کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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870095 | 909849 | 2008 | 7 صفحه PDF | دانلود رایگان |
A highly sensitive electrochemical immunoassay strategy based on the combination of ferrocene (Fc) label and poly(o-phenylenediamine) (PPD) film/gold nanoparticle (GNP) amplification for the detection of immunospecies is proposed using human IgG as the model analyte. A gold electrode is firstly modified with an electropolymerized film of poly(o-phenylenediamine), which provides a stable matrix with abundant amino-groups for the fabrication of sensing interface. Using glutaraldehyde as a cross-linker, cystamine is coupled onto the modified electrode. Subsequently, gold nanoparticle monolayer is assembled onto the resulting surface. Making use of the unique properties of gold nanoparticles, antibodies can be self-assembled onto the surface-confined gold nanoparticles via amine–Au affinity with a high loading amount and reserve high immunological activity. After the introduction of model analyte, the ferrocene (Fc)-labeled antibody is immobilized on the sensing interface by antibody–antigen specific reaction, resulting in a redox current signal. The peak current is proportional to the amount of the analyte. Under the optimized experimental conditions, the proposed sensing strategy provides a wide linear dynamic range from 25 to 1000 pg/mL with a low detection limit of 10 pg/mL. In addition, good reproducibility, high selectivity and stability are achieved. In particular, the extremely high stability of both poly(o-phenylenediamine) and gold nanoparticle monolayer allows the designed biosensing interface to withstand harsh regeneration treatment, making it reusable.
Journal: Biosensors and Bioelectronics - Volume 24, Issue 1, 15 September 2008, Pages 129–135