A facile colorimetric Pb²⁺ assay system has been developed based on the visible color change of gold nanoparticles (GNPs) modified with α2-microglobulin (α2M) protein. The α2M protein is a soluble and high-affinity receptor for Pb²⁺, which is well studied and regarded as the comparable positive control in Pb-binding protein researches. It was obtained through purifying recombinant protein from the expression of recombinant plasmids in Escherichia coli and was attached on GNPs to form GNPs-α2M sensor nanoparticles for detecting Pb²⁺, which has never been used for sensing Pb²⁺ in previous studies. When Pb²⁺ was introduced into the assay system, GNPs-α2M sensor nanoparticles can be triggered aggregation with the color change from pink to blue. The detection system exhibited good selectivity and sensitivity, which was attributed to the receptor specificity of α2M protein. Using this assay system, it can be distinguished 1.00 μM concentration of Pb²⁺ or more by naked eyes clearly. Furthermore, the UV-Vis absorbance ratio between 620 and 523 nm exhibited linearity relationship with the concentration of Pb²⁺ from 0.05 to 3 μM in assay system. In this research, GNPs-α2M sensor nanoparticles have highly specific capability to recognize Pb²⁺. The assay system constituted by GNPs-α2M sensor nanoparticles displays excellent convenience, selectivity, and sensitivity that provide promising potentials for on-site rapid test of Pb²⁺.

基于用α2-微球蛋白（α2M）修饰的金纳米颗粒（GNP）的可见颜色变化，开发了一种简便的比色Pb ²⁺分析系统。α2M蛋白是Pb ²⁺的可溶性和高亲和力受体，经过深入研究，被认为是Pb结合蛋白研究中可比的阳性对照。它是通过从重组质粒的表达纯化重组蛋白获得的大肠杆菌，并附着在的GNP形成的GNP-α2M传感器的纳米颗粒用于检测的Pb ²⁺，其从未被用于感测的Pb ²⁺在以前的研究。当铅²⁺引入测定系统后，可以触发GNPs-α2M传感器纳米粒子的聚集，其颜色从粉红色变为蓝色。该检测系统表现出良好的选择性和灵敏度，这归因于α2M蛋白的受体特异性。使用该测定系统，肉眼可清楚地区分^1.00μM或更高的Pb ²⁺浓度。此外，在测定系统中，620 nm和523 nm之间的UV-Vis吸收比与Pb ²⁺的浓度从0.05到3μM呈线性关系。在这项研究中，GNPs-α2M传感器纳米颗粒具有识别Pb ^2+的高特异性能力。由GNPs-α2M传感器纳米颗粒构成的测定系统显示出极好的便利性，选择性和灵敏度，为Pb ²⁺的现场快速测试提供了有希望的潜力。