Portable RT-PCR and MinION Nanopore Sequencing as a Proof-of-Concept SARS-CoV-2 Biosurveillance in Wastewater.

In this study, wastewater samples collected from a participating sentinel site were initially screened for the presence or absence of SARS-CoV-2 RNA using portable RT-PCR, with positive samples sequenced using a handheld MinION nanopore sequencing device. Genomic biosurveillance of SARS-CoV-2 and its variants within wastewater has been established as an early warning system of infectious disease spread in a given catchment area, due to good correlation between spikes in viral levels detected in wastewater coincident with increases in COVID-19 incidence rates. Moreover, viral titers detected in a single wastewater sample are reflective of pre-symptomatic, asymptomatic, and post-symptomatic cases, making wastewater-based epidemiology (WBE) a cost-effective, non-invasive public health surveillance method complementary to clinical diagnostic testing. The results of this study demonstrate the utility of population-scale SARS-CoV-2 epidemiology for insights into the viral evolution and transmission dynamics associated with specific SARS-CoV-2 variants that are necessary for effective strategies of containment and timely deployment of appropriate countermeasures.

In Operando Observation of Neuropeptide Capture and Release on Graphene Field-Effect Transistor Biosensors with Picomolar Sensitivity.

Transmission electron microscopy (TEM) is being pushed to new capabilities which enable studies on systems that were previously out of reach. Among recent innovations, TEM through liquid cells (LC-TEM) enables in operando observation of biological phenomena. This work applies LC-TEM to the study of biological components as they interact on an abiotic surface. Specifically, analytes or target molecules like neuropeptide Y (NPY) are observed in operando on functional graphene field-effect transistor (GFET) biosensors. Biological recognition elements (BREs) identified using biopanning with affinity to NPY are used to functionalize graphene to obtain selectivity. On working devices capable of achieving picomolar responsivity to neuropeptide Y, LC-TEM reveals translational motion, stochastic positional fluctuations due to constrained Brownian motion, and rotational dynamics of captured analyte. Coupling these observations with the electrical responses of the GFET biosensors in response to analyte capture and/or release will potentially enable new insights leading to more advanced and capable biosensor designs.