Rapid quantitative detection of Brucella melitensis by a label-free impedance immunosensor based on a gold nanoparticle-modified screen-printed carbon electrode

• Published in: Sensors (Basel, Switzerland) Vol. 13; no. 7; pp. 8551 - 8563
• Main Authors: Wu, Haiyun, Zuo, Yueming, Cui, Chuanjin, Yang, Wei, Ma, Haili, Wang, Xiaowen
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04.07.2013; MDPI
• Subjects: Animals; Antibodies; Antibodies, Immobilized - chemistry; Antibodies, Immobilized - metabolism; Antigens; Biosensing Techniques - instrumentation; Biosensing Techniques - methods; Biosensors; Brucella melitensis; Brucella melitensis - immunology; Brucella melitensis - isolation & purification; Brucella melitensis - metabolism; Brucellosis; Carbon; Carbon - chemistry; Colony Count, Microbial - instrumentation; Colony Count, Microbial - methods; E coli; Electrodes; Gold; Gold - chemistry; gold nanoparticle; Immunoassay - instrumentation; Immunoassay - methods; label-free immunosensor; Limit of Detection; Metal Nanoparticles - chemistry; Milk; Milk - microbiology; Nanoparticles; quantitative detection; screen-printed carbon electrode; Sensors; China
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s130708551

A rapid and simple method for quantitative monitoring of Brucella melitensis using electrochemical impedance spectroscopy (EIS) is reported for the first time. The label-free immunosensors were fabricated by immobilizing Brucella melitensis antibody on the surface of gold nanoparticle-modified screen-printed carbon electrodes (GNP-SPCEs). Cyclic voltammetry (CV) and EIS were used to characterize the Brucella melitensis antigen interaction on the surface of GNP-SPCEs with antibody. A general electronic equivalent model of an electrochemical cell was introduced for interpretation of the impedance components of the system. The results showed that the change in electron-transfer resistance (Rct) was significantly different due to the binding of Brucella melitensis cells. A linear relationship between the Rct variation and logarithmic value of the cell concentration was found from 4 × 10(4) to 4 × 10(6) CFU/mL in pure culture. The label-free impedance biosensor was able to detect as low as 1 × 10(4) and 4 × 10(5) CFU/mL of Brucella melitensis in pure culture and milk samples, respectively, in less than 1.5 h. Moreover, a good selectivity versus Escherichia coli O157:H7 and Staphylococcus aureus cells was obtained for our developed immunosensor demonstrating its specificity towards only Brucella melitensis.