title: Enzyme-free electrochemical immunosensor based on host-guest nanonets catalyzing amplification for procalcitonin detection.
abstract: An enzyme-free electrochemical immunosensor based on the host-guest nanonets of N,N-bis(ferrocenoyl)-diaminoethane/β-cyclodextrins/poly(amidoamine) dendrimer-encapsulated Au nanoparticles (Fc-Fc/β-CD/PAMAM-Au) for procalcitonin (PCT) detection has been developed in this study. The signal probe was constructed as follows: amine-terminated β-CD was adsorbed to PAMAM-Au first, and then the prepared Fc-Fc was recognized by the β-CD to form stable host-guest nanonets. Next, secondary antibodies (Ab2) were attached into the formed netlike nanostructure of Fc-Fc/β-CD/PAMAM-Au by chemical absorption between PAMAM-Au and -NH2 of β-CD. Herein, the PAMAM-Au act not only as nanocarriers for anchoring large amounts of the β-CD and Ab2 but also as nanocatalysts to catalyze the oxidation of ascorbic acid (AA) for signal amplification. Moreover, the Fc-Fc could be stably immobilized by the hydrophobic inner cavity of β-CD as well as improving solubility by the hydrophilic exterior of β-CD. With the unique structure of two ferrocene units, Fc-Fc not only affords more electroactive groups to make the electrochemical response more sensitive but also plays a role of combining dispersive β-CD-functionalized PAMAM-Au to form the netlike nanostructure. Furthermore, Fc-Fc exhibits good catalytic activity for AA oxidation. When the detection solution contained AA, the synergetic catalysis of PAMAM-Au and Fc-Fc to AA oxidation could be obtained, realizing enzyme-free signal amplification. The proposed immunosensor provided a linear range from 1.80 pg/mL to 500 ng/mL for PCT detection and a detection limit of 0.36 pg/mL under optimal experimental conditions. Moreover, the immunosensor has shown potential application in clinical detection of PCT.
authors: Key Laboratory of Luminescent and Real-Time Analytical Chemistry, Ministry of Education, College of Chemistry and Chemical Engineering, Southwest University , Chongqing 400715, People's Republic of China.
authors: Wen-Jun
authors: WJ
authors: Shen
authors: Ying
authors: Y
authors: Zhuo
authors: Ya-Qin
authors: YQ
authors: Chai
authors: Zhe-Han
authors: ZH
authors: Yang
authors: Jing
authors: J
authors: Han
authors: Ruo
authors: R
authors: Yuan
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002116:Calcitonin / Q000032:analysis*; D050091:Dendrimers / Q000737:chemistry; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D006046:Gold / Q000737:chemistry; D007118:Immunoassay / Q000295:instrumentation / Q000379:methods*; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry; D011498:Protein Precursors / Q000032:analysis*; D047392:beta-Cyclodextrins / Q000737:chemistry
chemical_list: D050091:Dendrimers; D011498:Protein Precursors; D047392:beta-Cyclodextrins; D006046:Gold; D002116:Calcitonin
keywords: N,N-bis(ferrocenoyl)diaminoethane (Fc-Fc); enzyme-free electrochemical immunosensor; poly(amidoamine) dendrimer-encapsulated Au nanoparticles (PAMAM-Au); procalcitonin (PCT); β-cyclodextrin (β-CD)