Liquid Crystal Ordering and Isotropic Gelation in Solutions of Four-Base-Long DNA Oligomers

Liquid crystal ordering is reported in aqueous solutions of the oligomer 5′-ATTAp-3′ and of the oligomer 5′-GCCGp-3′. In both systems, we quantitatively interpret ordering as stemming from the chaining of molecules <i>via</i> a “running-bond” type of pairing, a self-assembly process distinct from the duplex aggregation previously reported for longer oligonucleotides. While concentrated solutions of 5′-ATTAp-3′ show only a columnar liquid crystal phase, solutions of 5′-GCCGp-3′ display a rich phase diagram, featuring a chiral nematic phase analogous to those observed in solutions of longer oligonucleotides and two unconventional phases, a columnar crystal and, at high concentration, an isotropic amorphous gel. The appearance of these phases, which can be interpreted on the basis of features of 5′-GCCGp-3′molecular structure, suggests distinctive assembly motifs specific to ultrashort oligonucleotides

DataSheet_1_Serum antibody fingerprinting of SARS-CoV-2 variants in infected and vaccinated subjects by label-free microarray biosensor.pdf

Both viral infection and vaccination affect the antibody repertoire of a person. Here, we demonstrate that the analysis of serum antibodies generates information not only on the virus type that caused the infection but also on the specific virus variant. We developed a rapid multiplex assay providing a fingerprint of serum antibodies against five different SARS-CoV-2 variants based on a microarray of virus antigens immobilized on the surface of a label-free reflectometric biosensor. We analyzed serum from the plasma of convalescent subjects and vaccinated volunteers and extracted individual antibody profiles of both total immunoglobulin Ig and IgA fractions. We found that Ig level profiles were strongly correlated with the specific variant of infection or vaccination and that vaccinated subjects displayed a larger quantity of total Ig and a lower fraction of IgA relative to the population of convalescent unvaccinated subjects.</p