title: Fabrication of color changeable polystyrene spheres decorated by gold nanoparticles and their label-free biosensing.
abstract: A novel and simple method for gold nanoshell synthesis with controllable core and shell sizes is reported here. A new 'tree-shape' surfactant bis(amidoethyl-carbamoylethyl) octadecylamine (C18N3) was synthesized and used as the glue for the fast combination of gold nanoparticles and the subsequent gold shell outside. The functionalized polystyrene (PS) cores were covered by a surfactant (PS@C18N3) bilayer. The presence of the surfactant double layer played the role of 'glue' in this method, so that upon controlling the amount of surfactant, it was possible to achieve: the manipulation of gold seed density on the PS@C18N3 spheres, the preparation of PS@Au hybrid structures, and a red-shift in the extinction absorption from 520 to 750 nm. Besides, the as-prepared PS@Au composites supported on a glass substrate exhibited excellent effectiveness in the molecular recognition of human-immunoglobulin G (h-IgG) and goat anti-human-immunoglobulin G (goat anti-h-IgG), showing a rapid response within 20 min with a low detection limit of 10 ng ml(-1). This demonstrates that PS@Au prepared and assembled using our method is potentially useful as a nanosensor platform for immunoassay.
authors.affiliation: Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.
authors.forename: Yuetong
authors.initials: Y
authors.lastname: Xia
authors.forename: Wensheng
authors.initials: W
authors.lastname: Lu
authors.forename: Long
authors.initials: L
authors.lastname: Jiang
mesh_terms: D000588:Amines / Q000737:chemistry; D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D003116:Color; D006041:Goats; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay; D007074:Immunoglobulin G / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D054118:Nanospheres / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance
chemical_list: D000588:Amines; D007074:Immunoglobulin G; D011137:Polystyrenes; C527962:bis(amidoethyl-carbamoylethyl)octadecylamine; D006046:Gold