Dual-mode fluorescence and colorimetric smartphone-based sensing platform with oxidation-induced self-assembled nanoflowers for sarcosine detection.

Early prostatic cancer (PCa) diagnosis significantly improves the chances of successful treatment and enhances patient survival rates. Traditional enzyme cascade-based early cancer detection methods offer efficiency and signal amplification but are limited by cost, complexity, and enzyme dependency, affecting stability and practicality. Meanwhile, sarcosine (Sar) is commonly considered a biomarker for PCa development. It is essential to develop a Sar detection method based on cascade reactions, which should be efficient, low skill requirement, and suitable for on-site testing. To address this, our study introduces the synthesis of organic-inorganic self-assembled nanoflowers to optimize existing detection methods. The Sar oxidase (SOX)-inorganic hybrid nanoflowers (Cu 3 (PO 4) 2 :Ce@SOX) possess inherent fluorescent properties and excellent peroxidase activity, coupled with efficient enzyme loading. Based on this, we have developed a dual-mode multi-enzyme cascade nanoplatform combining fluorescence and colorimetric methods for the detection of Sar. The encapsulation yield of Cu 3 (PO 4) 2 :Ce@SOX reaches 84.5 %, exhibiting a remarkable enhancement in catalytic activity by 1.26–1.29 fold compared to free SOX. The present study employing a dual-signal mechanism encompasses 'turn-off' fluorescence signals ranging from 0.5 μM to 60 μM, with a detection limit of 0.226 μM, and 'turn-on' colorimetric signals ranging from 0.18 μM to 60 μM, with a detection limit of 0.120 μM. Furthermore, our study developed an intelligent smartphone sensor system utilizing cotton swabs for real-time analysis of Sar without additional instruments. The nano-platform exhibits exceptional repeatability and stability, rendering it well-suited for detecting Sar in authentic human urine samples. This innovation allows for immediate analysis, offering valuable insights for portable and efficient biosensors applicable to Sar and other analytes. A fluorescence and smartphone colorimetric sensing dual-mode multienzyme cascade based on oxidation-induced self-assembled nanoflowers for sarcosine's sensitive and selective detection. [Display omitted] • The simple synthesis method includes SOX as part of the enzyme-like catalyst. • The fluorescence was quenched by the SOX + Sar system, with activating nanozyme activity. • The generated H 2 O 2 has the effect of killing two birds with one stone for the cascade reaction system. • A chromogenic cotton swabs-based smartphone sensing system was developed for sarcosine analysis. [ABSTRACT FROM AUTHOR]