Poly-adenine-mediated fluorescent spherical nucleic acid probes for live-cell imaging of endogenous tumor-related...

Area of Science:

• Biotechnology
• Nanotechnology
• Molecular Biology

Background:

• Accurate identification of tumor-related mRNA in living cells is crucial for early cancer diagnosis and pathological research.
• Current methods for intracellular mRNA detection often face limitations in sensitivity and speed.

Purpose of the Study:

• To develop a novel probe for sensitive and quantitative intracellular mRNA detection.
• To achieve regulable sensitivity in mRNA detection by controlling DNA loading density on gold nanoparticles.
• To demonstrate the application potential in rapid and sensitive intracellular target imaging.

Main Methods:

• Fabrication of poly-adenine (polyA)-mediated fluorescent spherical nucleic acid (FSNA) probes using gold nanoparticles (AuNPs).
• Functionalization of AuNPs with polyA-tailed recognition sequences and hybridization with fluorescent reporter strands to create fluorescence-quenched probes.
• Utilizing strand displacement triggered by target mRNA to release reporter strands and recover fluorescence for detection.
• Investigating the effect of polyA tail length and DNA loading density on probe sensitivity.

Main Results:

• FSNA probes demonstrated fluorescence recovery upon binding to target mRNA through strand displacement.
• The detection limit of FSNA probes with a polyA20 tail was determined to be 0.31 nM, a ~55-fold improvement over thiolated probes without surface density regulation.
• Quantitative intracellular mRNA detection and imaging were successfully achieved within 2 hours.

Conclusions:

• PolyA-mediated FSNA probes offer a powerful platform for sensitive and regulable intracellular mRNA detection.
• These probes show significant potential for applications in rapid and sensitive intracellular target imaging, aiding early cancer diagnosis.
• Programmable control over DNA loading density on gold nano-interfaces allows for fine-tuning probe sensitivity.