Surface motifs regulated aggregation induced emission in AuAg nanoclusters combined with Ce(III)/Ce(IV) catalytic cyclic amplification strategy for sensitive bioanalysis

Abstract

Achieving high luminescence intensity in electrochemiluminescence biosensors is a challenge for metal nanoclusters (MNCs) due to their non-radiative relaxation-mediated self-quenching tendency. Here, the surface motifs [M(I)-SR] of MNCs were regulated based on aggregation-induced emission (AIE) strategy was proposed to mitigate non-radiative relaxation vibrations, and an efficient luminescent AuAg NCs was designed via host-guest assembly as a signal probe. The Au(I)-SR of AuAg NCs used glutathione (GSH) as a template and reducing agent, and the introduction of Ag(I) made the Au(I)-SR of AuAg NCs cross-linked and interlocked, resulting in AuAg NCs with denser surface patterns. The aggregation of surface motifs limited the ligand movement to reduce the non-radiative energy dissipation. Furthermore, the spontaneous catalytic cycle amplification strategy of Ce(III)/Ce(IV) redox pairs in the matrix material of Ce-MOF promoted the reaction of more co-reactants triethylamine (TEA), obtaining potent reducing radicals TEA* for further improving the ECL efficiency of AuAg NCs. Using cardiac troponin I (cTnI) as the analytical model, the biosensor exhibited a wide linear relationship range (50 fg·mL−1 - 500 ng·mL−1) and a low detection limit (4.77 fg·mL−1). The breakthrough in surface motifs regulation of MNCs guides a new way to design high luminiferous MNCs, and further expands the application potential of MNCs.