title: Gold nanoparticles-coated magnetic microspheres as affinity matrix for detection of hemoglobin A1c in blood by microfluidic immunoassay.
abstract: A novel microfluidic immunoassay system for specific detection of hemoglobin A1c (HbA1c) was developed based on a three-component shell/shell/core structured magnetic nanocomposite Au/chitosan/Fe(3)O(4), which was synthesized with easy handling feature of Fe(3)O(4) by magnet, high affinity for gold nanoparticles of chitosan and good immobilization ability for anti-human hemoglobin-A1c antibody (HbA1c mAb) of assembled colloidal gold nanoparticles. The resulting HbA1c mAb/Au/chitosan/Fe(3)O(4) magnetic nanoparticles were then introduced into microfluidic devices coupled with a gold nanoband microelectrode as electrochemical detector. After that, three-step rapid immunoreactions were carried out in the sequence of HbA1c, anti-human hemoglobin antibodies (Hb mAb) and the secondary alkaline phosphatase (AP)-conjugated antibody within 20 min. The current response of 1-naphtol obtained from the reaction between the secondary AP-conjugated antibody and 1-naphthyl phosphate (1-NP) increased proportionally to the HbA1c concentration. Under optimized electrophoresis and detection conditions, HbA1c responded linearly in the concentration of 0.05-1.5 μg mL(-1), with the detection limit of 0.025 μg mL(-1). This system was successfully employed for detection of HbA1c in blood with good accuracy and renewable ability. The proposed method proved its potential use in clinical immunoassay of HbA1c.
authors: Key Laboratory of Analytical Chemistry for Life Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
authors: Shao-Peng
authors: SP
authors: Chen
authors: Xiao-Dong
authors: XD
authors: Yu
authors: Jing-Juan
authors: JJ
authors: Xu
authors: Hong-Yuan
authors: HY
authors: Chen
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D001774:Blood Chemical Analysis; D048271:Chitosan / Q000737:chemistry; D004867:Equipment Design; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D006442:Glycated Hemoglobin / Q000032:analysis* / Q000276:immunology; D006046:Gold / Q000737:chemistry*; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D008863:Microspheres; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D053758:Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D012680:Sensitivity and Specificity
chemical_list: D048271:Chitosan; D052203:Ferrosoferric Oxide; D006442:Glycated Hemoglobin; D006046:Gold