Detection of lead(II) (Pb²⁺) ions in water is important for the protection of human health and environment. The growing demand for onsite detection still faces challenges for sensitive and easy-to-use methods. In this work, a novel surface plasmon resonance (SPR) biosensor based on GR-5 DNAzyme and gold nanoparticles (AuNPs) was developed. Thiolated DNAzyme was immobilized on the gold surface of the sensor chip followed by anchoring the substrate-functionalized AuNPs through the DNAzyme-substrate hybridization. The coupling between the localized surface plasmon (LSP) of AuNPs and the surface plasmon polaritons (SPP) on the gold sensor surface was used to improve the sensitivity. The substrate cleavage in the presence of Pb²⁺ ions was catalyzed by DNAzyme, leading to the removal of AuNPs and the diminished LSP-SPP coupling. The optimal detection limit was 80 pM for the sensor fabricated with 1 μM DNAzyme, corresponding to two or three orders of magnitude lower than the toxicity levels of Pb²⁺ in drinking water defined by WHO and USEPA. By tuning the surface coverage of DNAzyme, the sensitivity and dynamic range could be controlled. This sensor also featured high selectivity to Pb²⁺ ions and simple detection procedure. Successful detection of Pb²⁺ ions in groundwater indicates that this method has the prospect in the onsite detection of Pb²⁺ ions in water. Given the variety of AuNPs and metal-specific DNAzymes, this detection strategy would lead to the development of more sensitive and versatile heavy metal sensors.

水中铅（II）（Pb ²⁺）离子的检测对于保护人类健康和环境非常重要。对现场检测的需求不断增长，仍然面临着敏感和易于使用的方法的挑战。在这项工作中，基于GR-5 DNAzyme和金纳米粒子（AuNPs）的新型表面等离子体共振（SPR）生物传感器被开发出来。将巯基化的DNAzyme固定在传感器芯片的金表面上，然后通过DNAzyme与底物的杂交锚定底物官能化的AuNP。AuNPs的局部表面等离激元（LSP）和金传感器表面上的表面等离激元极化子（SPP）之间的耦合用于提高灵敏度。Pb ²⁺存在下的底物裂解离子被DNAzyme催化，导致AuNP的去除和LSP-SPP偶联的减弱。用1μMDNAzyme制成的传感器的最佳检测限为80 pM，比WHO和USEPA定义的饮用水中Pb ²⁺的毒性水平低两个或三个数量级。通过调节DNAzyme的表面覆盖率，可以控制灵敏度和动态范围。该传感器还具有对Pb ²⁺离子的高选择性和简单的检测程序。地下水中Pb ²⁺离子的成功检测表明该方法具有现场检测Pb ²⁺的前景。水中的离子。考虑到AuNPs和金属特异性DNA酶的多样性，这种检测策略将导致开发更灵敏，用途更广泛的重金属传感器。