Ligand-functionalized core/shell Ag@Au nanoparticles label-free amperometric immun-biosensor.
A novel label-free electrochemical immunoassay based on core/shell Ag@Au nanoparticles monolayer as sensing interface has been developed for probing IgG. Several coupling techniques, such as Ag nanoparticles, Au nanoparticles, and the core/shell Ag@Au nanoparticles with L-Cysteine (Cys) cross-linking, were investigated for the determination of IgG and a very good result was obtained with the core/shell Ag@Au nanoparticles coupling. With the core/shell Ag@Au nanoparticles coupling method, the effects of the incubation time and pH on amperometric responses of the immunoassay were studied. The strong attachment of the cross-linked complex to the core/shell Ag@Au nanoparticles surface resulted in an excellent storage lifetime of 33 days. A dynamic concentration range of 2.3 to 960 ng/mL with a detection limit of 10 ng/mL was observed. Analytical results of 30 human serum samples obtained using the developing technique are in satisfactory agreement with those given by ELISA. In addition, it presents some superior advantages over the traditional sandwich format in that the analyzing performances are direct, rapid, and simple without multiple separation and labeling steps.
Chongqing Key Laboratory of Analytical Chemistry, College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China.
Dianping
D
Tang
Ruo
R
Yuan
Yaqin
Y
Chai
D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D007074:Immunoglobulin G / Q000032:analysis*; D008024:Ligands; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012834:Silver / Q000737:chemistry*; D013194:Staining and Labeling
D007074:Immunoglobulin G; D008024:Ligands; D012834:Silver; D006046:Gold