Study of the interaction of flavonoids with 3-mercaptopropionic acid modified CdTe quantum dots mediated by cetyltrimethyl ammonium bromide in aqueous medium.
Flavonoids are polyphenols that help the maintenance of health, aiding the prevention of diseases. In this work, CdTe QDs coated with 3-mercaptopropionic acid (3MPA), with an average size of 2.7nm, were used as photoluminescence probe for flavonoids in different conditions. The interaction between 14 flavonoids and QDs was evaluated in aqueous dispersions in the absence and in the presence of cetyltrimethylammonium bromide (CTAB). To establish a relationship between photoluminescence quenching and the concentration of flavonoids, the Stern-Volmer model was used. In the absence of CTAB, the linear ranges for quercetin, morin and rutin were from 5.0×10-6molL-1to 6.0×10-5molL-1and from 1.0×10-5molL-1to 6.0×10-4molL-1for kaempferol. The sensibility of the Stern-Volmer curves (Ks) indicated that quercetin interacts more strongly with the probe: Ks quercetin>Ks kaempferol>Ks rutin>Ks morin. The conjugation extension in the 3 rings, and the acidic hydroxyl groups (positions 3'and 4') in the B-ring enhanced the interaction with 3MPA-CdTe QDs. The other flavonoids do not interact with the probe at 10-5molL-1level. In CTAB organized dispersions, Ks 3-hydroxyflavone>Ks 7-hydroxyflavone>Ks flavona>Ks rutinin the range from 1.0×10-6molL-1to 1.2×10-5molL-1for flavones and of 1.0×10-6molL-1to 1.0×10-5molL-1for rutin. Dynamic light scattering, conductometric measurements and microenvironment polarity studies were employed to elucidate the QDs-flavonoids interaction in systems containing CTAB. The quenching can be attributed to the preferential solubility of hydrophobic flavonoid in the palisade layer of the CTAB aggregates adsorbed on the surface of the 3MPA CdTe QDs.
Chemistry Department, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro, RJ, Brazil.
Ricardo Q
RQ
Aucelio
Chemistry Department, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro, RJ, Brazil.
Juliana M
JM
Carvalho
Chemistry Department, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro, RJ, Brazil.
Juliana T
JT
Real
Chemistry Department, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro, RJ, Brazil.
Luis
L
Maqueira-Espinosa
Chemistry Department, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900 Rio de Janeiro, RJ, Brazil.
Aurora
A
Pérez-Gramatges
Centro Federal de Educação Tecnológica Celso Suckow da Fonseca-CEFET/RJ, 27600-000 Valença, RJ, Brazil. Electronic address: andrea.silva@cefet-rj.br.
Andrea R
AR
da Silva
D015097:3-Mercaptopropionic Acid / Q000737:chemistry*; D019187:Cadmium Compounds / Q000737:chemistry*; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry*; D005419:Flavonoids / Q000737:chemistry*; D049449:Luminescence; D008823:Micelles; D010316:Particle Size; D011721:Pyrenes / Q000737:chemistry; D045663:Quantum Dots / Q000737:chemistry*; D012996:Solutions; D013501:Surface-Active Agents / Q000737:chemistry; D013691:Tellurium / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
D019187:Cadmium Compounds; D002593:Cetrimonium Compounds; D005419:Flavonoids; D008823:Micelles; D011721:Pyrenes; D012996:Solutions; D013501:Surface-Active Agents; D014867:Water; C030984:pyrene; D015097:3-Mercaptopropionic Acid; D013691:Tellurium; C028337:cadmium telluride; D000077286:Cetrimonium
CdTe quantum QDs; Flavonoids; cationic surfactant; photoluminescence quenching