title: A ratiometric fluorescent quantum dots based biosensor for organophosphorus pesticides detection by inner-filter effect.
abstract: In this work, we develop a novel and sensitive sensor for the detection of organophosphorus pesticides based on the inner-filter effect (IFE) between gold nanoparticles (AuNPs) and ratiometric fluorescent quantum dots (RF-QDs). The RF-QDs has been designed by hybridizing two differently colored CdTe QDs, in which the red emissive QDs entrapped in the silica sphere acting as the reference signal, and the green emissive QDs covalently attached on the silica surface serving as the response signal.The fluorescence of RF-QDs could be quenched by AuNPs based on IFE. Protamine could effectively turn on the fluorescence due to the electrostatic attraction between protamine and AuNPs. Trypsin can easily hydrolyze protamine, leading to the quench of the fluorescence. Then, the fluorescence could be recovered again by the addition of parathion-methyl (PM) which could inhibit the activity of trypsin. By measuring the fluorescence of RF-QDs, the inhibition efficiency of PM to trypsin activity was evaluated. Under the optimized conditions, the inhibition efficiency was proportional to the logarithm of PM concentration in the range of 0.04-400 ng mL(-1), with a detection limit of 0.018 ng mL(-1). Furthermore, the simple and convenient method had been used for PM detection in environmental and agricultural samples with satisfactory results.
authors.affiliation: Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun 130012, China.
authors.forename: Xu
authors.initials: X
authors.lastname: Yan
authors.affiliation: School of Pharmacy, Jilin University, Changchun 130021, China.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Li
authors.affiliation: College of Computer Science and Technology, Jilin University, Changchun 130012, China; Talent Development Institute, Daqing Oilfield Company, CNPC, 163000, China.
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Han
authors.affiliation: Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun 130012, China. Electronic address: suxg@jlu.edu.cn.
authors.forename: Xingguang
authors.initials: X
authors.lastname: Su
mesh_terms: D000818:Animals; D015374:Biosensing Techniques / Q000379:methods; D060766:Drinking Water / Q000032:analysis; D004785:Environmental Pollutants / Q000032:analysis*; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D008743:Methyl Parathion / Q000032:analysis*; D008892:Milk / Q000737:chemistry; D012275:Oryza / Q000737:chemistry; D010575:Pesticides / Q000032:analysis*; D045663:Quantum Dots / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods
chemical_list: D060766:Drinking Water; D004785:Environmental Pollutants; D005456:Fluorescent Dyes; D010575:Pesticides; D008743:Methyl Parathion; D006046:Gold
keywords: Gold nanoparticle; Inner-filter effect; Organophosphorus pesticides; Ratiometric fluorescent quantum dots