Search

Background: Since COVID-19 was declared the pandemic by the WHO, it has continued to spread. There is a need for rapid, efficient, and accurate diagnostic kits and techniques to control its spread. Objective: The diagnostic capability of the qRT-PCR-based Real-Q 2019-nCoV Detection Kit and dPCR-based Dr. PCR™ Di20K COVID-19 Detection Kit was compared and evaluated. Methods: Diagnostic tests for COVID-19 were performed using two different COVID-19 kits and 301 individual specimens with confirmed COVID-19 positive/negative at the government-accredited medical institution. Assessment of diagnostic capability was measured through diagnostic sensitivity, specificity, Cohen's Kappa coefficient, and dilutional linearity tests. Results: The COVID-19 diagnostic test results using two kits and 301 individual specimens perfectly matched the pre-diagnosis results of the medical institution. In addition, the measurement results of diagnostic sensitivity and specificity were "1", indicating high diagnostic capability. Cohen's Kappa coefficient value is "1", which means that the diagnosis concordance between the two kits is "Almost Perfect". As a result of dilutional linearity tests to evaluate their detection capability, both kits were measured with very high detection reliability. Conclusion: Here, we propose that the dPCR-based Dr. PCR™ Di20K COVID-19 Detection Kit has the advantages of the dPCR method reported in the previous study and is suitable for point-of-care testing (POCT) by overcoming the limitations of space, test time, cross-over contamination, and biosafety due to omitting RNA extraction process. [ABSTRACT FROM AUTHOR]

Background: Coronavirus disease of 2019 (COVID-19) is well known as a fatal disease, first discovered at Wuhan in China, ranging from mild to death, such as shortness of breath and fever. Early diagnosis of COVID-19 is a crucial point in preventing global prevalence. Objective: We aimed to evaluate the diagnostic competency and efficiency with the Allplex™ 2019-nCoV Assay kit and the Dr. PCR 20 K COVID-19 Detection kit, designed based on the qRT-PCR and dPCR technologies, respectively. Methods: A total of 30 negative and 20 COVID-19 positive specimens were assigned to the diagnostic test by using different COVID-19 diagnosis kits. Diagnostic accuracy was measured by statistical testing with sensitivity, specificity, and co-efficiency calculations. Results: Comparing both diagnostic kits, we confirmed that the diagnostic results of 30 negative and 20 positive cases were the same pre-diagnostic results. The diagnostic statistics test results were perfectly matched with value (1). Cohen's Kappa coefficient was demonstrated that the given kits in two different ways were "almost perfect" with value (1). In evaluating the detection capability, the dilutional linearity experiments substantiate that the Dr. PCR 20 K COVID-19 Detection kit could detect SARS-CoV-2 viral load at a concentration ten times lower than that of the Allplex™ 2019-nCoV Assay kit. Conclusions: In this study, we propose that the dPCR diagnosis using LOAA dPCR could be a powerful method for COVID-19 point-of-care tests requiring immediate diagnosis in a limited time and space through the advantages of relatively low sample concentration and small equipment size compared to conventional qRT-PCR. [ABSTRACT FROM AUTHOR]

Viral control of mitochondrial quality and content has emerged as an important mechanism for counteracting the host response to virus infection. Despite the knowledge of this crucial function of some viruses, little is known about how herpesviruses regulate mitochondrial homeostasis during infection. Human herpesvirus 8 (HHV-8) is an oncogenic virus causally related to AIDS-associated malignancies. Here, we show that HHV-8-encoded viral interferon regulatory factor 1 (vIRF-1) promotes mitochondrial clearance by activating mitophagy to support virus replication. Genetic interference with vIRF-1 expression or targeting to the mitochondria inhibits HHV-8 replication-induced mitophagy and leads to an accumulation of mitochondria. Moreover, vIRF-1 binds directly to a mitophagy receptor, NIX, on the mitochondria and activates NIX-mediated mitophagy to promote mitochondrial clearance. Genetic and pharmacological interruption of vIRF-1/NIX-activated mitophagy inhibits HHV-8 productive replication. Our findings uncover an essential role of vIRF-1 in mitophagy activation and promotion of HHV-8 lytic replication via this mechanism. Impaired removal of damaged mitochondria by mitophagy can activate innate immune signaling, but impact on virus replication remains unclear. Here the authors show that viral IRF-1 of human herpesvirus 8 activates mitophagy via interaction with the mitophagy receptor NIX and that vIRF-1 induced mitophagy supports productive infection. [ABSTRACT FROM AUTHOR]

A voltammetric enzyme electrode was developed based on nicotinamide-independent trimethylamine dehydrogenase (TMADH, EC 1.5.99.7), which catalyses the oxidation of trimethylamine (TMA) to dimethylamine and formaldehyde. A quaternized osmium hydrogel polymer, poly(vinylimidazole-[Os(4,4′-dimethyl-2,2′-bipyridine)Cl]) with ethylamine (PVI-Os-EA), was prepared as a potential redox mediator in an electrochemical biosensor. TMA was detected using TMADH that was co-immobilized with an osmium hydrogel polymer on electrodeposited gold nanoparticles (Au-NPs) on screen-printed carbon electrodes (SPCEs). The Au-NPs deposited onto SPCEs provided about a three times higher electrochemical response compared to that of a planar gold electrode. As TMA was catalyzed by wired TMADH, the electrical signal was monitored at 0.3 V versus Ag/AgCl by cyclic voltammetry and chronoamperometry. The anode currents increased linearly in proportion to the TMA concentration over the 0 ∼ 2.5 mM range with a detection limit of 1 μM ( R = 0.9972). [ABSTRACT FROM AUTHOR]

An amendment to this paper has been published and can be accessed via a link at the top of the paper. [ABSTRACT FROM AUTHOR]

A glucose-reactive enzyme-based biofuel cell system (EBFC) was recently introduced in the scientific community for biomedical applications, such as implantable artificial organs and biosensors for drug delivery. Upon direct contact with tissues or organs, an implanted EBFC can exert effects that damage or stimulate intact tissue due to its byproducts or generated electrical cues, which have not been investigated in detail. Here, we perform a fundamental cell culture study using a glucose dehydrogenase (GDH) as an anode enzyme and bilirubin oxidase (BOD) as a cathode enzyme. The fabricated EBFC had power densities of 15.26 to 38.33 nW/cm2 depending on the enzyme concentration in media supplemented with 25 mM glucose. Despite the low power density, the GDH-based EBFC showed increases in cell viability (~150%) and cell migration (~90%) with a relatively low inflammatory response. However, glucose oxidase (GOD), which has been used as an EBFC anode enzyme, revealed extreme cytotoxicity (~10%) due to the lethal concentration of H2O2 byproducts (~1500 µM). Therefore, with its cytocompatibility and cell-stimulating effects, the GDH-based EBFC is considered a promising implantable tool for generating electricity for biomedical applications. Finally, the GDH-based EBFC can be used for introducing electricity during cell culture and the fabrication of organs on a chip and a power source for implantable devices such as biosensors, biopatches, and artificial organs. [ABSTRACT FROM AUTHOR]