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

T.V. Torchynska, J.L. Casas Espinola, J. Douda, O.S. López de la Luz
Instituto Politecnico Nacional, MX

Keywords: CdSe/ZnS, CdSeTe/ZnS quantum dots, anti interleukin 10 antibody, bioconjugation, photoluminescence


Photoluminescence (PL) and Raman scattering spectra of none- and bio-conjugated CdSe/ZnS and CdSeTe/ZnS quantum dots (QDs) have been studied. QDs, characterized by emission at 605, 655 and 705nm, have been conjugated with anti Interleukin 10 antibodies (IL10). PL spectra of nonconjugated QDs are characterized by PL band related to exciton emission in cores. PL spectra of bioconjugated QDs have shifted into high energy and become asymmetric. The PL shift is explained by the Stark effect at the application of electric field created by electric dipoles of IL10 antibodies. To confirm the antibody electric dipoles the Raman scattering spectra have been investigated. It is revealed the stimulation of optical field near the surface of bio-conjugated QDs and increasing the Raman peak intensity that is attributed to the surface enhanced Raman scattering (SERS). Thus antibody biomolecules are characterized by electric dipole moments that permit them to interact with at SERS and to stimulate the shift of QD energy levels at the Stark effect. QD sizes have been numerically estimated. It is revealed that the PL energy shift in bioconjugated QDs is proportional to cubic degree of QD sizes. The explanation of this dependence has been done as well.