SARS-CoV-2 Virus-Like Particles with Plasmonic Au Cores and S1-Spike Protein Coronas

TL;DR

This study presents a safe, plasmonic virus-like particle platform mimicking SARS-CoV-2, enabling virus interaction studies and biosensing applications without handling live viruses.

Contribution

Developed a universal synthesis method for SARS-CoV-2 VLPs with gold cores and spike protein coronas, suitable for biosensing and interaction studies.

Findings

VLPs specifically bind SARS-CoV-2 antibodies

Localized surface plasmon resonance enables biosensing

Fluorescent labeling allows interaction visualization

Abstract

The COVID-19 pandemic has stimulated the scientific world to intensify virus-related studies, aimed at the development of quick and safe ways of detecting viruses in human body, studying the virus-antibody and virus-cell interactions, and designing nanocarriers for targeted antiviral therapies. However, research on dangerous viruses can only be performed in certified laboratories that follow strict safety procedures. Thus, developing deactivated virus constructs or safe-to-use virus-like objects, which imitate real viruses and allow performing virus-related studies in any research laboratory, constitutes an important scientific challenge. One of the groups of such species are the so-called virus-like particles (VLPs). Instead of capsids with viral DNA/RNA, VLPs have synthetic cores with real virus proteins attached to them. We have developed a method for the preparation of VLPs imitating the virus responsible for the COVID-19 disease: the SARS-CoV-2. The particles have Au cores surrounded by "coronas" of S1 domains of the virus's Spike protein. Importantly, they are safe to use and specifically interact with SARS-CoV-2 antibodies. Moreover, Au cores exhibit localized surface plasmon resonance (LSPR), which makes the synthesized VLPs suitable for biosensing applications. Within our studies, the effect allowed us to visualize the interaction between the VLPs and the antibodies and identify the characteristic vibrational signals. What is more, additional functionalization of the particles with a fluorescent label revealed their potential in studying specific virus-related interactions. Notably, the universal character of the developed synthesis method makes it potentially applicable for fabricating VLPs imitating other life-threatening viruses.