Electronic effects in CdSe/ZnS quantum dots conjugated to IL-10 antibodies

The paper presents the study of photoluminescence (PL) and Raman scattering spectra of nonconjugated and bioconjugated CdSe/ZnS core-shell quantum dots (QDs). CdSe/ZnS QDs used are characterized by color emission with the maxima at 605 nm (2.05eV) and 655 nm (1.89 eV). The QD conjugation has been performed with biomolecules the anti Interleukin 10 antibodies (anti IL 10 mAb). PL spectra of nonconjugated QDs are characterized by one symmetric PL band related to exciton emission in the CdSe core of QDs. PL spectra of bioconjugated QDs have changed essentially: PL band shifts into high energy side and becomes asymmetric. To explain last effect the model has been proposed which assumes that the PL spectrum transformation in bioconjugated QDs is connected with the Stark effect. To confirm the existence of electric dipoles in anti IL-10 mAb the Raman scattering spectra have been investigated. The enhancement of Raman scattering is observed in bioconjugated CdSe/ZnS QDs. The last effect testifies that the 11,10 antibodies are characterized, actually, by the electric dipole moment that permits them to interact with an electric field of excitation light and to provoke the surface enhanced Raman scattering (SERS) and the Stark effects in QDs..