Dual-Function Strategy for Enhanced Quercetin Detection Using Terbium(III) Ion-Bound Gold Nanoclusters

Area of Science:

• Nanomaterials Science
• Chemical Sensing
• Photochemistry

Background:

• Developing metal nanoclusters (NCs) with high fluorescence and sensing capabilities under physiological conditions remains challenging.
• Existing methods struggle with selective detection of analytes like quercetin (Que) and its analogues.
• Understanding photophysical mechanisms like proton-coupled electron transfer (PCET) and photoinduced electron transfer (PET) is crucial for probe design.

Purpose of the Study:

• To engineer high-performance metal NC-based probes by integrating PCET and PET mechanisms.
• To utilize terbium(III) (Tb³⁺) ions as a modulator for enhancing probe performance.
• To achieve highly sensitive and selective detection of quercetin (Que).

Main Methods:

• Design of Au₁₀(ATT)₆ NCs with 6-aza-2-thiothymidine (ATT) ligands.
• Modulation of PCET pathway by Tb³⁺ ion binding to inhibit proton transfer.
• Facilitation of donor-linker-acceptor PET reaction using Tb³⁺ as a bridge.
• Development of a Tb³⁺/Au₁₀(ATT)₆ NC-based probe for Que detection.

Main Results:

• Tb³⁺ binding to Au₁₀(ATT)₆ enhanced fluorescence over 10-fold, achieving a quantum yield of 7.2%.
• The probe exhibited a significantly lower limit of detection for Que (2.6 nM), reduced by nearly 3 orders of magnitude.
• Selective detection of Que in the presence of its glycosylated analogues was achieved.

Conclusions:

• The synergistic application of PCET and PET mechanisms, modulated by Tb³⁺, offers precise control over metal NC photoluminescence.
• This strategy enables the development of next-generation metal NC-based sensing technologies with superior sensitivity and selectivity.
• The findings open new avenues for molecular-level control in designing advanced fluorescent probes.