A novel "on-off-on" electrochemiluminescence strategy based on RNA cleavage propelled signal amplification and resonance energy transfer for Pb detection.

BACKGROUND

Lead (Pb) is one of the most toxic heavy-metal pollutants. Additionally, lead ions (Pb) can accumulate in the human body through the food chain, causing irreversible damage through organ damage and system disorders. In the past few years, the detection of Pb has mainly relied on instrumental methods such as atomic absorption spectroscopy (AAS) and inductively coupled plasma mass spectrometry (ICP-MS). Nonetheless, these techniques are complicated in terms of equipment and procedures, along with being time-intensive and expensive in terms of detection. These drawbacks have limited their wide application. Hence, there is a pressing need to develop detection techniques for Pb that are not only cost-efficient but also highly sensitive and specific.

RESULTS

A novel "on-off-on" electrochemiluminescence (ECL) sensor for detecting Pb was developed based on the resonance energy transfer (RET) effect between AuNPs and boron nitride quantum dots (BN QDs) and the recognition of Pb by DNAzyme along with the cleavage reaction of the substrate chain. Poly(6-carboxyindole)/stannic sulfide (P6ICA/SnS) nanocomposite was employed as a co-reaction accelerator to consequently facilitate the production of intermediate SO. This effective enhancement of the reaction led to an improved ECL intensity of BN QDs and enabled the sensor platform to exhibit a higher original ECL response. Benefiting from the combination of the DNAzyme signal amplification strategy with the "on-off-on" design, the ECL sensor showed satisfactory selectivity, good stability, and high sensitivity. This ECL sensor exhibited a linear detection range (LDR) of 10-10 M and a limit of detection (LOD) of 2.6 × 10 M.

SIGNIFICANCE

In the present work, an "on-off-on" ECL sensor is constructed based on RET effect for ultrasensitive detection of Pb. P6ICA/SnS was investigated as the co-reaction accelerator in this sensor. Moreover, this ECL sensor exhibited excellent analytical capability for detecting Pb in actual water samples, providing a method for detecting other heavy metal ions as well.