Vinayaka A C, Basheer S, Thakur M S
Fermentation Technology and Bioengineering Department, Central Food Technological Research Institute, A Constituent Laboratory of Council of Scientific and Industrial Research, Mysore, Karnataka, India.
Biosens Bioelectron. 2009 Feb 15;24(6):1615-20. doi: 10.1016/j.bios.2008.08.042. Epub 2008 Sep 2.
Quantum dots (QD) are semiconductor fluorescent nanoparticles, which can be made use of for environmental monitoring with high sensitivity. In view of the alarming levels of pesticides and herbicides being used in agriculture practices, there is a need for their rapid, sensitive and specific detection in food and environmental samples, as pesticides and herbicides are harmful to living beings even at trace levels. Present study was carried out to develop a reliable and rapid method for analysis and detection of 2,4-D (herbicide) using cadmium telluride quantum dot nanoparticle (CdTe QD). Fluoroimmunoassay based on the fluorescent property of quantum dot was used along with immunoassay to detect 2,4-D. CdTe capped with mercaptopropionic acid, was conjugated using N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride (EDC) and a coupling reagent like N-hydroxysuccinimide (NHS) to alkaline phosphatase (ALP) which was in turn conjugated to 2,4-D molecule. Anti 2,4-D-IgG antibodies were immobilized in an immunoreactor column using Sepharose CL-4B as an inert matrix. The detection of 2,4-D was carried out by fluoroimmunoassay-based biosensor using competitive binding between conjugated 2,4-D-ALP-CdTe and free 2,4-D with immobilized anti 2,4-D antibodies in an immunoreactor column. It was possible to detect 2,4-D upto 250pgmL(-1). Present study also emphasizes on the resonance energy transfer between ALP and CdTe QD as a result of bioconjugation, which can be used for future biosensor development based on quantum dot-biomolecular interactions.
量子点（QD）是半导体荧光纳米颗粒，可用于高灵敏度的环境监测。鉴于农业生产中农药和除草剂的使用量令人担忧，有必要在食品和环境样品中对其进行快速、灵敏和特异性检测，因为即使是痕量水平的农药和除草剂也对生物有害。本研究旨在开发一种可靠、快速的方法，用于使用碲化镉量子点纳米颗粒（CdTe QD）分析和检测2,4-D（除草剂）。基于量子点荧光特性的荧光免疫分析与免疫分析一起用于检测2,4-D。用巯基丙酸封端的CdTe，使用N-(3-二甲基氨基丙基)-N-乙基碳二亚胺盐酸盐（EDC）和N-羟基琥珀酰亚胺（NHS）等偶联剂与碱性磷酸酶（ALP）偶联，碱性磷酸酶又与2,4-D分子偶联。抗2,4-D-IgG抗体使用琼脂糖CL-4B作为惰性基质固定在免疫反应器柱中。通过基于荧光免疫分析的生物传感器，利用偶联的2,4-D-ALP-CdTe与游离2,4-D在免疫反应器柱中与固定的抗2,4-D抗体之间的竞争结合来检测2,4-D。能够检测低至250pgmL(-1)的2,4-D。本研究还强调了生物偶联导致的ALP与CdTe QD之间的共振能量转移，这可用于未来基于量子点-生物分子相互作用的生物传感器开发。
