Nicking enzyme-assisted signal-amplifiable Hg²⁺ detection using upconversion nanoparticles

Area of Science:

• Nanotechnology
• Environmental Science
• Biochemistry

Background:

• Mercury ions (Hg2+) pose significant environmental and health risks.
• Accurate and sensitive detection methods for Hg2+ are crucial for environmental monitoring.
• Existing detection methods may lack the required sensitivity or specificity.

Purpose of the Study:

• To develop a highly specific and sensitive isothermal method for mercury ion detection.
• To utilize DNA-conjugated upconversion nanoparticles for enhanced detection capabilities.
• To achieve a detection limit significantly lower than regulatory standards.

Main Methods:

• Conjugating DNA with thymine bases to NaYF4:Yb3+, Tm3+ upconversion nanoparticles.
• Employing luminescence resonance energy transfer (LRET) between nanoparticles (donor) and SYBR Green I (acceptor).
• Utilizing the nicking enzyme Nt. Alwl for signal amplification and enhanced selectivity toward Hg2+.

Main Results:

• The method demonstrated high specificity and sensitivity for Hg2+ detection.
• A lower detection limit of 0.14 nM for Hg2+ was achieved.
• The detection limit is substantially lower than the US Environmental Protection Agency (EPA) standard for drinking water.

Conclusions:

• The DNA-conjugated upconversion nanoparticle system provides a sensitive and specific platform for Hg2+ detection.
• The integration of LRET and enzymatic amplification enhances detection performance.
• This method holds promise for effective environmental monitoring of mercury contamination.