Alkaline phosphatase (ALP), as a crucial enzyme involved in many physiological activities, is always used as one of the significant biomarkers in clinical diagnosis. Herein, a novel, simple, and effective photothermal quantitative method based on the etching of MnO₂-coated gold nanoparticles (Au@MnO₂ NPs) was established for ALP activity assay with a household thermometer-based visual readout. The photothermal effect of Au@MnO₂ NPs is much higher than that of MnO₂ NPs or Au NPs. The MnO₂ shell of Au@MnO₂ NPs can be etched by ascorbic acid, a product of ALP-catalyzed hydrolysis of 2-phospho-l-ascorbic acid. With the etching of Au@MnO₂ NPs, the photothermal conversion efficiency decreased gradually, causing the decrease of the temperature increment of the solutions by degrees. A household thermometer, instead of large-scale and professional instruments, was used as a signal reader to realize the visual quantitative detection. The photothermal platform was used successfully for the determination of ALP with a wide linear range from 2.0 to 50 U/L and a detection limit as low as 0.75 U/L. Moreover, the inhibition efficiency of sodium vanadate for ALP activity was investigated, proving the photothermal quantitative method will be a potential platform for screening enzyme inhibitors. Such a sensitive, facile, and low-cost sensing assay provides a new prospect to develop platforms for point-of-care testing.

碱性磷酸酶（ALP）作为参与许多生理活动的关键酶，一直被用作临床诊断中的重要生物标志物之一。在此，建立了一种基于 MnO ₂包覆的金纳米粒子 (Au@MnO ₂ NPs)蚀刻的新颖、简单且有效的光热定量方法，用于使用基于家用温度计的视觉读数的 ALP 活性测定。_{Au@MnO 2} NPs的光热效应远高于MnO ₂ NPs或Au NPs。Au@MnO 2 NPs 的 MnO 2 壳_可以被_抗坏血酸蚀刻，抗坏血酸是 ALP 催化的 2-磷酸-1-抗坏血酸水解的产物。_{随着 Au@MnO 2}的蚀刻NPs的光热转换效率逐渐降低，导致溶液升温幅度逐渐减小。以家用温度计代替大型专业仪器，作为信号读取器，实现可视化定量检测。该光热平台成功用于ALP的测定，具有2.0~50 U/L的宽线性范围和低至0.75 U/L的检测限。此外，研究了钒酸钠对 ALP 活性的抑制效率，证明光热定量方法将成为筛选酶抑制剂的潜在平台。这种灵敏、简便和低成本的传感检测为开发即时检测平台提供了新的前景。