In this study, based on the oxidase-like (OXD) activity of platinum-nickel nanoparticles (Pt-Ni NPs) nanozyme and further in collaboration with 3,3′,5,5′-tetramethylbenzidine (TMB), a colorimetric/photothermal dual-mode probe for organophosphorus pesticides (OPs) detection was developed. TMB undergone the catalytic oxidation of Pt-Ni NPs to change from colorless to blue oxidized substance (oxTMB) and exhibited higher temperature under near-infrared irradiation. The hydrolysis product of acid phosphatase (ACP) with L-ascorbic acid 2-phosphate trisodium competed with the OXD-like activity of Pt-Ni NPs to prevent the oxidation of TMB. As the concentration of OPs grew, inhibiting the blocking effect by deactivating ACP, the generated oxTMB caused notable color and temperature changes in the reaction system. The dual-mode probe responded linearly to chlorpyrifos, with the detection limits for colorimetric and photothermal modes of 1.2 ng/mL and 1.66 ng/mL, respectively. This work proposes a simple and reliable colorimetric/photothermal platform for OPs identification, which overcomes the problem that single-mode detection probes are susceptible to external factors, and has broad application potential in the field of food safety.

中文翻译：

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基于铂镍纳米颗粒的类氧化酶纳米酶用于有机磷农药的比色/光热双模式检测

在这项研究中，基于铂镍纳米颗粒（Pt-Ni NPs）纳米酶的类氧化酶（OXD）活性，并进一步与3,3',5,5'-四甲基联苯胺（TMB）合作，一种比色/光热酶开发了用于有机磷农药（OPs）检测的双模式探针。 TMB经过Pt-Ni NPs的催化氧化，从无色变为蓝色氧化物质（oxTMB），并在近红外照射下表现出较高的温度。酸性磷酸酶（ACP）与L-抗坏血酸2-磷酸三钠的水解产物与Pt-Ni NPs的类OXD活性竞争，以防止TMB的氧化。随着 OP 浓度的增加，通过使 ACP 失活来抑制阻断效果，生成的 oxTMB 引起反应系统中显着的颜色和温度变化。双模式探针对毒死蜱呈线性响应，比色模式和光热模式的检测限分别为 1.2 ng/mL 和 1.66 ng/mL。该工作提出了一种简单可靠的OPs鉴定比色/光热平台，克服了单模检测探针易受外界因素影响的问题，在食品安全领域具有广泛的应用潜力。