via a modified reverse microemulsion and surface‑modified to minimize nonspecific binding and aggregation. The nanoparticle‑based sandwich assay achieves a 0.8 fM detection limit, shows strong signaling with trace DNA, and can discriminate single‑base mismatches.

Abstract

Sensitive DNA detection is extremely important in clinical diagnostics, gene therapy, and a variety of biomedical studies. We have developed a novel DNA bioanalysis method with a 0.8 fM (0.8 × 10-15 M) detection limit using a bioconjugated fluorescent nanoparticle-based sandwich assay. An organic dye silica nanoparticle is synthesized using a modified reverse microemulsion. The nanoparticles are highly fluorescent, extremely photostable, and easy for bioconjugation for bioanalysis. They exhibit an excellent signaling ability in the presence of trace amounts of DNA targets. With an effective surface modification, nonspecific binding and nanoparticle aggregation are minimized. In addition, the nanoparticle-based DNA bioanalysis assay can effectively discriminate one-base mismatched DNA sequences. We expect this nanoparticle-based assay to be widely useful in a number of biomedical applications where reproducible, selective, and ultrasensitive gene analysis is critical.