A Structural Comparison of Organoterminated Selenide, Diselenide, and Triselenide

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How Bound and Free Fatty Acids in Cellulose Films Impact Nonspecific Protein Adsorption

The effect of fatty acids and fatty acid esters to impair nonspecific protein adsorption on cellulose thin films is investigated. Thin films are prepared by blending trimethylsilyl cellulose solutions with either cellulose stearoyl ester or stearic acid at various ratios. After film formation by spin coating, the trimethylsilyl cellulose fraction of the films is converted to cellulose by exposure to HCl vapors. The morphologies and surface roughness of the blends were examined by atomic force microscopy revealing different feature shapes and sizes depending on the blend ratios. Nonspecific protein adsorption at the example of bovine serum albumin toward the blend thin films was tested by means of surface plasmon resonance spectroscopy in real-time. Incorporation of stearic acid into the cellulose leads to highly protein repellent surfaces regardless of the amount added. The stearic acid acts as a sacrificial compound that builds a complex with bovine serum albumin thereby inhibiting protein adsorption. For the blends where stearoyl ester is added to the cellulose films, the cellulose:cellulose stearoyl ester ratios of 3:1 and 1:1 lead to much lower nonspecific protein adsorption compared to pure cellulose, whereas for the other ratios, adsorption increases. Supplementary results were obtained from atomic force microscopy experiments performed in liquid during exposure to protein solution and surface free energy determinations

209Bi Quadrupole Relaxation Enhancement in Solids as a Step Towards New Contrast Mechanisms in Magnetic Resonance Imaging

<p>Motivated by the possibility of exploiting species containing high spin quantum number<br> nuclei (referred to as quadrupole nuclei) as novel contrast agents for Magnetic Resonance<br> Imaging, based on Quadrupole Relaxation Enhancement (QRE) effects, 1H spin-lattice<br> relaxation has been investigated for tris(2-methoxyphenyl)bismuthane and tris(2,6-<br> dimethoxyphenyl)bismuthane in powder. The relaxation experiment has been performed in<br> the magnetic field range of 0.5 T to 3 T (the upper limit corresponds to the field used in many<br> medical scanners). A very rich QRE pattern (several frequency specific 1H spin-lattice<br> relaxation rate maxima) has been observed for both compounds. Complementary Nuclear<br> Quadrupole Resonance experiments have been performed in order to determine the<br> quadrupole parameters (quadrupole coupling constant and asymmetry parameters) for 209Bi.<br> Knowing the parameters, the QRE pattern has been explained on the basis of a quantummechanical<br> picture of the system including single and double-quantum coherences for the<br> participating nuclei (1H and 209Bi). In this way the quantum-mechanical origin of the spintransitions leading to the QRE effects has been explained.</p

Adsorption Studies of Organophosphonic Acids on Differently Activated Gold Surfaces

In this study, the formation of self-assembled monolayers consisting of three organophosphonic acids (vinyl-, octyl-, and tetradecylphosphonic acid) from isopropanol solutions onto differently activated gold surfaces is studied in situ and in real time using multiparameter surface plasmon resonance (MP-SPR). Data retrieved from MP-SPR measurements revealed similar adsorption kinetics for all investigated organophosphonic acids (PA). The layer thickness of the immobilized PA is in the range of 0.6–1.8 nm corresponding to monolayer-like coverage and correlates with the length of the hydrocarbon chain of the PA molecules. After sintering the surfaces, the PA are irreversibly attached onto the surfaces as proven by X-ray photoelectron spectroscopy and attenuated total reflection infrared and grazing incidence infrared spectroscopy. Potential adsorption modes and interaction mechanisms are proposed

Additional file 1 of Engineering Saccharomyces cerevisiae for targeted hydrolysis and fermentation of glucuronoxylan through CRISPR/Cas9 genome editing

Supplementary Material 1: MOCLO cloning strateg

Interaction of Tissue Engineering Substrates with Serum Proteins and Its Influence on Human Primary Endothelial Cells

Polymer-based biomaterials particularly polycaprolactone (PCL) are one of the most promising substrates for tissue engineering. The surface chemistry of these materials plays a major role since it governs protein adsorption, cell adhesion, viability, degradation, and biocompatibility in the first place. This study correlates the interaction of the most abundant serum proteins (albumin, immunoglobulins, fibrinogen) with the surface properties of PCL and its influence on the morphology and metabolic activity of primary human arterial endothelial cells that are seeded on the materials. Prior to that, thin films of PCL are manufactured by spin-coating and characterized in detail. A quartz crystal microbalance with dissipation (QCM-D), a multiparameter surface plasmon resonance spectroscopy instrument (MP-SPR), wettability data, and atomic force microscopy are combined to elucidate the pH-dependent protein adsorption on the PCL substrates. Primary endothelial cells are cultured on the protein modified polymer, and conclusions are drawn on the significant impact of type and form of proteins coatings on cell morphology and metabolic activity

Enzymes as Biodevelopers for Nano- And Micropatterned Bicomponent Biopolymer Thin Films

The creation of nano- and micropatterned polymer films is a crucial step for innumerous applications in science and technology. However, there are several problems associated with environmental aspects concerning the polymer synthesis itself, cross-linkers to induce the patterns as well as toxic solvents used for the preparation and even more important development of the films (e.g., chlorobenzene). In this paper, we present a facile method to produce micro- and nanopatterned biopolymer thin films using enzymes as so-called biodevelopers. Instead of synthetic polymers, naturally derived ones are employed, namely, poly-3-hydroxybutyrate and a cellulose derivative, which are dissolved in a common solvent in different ratios and subjected to spin coating. Consequently, the two biopolymers undergo microphase separation and different domain sizes are formed depending on the ratio of the biopolymers. The development step proceeds via addition of the appropriate enzyme (either PHB-depolymerase or cellulase), whereas one of the two biopolymers is selectively degraded, while the other one remains on the surface. In order to highlight the enzymatic development of the films, video AFM studies have been performed in real time to image the development process in situ as well as surface plasmon resonance spectroscopy to determine the kinetics. These studies may pave the way for the use of enzymes in patterning processes, particularly for materials intended to be used in a physiological environment

Enzymes as Biodevelopers for Nano- And Micropatterned Bicomponent Biopolymer Thin Films

The creation of nano- and micropatterned polymer films is a crucial step for innumerous applications in science and technology. However, there are several problems associated with environmental aspects concerning the polymer synthesis itself, cross-linkers to induce the patterns as well as toxic solvents used for the preparation and even more important development of the films (e.g., chlorobenzene). In this paper, we present a facile method to produce micro- and nanopatterned biopolymer thin films using enzymes as so-called biodevelopers. Instead of synthetic polymers, naturally derived ones are employed, namely, poly-3-hydroxybutyrate and a cellulose derivative, which are dissolved in a common solvent in different ratios and subjected to spin coating. Consequently, the two biopolymers undergo microphase separation and different domain sizes are formed depending on the ratio of the biopolymers. The development step proceeds via addition of the appropriate enzyme (either PHB-depolymerase or cellulase), whereas one of the two biopolymers is selectively degraded, while the other one remains on the surface. In order to highlight the enzymatic development of the films, video AFM studies have been performed in real time to image the development process in situ as well as surface plasmon resonance spectroscopy to determine the kinetics. These studies may pave the way for the use of enzymes in patterning processes, particularly for materials intended to be used in a physiological environment

Enzymes as Biodevelopers for Nano- And Micropatterned Bicomponent Biopolymer Thin Films

The creation of nano- and micropatterned polymer films is a crucial step for innumerous applications in science and technology. However, there are several problems associated with environmental aspects concerning the polymer synthesis itself, cross-linkers to induce the patterns as well as toxic solvents used for the preparation and even more important development of the films (e.g., chlorobenzene). In this paper, we present a facile method to produce micro- and nanopatterned biopolymer thin films using enzymes as so-called biodevelopers. Instead of synthetic polymers, naturally derived ones are employed, namely, poly-3-hydroxybutyrate and a cellulose derivative, which are dissolved in a common solvent in different ratios and subjected to spin coating. Consequently, the two biopolymers undergo microphase separation and different domain sizes are formed depending on the ratio of the biopolymers. The development step proceeds via addition of the appropriate enzyme (either PHB-depolymerase or cellulase), whereas one of the two biopolymers is selectively degraded, while the other one remains on the surface. In order to highlight the enzymatic development of the films, video AFM studies have been performed in real time to image the development process in situ as well as surface plasmon resonance spectroscopy to determine the kinetics. These studies may pave the way for the use of enzymes in patterning processes, particularly for materials intended to be used in a physiological environment

Exploring Nonspecific Protein Adsorption on Lignocellulosic Amphiphilic Bicomponent Films

In this contribution, we explore the interaction of lignocellulosics and proteins aiming at a better understanding of their synergistic role in natural systems. In particular, the manufacturing and characterization of amphiphilic bicomponent thin films composed of hydrophilic cellulose and a hydrophobic lignin ester in different ratios is presented which may act as a very simplified model for real systems. Besides detailed characterizations of the films and mechanisms to explain their formation, nonspecific protein adsorption using bovine serum albumin (BSA) onto the films was studied using a quartz crystal microbalance with dissipation (QCM-D). As it turns out, the rather low nonspecific protein adsorption of BSA on cellulose is further reduced when these hydrophobic lignins are incorporated into the films. The lignin ester acts in these blend films as sacrificial component, probably via an emulsification mechanism. Additionally, the amphiphilicity of the films may prevent the adsorption of BSA as well. Although there are some indications, it remains unclear whether any kind of protein interactions in such systems are of specific nature