Binary light-up fluorescent probe based on silver nanoclusters for MicroRNA detection

Area of Science:

• Biochemistry
• Nanotechnology
• Molecular Diagnostics

Background:

• Silver nanoclusters (Ag NCs) exhibit unique fluorescence properties, making them valuable in biosensing applications.
• DNA matrices are commonly used for Ag NC synthesis, enhancing biocompatibility and environmental sensitivity.
• Ag NCs/DNA complexes can self-assemble and rearrange, altering optical properties for potential naked-eye detection.

Purpose of the Study:

• To develop a simple, one-step, turn-on, and highly specific biosensor for microRNA-210.
• To leverage fluorescent Ag NCs integrated with a binary DNA matrix for enhanced sensitivity and specificity.
• To create a microRNA detection assay that requires no additional steps after sample introduction.

Main Methods:

• Synthesis of non-fluorescent "dark" silver nanoclusters using a single strand of a binary DNA matrix with a 5'-CCCGTTTT-3' sequence.
• Optimization of the binary probe's structure and location for minimal background signal.
• Development of a turn-on fluorescence assay triggered by the binding of target microRNA-210.

Main Results:

• The "dark" Ag NC structures demonstrated stability for at least one month.
• A linear relationship between fluorescence intensity and microRNA-210 concentration was observed in the range of 5-500 nM.
• The sensor exhibited high specificity for microRNA-210, with a limit of detection (LOD) of 5 nM in serum samples.

Conclusions:

• A novel, highly specific, and sensitive turn-on fluorescent biosensor for microRNA-210 has been successfully developed.
• The binary DNA matrix design is crucial for achieving a bright green fluorescence signal only upon target binding.
• This sensor technology offers a promising platform for microRNA detection with potential for naked-eye readout and minimal sample processing.