Development of Highly Sensitive Immunosensor for Detection of <i>Staphylococcus aureus</i> Based on AuPdPt Trimetallic Nanoparticles Functionalized Nanocomposite

• Main Authors: En Han, Yun Zhang, Jianrong Cai, Xinai Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2021-04-01
• Series: Micromachines
• Subjects: trimetallic nanoparticles; electrochemical immunosensor; label-free detection; <i>Staphylococcus aureus</i>
• Online Access: https://www.mdpi.com/2072-666X/12/4/446

The rapid and sensitive detection of <i>Staphylococcus aureus</i> (<i>S. aureus</i>) is essential to ensure food safety and protect humans from foodborne diseases. In this study, a sensitive and facile electrochemical immunosensor using AuPdPt trimetallic nanoparticles functionalized multi-walled carbon nanotubes (MWCNTs-AuPdPt) as the signal amplification platform was designed for the label-free detection of <i>S. aureus</i>. The nanocomposite of MWCNTs-AuPdPt was prepared by an in situ growth method of loading AuPdPt trimetallic nanoparticles on the surface of MWCNTs. The synthesized MWCNTs-AuPdPt featured good conductivity and superior catalytic performance for hydrogen peroxide. The nanocomposite of MWCNTs-AuPdPt with good biocompatibility and high specific surface area was further functionalized by anti-<i>S. aureus</i> antibodies. The immobilized antibodies could efficiently capture <i>S. aureus</i> to the modified electrode by an immune reaction, which resulted in the change of catalytic current intensity to realize the sensitive detection of <i>S. aureus</i>. The designed immunosensor could detect <i>S. aureus</i> in a linear range from 1.1 × 10² to 1.1 × 10⁷ CFU mL⁻¹ with a low detection limit of 39 CFU mL⁻¹. Additionally, the proposed immunosensor was successfully applied to determine <i>S. aureus</i> in actual samples with acceptable results. This strategy provided a promising platform for highly sensitive determination of <i>S. aureus</i> and other pathogens in food products.