title: Host-guest interaction of adamantine with a β-cyclodextrin-functionalized AuPd bimetallic nanoprobe for ultrasensitive electrochemical immunoassay of small molecules.
abstract: A modular labeling strategy was presented for electrochemical immunoassay via supramolecular host-guest interaction between β-cyclodextrin (β-CD) and adamantine (ADA). An ADA-labeled antibody (ADA-Ab) was synthesized via amidation, and the number of ADA moieties loaded on a single antibody was calculated to be ~7. The β-CD-functionalized gold-palladium bimetallic nanoparticles (AuPd-CD) were synthesized in aqueous solution via metal-S chemistry and characterized with transmission electron microscopy and X-ray photoelectron spectra. After the ADA-Ab was bound to the antigen-modified electrode surface with a competitive immunoreaction, AuPd-CD as a signal tag was immobilized onto the immunosensor by a host-guest interaction, leading to a large loading of AuPd nanoparticles. The highly efficient electrocatalysis by AuPd nanoparticles for NaBH4 oxidation produced an ultrasensitive response to chloramphenicol as a model of a small molecule antigen. The immunoassay method showed a wide linear range from 50 pg/mL to 50 μg/mL and a detection limit of 4.6 pg/mL. The specific recognition of antigen by antibody resulted in good selectivity for the proposed method. The host-guest interaction strategy provided a universal labeling approach for the ultrasensitive detection of small molecule targets.
authors.affiliation: State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China.
authors.forename: Lisong
authors.initials: L
authors.lastname: Wang
authors.forename: Jianping
authors.initials: J
authors.lastname: Lei
authors.forename: Rongna
authors.initials: R
authors.lastname: Ma
authors.forename: Huangxian
authors.initials: H
authors.lastname: Ju
mesh_terms: D000547:Amantadine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D055664:Electrochemical Techniques / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D007118:Immunoassay; D007854:Lead / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D011485:Protein Binding / Q000502:physiology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D047392:beta-Cyclodextrins / Q000032:analysis* / Q000378:metabolism
chemical_list: D047392:beta-Cyclodextrins; D007854:Lead; C005660:adamantanine; D006046:Gold; D000547:Amantadine