10.1021/la504558z.s001 Urszula Bazylińska Urszula Bazylińska Sławomir Drozdek Sławomir Drozdek Marcin Nyk Marcin Nyk Julita Kulbacka Julita Kulbacka Marek Samoć Marek Samoć Kazimiera A. Wilk Kazimiera A. Wilk Core/Shell Quantum Dots Encapsulated in Biocompatible Oil-Core Nanocarriers as Two-Photon Fluorescent Markers for Bioimaging American Chemical Society 2014 Cremophor EL oil phases Poloxamer 403 CdSe silicone oil quantum dots MCF GM alveolar basal epithelial NIR core cell imaging polymer component nanocapsules exhibit encapsulated QDs 800 nm particle size luminescence properties transmission electron microscopy CLSM HUVEC bioimaging application cytotoxicity studies umbilical vein confocal laser scanning microscopy force microscopy excitation oleic acid transmission window intracellular localization mineral oil 2014-12-16 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Core_Shell_Quantum_Dots_Encapsulated_in_Biocompatible_Oil_Core_Nanocarriers_as_Two_Photon_Fluorescent_Markers_for_Bioimaging/2225176 Highly fluorescent quantum dots (QDs)-loaded nanocapsules, intended for fluorescent cell imaging, were prepared via an emulsification/solvent-evaporation method. CdSe/ZnS core/shell quantum dots were applied as cargo; Poloxamer 403 as the polymer component; Cremophor EL as the nonionic surfactant; and mineral oil, oleic acid, or silicone oil were applied as the oil phases. Transmission electron microscopy, atomic force microscopy, dynamic light scattering, and zeta potential measurements were used to characterize the novel QDs-labeled nanoparticles by particle size, distribution, and morphology, as well as by ζ-potential and physical stability. The fabricated long-lasting nanocapsules exhibit good luminescence properties upon both one-photon and two-photon excitation. The potential of the encapsulated QDs for fluorescent imaging was evaluated in cytotoxicity studies as well as in imaging of intracellular localization, accumulation, and distribution of QDs delivered to well-characterized human cancer cell linesdoxorubicin-sensitive breast (MCF-7/WT) and alveolar basal epithelial (A549)as well as on normal human umbilical vein endothelial (HUVEC) cells, as investigated by confocal laser scanning microscopy (CLSM). The colloidal CdSe/ZnS-loaded nanocapsules are shown to exhibit strong two-photon-induced luminescence upon excitation in the NIR optical transmission window spectral range, making them ideal markers for bioimaging application. The total two-photon cross section of a single nanocapsule was determined to be about 4.1 × 10<sup>6</sup> GM at 800 nm.