title: Aqueous Synthesis of PEGylated Quantum Dots with Increased Colloidal Stability and Reduced Cytotoxicity.
abstract: Ligands used on the surface of colloidal nanoparticles (NPs) have a significant impact on physiochemical properties of NPs and their interaction in biological environments. In this study, we report a one-pot aqueous synthesis of 3-mercaptopropionic acid (MPA)-functionalized CdTe/CdS/ZnS quantum dots (Qdots) in the presence of thiol-terminated methoxy polyethylene glycol (mPEG) molecules as a surface coordinating ligand. The resulting mPEG-Qdots were characterized by using ζ potential, FTIR, thermogravimetric (TG) analysis, and microscale thermophoresis (MST) studies. We investigated the effect of mPEG molecules and their grafting density on the Qdots photophysical properties, colloidal stability, protein binding affinity, and in vitro cellular toxicity. Moreover, cellular binding features of the resulting Qdots were examined by using three-dimensional (3D) tumor-like spheroids, and the results were discussed in detail. Promisingly, mPEG ligands were found to increase colloidal stability of Qdots, reduce adsorption of proteins to the Qdot surface, and mitigate Qdot-induced side effects to a great extent. Flow cytometry and confocal microscopy studies revealed that PEGylated Qdots exhibited distinctive cellular interactions with respect to their mPEG grafting density. As a result, mPEG molecules demonstrated a minimal effect on the ZnS shell deposition and the Qdot fluorescence efficiency at a low mPEG density, whereas they showed pronounced effect on Qdot colloidal stability, protein binding affinity, cytotoxicity, and nonspecific binding at a higher mPEG grafting amount.
authors.forename: Mehriban
authors.initials: M
authors.lastname: Akin
authors.forename: Rebecca
authors.initials: R
authors.lastname: Jonczyk
authors.forename: Johanna-Gabriela
authors.initials: JG
authors.lastname: Walter
authors.forename: Sergej
authors.initials: S
authors.lastname: Springer
authors.forename: Antonina
authors.initials: A
authors.lastname: Lavrentieva
authors.forename: Frank
authors.initials: F
authors.lastname: Stahl
authors.affiliation: Department of Physics, King's College London , The Strand, WC2R 2LS London, U.K.
authors.forename: Mark
authors.initials: M
authors.lastname: Green
authors.forename: Thomas
authors.initials: T
authors.lastname: Scheper
mesh_terms: D015097:3-Mercaptopropionic Acid / Q000737:chemistry / Q000633:toxicity; D000818:Animals; D019187:Cadmium Compounds / Q000737:chemistry* / Q000633:toxicity; D002417:Cattle; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003102:Colloids / Q000737:chemistry / Q000633:toxicity; D006801:Humans; D011092:Polyethylene Glycols / Q000737:chemistry* / Q000633:toxicity; D066329:Protein Aggregates / Q000187:drug effects; D045663:Quantum Dots / Q000737:chemistry* / Q000633:toxicity / Q000648:ultrastructure; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry* / Q000633:toxicity; D013691:Tellurium / Q000737:chemistry* / Q000633:toxicity; D014867:Water / Q000737:chemistry; D017967:Zinc Compounds / Q000737:chemistry* / Q000633:toxicity
chemical_list: D019187:Cadmium Compounds; D003102:Colloids; D066329:Protein Aggregates; D013440:Sulfides; D017967:Zinc Compounds; C034939:cadmium sulfide; D014867:Water; D012710:Serum Albumin, Bovine; D011092:Polyethylene Glycols; D015097:3-Mercaptopropionic Acid; C031238:zinc sulfide; D013691:Tellurium; C028337:cadmium telluride