A Regenerative Immunoaffinity Layer Based on the Outer Membrane of Z-Domains Autodisplaying <i>E. coli</i> for Immunoassays and Immunosensors

• Main Authors: Daseul Jeon, Jae-Chul Pyun, Joachim Jose, Min Park
• Format: Article
• Language: English
• Published: MDPI AG 2018-11-01
• Series: Sensors
• Subjects: autodisplay; Z-domains; immunoaffinity layer; regeneration; immunosensor; SPR biosensor
• Online Access: https://www.mdpi.com/1424-8220/18/11/4030

Through orientation control of antibodies, Z-domains autodisplaying <i>Escherichia coli</i> outer cell membrane (OM) may be utilized to improve the sensitivity and limit of detection (LOD) of immunoassays and immunosensors. A regenerative immunoaffinity layer based on Z-domains autodisplaying <i>E. coli</i> OM was developed for the surface plasmon resonance (SPR) biosensor. Regeneration conditions for the Z-domains autodisplaying <i>E. coli</i> OM-based immunoassays and immunosensors were optimized by varying pH and detergent concentration. An <i>E. coli</i> cell-based HRP immunoassay was tested and validated in three sequential regenerative immunoassays under optimal conditions. The OM of Z-domains autodisplaying <i>E. coli</i> was isolated and coated on the two-dimensional substrate (microplate). The OM-based HRP immunoassay was tested and validated in four regenerative immunoassays. This regenerative OM layer was applied to the SPR biosensor. Z-domains autodisplaying OM layered onto the gold surface of SPR biosensors was developed, and the OM-based regenerative immunoaffinity layer with orientation control was tested using CRP analyte. The SPR biosensor regenerative immunoaffinity layer demonstrated that CRP biosensing was repeated for five regeneration cycles with less than 2% signal difference. Therefore, the newly developed regenerative immunoaffinity layer with antibody orientation control may improve biosensing sensitivity and reduce the cost of medical diagnosis.