Electronic effects in Emission of core/shell CdSe/ZnS Quantum dots conjugated to anti-Interleukin 10 antibodies
- PDF / 174,838 Bytes
- 6 Pages / 432 x 648 pts Page_size
- 39 Downloads / 189 Views
Electronic effects in Emission of core/shell CdSe/ZnS Quantum dots conjugated to anti-Interleukin 10 antibodies
Janna Douda, Oscar S. Lopez de la Luz and Aaron I. Díaz Cano UPIITA, Instituto Politécnico Nacional, av. IPN, 2580, México D. F. 07320, México
ABSTRACT The paper presents the study of photoluminescence (PL) and Raman scattering spectra of nonconjugated and bioconjugated CdSe/ZnS core-shell quantum dots (QDs). Commercial 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 – anti Interleukin-10 antibodies (anti IL10 mAb). PL spectra of nonconjugated QDs are characterized by only one symmetric PL band related to the exciton emission in the CdSe core. PL spectra of bioconjugated QDs have changed: PL band shifts into the high energy side and becomes asymmetric. To explain these effects the model has been proposed which assumes that the PL spectrum transformation in bioconjugated QDs, apparently, is connected with the quantum confinement and/or the Stark effects. To confirm the existence of electric charges (or dipoles) in the anti-Interleukin 10 antibodies, which can provoke the Stark effect, the Raman scattering spectra have been investigated as well. The enhancement of Raman scattering is observed in bioconjugated CdSe/ZnS QDs. The last effect testifies that the IL10 antibodies are characterized, actually, by the electric charges (or dipoles) that permit 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. INTRODUCTION The integration of nanotechnology with biomedicine is expected to produce the major advances in bioengineering, early cancer diagnostic, biosensors, therapeutic etc [1, 2]. Semiconductor core/shell CdSe/ZnS quantum dots (QDs) due to their unique optical properties and dimensional similarities to biomolecules have attracted the great attention in biomedicine during a last decade [3-9]. These QDs used as bio-luminescent markers can vary the photoluminescence (PL) intensity when coupled to different biomolecules. The process of QD bioconjugation, as a rule, is accompanied by the variation of QD PL intensity mainly. The confirmation of the QD bioconjugation and the study its details using the detection of PL spectrum transformation are highly important as well. Additionally it is important to look for
A133
other optical effects such as Raman scattering in QD bioconjugation, which could offer the important information on the structure of bioconjugated QDs. This paper presents the results of PL and Raman scattering study of the CdSe/ZnS core/shell QDs with color emission at 605 and 655 nm in nonconjugated state and bioconjugated to the anti-Interleukin 10 antibodies (anti IL10 mAb). EXPERIMENTAL DETAILS The commercially available core-shell CdSe/ZnS QDs covered with a polyethylene glycol (PEG) polymer were used in a form of colloidal particles diluted in a phosphate buffer saline (PBS) w
Data Loading...
