Mathematical analysis of synthesis chemical reactions for virus building block polymers in vivo.

For numerous viruses, their capsid assembly is composed of two steps. The first step is that virus structural protein monomers are polymerized to building blocks. Then, these building blocks are cumulative and efficiently assembled to virus capsid shell. These building block polymerization reactions in the first step are fundamental for virus assembly, and some drug targets were found in this step. In this work, we focused on the first step. Often, virus building blocks consisted of less than six monomers. That is, dimer, trimer, tetramer, pentamer, and hexamer. We presented mathematical models for polymerization chemical reactions of these five building blocks, respectively. Then, we proved the existence and uniqueness of the positive equilibrium solution for these mathematical models one by one. Subsequently, we also analyzed the stability of the equilibrium states, respectively. These results may provide further insight into property of virus building block polymerization chemical reactions in vivo.

Modelling the effects of charge on antibiotic diffusion and adsorption in liquid crystalline virus suspensions.

We develop a microscopic model of antibiotic diffusion in virus suspensions in a liquid crystalline state. We then approximate this with an effective homogenised model that is more amenable to analytical investigation, to understand the effect of charge on the antibiotic tolerance. We show that liquid crystalline virus suspensions slow down antibiotics significantly, and that electric charge strongly contributes to this by influencing the effective diameter and adsorptive capacity of the liquid crystalline viruses so that charged antibiotics diffuse much slower than neutral ones; this can be directly and efficiently derived from the homogenised model and is in good agreement with experiments in microbiology. Charge is also found to affect the relationship between antibiotic diffusion and viral packing density in a nontrivial way. The results elucidate the effect of charge on antibiotic tolerance in liquid crystalline biofilms in a manner that is straightforwardly extendable to other soft matter systems.

Rational Design of 3D Polymer Corona Interfaces of Single-Walled Carbon Nanotubes for Receptor-Free Virus Recognition.

Facing the escalating threat of viruses worldwide, the development of efficient sensor elements for rapid virus detection has never been more critical. Traditional point-of-care (POC) sensors struggle due to their reliance on fragile biological receptors and limited adaptability to viral strains. In this study, we introduce a nanosensor design for receptor-free virus recognitions using near-infrared (NIR) fluorescent single-walled carbon nanotubes (SWCNTs) functionalized with a poly(ethylene glycol) (PEG)-phospholipid (PEG-lipid) array. Three-dimensional (3D) corona interfaces of the nanosensor array enable selective and sensitive detection of diverse viruses, including Ebola, Lassa, H3N2, H1N1, Middle East respiratory syndrome (MERS), severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1), and SARS-CoV-2, even without any biological receptors. The PEG-lipid components, designed considering chain length, fatty acid saturation, molecular weight, and end-group moieties, allow for precise quantification of viral recognition abilities. High-throughput automated screening of the array demonstrates how the physicochemical properties of the PEG-lipid/SWCNT 3D corona interfaces correlate with viral detection efficiency. Utilizing molecular dynamics and AutoDock simulations, we investigated the impact of PEG-lipid components on 3D corona interface formation, such as surface coverage and hydrodynamic radius and specific molecular interactions based on chemical potentials. Our findings not only enhance detection specificity across various antigens but also accelerate the development of sensor materials for promptly identifying and responding to emerging antigen threats.

Dynamics, allostery, and stabilities of whole virus particles by amide hydrogen/deuterium exchange mass spectrometry (HDXMS).

X-ray crystallography and cryo-electron microscopy have enabled the determination of structures of numerous viruses at high resolution and have greatly advanced the field of structural virology. These structures represent only a subset of snapshot end-state conformations, without describing all conformational transitions that virus particles undergo. Allostery plays a critical role in relaying the effects of varied perturbations both on the surface through environmental changes and protein (receptor/antibody) interactions into the genomic core of the virus. Correspondingly, allostery carries implications for communicating changes in genome packaging to the overall stability of the virus particle. Amide hydrogen/deuterium exchange mass spectrometry (HDXMS) of whole viruses is a powerful probe for uncovering virus allostery. Here we critically discuss advancements in understanding virus dynamics by HDXMS with single particle cryo-EM and computational approaches.

Leveraging bioanalytical characterization of fractionated monoclonal antibody pools to identify aggregation-prone and less filterable proteoforms during virus filtration.

Monoclonal antibodies (mAbs) are an essential class of biotherapeutics. A platform process is used for mAb development to ensure clinically safe and stable molecules. Regulatory authorities ensure that mAb production processes include sufficient viral clearance steps to achieve less than one virus particle per million doses of product. Virus filtration is used for size-based removal of enveloped and nonenveloped viruses during downstream processing of mAbs. Process development in mAb purification relies on empirical approaches and often includes adsorptive prefiltration to mitigate virus filter fouling. Opportunities for molecular-level prediction of mAb filterability are needed to plug the existing knowledge gap in downstream processing. A molecular-level approach to understanding the factors influencing mAb filterability may reduce process development time, material loss, and processing costs due to oversized virus filters. In this work, pH step gradient fractionation was applied on polished bulk mAb feed to obtain concentrated pools of fractionated mAb variants. Biophysical properties and quality attributes of fractionated pools, including oligomeric state (size), isoelectric point profile, diffusion interaction parameters, and glycoform profile, were determined using bioanalytical methods. Filterability (loading and throughput) of fractionated pools were evaluated. Statistical methods were used to obtain correlations between quality attributes of mAb fractions and filterability on the Viresolve Pro virus filter.