Rational Design of Nonmetal Material Self-Mediated Electron Transfer-Based Electrochemiluminescence Sensing Platform and Its Application

Monitoring the levels and metabolic changes of deoxyribonucleotides is crucial for various clinical disease research studies. In this study, we propose a highly efficient nonmetal material self-mediated electron transfer (ET)-based electrochemiluminescence (ECL) sensing platform. This platform utilizes deoxyguanosine monophosphate (dGMP) as a model nonmetal-based electron acceptor and strategically employs 6-aza-2-thiothymine-protected gold nanoclusters (ATT-AuNCs) with matched energy levels as the ECL donor. The ET-mediated quenching mechanism has been investigated using ECL technology, isothermal titration calorimetry measurements, and density functional theory (DFT) calculations. These investigations reveal that dGMP is uniquely capable of undergoing spontaneous ET with ATT-AuNCs compared with the other three deoxyribonucleotides (dAMP, dTMP, and dCMP). Furthermore, dGMP exhibits the lowest reorganization energy (λ) after ET, indicating superior ET kinetics, which results in more efficient ECL quenching and excellent detection selectivity. The achieved detection limit is as low as 2.7 × 10^-12 M, significantly outperforming most reported methodologies. Additionally, the proposed ET-ECL sensing platform demonstrates notable advantages, including high efficiency, simplicity, exceptional sensitivity, and excellent specificity. Consequently, this study establishes a new paradigm for studying nonmetal-mediated ET-based ECL mechanisms and provides a foundation for future high-performance sensing systems based on molecular ET behavior.