Enzyme linked oligonucleotide assay for the sensitive detection of SARS-CoV-2 variants

Polymerized Alizarin Red-Inorganic Hybrid Nanoarchitecture (PARIHN) as a Novel Fluorogenic Label for the Immunosorbent Assay of COVID-19

This study seeks to develop and implement a non-enzymatic fluorescent labeling for immunoassay and immunochromatographic assay (ICAs) targeting SARS-CoV-2, to meet the extensive interest and need for effective COVID-19 diagnosis. In this manuscript, we delineate the development, synthesis, and evaluation of a novel quinone polymer zinc hybrid nanoarchitecture, referred to as polymerized alizarin red-inorganic hybrid nanoarchitecture (PARIHN), which integrates an antibody for direct use in fluorescent immunoassays, offering enhanced sensitivity, reduced costs, and improved environmental sustainability. The designed nanoarchitecture can enhance the sensitivity of the immunoassay and enable rapid results without the complexities associated with enzymes, such as their low stability and high cost. At first, a chitosan-alizarin polymer was synthesized utilizing quinone-chitosan conjugation chemistry (QCCC). Then, the chitosan-alizarin polymer was embedded with the detection antibody using zinc ion, forming PARIHN, which was proven to be a stable label with the ability to enhance the assay stability and sensitivity of the immunoassay. PARIHN can react with phenylboronic acid (PBA) or boric acid through its alizarin content to produce fluorescence signals with an LOD of 15.9 and 2.6 pm for PBA and boric acid, respectively, which is the first use of a boric acid derivative in signal generation in the immunoassay. Furthermore, PARIHN demonstrated high practicality in detecting SARS-CoV-2 nucleoprotein in fluorescence (PBA and boric acid) systems with an LOD of 0.76 and 10.85 pm, respectively. Furthermore, owing to the high brightness of our PARIHN fluorogenic reaction, our labeling approach was extended to immunochromatographic assays for SARS-CoV-2 with high sensitivity down to 9.45 pg/mL.

Viral aptamer screening and aptamer-based biosensors for virus detection: A review

Virus-induced infectious diseases have a detrimental effect on public health and exert significant influence on the global economy. Therefore, the rapid and accurate detection of viruses is crucial for effectively preventing and diagnosing infections. Aptamer-based detection technologies have attracted researchers' attention as promising solutions. Aptamers, small single-stranded DNA or RNA screened via systematic evolution of ligands by exponential enrichment (SELEX), possess a high affinity towards their target molecules. Numerous aptamers targeting viral marker proteins or virions have been developed and widely employed in aptamer-based biosensors (aptasensor) for virus detection. This review introduces SELEX schemes for screening aptamers and discusses distinctive SELEX strategies designed explicitly for viral targets. Furthermore, recent advances in aptamer-based biosensing methods for detecting common viruses using different virus-specific aptamers are summarized. Finally, limitations and prospects associated with developing of aptamer-based biosensors are discussed.

Exploring monkeypox virus proteins and rapid detection techniques

Monkeypox (mpox) is an infectious disease caused by the mpox virus and can potentially lead to fatal outcomes. It resembles infections caused by viruses from other families, challenging identification. The pathogenesis, transmission, and clinical manifestations of mpox and other Orthopoxvirus species are similar due to their closely related genetic material. This review provides a comprehensive discussion of the roles of various proteins, including extracellular enveloped virus (EEV), intracellular mature virus (IMV), and profilin-like proteins of mpox. It also highlights recent diagnostic techniques based on these proteins to detect this infection rapidly.

Intrinsic factors behind long COVID: IV. Hypothetical roles of the SARS-CoV-2 nucleocapsid protein and its liquid-liquid phase separation

When the SARS-CoV-2 virus infects humans, it leads to a condition called COVID-19 that has a wide spectrum of clinical manifestations, from no symptoms to acute respiratory distress syndrome. The virus initiates damage by attaching to the ACE-2 protein on the surface of endothelial cells that line the blood vessels and using these cells as hosts for replication. Reactive oxygen species levels are increased during viral replication, which leads to oxidative stress. About three-fifths (~60%) of the people who get infected with the virus eradicate it from their body after 28 days and recover their normal activity. However, a large fraction (~40%) of the people who are infected with the virus suffer from various symptoms (anosmia and/or ageusia, fatigue, cough, myalgia, cognitive impairment, insomnia, dyspnea, and tachycardia) beyond 12 weeks and are diagnosed with a syndrome called long COVID. Long-term clinical studies in a group of people who contracted SARS-CoV-2 have been contrasted with a noninfected matched group of people. A subset of infected people can be distinguished by a set of cytokine markers to have persistent, low-grade inflammation and often self-report two or more bothersome symptoms. No medication can alleviate their symptoms efficiently. Coronavirus nucleocapsid proteins have been investigated extensively as potential drug targets due to their key roles in virus replication, among which is their ability to bind their respective genomic RNAs for incorporation into emerging virions. This review highlights basic studies of the nucleocapsid protein and its ability to undergo liquid-liquid phase separation. We hypothesize that this ability of the nucleocapsid protein for phase separation may contribute to long COVID. This hypothesis unlocks new investigation angles and could potentially open novel avenues for a better understanding of long COVID and treating this condition.

Liquid-liquid phase separation of nucleocapsid proteins during SARS-CoV-2 and HIV-1 replication

The leap of retroviruses and coronaviruses from animal hosts to humans has led to two ongoing pandemics and tens of millions of deaths worldwide. Retrovirus and coronavirus nucleocapsid proteins have been studied extensively as potential drug targets due to their central roles in virus replication, among which is their capacity to bind their respective genomic RNAs for packaging into nascent virions. This review focuses on fundamental studies of these nucleocapsid proteins and how their intrinsic abilities to condense through liquid-liquid phase separation (LLPS) contribute to viral replication. Therapeutic targeting of these condensates and methodological advances are also described to address future questions on how phase separation contributes to viral replication.