CdTe and CdSe quantum dots: synthesis, characterizations and applications in agriculture

• Published in: Advances in natural sciences. Nanoscience and nanotechnology Vol. 3; no. 4; pp. 043001 - 1-11
• Main Authors: Ung, Thi Dieu Thuy, Tran, Thi Kim Chi, Pham, Thu Nga, Nguyen, Duc Nghia, Dinh, Duy Khang, Nguyen, Quang Liem
• Format: Journal Article
• Language: English
• Published: IOP Publishing 08.11.2012
• Subjects: Cadmium selenides; Cadmium sulfides; Cadmium tellurides; CdSe; CdTe; clenbuterol; Fluorescence; fluorescence labeling; Influenza; Nanostructure; pesticide; Quantum dots; Synthesis; virus detection; Zinc sulfides
• ISSN: 2043-6262; 2043-6254; 2043-6254; 2043-6262
• DOI: 10.1088/2043-6262/3/4/043001

This paper highlights the results of the whole work including the synthesis of highly luminescent quantum dots (QDs), characterizations and testing applications of them in different kinds of sensors. Concretely, it presents: (i) the successful synthesis of colloidal CdTe and CdSe QDs, their core/shell structures with single- and/or double-shell made by CdS, ZnS or ZnSe/ZnS; (ii) morphology, structural and optical characterizations of the synthesized QDs; and (iii) testing examples of QDs as the fluorescence labels for agricultural-bio-medical objects (for tracing residual pesticide in agricultural products, residual clenbuterol in meat/milk and for detection of H5N1 avian influenza virus in breeding farms). Overall, the results show that the synthesized QDs have very good crystallinity, spherical shape and strongly emit at the desired wavelengths between ∼500 and 700 nm with the luminescence quantum yield (LQY) of 30-85%. These synthesized QDs were used in fabrication of the three testing fluorescence QD-based sensors for the detection of residual pesticides, clenbuterol and H5N1 avian influenza virus. The specific detection of parathion methyl (PM) pesticide at a content as low as 0.05 ppm has been realized with the biosensors made from CdTe/CdS and CdSe/ZnSe/ZnS QDs and the acetylcholinesterase (AChE) enzymes. Fluorescence resonance energy transfer (FRET)-based nanosensors using CdTe/CdS QDs conjugated with 2-amino-8-naphthol-6-sulfonic acid were fabricated that enable detection of diazotized clenbuterol at a content as low as 10 pg ml−1. For detection of H5N1 avian influenza virus, fluorescence biosensors using CdTe/CdS QDs bound on the surface of chromatophores extracted and purified from bacteria Rhodospirillum rubrum were prepared and characterized. The specific detection of H5N1 avian influenza virus in the range of 3-50 ng μl−1 with a detection limit of 3 ng μL−1 has been performed based on the antibody-antigen recognition.