Ionic Functionalization of Hydrophobic Colloidal Nanoparticles To Form Ionic Nanoparticles with Enzymelike Properties

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• 作者：Yuan Liu ; Daniel L. Purich ; Cuichen Wu ; Yuan Wu ; Tao Chen ; Cheng Cui ; Liqin Zhang ; Sena Cansiz ; Weijia Hou ; Yanyue Wang ; Shengyuan Yang ; Weihong Tan
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：December 2, 2015
• 年：2015
• 卷：137
• 期：47
• 页码：14952-14958
• 全文大小：451K
• ISSN：1520-5126

文摘

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鈥?5,5鈥?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.