Transient Hybridization Directed Nanoflare for Single-Molecule miRNA Imaging

Area of Science:

• Biotechnology
• Molecular Biology
• Cell Biology

Background:

• Accurate quantification of cellular microRNAs (miRNAs) is crucial for developing diagnostic biomarkers and understanding their role in cellular signaling.
• Existing single-molecule miRNA imaging methods face limitations in sensitivity and specificity due to hybridization-based probes.

Purpose of the Study:

• To develop a highly sensitive and specific single-molecule imaging method for cellular miRNA quantification.
• To demonstrate the capability of the new method for detecting and counting specific miRNA molecules within single cells.

Main Methods:

• Utilized conjugated polymer nanoparticle (CPN) labeled short DNA probes, termed nanoflares, for miRNA detection.
• Employed single-molecule kinetics signals generated by transient nanoflare-miRNA hybridization.
• Applied highly inclined and laminated optical sheet (HILO) microscopy for direct counting of single miR-21 molecules in cells.

Main Results:

• Achieved a remarkable detection limit of 1 fM for miRNA without amplification.
• Demonstrated high specificity, including discrimination between homologous miRNAs.
• Successfully quantified single miR-21 molecules in cells, revealing cell-to-cell variability and differential expression in tumor versus normal cells.

Conclusions:

• The nanoflare method offers unprecedented sensitivity and specificity for single-molecule miRNA imaging.
• This technique enables direct counting of intracellular miRNAs, providing insights into their expression dynamics and heterogeneity.
• The findings support the potential of nanoflares as a powerful tool for miRNA-based diagnostics and biological research.