In this work, a novel fluorescent method for the detection of dopamine (DA) was developed based on a fluorescent nanocomposite (Pdots@AMP-Cu) with polyphenol oxidase activity. Pdots@AMP-Cu was first prepared by the composite of fluorescent polymer dots and coordination nanostructures of adenosine monophosphate (AMP) and Cu²⁺. The Pdots@AMP-Cu exhibited obvious red fluorescence emission (668 nm), as well as polyphenol oxidase activity by catalyzing the substrate 2,4-DP and 4-AP, and resulted in obvious changes of the solution color from colorless to red. A novel detection method for DA was then developed based on Pdots@AMP-Cu. It is observed that DA can be oxidized by Pdots@AMP-Cu to form eumelanin, and at the same time, the fluorescence of Pdots@AMP-Cu is efficiently quenched by eumelanin due to electron transfer. A good linear relationship was observed between the fluorescent intensity and DA concentration from 10 to 400 μM, and the limit of detection for DA was 4 μM. Moreover, the proposed method exhibited high selectivity toward common amino acids, ascorbic acid, uric acid, etc. And it could also be utilized for DA sensing in human serum samples with satisfactory recoveries.

Graphical abstract

在这项工作中，基于具有多酚氧化酶活性的荧光纳米复合材料（Pdots @ AMP-Cu），开发了一种检测多巴胺（DA）的新型荧光方法。Pdots @ AMP-Cu首先由荧光聚合物点和单磷酸腺苷（AMP）和Cu ^2+的配位纳米结构复合而成。Pdots @ AMP-Cu通过催化底物2,4-DP和4-AP表现出明显的红色荧光发射（668 nm），以及多酚氧化酶活性，并导致溶液颜色从无色到红色的明显变化。然后基于Pdots @ AMP-Cu开发了一种新的DA检测方法。观察到DA可以被Pdots @ AMP-Cu氧化而形成真木兰，同时由于电子转移，Pumes @ AMP-Cu的荧光被真木兰有效地猝灭。荧光强度与DA浓度在10至400μM之间观察到良好的线性关系，DA的检出限为4μM。此外，该方法对常见氨基酸，抗坏血酸，尿酸等具有很高的选择性。

图形概要