title: Thiol-stabilized luminescent CdTe quantum dot as biological fluorescent probe for sensitive detection of methyl parathion by a fluoroimmunochromatographic technique.
abstract: Quantum dots (QDs) are preferred as high-resolution biological fluorescent probes because of their inherent optical properties compared with organic dyes. This intrinsic property of QDs has been made use of for sensitive detection of methylparathion (MP) at picogramme levels. The specificity of the assay was attributed to highly specific immunological reactions. Competitive binding between free MP and CdTe QD bioconjugated MP (MP-BSA-CdTe) with immobilized anti-MP IgY antibodies was monitored in a flow-injection system. The fluorescence intensity of MP-BSA-CdTe bioconjugate eluted from the column was found to be directly proportional to the free MP concentration. Hence, it was possible to detect MP in a linear range of 0.1-1 ng mL(-1) with a regression coefficient R(2) = 0.9905. In this investigation, IgY proved advantageous over IgG class immunoglobulins in terms of yield, stability, cost effectiveness, and enhancement of assay sensitivity. The photo-absorption spectrum of bioconjugated CdTe QD (lambda(max) = 310 nm) confirmed nano-biomolecular interactions. The results suggest the potential application of bioconjugation and nano-biomolecular interactions of QDs for biological labeling and target analyte detection with high sensitivity.
authors.affiliation: Fermentation Technology and Bioengineering Department, Central Food Technological Research Institute, Mysore 570020, India.
authors.forename: Raghuraj Singh
authors.initials: RS
authors.lastname: Chouhan
authors.forename: Aaydha Chidambara
authors.initials: AC
authors.lastname: Vinayaka
authors.forename: Munna Singh
authors.initials: MS
authors.lastname: Thakur
mesh_terms: D019187:Cadmium Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000276:immunology; D002845:Chromatography / Q000379:methods*; D005456:Fluorescent Dyes / Q000032:analysis / Q000138:chemical synthesis / Q000737:chemistry*; D007158:Immunologic Techniques; D008743:Methyl Parathion / Q000032:analysis* / Q000276:immunology; D045663:Quantum Dots; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013691:Tellurium / Q000737:chemistry* / Q000276:immunology
chemical_list: D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D013438:Sulfhydryl Compounds; D008743:Methyl Parathion; D013691:Tellurium; C028337:cadmium telluride