title: Recyclable Colorimetric Detection of Trivalent Cations in Aqueous Media Using Zwitterionic Gold Nanoparticles.
abstract: This report describes a colorimetric assay for trivalent metal cations (M(3+)) using gold nanoparticles (AuNPs)-modified with oppositely charged thiols that can form intermolecular zwitterionic surfaces. Zwitterionic AuNPs (Zw-AuNPs) are stable in high-salt solutions and well-dispersed in a wide range of pH values. M(3+) including Fe(3+), Al(3+), and Cr(3+) can effectively trigger the aggregation of Zw-AuNPs by interfering with their surface potential, and aggregated AuNPs can be regenerated and recycled by removing M(3+). In our approach, the output signal can be observed by the naked eye within a micromolar (μM) concentration range. Uniquely, our assay is capable of discriminating Fe(3+) from Fe(2+), which is challenging using traditional approaches. More importantly, Zw-AuNPs can be stored stably at room temperature for a long period (3 months) with constant detection performance. Both the cost-effectiveness and the long shelf life make Zw-AuNPs ideal for detecting M(3+) in resource-poor and remote areas.
authors.affiliation: Beijing Engineering Research Center for BioNanotechnology & Key Lab for Biological Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for NanoScience and Technology & University of the Chinese Academy of Sciences , 11 Beiyitiao, Zhongguancun, Beijing 100190, China.|Academy for Advanced Interdisciplinary Studies, Peking University , Beijing 100871, China.
authors.forename: Wenshu
authors.initials: W
authors.lastname: Zheng
authors.affiliation: MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University , Hangzhou 310027, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Li
authors.affiliation: Beijing Engineering Research Center for BioNanotechnology & Key Lab for Biological Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for NanoScience and Technology & University of the Chinese Academy of Sciences , 11 Beiyitiao, Zhongguancun, Beijing 100190, China.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Chen
authors.affiliation: MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University , Hangzhou 310027, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Ji
authors.affiliation: Beijing Engineering Research Center for BioNanotechnology & Key Lab for Biological Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for NanoScience and Technology & University of the Chinese Academy of Sciences , 11 Beiyitiao, Zhongguancun, Beijing 100190, China.
authors.forename: Xingyu
authors.initials: X
authors.lastname: Jiang