*Article* **Fabrication of Nano/Micro-Structured Electrospun Detection Card for the Detection of Pesticide Residues**

**Kun Feng 1, Meng-Yu Zhai 1, Yun-Shan Wei 1, Min-Hua Zong 1, Hong Wu 1,\* and Shuang-Yan Han 2,\***


**Abstract:** A novel nano/micro-structured pesticide detection card was developed by combining electrospinning and hydrophilic modification, and its feasibility for detecting different pesticides was investigated. Here, the plain and hydrophilic-modified poly(ε-caprolactone) (PCL) fiber mats were used for the absorption of indolyl acetate and acetylcholinesterase (AChE), respectively. By pre-treating the fiber mat with ethanol, its surface wettability was improved, thus, promoting the hydrolysis of the PCL fiber mat. Furthermore, the absorption efficiency of AChE was improved by almost two times due to the increased hydrophilicity of the modified fiber mat. Noteworthily, this self-made detection card showed a 5-fold, 2-fold, and 1.5-fold reduction of the minimum detectable concentration for carbofuran, malathion, and trichlorfon, respectively, compared to the national standard values. Additionally, it also exhibited good stability when stored at 4 ◦C and room temperature. The food detection test showed that this nano/micro-based detection card had better detectability than the commercial detection card. Therefore, this study offers new insights into the design of pesticide detection cards, which also broadens the application of electrospinning technique.

**Keywords:** nano/micro-structure; pesticide detection card; electrospinning; hydrophilic modification; sensitivity
