Ultrasensitive electrochemiluminescencent multivalent aptamer sensor based on energy and electron transfer dual...

An efficient "on-off-on" electrochemiluminescence (ECL) aptasensor utilizing dual-mechanism quenching was constructed for detecting furanyl fentanyl (FuF). The first signal "on" state was achieved by novel dual-ligand zinc metal-organic frameworks (Zn-MOFs), which were synthesized by self-assembly reaction using zinc atom clusters as metal nodes, achieving strong and stable ECL emission. The "off" state was realized by the energy and electron quenching effect of copper-doped WO₃. Specifically, in addition to the overlap of the UV-Vis spectrum, energy transfer existed between the acceptor and donor after doping copper. Therefore, copper created a "highway" for electron transfer between the donor and acceptor, which greatly improved the quenching efficiency. Simultaneously, employing multivalent aptamers as capture probes augmented the binding affinity and probability of association between aptamer and target through a synergistic multivalent effect. Consequently, the second "on" state was the ECL signal restored by introducing FuF. Benefiting from the combination of the multivalent aptamers strategy with the "on-off-on" design, the developed aptasensor showed excellent linearity (1.0 × 10^-13 to 1.0 × 10^-6 g/L) with a low limit of detection of 5.5 × 10^-14 g/L (S/N = 3). Additionally, it demonstrates a relative standard deviation (RSD) of less than 5% and good recovery ranging from 97.6 to 102%. The proposed aptasensor presents considerable potential for rapid, sensitive, and accurate determination of FuF.