ZnO-Based Electrochemical Immunosensor to Assess Vaccine-Induced Antibody-Mediated Immunity against Wild-Type and Gamma SARS-CoV-2 Strains

Abstract

The evaluation of serological responses to COVID-19 is crucial for population-level surveillance, developing new vaccines, and evaluating the efficacy of different immunization programs. Research and development of point-of-care test technologies remain essential to improving immunity assessment, especially for SARS-CoV-2 variants that partially evade vaccine-induced immune responses. In this work, an impedimetric biosensor based on the immobilization of the recombinant trimeric wild-type spike protein (S protein) on zinc oxide nanorods (ZnONRs) was employed for serological evaluation. We successfully assessed its applicability using serum samples from spike-based COVID-19 vaccines: ChAdOx1-S (Oxford–AstraZeneca) and BNT162b2 (Pfizer–BioNTech). Overall, the ZnONRs/ spike-modified electrode displayed accurate results for both vaccines, showing excellent potential as a tool for assessing and monitoring seroprevalence in the population. A refined outcome of this technology was achieved when the ZnO immunosensor was functionalized with the S protein from the P.1 linage (Gamma variant). Serological responses against samples from vaccinated individuals were acquired with excellent performance. Following studies based on traditional serological tests, the ZnONRs/spike immunosensor data reveal that ChAdOx1-S vaccinated individuals present significantly less antibody-mediated immunity against the Gamma variant than the BNT162b2 vaccine, highlighting the great potential of this point-of-care technology for evaluating vaccine-induced humoral immunity against different SARS-CoV-2 strains.

ZnO based 0–3D diverse nano-architectures, films and coatings for biomedical applications

“…Similarly, it has been found that ZnO plays an essential role in bio-conjugation between sensing materials and biomolecular species, such as viruses. 161 In a recent work, a ZnO NR based electrochemical impedimetric biosensor for detecting antibodies against the SARS-CoV-2 spike protein (in convalescent and vaccinated people) was developed by Nunez et al 162,163 The immobilization of the SARS-CoV-2 recombinant trimeric spike protein (S protein) on ZnO NR modified F-doped SnO 2 substrates for COVID-19 serology testing served as the foundation for this study. Morphological investigations were carried out which showed that the smooth surface of ZnO NRs (diameter 490 nm) became fade (covered) after SARS-CoV-2 recombinant spike protein immobilization.…”

Hybrid Impedimetric Biosensors for Express Protein Markers Detection

“…Nanomaterials made of metal oxides, like other nanomaterials, provide a high specific surface area for immobilization. Among metal oxides, nanoparticles and nanostructures of TiO 2 , ZnO, WO 3 , and others are most often used [51,[139][140][141][142][143][144][145]. The charge transfer resistance R ct in non-faradaic EIS biosensors can tend to infinity if dielectric materials are used for immobilization [146][147][148].…”