title: Fluorescence quenching studies on the interaction of catechin-quinone with CdTe quantum dots. Mechanism elucidation and feasibility studies.
abstract: Changes of the photoluminescent properties of QD in the presence of oxidized catechin (CQ) were investigated by absorption, steady-state fluorescence, fluorescence lifetime and dynamic light scattering measurements. Photoluminescence intensity and fluorescence lifetime was decreasing with increasing CQ concentration. Dynamic light scattering technique found the hydrodynamic diameter of QD suspension in water is in range of 45 nm, whereas in presence of CQ increased to mean values of 67 nm. Calculated from absorption peak position of excition band indicated on average QD size of 3.2 nm. Emission spectroscopy and time-resolved emission studies confirmed preservation of electronic band structure in QD-CQ aggregates. On basis of the presented results, the elucidated mechanism of QD fluorescence quenching is a result of the interaction between QD and CQ due to electron transfer and electrostatic attraction. The results of fluorescence quenching of water-soluble CdTe quantum dot (QD) capped with thiocarboxylic acid were used to implement a simple and fast method to determine the presence of native antioxidant quinones in aqueous solutions. Feasibility studies on this method carried out with oxidized catechin showed a linear relation between the QD emission and quencher concentration, in range from 1 up to 200 μM. The wide linear range of concentration dependence makes it possible to apply this method for the fast and sensitive detection of quinones in solutions.
authors.affiliation: Poznan Life Sciences University, Department of Biotechnology and Food Analysis, 60-637 Poznan, ul. Mazowiecka 34, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Dwiecki
authors.affiliation: Poznan Life Sciences University, Department of Physics, 60-637 Poznan, ul. Wojska Polskiego 38/42, Poland.
authors.forename: Grażyna
authors.initials: G
authors.lastname: Neunert
authors.affiliation: Poznan Life Sciences University, Department of Biotechnology and Food Analysis, 60-637 Poznan, ul. Mazowiecka 34, Poland.
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Nogala-Kałucka
authors.affiliation: Poznan Life Sciences University, Department of Physics, 60-637 Poznan, ul. Wojska Polskiego 38/42, Poland. Electronic address: polewski@up.poznan.pl.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Polewski
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D002392:Catechin / Q000737:chemistry*; D000067493:Dynamic Light Scattering; D005240:Feasibility Studies; D049449:Luminescence; D010084:Oxidation-Reduction; D045663:Quantum Dots / Q000737:chemistry*; D011809:Quinones / Q000737:chemistry*; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013691:Tellurium / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D011809:Quinones; D012996:Solutions; D002392:Catechin; D013691:Tellurium; C028337:cadmium telluride
keywords: Aggregation; Antioxidant; Electron transfer; Fluorescence; Quantum dot