Emission transformation in CdSe/ZnS quantum dots conjugated to biomolecules.

The variation of photoluminescence (PL) spectra in CdSe/ZnS quantum dots (QDs) at the conjugation to antibodies (ABs) has been investigated and discussed in this paper. Two types of CdSe/ZnS QDs with different CdSe core sizes (5.4 and 6.4nm) and emissions (605 and 655nm) were studied before and after the conjugation to anti-Interleukin-10 (IL-10) and anti-Pseudo rabies virus (PRV) ABs. The PL high energy shift and asymmetric shape of PL bands have been detected in bioconjugated QDs. Note that the bioconjugation impact on spectral characteristics of CdSe/ZnS QD emission has been not studied yet in details. The surface enhanced Raman scattering (SERS) effect is revealed in bioconjugated CdSe/ZnS QDs. The SERS effect testifies that the excitation light used at the Raman study generates the electric dipoles in AB molecules. At the same time, the permanent position of LO-phonon Raman lines in Raman spectra of nonconjugated and bioconjugated QDs confirms that QD materials do not change at the bioconjugation. It is shown as well that the compressive strains do not play any role in the PL high energy shift in bioconjugated QDs. PL spectra of pure anti IL-10 ABs, anti PRV ABs, a phosphate buffer saline (PBS) and PL spectrum dependences versus excitation light intensities have been investigated as well. Finally, the PL spectrum transformation in bioconjugated QDs is attributed to varying the quantum confinement effect in CdSe/ZnS QDs and the energy band profiles in QD cores. Both these effects are stimulated by the electromagnetic field of excited AB dipoles. The obtained results can be useful for sensitivity improving the QD bio-sensors.

Torchynska TV ，Polupan G ，Vega Macotela LG 《-》

Interface states and bio-conjugation of CdSe/ZnS core-shell quantum dots.

Torchynska TV 《-》

Peculiarities of Raman scattering in bioconjugated CdSe/ZnS quantum dots.

Cano AD ，Sandoval SJ ，Vorobiev Y ，Melgarejo FR ，Torchynska TV ... -  《-》

Photoluminescence spectra of CdSe/ZnS quantum dots in solution.

The spectral properties of CdSe/ZnS core-shell quantum dots (QDs) of 3 nm size have been studied under different organic solvents, concentrations and temperatures. Our results showed that the absorption spectra of CdSe/ZnS in benzene have two humps; one around 420 nm and another at 525 nm, with a steady increase in absorption along UV region, and the absorption spectral profile under a wide range of concentrations did not change. On the other hand, the photoluminescence (PL) spectra of CdSe/ZnS in benzene showed two bands one around 375 nm and the other around 550 nm. It could be seen that the band at 375 nm is due to the interaction between the shell (ZnS) with the solvent species in high excited state, and the band at 550 nm is due to core alone (CdSe).

Ibnaouf KH ，Prasad S ，Hamdan A ，Alsalhi M ，Aldwayyan AS ，Zaman MB ，Masilamani V ... -  《-》

Investigation of biocompatible and protein sensitive highly luminescent quantum dots/nanocrystals of CdSe, CdSe/ZnS and CdSe/CdS.

The size and shape dependent semiconductor quantum dots (0D nanoparticles) with color tunability demonstrating significant influence in a biological system and considered as ideal probes. Here, a non-coordinated colloidal approach was used for the synthesis of CdSe, CdSe/ZnS and CdSe/CdS core-shell quantum dots (QDs) of 3-4nm. The synthesized nanocrystals show a high crystallinity, examined by X-ray diffraction (XRD) and high-resolution electron microscopy (HRTEM). The core-shell semiconductor QDs exhibit stronger photoluminescence (PL) as compared to the core QDs. The strong PL with small full-width half maximum (FWHM) indicates that the prepared QDs have a nearly uniform size distribution and well dispersibility. The quantum yield (QY) of core-shell QDs increases due to the surface passivation. Further, the PL of BSA is quenched strongly by the presence of core-shell QDs and follows the well-known Stern-Volmer (S-V) relation, whereas the PL lifetime does not follow the S-V relation, demonstrating that the observed quenching is predominantly static in nature. Among CdSe core, CdSe/ZnS and CdSe/CdS core-shell QDs, the CdSe/ZnS QDs shows the least cytotoxicity and most biocompatibility. Thus, the prepared core-shell QDs are biocompatible and exhibit strong sensing ability.

Ratnesh RK ，Mehata MS 《-》