Comparison of Contact Electrification Mechanisms of Selected Polymers and Surface-Functionalized Molecules.

Among the possible alternatives for the improvement of contact electrification for triboelectric energy harvesting purposes, the functionalization of contact surfaces has attracted wide attention due to its versatility and cost-efficiency. Similarly, low-stiffness polymeric materials such as poly(dimethylsiloxane) (PDMS) are regarded as a promising choice of contact material for the same purpose. However, for defining the most efficient combinations of materials of the aforementioned types, a number of theoretical questions still frequently pose difficulties for practical implementation-related tasks.

Influence of the Sequence Motive Repeating Number on Protein Folding in Spider Silk Protein Films.

Like multiblock copolymers, spider silk proteins are built of repetitive sequence motives. One prominent repetitive motif is based on the consensus sequence of spidroin 4 of the spider ADF4. The number of the repeating sequence motives (C) determines the molecular weight of the recombinant ADF4-based, engineered spider silk protein denoted as eADF4(C).

Predicting the Density-Scaling Exponent of a Glass-Forming Liquid from Complex Dielectric Permittivity Measurements.

One of the challenging problems related to the liquid-glass transition phenomenon is establishing a link between the character of intermolecular interactions and the behavior of molecular dynamics. Introducing the density scaling concept, according to which dynamic quantities, e.g.

Dynamic matrices with DNA-encoded viscoelasticity for cell and organoid culture.

Three-dimensional cell and organoid cultures rely on the mechanical support of viscoelastic matrices. However, commonly used matrix materials lack control over key cell-instructive properties. Here we report on fully synthetic hydrogels based on DNA libraries that self-assemble with ultrahigh-molecular-weight polymers, forming a dynamic DNA-crosslinked matrix (DyNAtrix).

A New In Vitro Blood Flow Model for the Realistic Evaluation of Antimicrobial Surfaces.

Device-associated bloodstream infections can cause serious medical problems and cost-intensive postinfection management, defining a need for more effective antimicrobial coatings. Newly developed coatings often show reduced bacterial colonization and high hemocompatibility in established in vitro tests, but fail in animal studies or clinical trials. The poor predictive power of these models is attributed to inadequate representation of in vivo conditions.

Evaluation of the Composition, Thermal and Mechanical Behavior, and Color Changes of Artificially and Naturally Aged Polymers for the Conservation of Stained Glass Windows.

Investigations of historical conservation materials on historical stained glass windows of the Naumburg Cathedral in Germany offered an opportunity for the study of polymers, naturally aged in a non-controlled environment. This allowed the conservation history of the cathedral to be traced and expanded by valuable insights. The historical materials were characterized through the use of spectroscopy (FTIR, Raman), thermal analysis, PY-GC/MS, and SEC on taken samples.

Entropic repulsion of cholesterol-containing layers counteracts bioadhesion.

Control of adhesion is a striking feature of living matter that is of particular interest regarding technological translation. We discovered that entropic repulsion caused by interfacial orientational fluctuations of cholesterol layers restricts protein adsorption and bacterial adhesion. Moreover, we found that intrinsically adhesive wax ester layers become similarly antibioadhesive when containing small quantities (under 10 wt%) of cholesterol.

Encapsulation of Carbon Nanotubes by Styrene and Butyl Acrylate Particles via Suspension Polymerization for Polymerized Toner Applications.

Electrophotographic printing and copying processes primarily use toner, which is a mixture of colorant, polymer, and additives. Toner can be made using traditional mechanical milling techniques or more contemporary chemical polymerization techniques. Suspension polymerization provides spherical particles with less stabilizer adsorption, homogeneous monomers, higher purity, and easier control of the reaction temperature.

Supplement Treatment with NAC and Omega-3 Polyunsaturated Fatty Acids during Pregnancy Partially Prevents Schizophrenia-Related Outcomes in the Poly I:C Rat Model.

Background: Heightened levels of inflammation and oxidative stress are thought to be involved in the pathophysiology of schizophrenia. We aimed to assess whether intake of anti-inflammatory and anti-oxidant drugs during pregnancy prevents later schizophrenia-related outcomes in a neurodevelopmental rat model of this disorder.

Methods: Pregnant Wistar rats were injected with polyriboinosinic-polyribocytidilic acid (Poly I:C) or saline and subsequently treated with either N-acetyl cysteine (NAC) or omega-3 polyunsaturated fatty acids (PUFAs) until delivery.

Unusual nonlinear switching in branched carbon nanotube nanocomposites.

In this experimental study, we investigate the nonlinear dynamic response of nanocomposite beams composed of polybutylene terephthalate (PBT) and branched carbon nanotubes (bCNTs). By varying the weight fraction of bCNTs, we obtain frequency response curves for cantilever specimens under harmonic base excitations, measuring the tip displacement via 3D scanning laser vibrometry. Our findings reveal a surprising nonlinear softening trend in the steady-state response of the cantilevers, which gets switched into hardening for higher bCNT weight fractions and increasing oscillation amplitudes.

Discriminant Principal Component Analysis of ToF-SIMS Spectra for Deciphering Compositional Differences of MSC-Secreted Extracellular Matrices.

Identifying characteristic extracellular matrix (ECM) variants is a key challenge in mechanistic biology, bioengineering, and medical diagnostics. The reported study demonstrates the potential of time-of-flight secondary ion mass spectrometry (ToF-SIMS) to detect subtle differences between human mesenchymal stromal cell (MSC)-secreted ECM types as induced by exogenous stimulation or emerging pathology. ToF-SIMS spectra of decellularized ECM samples are evaluated by discriminant principal component analysis (DPCA), an advanced multivariate analysis technique, to decipher characteristic compositional features.

Sustained Release of Human Adipose Tissue Stem Cell Secretome from Star-Shaped Poly(ethylene glycol) Glycosaminoglycan Hydrogels Promotes Motor Improvements after Complete Transection in Spinal Cord Injury Rat Model.

Adipose tissue-derived stem cells (ASCs) have been shown to assist regenerative processes after spinal cord injury (SCI) through their secretome, which promotes several regenerative mechanisms, such as inducing axonal growth, reducing inflammation, promoting cell survival, and vascular remodeling, thus ultimately leading to functional recovery. However, while systemic delivery (e.g.

A "built-up" composite film with synergistic functionalities on Mg-2Zn-1Mn bioresorbable stents improves corrosion control effects and biocompatibility.

Control of premature corrosion of magnesium (Mg) alloy bioresorbable stents (BRS) is frequently achieved by the addition of rare earth elements. However, limited long-term experience with these elements causes concerns for clinical application and alternative methods of corrosion control are sought after. Herein, we report a "built-up" composite film consisting of a bottom layer of MgF conversion coating, a sandwich layer of a poly (1, 3-trimethylene carbonate) (PTMC) and 3-aminopropyl triethoxysilane (APTES) co-spray coating (PA) and on top a layer of poly (lactic-co-glycolic acid) (PLGA) ultrasonic spray coating to decorate the rare earth element-free Mg-2Zn-1Mn (ZM21) BRS for tailoring both corrosion resistance and biological functions.

Correlation between Processing Parameters, Morphology, and Properties of Injection-Molded Polylactid Acid (PLA) Specimens at Different Length Scales.

Polylactic acid (PLA) is one of the most promising bioplastic representatives that finds application in many different areas, e.g., as single-use products in the packaging industry, in the form of mulch film for agriculture, or in medical devices.

Plant Coumarins with Anti-HIV Activity: Isolation and Mechanisms of Action.

This review summarizes and systematizes the literature on the anti-HIV activity of plant coumarins with emphasis on isolation and the mechanism of their antiviral action. This review summarizes the information on the anti-HIV properties of simple coumarins as well as annulated furano- and pyranocoumarins and shows that coumarins of plant origin can act by several mechanisms: inhibition of HIV reverse transcriptase and integrase, inhibition of cellular factors that regulate HIV-1 replication, and transmission of viral particles from infected macrophages to healthy ones. It is important to note that some pyranocoumarins are able to act through several mechanisms or bind to several sites, which ensures the resistance of these compounds to HIV mutations.

Analysis of riboflavin/ultraviolet a corneal cross-linking by molecular spectroscopy.

Corneal cross-linking (CXL) with riboflavin and ultraviolet A light is a therapeutic procedure to restore the mechanical stability of corneal tissue. The treatment method is applied to pathological tissue, such as keratoconus and induces the formation of new cross-links. At present, the molecular mechanisms of induced cross-linking are still not known exactly.

Sustained release of valproic acid loaded on chitosan nanoparticles within hybrid of alginate/chitosan hydrogel with/without stem cells in regeneration of spinal cord injury.

Hydrogels have been increasingly applied in tissue regeneration and drug delivery systems (DDS). In this study, the capacity of valproic acid (Val) encapsulated within hybrid of alginate (Alg)-chitosan (Cs) (Alg-Cs) hydrogel containing Cs nanoparticle (Npch) with/without human endometrial stem cells (hEnSC) was initially examined for regeneration of spinal cord injury (SCI). To evaluate the stability of the synthesized hydrogels zeta potential necessary measurements were made.

β-Sheet Structure Formation within Binary Blends of Two Spider Silk Related Peptides.

Intrinsically disordered proteins (IDPs) play an important role in molecular biology and medicine because their induced folding can lead to so-called conformational diseases, where β-amyloids play an important role. Still, the molecular folding process into the different substructures, such as parallel/antiparallel or extended β-sheet/crossed β-sheet is not fully understood. The recombinant spider silk protein eADF4(Cx) consisting of repeating modules C, which are composed of a crystalline (pep-c) and an amorphous peptide sequence (pep-a), can be used as a model system for IDP since it can assemble into similar structures.

Inflammation-Controlled Anti-Inflammatory Hydrogels.

While autoregulative adaptation is a common feature of living tissues, only a few feedback-controlled adaptive biomaterials are available so far. This paper herein reports a new polymer hydrogel platform designed to release anti-inflammatory molecules in response to the inflammatory activation of human blood. In this system, anti-inflammatory peptide drugs, targeting either the complement cascade, a complement receptor, or cyclophilin A, are conjugated to the hydrogel by a peptide sequence that is cleaved by elastase released from activated granulocytes.

A Tumor Microenvironment Model of Pancreatic Cancer to Elucidate Responses toward Immunotherapy.

Pancreatic cancer is a devastating malignancy with minimal treatment options. Standard-of-care therapy, including surgery and chemotherapy, is unsatisfactory, and therapies harnessing the immune system have been unsuccessful in clinical trials. Resistance to therapy and disease progression are mediated by the tumor microenvironment, which contains excessive amounts of extracellular matrix and stromal cells, acting as a barrier to drug delivery.

Adhesive and Self-Healing Polyurethanes with Tunable Multifunctionality.

Many polyurethanes (PUs) are blood-contacting materials due to their good mechanical properties, fatigue resistance, cytocompatibility, biosafety, and relatively good hemocompatibility. Further functionalization of the PUs using chemical synthetic methods is especially attractive for expanding their applications. Herein, a series of catechol functionalized PU (C-PU-PTMEG) elastomers containing variable molecular weight of polytetramethylene ether glycol (PTMEG) soft segment are reported by stepwise polymerization and further introduction of catechol.

Spiropyran/Merocyanine Amphiphile in Various Solvents: A Joint Experimental-Theoretical Approach to Photophysical Properties and Self-Assembly.

This joint experimental-theoretical work focuses on molecular and photophysical properties of the spiropyran-containing amphiphilic molecule in organic and aqueous solutions. Being dissolved in tested organic solvents, the system demonstrates positive photochromism, i.e.