A novel immunosensor for detecting toxoplasma gondii-specific IgM based on goldmag nanoparticles and graphene sheets

作者：Jiang, Shuting; Hua, Erhui; Liang, Mo; Liu, Bei; Xie, Guoming^*

来源：Colloids and Surfaces B: Biointerfaces , 2013, 101: 481-486.

DOI：10.1016/j.colsurfb.2012.07.021

• Toxoplasma gondii-specific IgM
• Goldmag nanoparticles
• Graphene sheets
• Gold nanoparticles
• Electrochemical immunosensor

A novel electrochemical immunosensor for detecting toxoplasma gondii-specific IgM (Tg-IgM) was constructed based on goldmag (Au-Fe3O4) nanoparticles and graphene sheets (GS). Thionine (Thi), as a mediator, was first electropolymerized on a nafion-GS (Nf-GS) modified electrode. Subsequently, gold nanoparticles (AuNPs) were attached onto the poly-thionine film through pi-stacking interactions, and then were used to immobilize toxoplasma gondii antigen (Tg-Ag) for immunosensor fabrication. A sandwich-type immunoassay for Tg-IgM was performed using Au-Fe3O4 labeled anti-IgM-horseradish peroxidase (HRP) as trace label. Electrochemical detection was carried out in the presence of H2O2 as HRP substrate. Using Au-Fe3O4 provided a simple, non-chemical damaging method for regeneration, and enhanced the HRP reduction ability toward H2O2. The AuNPs/Thi/Nf-GS nanocomposite also had good conductivity and biocompatibility, which effectively improved the immunosensor sensitivity. Under optimal conditions, the immunosensor can detect Tg-IgM in two linear ranges from 0.0375 to 1.2 AU mL(-1) and from 2.0 to 18 AU mL(-1) with a detection limit of 0.016 AU mL(-1) (S/N=3). The immunosensor exhibited good reproducibility, stability, and selectivity as well.

• 出版日期2013-1-1
• 单位重庆医科大学