title: Ionic Functionalization of Hydrophobic Colloidal Nanoparticles To Form Ionic Nanoparticles with Enzymelike Properties.
abstract: Inorganic colloidal nanoparticles (NPs) stabilized by a layer of hydrophobic surfactant on their surfaces have poor solubility in the aqueous phase, thus limiting their application as biosensors under physiological conditions. Here we report a simple model to ionize various types of hydrophobic colloidal NPs, including FePt, cubic Fe3O4, Pd, CdSe, and NaYF4 (Yb 30%, Er 2%, Nd 1%) NPs, to multicharged (positive and negative) NPs via ligand exchange. Surfaces of neutral hydrophobic NPs were converted to multicharged ions, thus making them soluble in water. Furthermore, peroxidase-like activity was observed for ionic FePt, Fe3O4, Pd, and CdSe NPs, of which FePt and CdSe catalyzed the oxidation of the colorless substrate 3,3',5,5'-tetramethylbenzidine (TMB) to the blue-colored product in the absence of H2O2, while Pd and Fe3O4 catalyzed the oxidization of TMB in the presence of H2O2. With the benefit of the ionic functionalization protocols described herein, colloidal NPs should gain wider use as biomarkers, nanozymes, and biosensors.
authors.affiliation: Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Health Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida , Gainesville, Florida 32611-7200, United States.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida , Gainesville, Florida 32610-0245, United States.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Purich
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, and Collaborative Research Center of Molecular Engineering for Theranostics, Hunan University , Changsha, 410082, China.
authors.forename: Cuichen
authors.initials: C
authors.lastname: Wu
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, and Collaborative Research Center of Molecular Engineering for Theranostics, Hunan University , Changsha, 410082, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, and Collaborative Research Center of Molecular Engineering for Theranostics, Hunan University , Changsha, 410082, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.affiliation: Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Health Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida , Gainesville, Florida 32611-7200, United States.
authors.forename: Cheng
authors.initials: C
authors.lastname: Cui
authors.affiliation: Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Health Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida , Gainesville, Florida 32611-7200, United States.
authors.forename: Liqin
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Health Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida , Gainesville, Florida 32611-7200, United States.
authors.forename: Sena
authors.initials: S
authors.lastname: Cansiz
authors.affiliation: Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Health Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida , Gainesville, Florida 32611-7200, United States.
authors.forename: Weijia
authors.initials: W
authors.lastname: Hou
authors.affiliation: Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Health Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida , Gainesville, Florida 32611-7200, United States.
authors.forename: Yanyue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Health Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida , Gainesville, Florida 32611-7200, United States.
authors.forename: Shengyuan
authors.initials: S
authors.lastname: Yang
authors.affiliation: Center for Research at Bio/Nano Interface, Department of Chemistry and Department of Physiology and Functional Genomics, Health Cancer Center, UF Genetics Institute and McKnight Brain Institute, University of Florida , Gainesville, Florida 32611-7200, United States.|Molecular Science and Biomedicine Laboratory, State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering and College of Biology, and Collaborative Research Center of Molecular Engineering for Theranostics, Hunan University , Changsha, 410082, China.
authors.forename: Weihong
authors.initials: W
authors.lastname: Tan
mesh_terms: D003102:Colloids / Q000737:chemistry*; D004798:Enzymes / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007477:Ions; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D003102:Colloids; D004798:Enzymes; D007477:Ions