Numerous safe and effective COVID-19 vaccines have been developed worldwide that utilize various delivery technologies and engineering strategies. We show here that vaccines containing prefusion-stabilizing S mutations elicit antibody responses in humans with enhanced recognition of S and the S 1 subunit relative to postfusion S, as compared to vaccines lacking these mutations or natural infection. Prefusion S and S 1 antibody binding titers positively and equivalently correlated with neutralizing activity and depletion of S 1 -directed antibodies completely abrogated plasma neutralizing activity. We show that neutralizing activity is almost entirely directed to the S 1 subunit and that variant cross-neutralization is mediated solely by RBD-specific antibodies. Our data provide a quantitative framework for guiding future S engineering efforts to develop vaccines with higher resilience to the emergence of variants than current technologies.

To address the ongoing SARS-CoV-2 pandemic and prepare for future coronavirus outbreaks, understanding the protective potential of epitopes conserved across SARS-CoV-2 variants and coronavirus lineages is essential. We describe a highly conserved, conformational S2 domain epitope present only in the prefusion core of β-coronaviruses: SARS-CoV-2 S2 apex residues 980–1006 in the flexible hinge. Antibody RAY53 binds the native hinge in MERS-CoV and SARS-CoV-2 spikes on the surface of mammalian cells and mediates antibody-dependent cellular phagocytosis and cytotoxicity against SARS-CoV-2 spike in vitro. Hinge epitope mutations that ablate antibody binding compromise pseudovirus infectivity, but changes elsewhere that affect spike opening dynamics, including those found in Omicron BA.1, occlude the epitope and may evade pre-existing serum antibodies targeting the S2 core. This work defines a third class of S2 antibody while providing insights into the potency and limitations of S2 core epitope targeting.

Conductive graphene‐based inks can be tailored for functional applications and, in particular, for printed electronics. Transparent, flexible, and easy printable materials are nowadays increasingly required for sensing applications. In this context, a capacitive multitouch sensing surface is developed using conductive graphene nanoparticles‐based ink with carboxymethyl cellulose as a binder. The rheological properties of the ink are tailored to be printed by the screen‐printing technique. The touchscreen is based on printed conductive lines and columns and thus the characteristics of the printed lines are optimized based on the line width and number of printing steps. The optimal printed conditions are 0.5 mm of width and five printing steps, leading to electrical resistance of 2.4 kΩ. The screen‐printed flexible touchscreen is composed of 40 columns × 28 rows. An electric circuit and a graphic interface are also developed leading to an 8” touchscreen with multitouch capabilities and fast signal processing.

No abstract

No abstract