Single-step colorimetric detection of acid phosphatase in human urine using an oxidase-mimic platinum nanozyme

Abstract

Acid phosphatase (ACP) is an important diagnostic biomarker for several diseases, especially those of the prostate and kidney. Nanozyme-based approaches have shown promise in the detection of ACP in human serum. However, the serum ACP levels cannot differentiate between the prostatic and renal ACP levels, and thus do not provide a true reflection of the disease state. To address this challenge, we demonstrate the potential of an oxidase-mimicking Pt nanozyme for the detection of ACP in human urine. The sensing strategy is based on the antioxidant capability of ascorbic acid that is produced in situ by the enzymatic activity of ACP and inhibits the nanozyme-mediated oxidation of the chromogenic substrate. Notably, the high activity of the Pt nanozyme across a wide pH range allowed the typical two-step ACP assay to be performed in a single step. This could reduce the assay time by half to 20 min. The deployment potential of this Pt nanozyme ACP sensor in complex biological fluids is demonstrated by estimating ACP in human urine samples in the 2–80 mU mL⁻¹ range, a concentration that is conducive to differentiating between a healthy and diseased scenario. The simplicity of a rapid, one-step, colour-based ACP detection method facilitated by Pt nanozyme offers potential applicability in clinical diagnostics of kidney and prostatic diseases.