The Separation Power of Highly Porous 3D Nanofiber Sponges.

Sponges formed by the self-assembly of nanofiber building blocks are versatile materials used in various fields such as filtration, thermal insulation, scaffolding or sound absorption. Their potential seems to be constantly expanding given the variety of possible fiber materials, from bio-based to fossil polymers to inorganic nanofibers. In general, nanofiber sponges - also called nanofiber aerogels - are flexible, have low density, and a large specific surface area thanks to their tunable open-porous nanofiber based architecture.

Acrylonitrile and Pullulan Based Nanofiber Mats as Easily Accessible Scaffolds for 3D Skin Cell Models Containing Primary Cells.

(1) Background: Three-dimensional (3D) collagen I-based skin models are commonly used in drug development and substance testing but have major drawbacks such as batch-to-batch variations and ethical concerns. Recently, synthetic nanofibrous scaffolds created by electrospinning have received increasing interest as potential alternatives due to their morphological similarities to native collagen fibrils in size and orientation. The overall objective of this proof-of-concept study was to demonstrate the suitability of two synthetic polymers in creating electrospun scaffolds for 3D skin cell models.

3D PCL/Gelatin/Genipin Nanofiber Sponge as Scaffold for Regenerative Medicine.

Recent advancements in tissue engineering and material science have radically improved in vitro culturing platforms to more accurately replicate human tissue. However, the transition to clinical relevance has been slow in part due to the lack of biologically compatible/relevant materials. In the present study, we marry the commonly used two-dimensional (2D) technique of electrospinning and a self-assembly process to construct easily reproducible, highly porous, three-dimensional (3D) nanofiber scaffolds for various tissue engineering applications.

Universities of Applied Sciences.

When the SARS-CoV-2 pandemic started, science came to the immediate attention of the broad public. People and politicians were hanging on every word of medical doctors, virologists, molecular biologists, data scientists and many others in the hope of finding other protective measures than those used for centuries such as basic hygiene, distance, or quarantine. Here, at the Institute of Chemistry and Biotechnology at the Zurich University of Applied Sciences (ZHAW) we were also willing to provide scientific solutions to overcome the pandemic.

A Novel Microfiber Wipe for Delivery of Active Substances to Human Skin: Clinical Proof of Concept.

A novel technology for the delivery of active substances to the skin based on microfibers loaded with dried active substances was developed. The objective of this work was to demonstrate deposition of the active substances on the skin including concurrent cleansing properties of the wipe. As model active substance to measure deposition capacity Niacinamide was used and as parameter to measure cleansing capacities of the wipe squalene uptake was measured.

In Vitro Endothelialization of Surface-Integrated Nanofiber Networks for Stretchable Blood Interfaces.

Despite major technological advances within the field of cardiovascular engineering, the risk of thromboembolic events on artificial surfaces in contact with blood remains a major challenge and limits the functionality of ventricular assist devices (VADs) during mid- or long-term therapy. Here, a biomimetic blood-material interface is created via a nanofiber-based approach that promotes the endothelialization capability of elastic silicone surfaces for next-generation VADs under elevated hemodynamic loads. A blend fiber membrane made of elastic polyurethane and low-thrombogenic poly(vinylidene fluoride- co-hexafluoropropylene) was partially embedded into the surface of silicone films.

Prediction of Steam Burns Severity using Raman Spectroscopy on ex vivo Porcine Skin.

Skin burns due to accidental exposure to hot steam have often been reported to be more severe than the ones occurring from dry heat. While skin burns due to flames or radiant heat have been thoroughly characterized, the mechanisms leading to steam burns are not well understood and a conundrum still exists: can second degree burns occur without destruction of the epidermis, i.e.

Exploration of Ultralight Nanofiber Aerogels as Particle Filters: Capacity and Efficiency.

Ultralight nanofiber aerogels (NFAs) or nanofiber sponges are a truly three-dimensional derivative of the intrinsically flat electrospun nanofiber mats or membranes (NFMs). Here we investigated the potential of such materials for particle or aerosol filtration because particle filtration is a major application of NFMs. Ultralight NFAs were synthesized from electrospun nanofibers using a solid-templating technique.

Surface modifications for antimicrobial effects in the healthcare setting: a critical overview.

The spread of infections in healthcare environments is a persistent and growing problem in most countries, aggravated by the development of microbial resistance to antibiotics and disinfectants. In addition to indwelling medical devices (e.g.

The relationship between skin function, barrier properties, and body-dependent factors.

Background: Skin is a multilayer interface between the body and the environment, responsible for many important functions, such as temperature regulation, water transport, sensation, and protection from external triggers.

Objectives: This paper provides an overview of principal factors that influence human skin and describes the diversity of skin characteristics, its causes and possible consequences. It also discusses limitations in the barrier function of the skin, describing mechanisms of absorption.

Anti-microbial coating innovations to prevent infectious diseases (AMiCI): Cost action ca15114.

Worldwide, millions of patients are affected annually by healthcare-associated infection (HCAI), impacting up to 80,000 patients in European Hospitals on any given day. This represents not only public health risk, but also an economic burden. Complementing routine hand hygiene practices, cleaning and disinfection, antimicrobial coatings hold promise based, in essence, on the application of materials and chemicals with persistent bactericidal or -static properties onto surfaces or in textiles used in healthcare environments.

From Short Electrospun Nanofibers to Ultralight Aerogels with Tunable Pore Structure.

Nanofiber production by electrospinning has made great progress over the past two decades. Recently the research area was revolutionized by a novel post-processing approach. By cutting the endless and intertwined nanofibers into short pieces, it is now possible to reassemble them into interconnected 3D structures.

In vivo confirmation of hydration-induced changes in human-skin thickness, roughness and interaction with the environment.

The skin properties, structure, and performance can be influenced by many internal and external factors, such as age, gender, lifestyle, skin diseases, and a hydration level that can vary in relation to the environment. The aim of this work was to demonstrate the multifaceted influence of water on human skin through a combination of in vivo confocal Raman spectroscopy and images of volar-forearm skin captured with the laser scanning confocal microscopy. By means of this pilot study, the authors have both qualitatively and quantitatively studied the influence of changing the depth-dependent hydration level of the stratum corneum (SC) on the real contact area, surface roughness, and the dimensions of the primary lines and presented a new method for characterizing the contact area for different states of the skin.

Multiparameter toxicity assessment of novel DOPO-derived organophosphorus flame retardants.

Halogen-free organophosphorus flame retardants are considered as replacements for the phased-out class of polybrominated diphenyl ethers (PBDEs). However, toxicological information on new flame retardants is still limited. Based on their excellent flame retardation potential, we have selected three novel 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivatives and assessed their toxicological profile using a battery of in vitro test systems in order to provide toxicological information before their large-scale production and use.

Skin Concentrations of Topically Applied Substances in Reconstructed Human Epidermis (RHE) Compared with Human Skin Using in vivo Confocal Raman Microscopy.

Detailed knowledge about the skin concentration of topically applied substances is important to understand their local pharmacological activity. In particular since in vitro models of reconstructed human epidermis are increasingly used as models for diseased skin. In general, diffusion cell experiments are performed to determine the diffusion flux of test substances through either skin models or excised skin both from humans and animals.

Surface chemistry at Swiss Universities of Applied Sciences.

In the Swiss Universities of Applied Sciences, a number of research groups are involved in surface science, with different methodological approaches and a broad range of sophisticated characterization techniques. A snapshot of the current research going on in different groups from the University of Applied Sciences and Arts Western Switzerland (HES-SO), the Zurich University of Applied Sciences (ZHAW) and the University of Applied Sciences and Arts Northwestern Switzerland (FHNW) is given.

Membrane-particle interactions in an asymmetric flow field flow fractionation channel studied with titanium dioxide nanoparticles.

Asymmetric flow field flow fractionation operated in a multidetector approach (A4F-MDA) is a powerful tool to perform size-classified nanoparticle analysis. Recently several publications mentioned insufficient recovery rates and even retention time shifts attributed to unspecific membrane-particle interactions. One hypothesis to explain this phenomenon is based on the surface charge (zeta-potential) of the membrane material and the particle.

Surface distribution and depths profiling of particulate organic UV absorbers by Raman imaging and tape stripping.

Tape stripping in conjunction with scanning Raman microscopy was used for assessing the lateral and vertical distribution of an organic particulate UV filter, methylene bis-benzotriazolyl tetramethylbutylphenol (MBBT), in a sunscreen formulation. On the volar forearms of three volunteers, 1 mg cm(-2) formulation containing 10% MBBT was applied, and the average amount of MBBT was measured by Raman scanning microscopy in 15 consecutive tape strippings. The recovery of MBBT was 91.

Membranes for specific adsorption: immobilizing molecularly imprinted polymer microspheres using electrospun nanofibers.

Molecularly imprinted polymer microspheres were immobilized within a polymer nanofiber membrane by electrospinning. Such membranes simplify the handling of functional microspheres and provide specific recognition capabilities for solid-phase extraction and filtration applications. In this study, microspheres were prepared by precipitation polymerization of methacrylic acid and divinylbenzene as a cross-linker with the target molecule (-)-cinchonidine and then, they were electrospun into a non-woven polyacrylonitrile nanofiber membrane.

Mechanisms for the dehydrogenation of alkanes on platinum: insights gained from the reactivity of gaseous cluster cations, Ptn + n=1-21.

Rates for the dihydrogen elimination of methane, ethane, and propane with cationic platinum clusters, Pt(n) (+) (1 View Article and Find Full Text PDF

Reactions of platinum clusters Pt(n)(+/-), n = 1-21, with CH4: to react or not to react.

The relative reactivity of any given neutral platinum cluster falls in-between that of the corresponding anion and cation.

Reaction dynamics simulations of the identity S(N)2 reaction H(2)O + HOOH(2)(+)--> H(2)OOH(+)+ H(2)O. Requirements for reaction and competition with proton transfer.

Despite the fact that the transition structure of the gas phase S(N)2 reaction H(2)O + HOOH(2)(+)--> HOOH(2)(+)+ H(2)O is well below the reactants in potential energy, the reaction has not yet been observed by experiment. Variational transition state RRKM theory reveals a strong preference for the competing proton transfer reaction H(2)O + HOOH(2)(+)--> H(3)O(+)+ HOOH due to entropy factors. Born-Oppenheimer reaction dynamics simulations confirm these results.

Unprecedented ROMP activity of low-valent rhenium-nitrosyl complexes: Mechanistic evaluation of an electrophilic olefin metathesis system.

The reaction of [Re(H)(NO)2(PR3)2] complexes (1 a: R = PCy3; 1 b: R = PiPr3) with [H(OEt2)2][BAr(F)4] ([BAr(F)4] = tetrakis{3,5-bis(trifluoromethyl)phenyl}borate) in benzene at room temperature gave the corresponding cations [Re(NO)2(PR3)2][BAr(F)4] (2 a and 2 b). The addition of phenyldiazomethane to benzene solutions of 2 a and 2 b afforded the moderately stable cationic rhenium(I)-benzylidene-dinitrosyl-bis(trialkyl)phosphine complexes 3 a and 3 b as [BAr(F)4]- salts in good yields. The complexes 2 a and 2 b catalyze the ring-opening metathesis polymerization (ROMP) of highly strained nonfunctionalized cyclic olefins to give polymers with relatively high polydispersity indices, high molecular weights and over 80 % Z configuration of the double bonds in the chain backbone.

C-H activation of alkanes on Rh+ n (n=1-30) clusters: size effects on dehydrogenation.

The rate coefficients for the dehydrogenation of ethane, propane, and isobutane with cationic rhodium atoms Rh+ and clusters Rh+ n of up to 30 atoms were measured under single-collision conditions in a Fourier-transform ion cyclotron resonance mass spectrometer. The reaction rates are cluster size dependent and parallel for all the three alkanes. While the reactions proceed close to the theoretical collision rates for a large number of clusters, characteristic minima are observed for Rh+ (5/6/9/19/28).