title: Stimuli-responsive SERS nanoparticles: conformational control of plasmonic coupling and surface Raman enhancement.
abstract: Stimuli-responsive surface-enhanced Raman scattering (SERS) nanoparticles have been developed by using colloidal gold nanocrystals and a class of thiolated block copolymers consisting of a pH-responsive polymer segment, an amphiphilic polyethylene glycol segment, and a lipoic acid anchoring group. The results demonstrate that SERS signals can be switched on and off by molecular conformations in response to pH. An important finding is that neutralized polymethacrylic acid (PMAA) molecules are able to interact with amphiphilic polyethylene glycol (PEG) chains, leading to highly compact and intermingled copolymer structures on the surface of nanoparticles. This type of molecular conformation change provides a new strategy for controlling plasmonic coupling and electromagnetic Raman enhancement and raises the possibility of using SERS nanoparticle tags for biomolecular binding and enzymatic cleavage studies.
authors.affiliation: Department of Biomedical Engineering, Emory University, 101 Woodruff Circle Suite 2001, Atlanta, Georgia 30322, USA.
authors.forename: Ximei
authors.initials: X
authors.lastname: Qian
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Shuming
authors.initials: S
authors.lastname: Nie
mesh_terms: D003102:Colloids / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D008968:Molecular Conformation; D011092:Polyethylene Glycols / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D003102:Colloids; D011109:Polymethacrylic Acids; C030613:polymethacrylic acid; D011092:Polyethylene Glycols; D006046:Gold