Colorimetric and photothermal dual-mode sensing platform for point-of-care testing of acid phosphatase activity and inhibitor screening based on oxidase-mimetic activity of Pt-Ni alloy nanoparticles

It is vital to exploit sensitive and portable means for the reliable assay of acid phosphatase (ACP) activity and its inhibitors screening in clinical diagnosis and drug therapy. Herein, the Pt-Ni alloy nanoparticles (Pt-Ni ANPs) with enhanced oxidase-mimetic activity were successfully prepared and applied to oxidize the achromatous 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxTMB. The oxTMB, as an effective photothermal agent, can transform photon energy to heat under an 808 nm laser illumination. The absorbance and temperature of the reaction solution increased significantly when TMB was oxidized to oxTMB by the oxidase-like Pt-Ni ANPs. However, the ACP can hydrolyze 2-Phospho-L-ascorbic acid trisodium salt (AAP) to produce ascorbic acid (AA), and then the production of AA, as a powerful reductant, can efficiently reduce oxTMB and react with singlet oxygen ( 1 O 2 ) to suppress the oxidase-mimicking activity of Pt-Ni ANPs, causing an obvious decrease in absorption spectrum and temperature of the assay system. A colorimetric and photothermal dual-mode detection platform was established for ACP activity assay by integrating colorimetric and temperature signals. Moreover, the potential application of this strategy was also verified by sensing ACP activity in human serum samples and its inhibitor screening. This dual-mode sensing platform not only improves sensitivity and precision but also meets the needs of diversity detection, which offers new insights for efficient monitoring of ACP activity and inhibitor screening in resource-poor settings.