Sensitive multiplexed DNA detection using silica nanoparticles as the target capturing platform.

Area of Science:

• Biotechnology
• Nanotechnology
• Molecular Diagnostics

Background:

• Multiplexed DNA detection is crucial for accurate disease diagnosis.
• Existing methods may lack sensitivity or require complex procedures.
• Silica nanoparticles offer a versatile platform for bio-assays.

Purpose of the Study:

• To develop a simple and sensitive method for simultaneous detection of two DNA sequences using a single silica nanoparticle.
• To demonstrate the efficacy of this multiplexed assay for human papillomavirus (HPV) 16 and 18 detection.

Main Methods:

• Carboxyl-modified silica nanoparticles were prepared via microemulsion.
• Avidin was immobilized on nanoparticles, followed by biotin-avidin interaction for nano-platform formation.
• Capture DNA strands for HPV-16 and HPV-18 were conjugated to the same nanoparticles.
• A one-step hybridization assay was performed with fluorescently labeled probes for simultaneous detection.

Main Results:

• Quantified avidin binding capacity (~8 avidin/NP) and DNA capture strand conjugation (13.5 pmol C-16 and 15.5 pmol C-18 per mg NPs).
• Demonstrated linear fluorescence response to target DNA concentration (0.5–9 nM).
• Achieved low detection limits for HPV-16 (0.17 nM) and HPV-18 (0.78 nM).

Conclusions:

• The developed silica nanoparticle-based biobarcode assay enables simple, sensitive, and simultaneous detection of multiple DNA targets.
• This method holds promise for efficient and accurate diagnostic applications, particularly for viral infections like HPV.