Development of a real-time SARS-CoV-2 biosensing system to improve health-worker safety

Recent data on the Covid-19 pandemic suggest that healthcare workers are at risk of infection by SARS-CoV-2, particularly when they are not wearing adequate personal protective equipment (PPE). Airborne transmission of SARS-CoV-2 has been recognized as a critical issue. With the SARS-CoV-2 virus becoming more widespread, virus variants continuously emerging and many pandemic measures lifted, monitoring airborne viruses will remain important in key settings such as hospitals and nursing homes, to enable on-site virus detection and facilitate early-stage infection risk evaluation, thus reducing possible outbreak of the disease and protecting vulnerable populations.

In this project, we have developed and validated a novel dual-functional, localized surface plasmon resonance (LSPR) biosensor and will apply the sensing system to improve detection and on-site monitoring of SARS-CoV-2 in clinical settings, which will provide epidemiological surveillance of the airborne virus to identify problematic procedures and behaviours that lead to the spread of SARS-CoV-2 particles in the air in health care settings.

The real-time sensing system with an integrated aerosol sampler, a micro-processing system and an LSPR (localised surface plasmon resonance) biosensor have been miniaturized into a portable system and applied for airborne virus detection, discrimination and identification. The biosensor can quantify the SARS-CoV-2 in the air. The airborne virus concentrations in the Covid-19 patient rooms will be obtained and the epidemiological behaviour and transmission characteristics will be elucidated. The key drivers for the spread of viral aerosols, such as certain patient treatment procedures, behaviours like donning/doffing PPE or ventilation situations, will be identified.

This project provides an alternative and reliable method in clinical diagnosis and a critical tool for monitoring of SARS-CoV-2 transmission. The real-time detection system will contribute evidence on the role of airborne SARS-CoV-2 transmission and to risk assessment for healthcare workers. The proposed monitoring of airborne viruses in health care settings can facilitate the tracking of the epidemiological situation, the warning of increasing infection risks, the identification of key drivers leading to virus spread in the Covid ward and the understanding of the transmission dynamics. This study could improve the safety of health care workers by informing the appropriate PPE to be used according to the risk assessment.

Development of a real-time biosensing system of SARS-CoV-2 to improve health-worker safety during the COVID-19 pandemic

Recent results demonstrated an increased risk of COVID-19 infection among healthcare workers (HCW), particularly when access to personal protective equipment (PPE) was inadequate. During the COVID-19 pandemic, access to PPE has become complicated by a surge in worldwide demand combined with production limitations and logistical barriers. Since their introduction in hospitals in the 1990s, filtering facepiece (FFP) masks, mostly of the FFP2 type, are used by HCWs to protect themselves against bioaerosols due to tuberculosis, measles and selected respiratory viruses. The COVID-19 pandemic due to the novel SARS-CoV-2 has sparked debate around judicious and safe use of face masks for the protection of HCWs who provide direct care for COVID-19 patients. At the heart of the discussion is the question whether SARS-CoV-2 is transmitted by droplets or aerosols, or by both. While the former are large (>5µm) and fall rapidly to the ground, the latter are small (<5µm) and can stay in the air and travel much farther than the 1-2 metres normally considered a safe distance to infected patients. Today, we have little information on physical spread and infectious dose of SARS-CoV-2, and the discussion about the choice of face masks is based on indirect data. The starting hypothesis of this project is that decision-making regarding mask-wearing for HCW in the current situation of inadequate mask supply, coupled with uncertainty regarding airborne COVID-19 transmission, can be improved if direct detection of SARS-CoV-2 in aerosols can be implemented in clinical situations where aerosolisation is expected. This would be achieved by installing biosensors. Currently, the reverse transcription polymerase chain reaction (RT-PCR) technology is the most sensitive method for SARS-CoV-2 detection in respiratory secretions and it is routinely used to diagnose COVID-19. A reliable biosensing system that can detect SARS-CoV-2 rapidly, quantitatively and in real-time, supplementing RT-PCR technology would significantly help to understand SARS-CoV-2 transmission and inform recommendations for safe and practical use of PPE, and particularly face masks. In this project, we will validate a novel dual-functional, localized surface plasmon resonance (LSPR) biosensor to improve detection and on-line monitoring of SARS-CoV-2 in clinical settings. The two-dimensional gold nano-islands (AuNIs), functionalized with complementary DNA, can perform sensitive detection of selected sequences from SARS-CoV-2 through nucleic acid hybridization. For better sensing performance, the plasmonic photothermal effect, generated by the same AuNIs chip, and an additional laser irradiance can elevate the local temperature and facilitate the specific discrimination of two similar gene sequences. We aim to integrate a bioaerosol sampling system with a specific biosensor, to allow continuous real-time monitoring the shedding of SARS-CoV-2 virus in droplets or aerosols, aiming to rapidly and continuously collect airborne virus with a high collection efficiency and stable microbial recovery. The collected virus can be efficiently enriched in the sampling liquid and subsequently introduced into the integrated micro-system for virus lysis and nucleic acid extraction. This system is to be tested in clinical situations and with real COVID-19 patients with the aim to understand transmission of SARS-CoV-2 in patient surroundings. In parallel, a cluster-randomised, controlled, cross-over study will evaluate the benefits of wearing surgical masks vs. FFP2 masks during COVID-19 patient care (outside aerosol-generating procedures). To date, no study has combined virus detection technology with a cluster-randomised trial to address the question of appropriate face mask usage in COVID-19 care.