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result(s) for
"Pinsky, Benjamin A."
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Electric field-driven microfluidics for rapid CRISPR-based diagnostics and its application to detection of SARS-CoV-2
2020
The rapid spread of COVID-19 across the world has revealed major gaps in our ability to respond to new virulent pathogens. Rapid, accurate, and easily configurable molecular diagnostic tests are imperative to prevent global spread of new diseases. CRISPR-based diagnostic approaches are proving to be useful as field-deployable solutions. In one basic form of this assay, the CRISPR–Cas12 enzyme complexes with a synthetic guide RNA (gRNA). This complex becomes activated only when it specifically binds to target DNA and cleaves it. The activated complex thereafter nonspecifically cleaves single-stranded DNA reporter probes labeled with a fluorophore−quencher pair.We discovered that electric field gradients can be used to control and accelerate this CRISPR assay by cofocusing Cas12–gRNA, reporters, and target within a microfluidic chip. We achieve an appropriate electric field gradient using a selective ionic focusing technique known as isotachophoresis (ITP) implemented on a microfluidic chip. Unlike previous CRISPR diagnostic assays, we also use ITP for automated purification of target RNA from raw nasopharyngeal swab samples. We here combine this ITP purification with loop-mediated isothermal amplification and the ITP-enhanced CRISPR assay to achieve detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA (from raw sample to result) in about 35 min for both contrived and clinical nasopharyngeal swab samples. This electric field control enables an alternate modality for a suite of microfluidic CRISPR-based diagnostic assays.
Journal Article
Neutralization against BA.2.75.2, BQ.1.1, and XBB from mRNA Bivalent Booster
by
Porter-Morrison, Andrea
,
Douek, Daniel C.
,
Davis-Gardner, Meredith E.
in
Antibodies
,
Coronavirus
,
Coronaviruses
2023
One or two monovalent vaccine boosters showed a large decrease in neutralization activity against omicron subvariants. The BA.5-containing bivalent booster improved neutralizing activity against all omicron subvariants.
Journal Article
Report from the American Society for Microbiology COVID-19 International Summit, 23 March 2020: Value of Diagnostic Testing for SARS–CoV-2/COVID-19
by
Storch, Gregory A.
,
Bertuzzi, Stefano
,
Theel, Elitza S.
in
Antibodies, Viral - blood
,
Asymptomatic
,
Betacoronavirus - genetics
2020
[...]what to do with test results? Since SARS–CoV-2 is a new virus, there is little evidence to fall back on for test utilization and diagnostic stewardship (1). [...]the true clinical sensitivity of any of these tests is unknown (and is certainly not 100%, as in the hypothetical scenario); a negative test does not therefore negate the possibility that an individual is infected. Testing patients for SARS–CoV-2 helps identify those who are infected, which is useful for individual patient management, as well as for implementation of mitigation strategies to prevent spread in health care facilities and in the community alike (Fig. 1). Alternative strategies for specimen collection, including home collection, should therefore be considered either by a health care provider or patients themselves (or a parent in the case of young children); the use of alternative specimen types, such as oral fluid or nasal swabs (if they are shown to provide results equivalent to those from nasopharyngeal swabs) should also be considered. Spread to health care workers and within health care and long-term-care facilities is a primary consideration for prioritization of testing; testing of patients likely to have SARS–CoV-2 who are in health care facilities or long-term-care facilities, alongside potentially ill workers critical to the pandemic response, including health care workers, public health officials, and other essential leaders, is a priority.
Journal Article
Infection and Vaccine-Induced Neutralizing-Antibody Responses to the SARS-CoV-2 B.1.617 Variants
by
Douek, Daniel C
,
Sibai, Mamdouh
,
Davis-Gardner, Meredith E
in
Antibodies
,
Coronavirus
,
Coronaviruses
2021
Among samples obtained from persons who had received the mRNA-1273 or BNT162b2 vaccines, neutralizing antibody titers against the B.1.617.1 variant were 6.8 times lower than those against the WA1/2020 variant, and titers against the B.1.617.2 variant were 2.9 times lower than those against WA1/2020.
Journal Article
Triplex Real-Time RT-PCR for Severe Acute Respiratory Syndrome Coronavirus 2
by
Stittleburg, Victoria
,
Saklawi, Youssef
,
Waggoner, Jesse J.
in
Betacoronavirus - genetics
,
Betacoronavirus - isolation & purification
,
Coronaviruses
2020
Most reverse transcription PCR protocols for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) include 2-3 targets for detection. We developed a triplex, real-time reverse transcription PCR for SARS-CoV-2 that maintained clinical performance compared with singleplex assays. This protocol could streamline detection and decrease reagent use during current high SARS-CoV-2 testing demands.
Journal Article
Rapid genetic screening with high quality factor metasurfaces
2023
Genetic analysis methods are foundational to advancing personalized medicine, accelerating disease diagnostics, and monitoring the health of organisms and ecosystems. Current nucleic acid technologies such as polymerase chain reaction (PCR) and next-generation sequencing (NGS) rely on sample amplification and can suffer from inhibition. Here, we introduce a label-free genetic screening platform based on high quality (high-
Q
) factor silicon nanoantennas functionalized with nucleic acid fragments. Each high-
Q
nanoantenna exhibits average resonant quality factors of 2,200 in physiological buffer. We quantitatively detect two gene fragments, SARS-CoV-2 envelope (E) and open reading frame 1b (ORF1b), with high-specificity via DNA hybridization. We also demonstrate femtomolar sensitivity in buffer and nanomolar sensitivity in spiked nasopharyngeal eluates within 5 minutes. Nanoantennas are patterned at densities of 160,000 devices per cm
2
, enabling future work on highly-multiplexed detection. Combined with advances in complex sample processing, our work provides a foundation for rapid, compact, and amplification-free molecular assays.
The authors present a high quality factor metasurface that enables sensitive and highly-parallelized detection of biomolecules. Amplification-free detection of gene fragments down to femtomolar levels is demonstrated within 5 minutes, for rapid nucleic acid analysis.
Journal Article
Human Monkeypox without Viral Prodrome or Sexual Exposure, California, USA, 2022
by
Huang, ChunHong
,
Salinas, Jorge L.
,
Srinivasan, Krithika
in
California
,
Case studies
,
Diagnosis
2022
We report human monkeypox in a man who returned to the United States from the United Kingdom and reported no sexual contact. He had vesicular and pustular skin lesions but no anogenital involvement. The potential modes of transmission may have implications for the risk of spread and for epidemic control.
Journal Article
An intranasal ASO therapeutic targeting SARS-CoV-2
2022
The COVID-19 pandemic is exacting an increasing toll worldwide, with new SARS-CoV-2 variants emerging that exhibit higher infectivity rates and that may partially evade vaccine and antibody immunity. Rapid deployment of non-invasive therapeutic avenues capable of preventing infection by all SARS-CoV-2 variants could complement current vaccination efforts and help turn the tide on the COVID-19 pandemic. Here, we describe a novel therapeutic strategy targeting the SARS-CoV-2 RNA using locked nucleic acid antisense oligonucleotides (LNA ASOs). We identify an LNA ASO binding to the 5′ leader sequence of SARS-CoV-2 that disrupts a highly conserved stem-loop structure with nanomolar efficacy in preventing viral replication in human cells. Daily intranasal administration of this LNA ASO in the COVID-19 mouse model potently suppresses viral replication (>80-fold) in the lungs of infected mice. We find that the LNA ASO is efficacious in countering all SARS-CoV-2 “variants of concern” tested both in vitro and in vivo. Hence, inhaled LNA ASOs targeting SARS-CoV-2 represents a promising therapeutic approach to reduce or prevent transmission and decrease severity of COVID-19 in infected individuals. LNA ASOs are chemically stable and can be flexibly modified to target different viral RNA sequences and could be stockpiled for future coronavirus pandemics.
Despite approved vaccines and anti-virals to prevent and treat SARS-CoV-2 infection, there is a need for further development of efficient antiviral therapeutic strategy. Here, Zhu et al. develop locked nucleic acid antisense oligonucleotides (LNA ASOs) targeting the 5’ leader sequence of SARS-CoV-2 RNA to interfere with replication of wildtype virus and variants of concern. Daily intranasal administration in K18-hACE2 humanized mice suppresses viral infection in lung.
Journal Article
Strand-Specific Reverse Transcription PCR for Detection of Replicating SARS-CoV-2
by
Huang, ChunHong
,
Sibai, Mamdouh
,
Jiang, Becky
in
Adult
,
Clinical Decision-Making
,
Coronaviruses
2021
We developed an assay that detects minus-strand RNA as a surrogate for actively replicating severe acute respiratory syndrome coronavirus 2. We detected minus-strand RNA in 41 persons with coronavirus disease up to 30 days after symptom onset. This assay might inform clinical decision-making about patient infectiousness.
Journal Article
Standardized preservation, extraction and quantification techniques for detection of fecal SARS-CoV-2 RNA
2021
Patients with COVID-19 shed SARS-CoV-2 RNA in stool, sometimes well after their respiratory infection has cleared. This may be significant for patient health, epidemiology, and diagnosis. However, methods to preserve stool, and to extract and quantify viral RNA are not standardized. We test the performance of three preservative approaches at yielding detectable SARS-CoV-2 RNA: the OMNIgene-GUT kit, Zymo DNA/RNA shield kit, and the most commonly applied, storage without preservative. We test these in combination with three extraction kits: QIAamp Viral RNA Mini Kit, Zymo Quick-RNA Viral Kit, and MagMAX Viral/Pathogen Kit. We also test the utility of ddPCR and RT-qPCR for the reliable quantification of SARS-CoV-2 RNA from stool. We identify that the Zymo DNA/RNA preservative and the QiaAMP extraction kit yield more detectable RNA than the others, using both ddPCR and RT-qPCR. Taken together, we recommend a comprehensive methodology for preservation, extraction and detection of RNA from SARS-CoV-2 and other coronaviruses in stool.
While the analysis of SARS-CoV-2 RNA in stool samples has led to important insights regarding the disease, quantification is currently challenging. Here the authors use patient samples to benchmark preservation, extraction and quantification methods to optimise detection of viral RNA.
Journal Article