title: CdTe quantum dots as a novel biosensor for Serratia marcescens and Lipopolysaccharide.
abstract: The main objective of this work is to synthesize CdTe quantum dots (QDs) conjugated with Concanavalin A (Con A) as a novel biosensor to be selective and specific for the detection of Lipopolysaccharide (LPS). In addition, the conjugated CdTe QDs-Con A was used as fluorescence labels to capture Serratia marcescens bacteria through the recognition between CdTe QDs-Con A and LPS of S. marcescens. The appearance of the lattice plans in the high resolution transmission electron photograph indicated a high crystalline with an average size of 4-5 nm for the CdTe QDs. The results showed that the relative fluorescence intensity of CdTe QDs-Con A decreased linearly with LPS concentration in the range from 10 to 90 fg/mL and with correlation coefficient (R(2)) equal to 0.9713. LPS surrounding the S. marcescens bacteria was bound to the CdTe QDs-Con A and leads to quenching of PL intensity. It was found that a good linear relationship between the relative PL intensity and the logarithmic of cell population of S. marcescens in range from 1×10 to 1×10(6) CFU/mL at pH 7 with R(2) of 0.952 was established.
authors.affiliation: Department of Materials Science, Institute of Graduate Studies and Research, Alexandria University, 163 Horreya Avenue, El-Shatby, P.O. Box 832, Alexandria, Egypt. Electronic address: shebrahim@alex-igsr.edu.eg.
authors.forename: Sh
authors.initials: Sh
authors.lastname: Ebrahim
authors.affiliation: Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, 163 Horreya Avenue, El-Shatby, P.O. Box 832, Alexandria, Egypt.
authors.forename: M
authors.initials: M
authors.lastname: Reda
authors.affiliation: Department of Biotechnology, Institute of Graduate Studies and Research, Alexandria University, 163 Horreya Avenue, El-Shatby, P.O. Box 832, Alexandria, Egypt.
authors.forename: A
authors.initials: A
authors.lastname: Hussien
authors.affiliation: Department of Industrial Pharmacy, Faculty of Pharmacy, Alexandria University, Alexandria, Egypt.
authors.forename: D
authors.initials: D
authors.lastname: Zayed
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D019187:Cadmium Compounds / Q000737:chemistry*; D003208:Concanavalin A / Q000737:chemistry; D005453:Fluorescence; D008070:Lipopolysaccharides / Q000032:analysis / Q000302:isolation & purification*; D045663:Quantum Dots / Q000737:chemistry*; D012706:Serratia marcescens / Q000302:isolation & purification*; D013050:Spectrometry, Fluorescence; D013691:Tellurium / Q000737:chemistry*; D013864:Thioglycolates / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D008070:Lipopolysaccharides; D013864:Thioglycolates; D003208:Concanavalin A; C017487:2-mercaptoacetate; D013691:Tellurium
keywords: Biosensors; CdTe; Lipopolysaccharide; Quantum dots; Serratia marcescens