Label-free aptamer-based sensor for specific detection of malathion residues by surface-enhanced Raman scattering

Yonghui Nie; Yuanjie Teng; Pan Li; Wenhan Liu; Qianwei Shi; Yuchao Zhang

doi:10.1016/j.saa.2017.10.030

Label-free aptamer-based sensor for specific detection of malathion residues by surface-enhanced Raman scattering

Spectrochim Acta A Mol Biomol Spectrosc. 2018 Feb 15:191:271-276. doi: 10.1016/j.saa.2017.10.030. Epub 2017 Oct 10.

Authors

Yonghui Nie¹, Yuanjie Teng², Pan Li¹, Wenhan Liu³, Qianwei Shi¹, Yuchao Zhang¹

Affiliations

¹ State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
² State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China. Electronic address: yuanjieteng@zjut.edu.cn.
³ State Key Laboratory Breeding Base of Green Chemistry-Synthesis Technology, College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310032, China. Electronic address: liuwh@zjut.edu.cn.

PMID: 29045930
DOI: 10.1016/j.saa.2017.10.030

Abstract

A novel label-free aptamer surface-enhanced Raman scattering (SERS) sensor for trace malathion residue detection was proposed. In this process, the binding of malathion molecule with aptamer is identified directly. The silver nanoparticles modified with positively charged spermine served as enhancing and capture reagents for the negatively charged aptamer. Then, the silver nanoparticles modified by aptamer were used to specifically capture the malathion. The SERS background spectra of spermine, aptamer, and malathion were recorded and distinguished with the spectrum of malathion-aptamer. To enhance the characteristic peak signal of malathion captured by the aptamer, the aggregate reagents (NaCl, KCl, MgCl₂) were compared and selected. The selectivity of this method was verified in the mixed-pesticide standard solution, which included malathion, phosmet, chlorpyrifos-methyl, and fethion. Results show that malathion can be specifically identified when the mixed-pesticide interferences existed. The standard curve was established, presenting a good linear range of 5×10^-7 to 1×10^-5mol·L^-1. The spiked experiments for tap water show good recoveries from 87.4% to 110.5% with a relative standard deviation of less than 4.22%. Therefore, the proposed label-free aptamer SERS sensor is convenient, specifically detects trace malathion residues, and can be applied for qualitative and quantitative analysis of other pesticides.

Keywords: Ag colloids; Aptamer; Malathion; Pesticides; Surface-enhanced Raman scattering.