Development of polypyrrole (nano)structures decorated with gold nanoparticles toward immunosensing for COVID-19 serological diagnosis

Abstract

The rapid and reliable detection of SARS-CoV-2 seroconversion in humans is crucial for suitable infection control. In this sense, many studies have focused on increasing the sensibility, lowering the detection limits and minimizing false negative/positive results. Thus, biosensors based on nanoarchitectures of conducting polymers (CPs) are promising alternatives to more traditional materials, since they can hold improved surface area, higher electrical conductivity and electrochemical activity. In this work, we reported the analytical comparison of two different CPs morphologies for the development of an impedimetric biosensor to monitor SARS-CoV-2 seroconversion in humans. Biosensors based on polypyrrole (PPy), synthesized in both globular and nanotubular (NTs) morphology, and gold nanoparticles (AuNPs) are reported, using a self-assembly monolayer of 3-mercaptopropionic acid and covalently linked SARS-CoV-2 Nucleocapsid protein. Firstly, the novel hybrid materials were characterized by electron microscopy and electrochemical measurements, and the biosensor step-by-step construction was characterized by electrochemical and spectroscopic techniques. As a proof of concept, the biosensor was used for the impedimetric detection of anti-SARS-CoV-2 Nucleocapsid protein monoclonal antibodies. The results showed a linear response for different antibody concentrations, good sensibility and possibility to quantify 7.442 and 0.4 ng mL -1 of monoclonal antibody for PPy in the globular and nanotubular morphology, respectively. The PPy-NTs biosensor was able to discriminate serum obtained from COVID-19 positive vs negative clinical samples and is a promising tool for COVID-19 immunodiagnostic, which can contribute to further studies concerning rapid, efficient, and reliable detections.

Antiviral effects of coinage metal-based nanomaterials to combat COVID-19 and its variants

“…90 Concisely, Au has been proved to be an efficient antiviral agent and has the potential to deal with SARS-CoV-2 and variants for detection and treatment. [129][130][131] Au NPs are reported to be an excellent carrier for antiviral drug delivery. 132 Besides it, modified Au NPs possess a tremendous ability to attach to the spikes proteins and envelop the virus, which leads to inhibition of viral entry and deactivation.…”

Recent Development of Photoresponsive Liposomes Based on Organic Photosensitizers, Au Nanoparticles, and Azobenzene Derivatives for Nanomedicine

“…The application of Au nanoparticles is a notable highlight of nanotechnology development. For example, Hryniewicz 70 developed a conductive polymer nanosensor based on Au nanoparticles to monitor human SARS-CoV-2 seroconversion, which can be used to aid in the diagnosis of coronavirus with improved sensitivity. Ligiero 71 reported that the increase in the particle size of Au nanoparticles would lead to an increase in the hydrodynamic diameter during the antigen−antibody interactions in conditions containing SARS-CoV-2 S-protein, for which the SARS-CoV-2 S-protein was found in less than 5 min.…”

An Exploration of Nanoparticle-Based Diagnostic Approaches for Coronaviruses: SARS-CoV-2, SARS-CoV and MERS-CoV

“…With a calculated detection limit of 0.084 nM (5.9 fM), the authors believe that the approach could be a promising candidate for sensitive, easy-to-perform and cheap point-of-care for rapid SARS-CoV-2 detection [ 96 ]. Lastly, nanoarchitectures of CPs, such as poly-pyrrole have been investigated for COVID-19 diagnostic applications due to their stability, ease of synthesis and electroactivity in phosphate buffer (pH 7.4) [ 97 ]. By incorporating AuNPs within poly-pyrrole nanotubular morphologies, Hryniewicz et al added further stability, biocompatibility and selectivity to the CPs formulations, making it a promising biosensing tool for COVID-19 antibodies [ 97 ].…”

“…Lastly, nanoarchitectures of CPs, such as poly-pyrrole have been investigated for COVID-19 diagnostic applications due to their stability, ease of synthesis and electroactivity in phosphate buffer (pH 7.4) [ 97 ]. By incorporating AuNPs within poly-pyrrole nanotubular morphologies, Hryniewicz et al added further stability, biocompatibility and selectivity to the CPs formulations, making it a promising biosensing tool for COVID-19 antibodies [ 97 ]. The authors tested two morphologies (globular and nanotubular) of poly-pyrrole implanted with AuNPs against SARS-CoV-2 Nucleocapsid (N) protein.…”

“…The detection limits for the globular and nanotubular formulations were 7.442 and 0.4 ng/mL, respectively. As such, when adopting a nano-scale form, the nanotubular morphology showcased 8-fold higher sensitivity than its globular counterpart [ 97 ]. Furthermore, the nanotubular biosensor was tested against serum from positive and negative COVID-19 patients, where it successfully distinguished between all tested samples within 1 h. Given the small volume of serum needed to obtain a result, finger-prick blood tests for COVID-19 diagnosis and immunosurveillance could be a promising translation of this technology in a clinical setting [ 97 ].…”