A Blood Drying Process for DNA Amplification.

The presence of numerous inhibitors in blood makes their use in nucleic acid amplification techniques difficult. Current methods for extracting and purifying pathogenic DNA from blood involve removal of inhibitors, resulting in low and inconsistent DNA recovery rates. To address this issue, a biphasic method is developed that simultaneously achieves inhibitor inactivation and DNA amplification without the need for a purification step. Inhibitors are physically trapped in the solid-phase dried blood matrix by blood drying, while amplification reagents can move into the solid nano-porous dried blood and initiate the amplification. It is demonstrated that the biphasic method has significant improvement in detection limits for bacteria such as Escherichia coli, Methicillin-resistant Staphylococcus aureus, Methicillin-Sensitive Staphylococcus aureus using loop-mediated isothermal amplification (LAMP) and recombinase polymerase amplification (RPA). Several factors, such as drying time, sample volume, and material properties are characterized to increase sensitivity and expand the application of the biphasic assay to blood diagnostics. With further automation, this biphasic technique has the potential to be used as a diagnostic platform for the detection of pathogens eliminating lengthy culture steps.

A Comparative Study on the Lysosomal Cation Channel TMEM175 Using Automated Whole-Cell Patch-Clamp, Lysosomal Patch-Clamp, and Solid Supported Membrane-Based Electrophysiology: Functional Characterization and High-Throughput Screening Assay Development.

The lysosomal cation channel TMEM175 is a Parkinson's disease-related protein and a promising drug target. Unlike whole-cell automated patch-clamp (APC), lysosomal patch-clamp (LPC) facilitates physiological conditions, but is not yet suitable for high-throughput screening (HTS) applications. Here, we apply solid supported membrane-based electrophysiology (SSME), which enables both direct access to lysosomes and high-throughput electrophysiological recordings. In SSME, ion translocation mediated by TMEM175 is stimulated using a concentration gradient at a resting potential of 0 mV. The concentration-dependent K+ response exhibited an I/c curve with two distinct slopes, indicating the existence of two conducting states. We measured H+ fluxes with a permeability ratio of PH/PK = 48,500, which matches literature findings from patch-clamp studies, validating the SSME approach. Additionally, TMEM175 displayed a high pH dependence. Decreasing cytosolic pH inhibited both K+ and H+ conductivity of TMEM175. Conversely, lysosomal pH and pH gradients did not have major effects on TMEM175. Finally, we developed HTS assays for drug screening and evaluated tool compounds (4-AP, Zn as inhibitors; DCPIB, arachidonic acid, SC-79 as enhancers) using SSME and APC. Additionally, we recorded EC50 data for eight blinded TMEM175 enhancers and compared the results across all three assay technologies, including LPC, discussing their advantages and disadvantages.

Molecular mechanisms of the virulence and efficacy of a highly virulent Vibrio anguillarum strain and its formalin-inactivated vaccine in rainbow trout.

In this study, we have isolated four strains of Vibrio anguillarum, revealing that they share the same serotype of O1, biochemical characteristics and virulence factor genes. However, there were differences in haemolytic activity among the bacterial strains; a strain with lower pathogenicity showed γ-haemolytic activity, whereas other virulent strains showed α-haemolytic activity on blood agar and higher empA gene expression in RTG-2 cell line. The most virulent strain was V. anguillarum RTBHR from diseased masu salmon (Oncorhynchus masou), which resulted in mortality of 100% and 93.3% when injected intraperitoneally at concentrations of 9 × 105 and 6.3 × 105 colony-forming units/fish in rainbow trout (Oncorhynchus mykiss) and Coho salmon (Oncorhynchus kisutch), respectively. A formalin-inactivated vaccine of V. anguillarum RTBHR induced a protective and specific immunity in rainbow trout as the vaccinated fish exhibited low cumulative mortality in a challenge test and a high specific antibody response in enzyme-linked immunosorbent assay at 8 weeks post-vaccination. The produced antibody was bound to bacterial proteins of 30-37 kDa in size. This adaptive immune response was detected as early as day 1, with quantitative polymerase chain reaction analysis revealing the upregulated expression of genes encoding for TCRα, T-bet, mIgM and sIgM in rainbow trout. This suggested that the vaccine induced T (probably a more dominant Th1 response) and B cell responses. In conclusion, the vaccine successfully protected fish from V. anguillarum infection by eliciting cellular and humoral immune responses.

Mechanisms of the Device Property Alteration Generated by the Proton Irradiation in GaN-Based MIS-HEMTs Using Extremely Thin Gate Insulator.

Recently, we reported that device performance degradation mechanisms, which are generated by the γ-ray irradiation in GaN-based metal-insulator-semiconductor high electron mobility transistors (MIS-HEMTs), use extremely thin gate insulators. When the γ-ray was radiated, the total ionizing dose (TID) effects were generated and the device performance deteriorated. In this work, we investigated the device property alteration and its mechanisms, which were caused by the proton irradiation in GaN-based MIS-HEMTs for the 5 nm-thick Si3N4 and HfO2 gate insulator. The device property, such as threshold voltage, drain current, and transconductance varied by the proton irradiation. When the 5 nm-thick HfO2 layer was employed for the gate insulator, the threshold voltage shift was larger than that of the 5 nm-thick Si3N4 gate insulator, despite the HfO2 gate insulator exhibiting better radiation resistance compared to the Si3N4 gate insulator. On the other hand, the drain current and transconductance degradation were less for the 5 nm-thick HfO2 gate insulator. Unlike the γ-ray irradiation, our systematic research included pulse-mode stress measurements and carrier mobility extraction and revealed that the TID and displacement damage (DD) effects were simultaneously generated by the proton irradiation in GaN-based MIS-HEMTs. The degree of the device property alteration was determined by the competition or superposition of the TID and DD effects for the threshold voltage shift and drain current and transconductance deterioration, respectively. The device property alteration was diminished due to the reduction of the linear energy transfer with increasing irradiated proton energy. We also studied the frequency performance degradation that corresponded to the irradiated proton energy in GaN-based MIS-HEMTs using an extremely thin gate insulator.

A culture-free biphasic approach for sensitive and rapid detection of pathogens in dried whole-blood matrix.

Blood stream infections (BSIs) cause high mortality, and their rapid detection remains a significant diagnostic challenge. Timely and informed administration of antibiotics can significantly improve patient outcomes. However, blood culture, which takes up to 5 d for a negative result, followed by PCR remains the gold standard in diagnosing BSI. Here, we introduce a new approach to blood-based diagnostics where large blood volumes can be rapidly dried, resulting in inactivation of the inhibitory components in blood. Further thermal treatments then generate a physical microscale and nanoscale fluidic network inside the dried matrix to allow access to target nucleic acid. The amplification enzymes and primers initiate the reaction within the dried blood matrix through these networks, precluding any need for conventional nucleic acid purification. High heme background is confined to the solid phase, while amplicons are enriched in the clear supernatant (liquid phase), giving fluorescence change comparable to purified DNA reactions. We demonstrate single-molecule sensitivity using a loop-mediated isothermal amplification reaction in our platform and detect a broad spectrum of pathogens, including gram-positive methicillin-resistant and methicillin-susceptible Staphylococcus aureus bacteria, gram-negative Escherichia coli bacteria, and Candida albicans (fungus) from whole blood with a limit of detection (LOD) of 1.2 colony-forming units (CFU)/mL from 0.8 to 1 mL of starting blood volume. We validated our assay using 63 clinical samples (100% sensitivity and specificity) and significantly reduced sample-to-result time from over 20 h to <2.5 h. The reduction in instrumentation complexity and costs compared to blood culture and alternate molecular diagnostic platforms can have broad applications in healthcare systems in developed world and resource-limited settings.

Magnetic-Plasmonic Multimodular Hollow Nanoreactors for Compartmentalized Orthogonal Tandem Catalysis.

In tandem catalytic systems, controlling the reaction steps and side reactions is extremely challenging. Here, we demonstrate a nanoreactor platform comprising magnetic- and plasmonic-coupled catalytic modules that synchronizes reaction steps at unconnected neighboring reaction sites via decoupled nanolocalized energy harvested using distinct antennae reactors while minimizing the interconflicting effects. As was desired, the course of the reaction and product yields can be controlled by a convenient remote operation of alternating magnetic field (AMF) and near-infrared light (NIR). Following this strategy, a tandem reaction involving [Pd]-catalyzed Suzuki-Miyaura C-C cross-coupling and [Pt]-catalyzed aerobic alcohol oxidation enabled an excellent yield of cinnamaldehyde (ca. 95%) by overcoming the risk of side reactions. The customization scope for using different catalytic metals (Pt, Pd, Ru, and Rh) with in situ control over product release through remotely operable benign energy sources opens avenues for designing diverse catalytic schemes for targeted applications.

Pathogenic Mechanism of a Highly Virulent Infectious Hematopoietic Necrosis Virus in Head Kidney of Rainbow Trout (Oncorhynchusmykiss) Analyzed by RNA-Seq Transcriptome Profiling.

Infectious hematopoietic necrosis virus (IHNV) is a pathogen that causes high rates of mortality in salmonid fishes. Therefore, an RNA-seq-based transcriptome analysis was performed in the head kidney of rainbow trout infected with a highly virulent IHNV strain to understand the pathogenesis of and defense strategies for IHNV infection in rainbow trout. The results showed that the numbers of DEGs were 618, 2626, and 774 (control vs. IHNV) on days 1, 3, and 5, respectively. Furthermore, the enrichment analysis of gene ontology (GO) annotations to classify DEGs showed that GO terms considerably associated with DEGs were gluconeogenesis, inflammatory response, and cell adhesion in the Biological Process (BP) category, apical plasma membrane, extracellular matrix (ECM) in the Cellular Component category, and transporter activity, integrin binding, and protein homodimerization activity in the Molecular Function category, on days 1, 3, and 5, respectively. Notably, GO terms in the BP category, including the negative regulation of type I interferon production and positive regulation of interleukin-1ß secretion, were commonly identified at all time points. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, complement and coagulation cascades were commonly identified at all time points. Importantly, the widely recognized GO terms and KEGG pathways extensively linked to DEGs were related to energy metabolism on day 1, the immune response on day 3, and cell proliferation on day 5. Furthermore, protein-protein interaction networks and centrality analysis showed that the metabolism and signaling transduction pathways were majorly upregulated. Conclusively, the virulent IHNV infection drives pathogenesis by activating the metabolic energy pathway for energy use for viral replication, facilitating necrosis through autophagy, and causing a shutoff response of the host immune system through the downregulation of type I IFN at the initial stage of infection.

Discovery of MK-1454: A Potent Cyclic Dinucleotide Stimulator of Interferon Genes Agonist for the Treatment of Cancer.

Stereochemically and structurally complex cyclic dinucleotide-based stimulator of interferon genes (STING) agonists were designed and synthesized to access a previously unexplored chemical space. The assessment of biochemical affinity and cellular potency, along with computational, structural, and biophysical characterization, was applied to influence the design and optimization of novel STING agonists, resulting in the discovery of MK-1454 as a molecule with appropriate properties for clinical development. When administered intratumorally to immune-competent mice-bearing syngeneic tumors, MK-1454 exhibited robust tumor cytokine upregulation and effective antitumor activity. Tumor shrinkage in mouse models that are intrinsically resistant to single-agent therapy was further enhanced when treating the animals with MK-1454 in combination with a fully murinized antimouse PD-1 antibody, mDX400. These data support the development of STING agonists in combination with pembrolizumab (humanized anti-PD-1 antibody) for patients with tumors that are partially responsive or nonresponsive to single-agent anti-PD-1 therapy.

A kinase-cGAS cascade to synthesize a therapeutic STING activator.

The introduction of molecular complexity in an atom- and step-efficient manner remains an outstanding goal in modern synthetic chemistry. Artificial biosynthetic pathways are uniquely able to address this challenge by using enzymes to carry out multiple synthetic steps simultaneously or in a one-pot sequence1-3. Conducting biosynthesis ex vivo further broadens its applicability by avoiding cross-talk with cellular metabolism and enabling the redesign of key biosynthetic pathways through the use of non-natural cofactors and synthetic reagents4,5. Here we describe the discovery and construction of an enzymatic cascade to MK-1454, a highly potent stimulator of interferon genes (STING) activator under study as an immuno-oncology therapeutic6,7 (ClinicalTrials.gov study NCT04220866 ). From two non-natural nucleotide monothiophosphates, MK-1454 is assembled diastereoselectively in a one-pot cascade, in which two thiotriphosphate nucleotides are simultaneously generated biocatalytically, followed by coupling and cyclization catalysed by an engineered animal cyclic guanosine-adenosine synthase (cGAS). For the thiotriphosphate synthesis, three kinase enzymes were engineered to develop a non-natural cofactor recycling system in which one thiotriphosphate serves as a cofactor in its own synthesis. This study demonstrates the substantial capacity that currently exists to use biosynthetic approaches to discover and manufacture complex, non-natural molecules.

Microfluidic point-of-care device for detection of early strains and B.1.1.7 variant of SARS-CoV-2 virus.

Since the beginning of the COVID-19 pandemic, several mutations of the SARS-CoV-2 virus have emerged. Current gold standard detection methods for detecting the virus and its variants are based on PCR-based diagnostics using complex laboratory protocols and time-consuming steps, such as RNA isolation and purification, and thermal cycling. These steps limit the translation of technology to the point-of-care and limit accessibility to under-resourced regions. While PCR-based assays currently offer the possibility of multiplexed gene detection, and commercial products of single gene PCR and isothermal LAMP at point-of-care are also now available, reports of isothermal assays at the point-of-care with detection of multiple genes are lacking. Here, we present a microfluidic assay and device to detect and differentiate the Alpha variant (B.1.1.7) from the SARS-CoV-2 virus early strains in saliva samples. The detection assay, which is based on isothermal RT-LAMP amplification, takes advantage of the S-gene target failure (SGTF) to differentiate the Alpha variant from the SARS-CoV-2 virus early strains using a binary detection system based on spatial separation of the primers specific to the N- and S-genes. We use additively manufactured plastic cartridges in a low-cost optical reader system to successfully detect the SARS-CoV-2 virus from saliva samples (positive amplification is detected with concentration ≥10 copies per µL) within 30 min. We demonstrate that our platform can discriminate the B.1.1.7 variant (USA/CA_CDC_5574/2020 isolate) from SARS-CoV-2 negative samples, but also from the SARS-CoV-2 USA-WA1/2020 isolate. The reliability of the developed point-of-care device was confirmed by testing 38 clinical saliva samples, including 20 samples positive for Alpha variant (sensitivity > 90%, specificity = 100%). This study highlights the current relevance of binary-based testing, as the new Omicron variant also exhibits S-gene target failure and could be tested by adapting the approach presented here.

Functional characterization of a novel tumor necrosis factor gene (TNF-New) in rock bream (Oplegnathus fasciatus).

The novel tumor necrosis factor (TNF-New or TNFN) gene has been identified only in teleost such as zebrafish, medaka (Oryzias latipes), fugu (Takifugu rubripes), and rainbow trout (Oncorhynchus mykiss). In this study, a putative TNFN gene in rock bream (named RB-TNFN) was cloned and its functional expression in the immune system was analyzed. Although it was previously reported to share a high degree of homology with mammalian lymphotoxin (LT)-ß, in silico analysis revealed that RB-TNFN differed slightly from mammalian LT-ß in its genomic structure, phylogenetic relationship, and predicted protein tertiary structure, whereas the genomic location of TNFN (immediately behind TNF-α) was the same as that of LT-ß. In healthy rock bream, RB-TNFN gene expression was the highest in the liver and the lowest in the head kidney. In vitro, it was significantly upregulated in head kidney cells following polyinosinic:polycytidylic acid, concanavalin A, phytohemagglutinin, or calcium ionophore (CI) stimulation and in spleen cells by lipopolysaccharide (LPS), CI, and rock bream iridovirus (RBIV). In vivo, it was upregulated in the spleen, liver, and gut on day 1 and in the blood on day 3 following LPS injection, and in the blood, head kidney, and liver following RBIV vaccination. Post-RBIV infection, the vaccinated group showed a significantly higher TNFN gene expression in the head kidney and blood than the unvaccinated group. Treatment with recombinant TNFN protein (RB-rTNFN) resulted in significantly upregulated interleukin-1ß expression in the head kidney, spleen, blood, liver, and peritoneal cells. It also enhanced IL-8 gene expression in the head kidney, blood, and peritoneal cells, and interferon γ gene expression in the gut and gills on day 1. TNFN and cyclo-oxygenase-2 gene expression was upregulated in peritoneal cells on day 3. Flow cytometry analysis revealed a significant increase in the peritoneal lymphocyte population after the intraperitoneal (i.p.) injection of RB-rTNFN. These results suggest that RB-TNFN mediated innate and adaptive immunity in rock bream.

Detection of SARS-CoV-2 Virus Amplification Using a Crumpled Graphene Field-Effect Transistor Biosensor.

The rapid and unexpected spread of SARS-CoV-2 worldwide has caused unprecedented disruption to daily life and has brought forward critical challenges for public health. The disease was the largest cause of death in the United States in early 2021. Likewise, the COVID-19 pandemic has highlighted the need for rapid and accurate diagnoses at scales larger than ever before. To improve the availability of current gold standard diagnostic testing methods, the development of point-of-care devices that can maintain gold standard sensitivity while reducing the cost and providing portability is much needed. In this work, we combine the amplification capabilities of reverse transcriptase loop-mediated isothermal amplification (RT-LAMP) techniques with high-sensitivity end-point detection of crumpled graphene field-effect transistors (cgFETs) to develop a portable detection cell. This electrical detection method takes advantage of the ability of graphene to adsorb single-stranded DNA due to noncovalent π-π bonds but not double-stranded DNA. These devices have demonstrated the ability to detect the presence of the SARS-CoV-2 virus in a range from 10 to 104 copies/µL in 20 viral transport medium (VTM) clinical samples. As a result, we achieved 100% PPV, NPV, sensitivity, and specificity with 10 positive and 10 negative VTM clinical samples. Further, the cgFET devices can differentiate between positive and negative VTM clinical samples in 35 min based on the Dirac point shift. Likewise, the improved sensing capabilities of the crumpled gFET were compared with those of the traditional flat gFET devices.

Transcriptome Analysis in the Head Kidney of Rainbow Trout (Oncorhynchus mykiss) Immunized with a Combined Vaccine of Formalin-Inactivated Aeromonas salmonicida and Vibrio anguillarum.

This study aimed to identify the molecular mechanisms regulated by a combined vaccine against Aeromonas salmonicida and Vibrio anguillarum (O1 serotype). These bacteria cause furunculosis and vibriosis, respectively, and are associated with a high mortality in rainbow trout in Korea. The vaccine upregulated gene expression of TCRα, T-bet, sIgM, and mIgM, markers of an activated adaptive immune response. On days 1, 3, and 5, transcriptome analysis revealed 862 (430 up- and 432 downregulated), 492 (204 up- and 288 downregulated), and 741 (270 up- and 471 downregulated) differentially expressed genes (DEGs), respectively. Gene ontology (GO) enrichment analysis identified 377 (108 MF, 132 CC, 137 BP), 302 (60 MF, 180 CC, 62 BP), and 314 (115 MF, 129 CC, 70 BP) GOs at days 1, 3, and 5, respectively. Kyoto Encyclopedia of Genetic and Genomic enrichment analysis identified eight immune system-related pathways like cytokine-cytokine receptor interaction, NF-kappaB signaling pathway, TNF signaling pathway, NOD-like receptor signaling pathway, cytosolic DNA sensing pathway, cell adhesion molecule, complement and coagulation cascade, and antigen processing and presentation. In the analysis of the protein-protein interaction of immune-related DEGs, a total of 59, 21, and 21 interactional relationships were identified at days 1, 3, and 5, respectively, with TNF having the highest centrality at all three time points.

Van der Waals Heterostructure of Hexagonal Boron Nitride with an AlGaN/GaN Epitaxial Wafer for High-Performance Radio Frequency Applications.

While two-dimensional (2D) hexagonal boron nitride (h-BN) is emerging as an atomically thin and dangling bond-free insulating layer for next-generation electronics and optoelectronics, its practical implementation into miniaturized integrated circuits has been significantly limited due to difficulties in large-scale growth directly on epitaxial semiconductor wafers. Herein, the realization of a wafer-scale h-BN van der Waals heterostructure with a 2 in. AlGaN/GaN high-electron mobility transistor (HEMT) wafer using metal-organic chemical vapor deposition is presented. The combination of state-of-the-art microscopic and spectroscopic analyses and theoretical calculations reveals that the heterointerface between ∼2.5 nm-thick h-BN and AlGaN layers is atomically sharp and exhibits a very weak van der Waals interaction without formation of a ternary or quaternary alloy that can induce undesired degradation of device performance. The fabricated AlGaN/GaN HEMT with h-BN shows very promising performance including a cutoff frequency (fT) and maximum oscillation frequency (fMAX) as high as 28 and 88 GHz, respectively, enabled by an effective passivation of surface defects on the HEMT wafer to deliver accurate information with minimized power loss. These findings pave the way for practical implementation of 2D materials integrated with conventional microelectronic devices and the realization of future all-2D electronics.

Establishing and Validating Cellular Functional Target Engagement Assay for Selective IRAK4 Inhibitor Discovery.

One of the main reasons for the lack of drug efficacy in late-stage clinical trials is the lack of specific and selective target engagement. To increase the likelihood of success of new therapeutics, one approach is to conduct proximal target engagement testing during the early phases of preclinical drug discovery. To identify and optimize selective IRAK4 inhibitors, a kinase that has been implicated in multiple inflammatory and autoimmune diseases, we established an electrochemiluminescence (ECL)-based cellular endogenous IRAK1 activation assay as the most proximal functional evaluation of IRAK4 engagement to support structure-activity relationship (SAR) studies. Since IRAK1 activation is dependent on both the IRAK4 scaffolding function in Myddosome formation and IRAK4 kinase activity for signal transduction, this assay potentially captures inhibitors with different mechanisms of action. Data from this IRAK1 assay with compounds representing different structural classes showed statistically significant correlations when compared with results from both IRAK4 biochemical kinase activity and functional peripheral blood mononuclear cell (PBMC)-derived tumor necrosis factor α (TNFα) secretion assays, validating the biological relevancy of the IRAK1 target engagement as a biomarker of the IRAK4 activity. Plate uniformity and potency reproducibility evaluations demonstrated that this assay is amenable to high throughput. Using Bland-Altman assay agreement analysis, we demonstrated that incorporating such proximal pharmacological assessment of cellular target engagement to an in vitro screening funnel for SAR studies can prevent compound optimization toward off-target activity.

Au/Pt-Egg-in-Nest Nanomotor for Glucose-Powered Catalytic Motion and Enhanced Molecular Transport to Living Cells.

Nanostructures converting chemical energy to mechanical work by using benign metabolic fuels, have huge implications in biomedical science. Here, we introduce Au/Pt-based Janus nanostructures, resembling to "egg-in-nest" morphology (Au/Pt-ENs), showing enhanced motion as a result of dual enzyme-relay-like catalytic cascade in physiological biomedia, and in turn showing molecular-laden transport to living cells. We developed dynamic-casting approach using silica yolk-shell nanoreactors: first, to install a large Au-seed fixing the silica-yolk aside while providing the anisotropically confined concave hollow nanospace to grow curved Pt-dendritic networks. Owing to the intimately interfaced Au and Pt catalytic sites integrated in a unique anisotropic nest-like morphology, Au/Pt-ENs exhibited high diffusion rates and displacements as the result of glucose-converted oxygen concentration gradient. High diffusiophoresis in cell culture media increased the nanomotor-membrane interaction events, in turn facilitated the cell internalization. In addition, the porous network of Au/Pt-ENs facilitated the drug-molecule cargo loading and delivery to the living cells.

Silica Jar-with-Lid as Chemo-Enzymatic Nano-Compartment for Enantioselective Synthesis inside Living Cells.

Nanodevices, harvesting the power of synthetic catalysts and enzymes to perform enantioselective synthesis inside cell, have never been reported. Here, we synthesized round bottom jar-like silica nanostructures (SiJARs) with a chemo-responsive metal-silicate lid. This was isolated as an intermediate structure during highly controlled solid-state nanocrystal-conversion at the arc-section of silica shell. Different catalytic noble metals (Pt, Pd, Ru) were selectively modified on the lid-section through galvanic reactions. And, lid aperture-opening was regulated by mild acidic conditions or intracellular environment which accommodated the metal nanocrystals and enzymes, and in turn created an open-mouth nanoreactor. Distinct from the free enzymes, SiJARs performed asymmetric aldol reactions with high activity and enantioselectivity (yield >99 %, ee=95 %) and also functioned as the artificial catalytic organelles inside living cells. This work bridges the enormous potential of sophisticated nanocrystal-conversion chemistry and advanced platforms for new-to-nature catalysis.

COVID-19 Point-of-Care Diagnostics: Present and Future.

Point-of-care (POC) detection technologies that enable decentralized, rapid, sensitive, low-cost diagnostics of COVID-19 infection are urgently needed around the world. With many technologies approved for commercialization in the past 10 months, the field of COVID-19 POC diagnostics is rapidly evolving. In this Perspective, we analyze the current state of POC technologies for the diagnosis and monitoring of COVID-19 infection and discuss future challenges in COVID-19 diagnostics. As the COVID-19 pandemic becomes endemic, the advances gained during this past year will likely also be utilized for future prediction of emerging outbreaks and pandemics.

Reverse Transcription Loop-Mediated Isothermal Amplification Assay for Ultrasensitive Detection of SARS-CoV-2 in Saliva and Viral Transport Medium Clinical Samples.

The COVID-19 pandemic has underscored the shortcomings in the deployment of state-of-the-art diagnostics platforms. Although several polymerase chain reaction (PCR)-based techniques have been rapidly developed to meet the growing testing needs, such techniques often need samples collected through a swab, the use of RNA extraction kits, and expensive thermocyclers in order to successfully perform the test. Isothermal amplification-based approaches have also been recently demonstrated for rapid severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection by minimizing sample preparation while also reducing the instrumentation and reaction complexity. In addition, there are limited reports of saliva as the sample source, and some of these indicate inferior sensitivity when comparing reverse transcription loop-mediated isothermal amplification (RT-LAMP) with PCR-based techniques. In this paper, we demonstrate an improved sensitivity assay from saliva using a two-step RT-LAMP assay, where a short 10 min RT step is performed with only B3 and backward inner primers before the final reaction. We show that while the one-step RT-LAMP demonstrates satisfactory results, the optimized two-step approach allows detection of only few molecules per reaction and performs significantly better than the one-step RT-LAMP and conventional two-step RT-LAMP approaches with all primers included in the RT step. We show control measurements with RT-PCR, and importantly, we demonstrate RNA extraction-free RT-LAMP-based assays for detection of SARS-CoV-2 from viral transport media and saliva clinical samples.

Discovery of Diaminopyrimidine Carboxamide HPK1 Inhibitors as Preclinical Immunotherapy Tool Compounds.

Hematopoietic progenitor kinase 1 (HPK1), a serine/threonine kinase, is a negative immune regulator of T cell receptor (TCR) and B cell signaling that is primarily expressed in hematopoietic cells. Accordingly, it has been reported that HPK1 loss-of-function in HPK1 kinase-dead syngeneic mouse models shows enhanced T cell signaling and cytokine production as well as tumor growth inhibition in vivo, supporting its value as an immunotherapeutic target. Herein, we present the structurally enabled discovery of novel, potent, and selective diaminopyrimidine carboxamide HPK1 inhibitors. The key discovery of a carboxamide moiety was essential for enhanced enzyme inhibitory potency and kinome selectivity as well as sustained elevation of cellular IL-2 production across a titration range in human peripheral blood mononuclear cells. The elucidation of structure-activity relationships using various pendant amino ring systems allowed for the identification of several small molecule type-I inhibitors with promising in vitro profiles.