Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan.
Institute of Biophotonics, National Yang-Ming University, Taipei 11221, Taiwan.
Biosens Bioelectron. 2016 Jan 15;75:88-95. doi: 10.1016/j.bios.2015.08.010. Epub 2015 Aug 10.
The widespread and intensive use of neonicotinoid insecticides induces negative cascading effects on ecosystems. It is desirable to develop a portable sensitive sensing platform for on-site screening of high-risk pesticides. We combined an indirect competitive immunoassay, highly sensitive surface plasmon resonance (SPR) biochip and a simple portable imaging setup for label-free detection of imidacloprid pesticides. The SPR biochip consists of several capped nanoslit arrays with different periods which form a spectral image on the chip. The qualitative and semiquantitative analyses of pesticides can be directly observed from the spot shift on the chip. The precise semiquantitative analyses can be further completed by using image processing in a smartphone. We demonstrate simultaneous detection of four different concentrations of imidacloprid pesticides. The visual detection limit is about 1ppb, which is well below the maximum residue concentration permitted by law (20ppb). Compared to the one-step strip assay, the proposed chip is capable of performing semiquantitative analyses and multiple detection. Compared to the enzyme-linked immunosorbent assay, our method is label-free and requires simple washing steps and short reaction time. In addition, the label-free chip has a comparable sensitivity but wider working range than those labeling techniques.
新烟碱类杀虫剂的广泛和密集使用对生态系统产生了负面的级联效应。因此，开发一种用于现场筛选高危农药的便携式灵敏传感平台是很有必要的。我们将间接竞争免疫测定法、高灵敏度的表面等离子体共振（SPR）生物芯片和简单的便携式成像设备相结合，用于无标记检测吡虫啉类农药。SPR 生物芯片由具有不同周期的几个加盖纳米狭缝阵列组成，在芯片上形成光谱图像。可以直接从芯片上的斑点移动来观察农药的定性和半定量分析。通过智能手机中的图像处理，可以进一步完成精确的半定量分析。我们演示了同时检测四种不同浓度的吡虫啉类农药。目视检测限约为 1ppb，远低于法律允许的最大残留浓度（20ppb）。与一步式条带测定法相比，该芯片能够进行半定量分析和多种检测。与酶联免疫吸附测定法相比，我们的方法是无标记的，只需要简单的洗涤步骤和短的反应时间。此外，无标记芯片的灵敏度相当，但工作范围比标记技术更广。
