title: One-step synthesis of amino-dextran-protected gold and silver nanoparticles and its application in biosensors.
abstract: A sensitive method for the detection of the lectin protein concanavalin A (Con A) was developed using amino-dextran (AD)-protected gold (AD-Au) and silver nanoparticles (AD-Ag) as sensitive optical probes. The AD-Au and AD-Ag nanoparticles were synthesized by directly applying amino-dextran as a reductive and protective reagent. The size of the nanoparticles could be altered by changing the molar ratio of AD to the metal salt. The amino-dextran bound to Con A by forming a 4:1 Au-Con A complex at neutral pH, and the nanoparticles were induced to aggregate by Con A. The absorption intensity of the nanoparticles decreased linearly with as the Con A concentration was increased from 3.85 x 10(-8) to 6.15 x 10(-7) M. The Au-Con A complex was dissociated by the disaccharide isomaltose, which has a higher affinities for Con A than Au; this competitive strategy could also be used to detect similar types of saccharides.
authors.affiliation: State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Ma
authors.forename: Nan
authors.initials: N
authors.lastname: Li
authors.forename: Cheng
authors.initials: C
authors.lastname: Yang
authors.forename: Xiurong
authors.initials: X
authors.lastname: Yang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D003208:Concanavalin A / Q000032:analysis*; D003911:Dextrans / Q000138:chemical synthesis / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D055095:Optics and Photonics; D010316:Particle Size; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry*
chemical_list: D003911:Dextrans; D003208:Concanavalin A; D012834:Silver; D006046:Gold