Journal of Colloid and Interface Science, Vol.588, 101-109, 2021
Stabilization of surface-bound antibodies for ELISA based on a reversable zeolitic imidazolate framework-8 coating
Immunoassays typically must be stored under refrigerated conditions because antibodies, after being immobilized to solid surfaces, tend to lose their recognition capabilities to target antigens under non refrigerated conditions. This requirement hinders application of immunoassays in resource-limited settings including rural clinics in tropical regions, disaster struck areas, and low-income countries, where refrigeration may not be feasible. In this work, a facile approach based on a reversable zeolitic imidazolate framework-8 (ZIF-8) coating is introduced to stabilize surface-bound antibodies on enzyme-linked immunosorbent assay (ELISA) plates under non-refrigerated conditions. Using a sandwich ELISA for the detection of neutrophil gelatinase-associated lipocalin (NGAL), a urine biomarker for acute kidney injury, as a model system, ZIF-8 is demonstrated to be able to uniformly coat the surface-bound anti-NGAL IgG, and stabilize the dynamic range and detection sensitivity of the assay after storage at an elevated temperature (50 degrees C) for at least 4 weeks. The stabilization efficacy of the ZIF-8 coating is comparable to the current "gold standard" refrigeration approach, and superior to the commonly used sucrose coating method. This approach will greatly improve the shelf-life and stability of antibody-coated ELISAs and other types of assays which utilize surface-bound antibodies, thus extending biomedical research and medical diagnostics to resource-limited settings. (c) 2020 Elsevier Inc. All rights reserved.
Keywords:Surface-bound antibody;ELISA;Zeolitic imidazolate framework-8;Stabilization;Single molecule force spectroscopy