Disposable sensors are low-cost and easy-to-use sensing devices intended for short-term or rapid single-point measurements. The growing demand for fast, accessible, and reliable information in a vastly connected world makes disposable sensors increasingly important. The areas of application for such devices are numerous, ranging from pharmaceutical, agricultural, environmental, forensic, and food sciences to wearables and clinical diagnostics, especially in resource-limited settings. The capabilities of disposable sensors can extend beyond measuring traditional physical quantities (for example, temperature or pressure); they can provide critical chemical and biological information (chemo- and biosensors) that can be digitized and made available to users and centralized/decentralized facilities for data storage, remotely. These features could pave the way for new classes of low-cost systems for health, food, and environmental monitoring that can democratize sensing across the globe. Here, a brief insight into the materials and basics of sensors (methods of transduction, molecular recognition, and amplification) is provided followed by a comprehensive and critical overview of the disposable sensors currently used for medical diagnostics, food, and environmental analysis. Finally, views on how the field of disposable sensing devices will continue its evolution are discussed, including the future trends, challenges, and opportunities.

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Disposable Sensors in Diagnostics, Food, and Environmental Monitoring.

https://espace.library.uq.edu.au/view/UQ:295107/UQ295107OA.pdf

The flavivirus NS1 protein: molecular and structural biology, immunology, role in pathogenesis and application as a diagnostic biomarker.

Background The COVID-19 pandemic has generated a new era in the world while we still figure out the consequences in different aspects of our daily life. The food supply chain and the food industry do not comprise an exception. Scope and approach This review summarizes the possible transmission ways of COVID-19 through the foods, food supply chain, surfaces, and environment before exploring the development of corresponding detection tools of SARS-CoV-2. For the time being, the possibility of transmission through the food sector is considered negligible, and tracing of SARS-CoV-2 in working environments is not considered as a priority by public authorities. However, the adverse effects on the environment, food systems, and people along the food supply chain are already evident. Key findings and conclusions As long as we move from farm to fork, more safety measures are needed since more people (and subsequently more potential sources of infection) are involved in the process. The need for developing respective bioanalytical protocols for food and environmental safety applications to adapt in the post-lockdown period is also highlighted.

Safety of foods, food supply chain and environment within the COVID-19 pandemic

West Nile virus (WNV) is an emerging neurotropic flavivirus that is transmitted to humans through the bite of an infected mosquito. WNV has disseminated broadly in the Western hemisphere and now poses a significant public health risk. The continuing spread of WNV, combined with the lack of specific therapeutics or vaccines to combat or prevent infection, imparts a pressing need to identify the viral and host processes that control the outcome of and immunity to WNV infection. Here, we provide an overview of recent research that has revealed the virus-host interface controlling WNV infection and immunity.

West Nile virus infection and immunity

Flaviviruses, the human pathogens responsible for dengue fever, West Nile fever, tick-borne encephalitis, and yellow fever, are endemic in tropical and temperate parts of the world. The flavivirus nonstructural protein 1 (NS1) functions in genome replication as an intracellular dimer and in immune system evasion as a secreted hexamer. We report crystal structures for full-length, glycosylated NS1 from West Nile and dengue viruses. The NS1 hexamer in crystal structures is similar to a solution hexamer visualized by single-particle electron microscopy. Recombinant NS1 binds to lipid bilayers and remodels large liposomes into lipoprotein nanoparticles. The NS1 structures reveal distinct domains for membrane association of the dimer and interactions with the immune system and are a basis for elucidating the molecular mechanism of NS1 function.

/pdf/flavivirus-ns1-structures-reveal-surfaces-for-associations-4rr3fpoqh2.pdf

Flavivirus NS1 structures reveal surfaces for associations with membranes and the immune system.

We have developed a simple and sensitive method for the detection of influenza A virus based on giant magnetoresistance (GMR) biosensor. This assay employs monoclonal antibodies to viral nucleoprotein (NP) in combination with magnetic nanoparticles (MNPs). Presence of influenza virus allows the binding of MNPs to the GMR sensor and the binding is proportional to the concentration of virus. Binding of MNPs onto the GMR sensor causes change in the resistance of sensor, which is measured in a real time electrical readout. GMR biosensor detected as low as 1.5 × 10(2) TCID50/mL virus and the signal intensity increased with increasing concentration of virus up to 1.0 × 10(5) TCID50/mL. This study showed that the GMR biosensor assay is relevant for diagnostic application since the virus concentration in nasal samples of influenza virus infected swine was reported to be in the range of 10(3) to 10(5) TCID50/mL.

Giant magnetoresistance-based biosensor for detection of influenza A virus

Nanotechnology: review of concepts and potential application of sensing platforms in food safety.

Influenza A virus (IAV) is a common respiratory pathogen infecting many hosts including humans, pigs (swine influenza virus or SIV), and birds (avian influenza virus or AIV). Monitoring swine and avian influenza viruses in the wild, farms, and live poultry markets is of great significance for human and veterinary public health. A portable, sensitive, and quantitative immunoassay device will be of high demand especially in the rural and resource-limited areas. We report herein our Z-Lab point-of-care (POC) device for sensitive and specific detection of swine influenza viruses with minimum sample handling and laboratory skill requirements. In the present study, a portable and quantitative immunoassay platform based on giant magnetoresistive (GMR) technology is used for the detection of IAV nucleoprotein (NP) and purified H3N2v. Z-Lab displays quantitative results in less than 10 min with sensitivities down to 15 ng/mL and 125 TCID50/mL for IAV nucleoprotein and purified H3N2v, respectively. This platform al...

Portable GMR Handheld Platform for the Detection of Influenza A Virus

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), is a threat to the global healthcare system and economic security. As of Ju...

Magnetic Nanosensor-Based Virus and Pathogen Detection Strategies Before and During COVID-19

We demonstrate the presence of nonstructural protein 1 (NS1)-specific antibodies in a significant proportion of convalescent-phase human serum samples obtained from a cohort in an area where Japanese encephalitis virus (JEV) is endemic. Sera containing antibodies to NS1 but not those with antibodies to other JEV proteins, such as envelope, brought about complement-mediated lysis of JEV-infected BHK-21 cells. Target cells infected with a recombinant poxvirus expressing JEV NS1 on the cell surface confirmed the NS1 specificity of cytolytic antibodies. Mouse anti-NS1 cytolytic sera caused a complement-dependent reduction in virus output from infected human cells, demonstrating their important role in viral control. Antibodies elicited by JEV NS1 did not cross lyse West Nile virus- or dengue virus-infected cells despite immunoprecipitating the NS1 proteins of these related flaviviruses. Additionally, JEV NS1 failed to bind complement factor H, in contrast to NS1 of West Nile virus, suggesting that the NS1 proteins of different flaviviruses have distinctly different mechanisms for interacting with the host. Our results also point to an important role for JEV NS1-specific human immune responses in protection against JE and provide a strong case for inclusion of the NS1 protein in next generation of JEV vaccines.

Venkatramana D. Krishna

Papers

Giant magnetoresistance-based biosensor for detection of influenza A virus

Nanotechnology: review of concepts and potential application of sensing platforms in food safety.

Portable GMR Handheld Platform for the Detection of Influenza A Virus

Magnetic Nanosensor-Based Virus and Pathogen Detection Strategies Before and During COVID-19

Virus-Specific Cytolytic Antibodies to Nonstructural Protein 1 of Japanese Encephalitis Virus Effect Reduction of Virus Output from Infected Cells