One-pot aqueous synthesis of highly strained CdTe/CdS/ZnS nanocrystals and their interactions with cells

Mehriban Ulusoy, Johanna Gabriela Walter, Antonina Lavrentieva, Imme Kretschmer, Lydia Sandiford, Alix Le Marois, Rebecca Bongartz, Pooyan Aliuos, Klaus Suhling, Frank Stahl, Mark Green*, Thomas Scheper

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

In this work, a very simple one-pot synthetic approach was developed to generate aqueous CdTe/CdS/ZnS type-II/type-I red-emitting nanocrystals (NCs). Strain-induced optical properties of CdTe/CdS particles having core(small)/shell(thick) structure with a maximum quantum yield (QYmax) ∼ 57% were further improved with the overgrowth of a ZnS shell, resulting in a core(small)/shell(thick)/shell(small) structure (QYmax ∼ 64%). The spectral properties were tuned further to the near-infrared region as the ZnS shell grew in thickness. X-ray powder diffraction (XRD) analysis and high-resolution transmission electron microscope (HRTEM) images showed the crystalline structure of NCs proving the epitaxial growth of ZnS without crystalline defects. Under continuous UV-irradiation for 5 h, the NCs did not exhibit any photo-degradation but instead displayed a photo-annealing process. These extremely photostable NCs were further characterized in terms of their cytotoxicity and their cell labeling performances. The presence of a ZnS shell was found to reduce the toxicity of the CdTe/CdS NCs. Furthermore, aptamer-conjugated NCs were successfully utilized in targeted cell imaging. Promisingly, the aptamer-NCs bioconjugates were internalized by A549 cells within 2 hours of incubation and retained their fluorescence even after 24 hours of internalization.

Original languageEnglish
Pages (from-to)7485-7494
Number of pages10
JournalRSC Advances
Volume5
Issue number10
DOIs
Publication statusPublished - 2015

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