title: Controllable aggregation and reversible pH sensitivity of AuNPs regulated by carboxymethyl cellulose.
abstract: A pH-sensitive gold nanoparticle-cysteamine/carboxymethyl cellulose (Au-CA/CMC) dispersion system was prepared by a simple approach. Gold nanoparticles (AuNPs) were first synthesized by directly reducing chloroauric acid (HAuCl(4)) with sodium carboxymethyl cellulose (CMC). Then the AuNPs were decorated by an electrostatic compound of cysteamine hydrochloride (CA) and sodium carboxymethyl cellulose (CMC) through ligand exchange to get the assembly of Au-CA/CMC. The Au-CA/CMC dispersion system exhibits strongly reversible pH-responsive behavior with the aggregation of AuNPs caused by the combined action of the chain conformation change of CMC and electrostatic interactions between CA and CMC at different pH values. Finally, the reversible aggregation mechanism of AuNPs in the Au-CA/CMC dispersion system has been investigated by transmission electron microscopy (TEM) and ultraviolet-visible spectroscopy (UV-vis spectroscopy). This study provides a new method to fabricate a stimuli-responsive system free from complicated organic synthesis without using a toxic reducing agent.
authors.affiliation: State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Junjun
authors.initials: J
authors.lastname: Tan
authors.forename: Ruigang
authors.initials: R
authors.lastname: Liu
authors.forename: Wen
authors.initials: W
authors.lastname: Wang
authors.forename: Wenyong
authors.initials: W
authors.lastname: Liu
authors.forename: Ye
authors.initials: Y
authors.lastname: Tian
authors.forename: Min
authors.initials: M
authors.lastname: Wu
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
mesh_terms: D002266:Carboxymethylcellulose Sodium / Q000737:chemistry*; D003543:Cysteamine / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D055772:Green Chemistry Technology; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D019163:Reducing Agents / Q000737:chemistry; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D014867:Water / Q000737:chemistry
chemical_list: D019163:Reducing Agents; D012996:Solutions; D014867:Water; D003543:Cysteamine; D006046:Gold; D002266:Carboxymethylcellulose Sodium