title: Hydrodynamic size-dependent cellular uptake of aqueous QDs probed by fluorescence correlation spectroscopy.
abstract: Aqueous quantum dots (QDs) directly synthesized with various thiol ligands have been investigated as imaging probes in living cells. However, the effect of the surface chemistry of these ligands on QDs' cellular uptakes and their intracellular fate remains poorly understood. In this work, four CdTe QDs were directly synthesized under aqueous conditions using four different thiols as stabilizers and their interactions with cells were investigated. Fluorescence correlation spectroscopy (FCS), X-ray photoelectron spectroscopy (XPS), and zeta potential measurements on QDs primarily show that the surface structure of these QDs is highly dependent on the thiol ligands used in the preparation of QDs' precursors, including its layer thicknesses, densities, and surface charges. Subsequently, FCS integrated with the maximum-entropy-method-based FCS (MEMFCS) was used to investigate the concentration distribution and dynamics of these QDs in living A-427 cells. Our findings indicate that QDs' surface characteristics affect cell membrane adsorption and subsequent internalization. More critically, we show that the cellular uptake of aqueous QDs is dependent on their hydrodynamic diameter and might have the potential to escape trapped environments to accumulate in the cytoplasm.
authors.affiliation: Department of Agricultural and Biological Engineering, Bindley Bioscience Center, Purdue University, West Lafayette, Indiana 47907, USA.
authors.forename: Chaoqing
authors.initials: C
authors.lastname: Dong
authors.forename: Joseph
authors.initials: J
authors.lastname: Irudayaraj
mesh_terms: D019187:Cadmium Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000493:pharmacokinetics*; D002478:Cells, Cultured; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry / Q000493:pharmacokinetics*; D006801:Humans; D057446:Hydrodynamics; D010316:Particle Size; D045663:Quantum Dots; D013050:Spectrometry, Fluorescence; D013499:Surface Properties; D013691:Tellurium / Q000737:chemistry / Q000493:pharmacokinetics*; D014867:Water / Q000737:chemistry
chemical_list: D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D014867:Water; D013691:Tellurium; C028337:cadmium telluride