SARS-CoV-2 detection by a clinical diagnostic RT-LAMP assay [version 1; peer review: 1 approved with reservations]

The ongoing pandemic of SARS-CoV-2 calls for rapid and cost-effective methods to accurately identify infected individuals. The vast majority of patient samples is assessed for viral RNA presence by RT-qPCR. Our biomedical research institute, in collaboration between partner hospitals and an accredited clinical diagnostic laboratory, established a diagnostic testing pipeline that has reported on more than 252,000 RT-qPCR results since its commencement at the beginning of April 2020. However, due to ongoing demand and competition for critical resources, alternative testing strategies were sought. In this work, we present a clinically-validated procedure for high-throughput SARSCoV-2 detection by RT-LAMP in 25 minutes that is robust, reliable, repeatable, sensitive, specific, and inexpensive

Lateral Dynamics of Surfactants at the Free Water Surface: A Computer Simulation Study

International audienc

Influence of Surface Concentration on Poly(vinyl alcohol) Behavior at the Water–Vacuum Interface: A Molecular Dynamics Simulation Study

Poly(vinyl alcohol) (PVA) is an amphiphilic macromolecule with surfactant activity. The peculiar behavior of this polymer at the water–air interface is at the basis of its use as material for hydrated microdevices, films, and nanofibers. This work aims to investigate the behavior of PVA and water within the surface domain of highly diluted aqueous solutions by means of atomistic molecular dynamics simulations. Monodisperse atactic oligomers of 30 residues were distributed within water slabs in a vacuum box and allowed to diffuse toward the surface. After equilibration, structural features and dynamical properties of polymer chains and water in the interfacial domains were analyzed as a function of PVA surface concentration at 293 K. Surface pressure values obtained from simulations are in agreement with experimental values at corresponding polymer specific surface areas. In the explored concentration range of 6–34 μmol of residues/m2, the chains display a transition between two states. At lower surface concentrations, elongated, quite rigid structures are adsorbed on the surface, whereas partially submerged globular aggregates, locally covered by thin water layers, are formed at higher surface concentrations. At PVA concentrations higher than about 20 μmol of residues/m2, the percolation of chain aggregates over the interface plane produces a surface-confined polymer network with stable pores filled by water molecules. A substantial slowing of polymer and water dynamics in the interfacial domains is highlighted by the mean squared displacement time behavior of terminal residues and the interaction time of PVA–water hydrogen bonding. The diffusion coefficient of water and lifetime of hydrogen bonds between solvent molecules are halved and doubled, respectively, at the interface with the highest polymer concentration. The attenuation of water and polymer mobility concur to stabilize PVA hydrated networks in contact with air