A novel electrochemiluminescence (ECL) biosensor based on CdSe@CdS quantum dots (QDs) functionalized MoS₂ modified electrode was developed for sensitive detection of Pb(II) using HRP-mimicking DNAzyme biocatalytic precipitation (BCP) for ECL signal quenching. Polycationic poly(diallyldimethylammonium chloride) (PDDA) and negatively charged QDs were adsorbed on the surface of MoS₂, in sequence, to form the MoS₂–QDs composites, which were employed as a matrix for the immobilization of the G-rich DNA strand, i.e., T30695. The MoS₂–QDs were characterized by UV-vis absorption spectroscopy, fluorescence spectroscopy, energy dispersive spectrometry, transmission electron microscopy, and field emission scanning electron microscopy. CdSe@CdS QDs can produce an ECL signal using 0.1 M K₂S₂O₈ as a co-reactant. T30695 can combine with Pb(II) ions to form a stable parallel G-quadruplex. The G-quadruplex can further combine with hemin to form DNAzyme, which can catalyze H₂O₂ and oxidize 4-chloro-1-naphthol (4-CN) to produce an insoluble precipitation of benzo-4-chlorohexadienone on the surface of the sensor. When the concentration of Pb(II) in the solution was increased, more of DNAzyme was generated and subsequently more 4-CN molecules were oxidized catalytically, leading to a decrease of the ECL signal. Using this quenching strategy, the ECL signal of the biosensor was linearly dependent on the logarithm of the Pb(II) concentration ranging from 1.0 × 10⁻¹⁵ to 1.0 × 10⁻¹¹ M with a detection limit of 0.98 f M. The stability and selectivity of the sensor were also investigated. The sensor was applied in the determination of Pb(II) in the real water samples and satisfactory results were obtained.

中文翻译：

---

基于CdSe @ CdS功能化的MoS ₂和基于血红素/ G-四链体的DNA酶生物催化沉淀的电化学发光传感器，用于Pb（ii）的 灵敏检测

开发了一种基于CdSe @ CdS量子点（QDs）功能化的MoS ₂修饰电极的新型电化学发光（ECL）生物传感器，用于使用HRP模拟DNAzyme生物催化沉淀（BCP）进行ECL信号猝灭的灵敏检测Pb（II）。将聚阳离子聚二烯丙基二甲基氯化铵（PDDA）和带负电荷的QD依次吸附在MoS ₂的表面上，形成MoS ₂ -QDs复合材料，将其用作固定富G DNA链的基质，我。例如T30695。MoS ₂–QD通过紫外可见吸收光谱，荧光光谱，能量色散光谱，透射电子显微镜和场发射扫描电子显微镜进行表征。CdSe @ CdS QD可以使用0.1 MK ₂ S ₂ O ₈作为共反应物来产生ECL信号。T30695可与Pb（II）离子结合形成稳定的平行G四联体。G-四链体可以进一步与血红素结合形成DNA酶，该酶可以催化H ₂ O ₂并氧化4-氯-1-萘酚（4-CN），从而在其表面产生不溶性的苯并4-氯己二酮沉淀。传感器。当Pb（II溶液中）的增加，产生了更多的DNAzyme，随后更多的4-CN分子被催化氧化，导致ECL信号降低。使用这种淬灭策略，生物传感器的ECL信号线性依赖于Pb（II）浓度的对数，范围为1.0×10 ^-15至1.0×10 ^-11 M，检测极限为0.98 fM。还研究了传感器的选择性。该传感器用于实际水样中铅（Ⅱ）的测定，结果令人满意。