Osteogenic Potential and Long-Term Enzymatic Biodegradation of PHB-based Scaffolds with Composite Magnetic Nanofillers in a Magnetic Field.

Millions of people worldwide suffer from musculoskeletal damage, thus using the largest proportion of rehabilitation services. The limited self-regenerative capacity of bone and cartilage tissues necessitates the development of functional biomaterials. Magnetoactive materials are a promising solution due to clinical safety and deep tissue penetration of magnetic fields (MFs) without attenuation and tissue heating.

DNA polymerase ε and δ variants drive mutagenesis in polypurine tracts in human tumors.

Alterations in the exonuclease domain of DNA polymerase ε cause ultramutated cancers. These cancers accumulate AGA>ATA transversions; however, their genomic features beyond the trinucleotide motifs are obscure. We analyze the extended DNA context of ultramutation using whole-exome sequencing data from 524 endometrial and 395 colorectal tumors.

Adhesion of and to Films and Electrospun Fibrous Scaffolds from Composites of Poly(3-hydroxybutyrate) with Magnetic Nanoparticles in a Low-Frequency Magnetic Field.

The ability of materials to adhere bacteria on their surface is one of the most important aspects of their development and application in bioengineering. In this work, the effect of the properties of films and electrospun scaffolds made of composite materials based on biosynthetic poly(3-hydroxybutyrate) (PHB) with the addition of magnetite nanoparticles (MNP) and their complex with graphene oxide (MNP/GO) on the adhesion of and under the influence of a low-frequency magnetic field and without it was investigated. The physicochemical properties (crystallinity; surface hydrophilicity) of the materials were investigated by X-ray structural analysis, differential scanning calorimetry and "drop deposition" methods, and their surface topography was studied by scanning electron and atomic force microscopy.

AFM-TEM correlation microscopy and its application to lipid nanoparticles.

So far, only a few articles have demonstrated the possibility of correlated AFM-TEM imaging - sequential imaging of the same individual objects using atomic-force microscopy (AFM) and transmission electron microscopy (TEM). The current work contributes to the development of this approach by giving a step-by-step procedure, which yields pairs of correlated AFM-TEM images. We describe the application of correlation AFM-TEM microscopy to lipid nanoparticles (small extracellular vesicles and liposomes).

Poly(3-hydroxybutyrate) 3D-Scaffold-Conduit for Guided Tissue Sprouting.

Scaffold biocompatibility remains an urgent problem in tissue engineering. An especially interesting problem is guided cell intergrowth and tissue sprouting using a porous scaffold with a special design. Two types of structures were obtained from poly(3-hydroxybutyrate) (PHB) using a salt leaching technique.

Size Distribution of Inactivated Tick-Borne Encephalitis Virus Particles Revealed by a Comprehensive Physicochemical Approach.

Tick-borne encephalitis virus (TBEV) is an enveloped RNA virus, a member of the genus (family ). Here, we provide a detailed analysis of the size and structure of the inactivated TBEV vaccine strain Sofjin-Chumakov. Four analytical methods were used to analyze individual TBEV particles-negative staining TEM, cryo-EM, atomic force microscopy (AFM), and nanoparticle tracking analysis (NTA).

Electrospun Magnetic Composite Poly-3-hydroxybutyrate/Magnetite Scaffolds for Biomedical Applications: Composition, Structure, Magnetic Properties, and Biological Performance.

Magnetically responsive composite polymer scaffolds have good potential for a variety of biomedical applications. In this work, electrospun composite scaffolds made of polyhydroxybutyrate (PHB) and magnetite (FeO) particles (MPs) were studied before and after degradation in either PBS or a lipase solution. MPs of different sizes with high saturation magnetization were synthesized by the coprecipitation method followed by coating with citric acid (CA).

Immune Escape Associated with RBD Omicron Mutations and SARS-CoV-2 Evolution Dynamics.

The evolution and the emergence of new mutations of viruses affect their transmissibility and/or pathogenicity features, depending on different evolutionary scenarios of virus adaptation to the host. A typical trade-off scenario of SARS-CoV-2 evolution has been proposed, which leads to the appearance of an Omicron strain with lowered lethality, yet enhanced transmissibility. This direction of evolution might be partly explained by virus adaptation to therapeutic agents and enhanced escape from vaccine-induced and natural immunity formed by other SARS-CoV-2 strains.

Honeycomb-Structured Porous Films from Poly(3-hydroxybutyrate) and Poly(3-hydroxybutyrate--3-hydroxyvalerate): Physicochemical Characterization and Mesenchymal Stem Cells Behavior.

Surface morphology affects cell attachment and proliferation. In this research, different films made of biodegradable polymers, poly(3-hydroxybutyrate) (PHB) and poly(3-hydroxybutyrate--3-hydroxyvalerate) (PHB--HV), containing different molecular weights, with microstructured surfaces were investigated. Two methods were used to obtain patterned films-water-assisted self-assembly ("breath figure") and spin-coating techniques.

Models of head and neck squamous cell carcinoma using bioengineering approaches.

The use of bioengineering methods and approaches is extremely promising for the development of experimental models of cancer, especially head and neck squamous cell carcinomas (HNSCC) that are characterized by early metastasis and rapid progression., for testing novel anticancer drugs and diagnostics. This review summarizes the most relevant HNSCC tumor models used to this day as well as future directions for improved modeling of the malignant disease.

Computational Analysis of Mutations in the Receptor-Binding Domain of SARS-CoV-2 Spike and Their Effects on Antibody Binding.

Currently, SARS-CoV-2 causing coronavirus disease 2019 (COVID-19) is responsible for one of the most deleterious pandemics of our time. The interaction between the ACE2 receptors at the surface of human cells and the viral Spike (S) protein triggers the infection, making the receptor-binding domain (RBD) of the SARS-CoV-2 S-protein a focal target for the neutralizing antibodies (Abs). Despite the recent progress in the development and deployment of vaccines, the emergence of novel variants of SARS-CoV-2 insensitive to Abs produced in response to the vaccine administration and/or monoclonal ones represent a potential danger.

Mechanisms of Formation, Structure, and Dynamics of Lipoprotein Discs Stabilized by Amphiphilic Copolymers: A Comprehensive Review.

Amphiphilic copolymers consisting of alternating hydrophilic and hydrophobic units account for a major recent methodical breakthrough in the investigations of membrane proteins. Styrene-maleic acid (SMA), diisobutylene-maleic acid (DIBMA), and related copolymers have been shown to extract membrane proteins directly from lipid membranes without the need for classical detergents. Within the particular experimental setup, they form disc-shaped nanoparticles with a narrow size distribution, which serve as a suitable platform for diverse kinds of spectroscopy and other biophysical techniques that require relatively small, homogeneous, water-soluble particles of separate membrane proteins in their native lipid environment.

Competitive Biosynthesis of Bacterial Alginate Using 12 for Tissue Engineering Applications.

This study investigated the effect of various cultivation conditions (sucrose/phosphate concentrations, aeration level) on alginate biosynthesis using the bacterial producing strain 12 by the full factorial design (FFD) method and physicochemical properties (e.g., rheological properties) of the produced bacterial alginate.

Structural characterization of β-propiolactone inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) particles.

The severe COVID-19 pandemic drives the research toward the SARS-CoV-2 virion structure and the possible therapies against it. Here, we characterized the β-propiolactone inactivated SARS-CoV-2 virions using transmission electron microscopy (TEM) and atomic force microscopy (AFM). We compared the SARS-CoV-2 samples purified by two consecutive chromatographic procedures (size exclusion chromatography [SEC], followed by ion-exchange chromatography [IEC]) with samples purified by ultracentrifugation.

Long-term humoral immunogenicity, safety and protective efficacy of inactivated vaccine against COVID-19 (CoviVac) in preclinical studies.

The unprecedented in recent history global COVID-19 pandemic urged the implementation of all existing vaccine platforms to ensure the availability of the vaccines against COVID-19 to every country in the world. Despite the multitude of high-quality papers describing clinical trials of different vaccine products, basic detailed data on general toxicity, reproductive toxicity, immunogenicity, protective efficacy and durability of immune response in animal models are scarce. Here, we developed a β-propiolactone-inactivated whole virion vaccine CoviVac and assessed its safety, protective efficacy, immunogenicity and stability of the immune response in rodents and non-human primates.

Lipid Dynamics in Diisobutylene-Maleic Acid (DIBMA) Lipid Particles in Presence of Sensory Rhodopsin II.

Amphiphilic diisobutylene/maleic acid (DIBMA) copolymers extract lipid-encased membrane proteins from lipid bilayers in a detergent-free manner, yielding nanosized, discoidal DIBMA lipid particles (DIBMALPs). Depending on the DIBMA/lipid ratio, the size of DIBMALPs can be broadly varied which makes them suitable for the incorporation of proteins of different sizes. Here, we examine the influence of the DIBMALP sizes and the presence of protein on the dynamics of encased lipids.

A Three-Dimensional Model of the Yeast Transmembrane Sensor Wsc1 Obtained by SMA-Based Detergent-Free Purification and Transmission Electron Microscopy.

The cell wall sensor Wsc1 belongs to a small family of transmembrane proteins, which are crucial to sustain cell integrity in yeast and other fungi. Wsc1 acts as a mechanosensor of the cell wall integrity (CWI) signal transduction pathway which responds to external stresses. Here we report on the purification of Wsc1 by its trapping in water-soluble polymer-stabilized lipid nanoparticles, obtained with an amphipathic styrene-maleic acid (SMA) copolymer.

The Growth of 3T3 Fibroblasts on PHB, PLA and PHB/PLA Blend Films at Different Stages of Their Biodegradation In Vitro.

Over the past century there was a significant development and extensive application of biodegradable and biocompatible polymers for their biomedical applications. This research investigates the dynamic change in properties of biodegradable polymers: poly(3-hydroxybutyrate (PHB), poly-l-lactide (PLA), and their 50:50 blend (PHB/PLA)) during their hydrolytic non-enzymatic (in phosphate buffered saline (PBS), at pH = 7.4, 37 °C) and enzymatic degradation (in PBS supplemented with 0.

Effects of Recombinant Spidroin rS1/9 on Brain Neural Progenitors After Photothrombosis-Induced Ischemia.

The existence of niches of stem cells residence in the ventricular-subventricular zone and the subgranular zone in the adult brain is well-known. These zones are the sites of restoration of brain function after injury. Bioengineered scaffolds introduced in the damaged loci were shown to support neurogenesis to the injury area, thus representing a strategy to treat acute neurodegeneration.

Poly(3-hydroxybutyrate)/hydroxyapatite/alginate scaffolds seeded with mesenchymal stem cells enhance the regeneration of critical-sized bone defect.

A critical-sized calvarial defect in rats is employed to reveal the osteoinductive properties of biomaterials. In this study, we investigate the osteogenic efficiency of hybrid scaffolds based on composites of a biodegradable and biocompatible polymer, poly(3-hydroxybutyrate) (PHB) with hydroxyapatite (HA) filled with alginate (ALG) hydrogel containing mesenchymal stem cells (MSCs) on the regeneration of the critical-sized radial defect of the parietal bone in rats. The scaffolds based on PHB and PHB/HA with desired shapes were prepared by two-stage salt leaching technique using a mold obtained by three-dimensional printing.

Akt and Src mediate the photocrosslinked fibroin-induced neural differentiation.

Neural transplantation is a promising modality for treatment of neurodegenerative diseases, traumatic brain injury and stroke. Biocompatible scaffolds with optimized properties improve the survival of transplanted neural cells and differentiation of progenitor cells into the desired types of neurons. Silk fibroin is a biocompatible material for tissue engineering.

Lipid dynamics in nanoparticles formed by maleic acid-containing copolymers: EPR spectroscopy and molecular dynamics simulations.

Amphiphilic maleic acid-containing copolymers account for a recent methodical breakthrough in the study of membrane proteins. Their application enables a detergent-free extraction of membrane proteins from lipid bilayers, yielding stable water-soluble, discoidal lipid bilayer particles with incorporated proteins, which are wrapped with copolymers. Although many studies confirm the potential of this approach for membrane protein research, the interactions between the maleic acid-containing copolymers and extracted lipids, as well as possible effects of the copolymers on lipid-embedded proteins deserve further scrutinization.

Proton leakage across lipid bilayers: Oxygen atoms of phospholipid ester linkers align water molecules into transmembrane water wires.

Up to half of the cellular energy gets lost owing to membrane proton leakage. The permeability of lipid bilayers to protons is by several orders of magnitude higher than to other cations, which implies efficient proton-specific passages. The nature of these passages remains obscure.

Styrene/Maleic Acid Copolymers Form SMALPs by Pulling Lipid Patches out of the Lipid Bilayer.

Amphiphilic copolymers composed of styrene and maleic acid (SMA) monomers caused a major methodical breakthrough in the study of membrane proteins. They were found to directly release phospholipids and membrane proteins both from artificial and natural lipid bilayers, yielding stable water-soluble discoidal SMA/lipid particles (SMALPs) of uniform size. Although many empirical studies indicate the great potency of SMALPs for membrane protein research, the mechanisms of their formation remain obscure.

Fabrication of hydrogel scaffolds via photocrosslinking of methacrylated silk fibroin.

Silk fibroin is a promising biomaterial for tissue engineering due to its valuable mechanical and biological properties. However, being a natural product and a protein, it lacks the processability and uniform quality of an advanced synthetic material. Here we propose a way to overcome this contradiction using novel fibroin photocrosslinkable derivative (FBMA).