An effective and precise electrochemiluminescence resonance energy transfer (ECL-RET), including the efficient regulation over the proximity of a donor and an acceptor and the reliable stimuli responsive as well as the avoidance of undesirable probes leakage, etc., is significant for the development of an accurate and sensitive ECL detection method; yet, the current literature in documentation involves only a limited range of such ECL-RET systems. Herein, we propose an ECL-RET strategy with dually quenched ultralow background signals and a dual-stimuli responsive, accurate signal output for the ultrasensitive and reliable detection of anatoxin-a (ATX-a). The dual quenching is accomplished by an integrated ECL-RET probe of metal organic frameworks (MOFs) encapsulated into Ru­(bpy)3 2+ (Ru-MOF) (donor) coated with silver nanoparticles (AgNPs) shell (acceptor 1) and close proximity with DNA-ferrocene (Fc) (acceptor 2). Multistimuli responsive DNAzyme facilitated the accurate signal switch by both target ATX-a and hydrogen peroxide (H2O2). Because of the specific recognition of the aptamer toward ATX-a, an intricate design of the DNA sequence enabled the exposure of the Ag+-dependent DNAzyme sequence and H2O2 in situ generated Ag+ triggering a catalytic cleavage reaction to freely release the two ECL-RET energy acceptors, thus switching the ECL signal significantly and achieving ultrasensitive detection. It is noteworthy that AgNPs are key in this ECL-RET strategy, serving both as the gate-keepers for avoiding ECL probes leakage and also the ECL energy acceptors, and mostly importantly serving as the redox substrate for the subsequent DNAzyme catalytic signal switch. The proposed ECL-RET aptasensor for ATX-a detection displayed splendid monitoring performance with a quite low detection limit of 0.00034 mg mL–1. This sensor not only led to the development of a dual-quenching ECL-RET system but also provided meaningful multistimuli responsive ECL biosensing platform construction, which shows a promising application prospect in complicated sample analysis.

Endowing specificity and controllability with the electrochemiluminescence (ECL) thermosensitive hydrogels is vitally crucial to expanding their sensing applications. Herein, a novel photocontrolled thermosensitive electrochemiluminescence hydrogel (PT-ECL hydrogel) sensing platform with sufficient simplicity, specificity, and precise controllability is proposed, for the first time, by the integration of Ru(bpy) 3 2+ (bpy = 2,2′bipyridine) derivatives (signal reporter), split aptamers (recognition unites), and Au nanorods (AuNRs) (photothermal energy converter) into the poly(Nisopropylacrylamide) (pNIPAM) matrix. In the presence of the model target isocarbophos (ICP), the conjugation of two split aptamers initiated the ECL− resonance energy transfer (ECL-RET) between the Au nanorods and the Ru(bpy) 3 2+ centers. Surprisingly, under the irradiation of near-infrared (NIR) light, the photothermal effect of AuNRs prompted the shrinkage of the hydrogel, resulting in the enhancement of the ECL-RET and further ∼7 times signal amplification. Consequently, the PT-ECL hydrogel sensing platform performed well for ICP detection with a low detection limit of 20 pM (S/N = 3) and a wide linear range from 50 pM to 4 μM, with great stability and repeatability. Obviously, the results showed that AuNRs utilized in this study served the role as not only the ECL-RET acceptor but also the photothermal converter to prompt the phase change of the PT-ECL hydrogel precisely and simply controlled by NIR light. Use of the proposed PT-ECL hydrogel detection scheme is a first step toward enabling a newly upgraded highly sensitive and selective hydrogel-based assay and also paving the way for the application of smart photothermal reagents.

Synergetic photothermal therapy (PTT) with gene therapy (GT) has drawn emerging interests in the improvement of cancer therapeutic efficiency, while the co-delivery of photothermal agents (PTAs) and therapeutic genes by...

Three dimensional (3D) DNA walkers hold great potential in serving as an ideal candidate for signal transduction and amplification in bio-assays.

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Thioflavin T (ThT), as one of the most exciting fluorogenic molecules, boasts the "molecular-rotor" ability to induce DNA sequences containing guanine repeats to fold into G-quadruplex structures. It has been demonstrated to sense this change by its remarkable fluorescence enhancement. In this work, taking T4 polynucleotide kinase (PNK) as a model, the ThT/G-quadruplex based platform and λexonuclease (λexo) cleavage reaction were combined to design a label-free "turn-on" strategy for fast, simple and accurate detection of T4 PNK activity and its inhibition. In the presence of T4 PNK, the designed thioflavin T based molecular beacon (TMB) DNA probe could be phosphorylated and then digested by the cleavage of λexo, releasing the G-quartets. These then bound to ThT to form ThT/G-quadruplexes with an obvious fluorescence generation, for the "turn-on" detection of T4 PNK. In comparison to traditional methods, the proposed TMB probe is convenient, requiring no sophisticated labeling and separation processes and displaying high analytical performance. It exhibits a satisfying detection result for the activity of T4 PNK with a low detection limit of 0.001 U mL(-1). This is not only meaningful for further research on disease-related biochemical processes, but also valuable for molecular-target therapies.

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