Through orientation control of antibodies, Z-domains autodisplaying Escherichia coli 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 E. coli OM was developed for the surface plasmon resonance (SPR) biosensor. Regeneration conditions for the Z-domains autodisplaying E. coli OM-based immunoassays and immunosensors were optimized by varying pH and detergent concentration. An E. coli cell-based HRP immunoassay was tested and validated in three sequential regenerative immunoassays under optimal conditions. The OM of Z-domains autodisplaying E. coli 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.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIP) (NRF-2016R1D1A3B03934169), Republic of Korea, and Hallym University Research Fund, 2018 (HRF-201806-013).
© 2018 by the authors. Licensee MDPI, Basel, Switzerland.
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering