PdPt bimetallic nanowires with efficient oxidase mimic activity for the colorimetric detection of acid phosphatase in acidic media

In this study, we found that PdPt bimetallic alloy nanowires (Pd/Pt NWs) exhibited excellent oxidase-like activity in acidic media. Their oxidase-like activity could be readily tailored by a well-defined Pd/Pt ratio, while the nanowires with Pd/Pt ratio of 1 : 3 (defined as Pd/Pt-1 : 3 NWs) proved to exhibit the most efficient catalytic oxidation activity. By using their excellent oxidase-like activity, we developed a simple colorimetric assay to detect the activity of acid phosphatase (ACP) based on its catalytic hydrolysate, ascorbic acid (AA), which effectively inhibited the action of the Pd/Pt-1 : 3 NW-mediated TMB-oxidized chromogenic reaction. Good linearity between the absorbance change and activity of ACP was obtained in the range of 0.17-2.67 U L-1, with the limit of detection as low as 0.06 U L-1. Moreover, the proposed method was also adopted to determine the ACP activity in mimicking physiological sample solutions with satisfactory results, illustrating its great potential for biological analysis.