Efficient material-induced activation of monocyte-derived dendritic cells releasing surface molecules, matrix metalloproteinases, and growth factors needed for regenerative tissue remodeling.

New experimental approaches for tissue repair have recently been proposed and include the application of natural or synthetic biomaterials and immune cells. Herein, fully synthetic poly(glycidyl ether) (PGE) copolymer coatings are evaluated as bioinstructive materials for the culture and intrinsic activation of human immune cells. Immature monocyte-derived dendritic cells (moDCs) are exposed to PGE brush and gel coatings of varying copolymer composition, wettability, and deformability immobilized on polystyrene culture dishes.

Osmolytes Modulate Photoactivation of Phytochrome: Probing Protein Hydration.

Phytochromes are bistable red/far-red light-responsive photoreceptor proteins found in plants, fungi, and bacteria. Light-activation of the prototypical phytochrome Cph1 from the cyanobacterium sp. PCC 6803 allows photoisomerization of the bilin chromophore in the photosensory module and a subsequent series of intermediate states leading from the red absorbing Pr to the far-red-absorbing Pfr state.

Multiomics Analysis Provides Insight into the Laboratory Evolution of toward the Metabolic Usage of Fluorinated Indoles.

Organofluorine compounds are known to be toxic to a broad variety of living beings in different habitats, and chemical fluorination has been historically exploited by mankind for the development of therapeutic drugs or agricultural pesticides. On the other hand, several studies so far have demonstrated that, under appropriate conditions, living systems (in particular bacteria) can tolerate the presence of fluorinated molecules (e.g.

Mechanism of discrimination of isoleucyl-tRNA synthetase against nonproteinogenic α-aminobutyrate and its fluorinated analogues.

Isoleucyl-tRNA synthetase (IleRS) is a paradigm for understanding how specificity against smaller hydrophobic substrates evolved in both the synthetic and editing reactions. IleRS misactivates nonproteinogenic norvaline (Nva) and proteinogenic valine (Val), with a 200-fold lower efficiency than the cognate isoleucine (Ile). Translational errors are, however, prevented by IleRS hydrolytic editing.

Enhanced Permeability and Retention-like Extravasation of Nanoparticles from the Vasculature into Tuberculosis Granulomas in Zebrafish and Mouse Models.

The enhanced permeability and retention (EPR) effect is the only described mechanism enabling nanoparticles (NPs) flowing in blood to reach tumors by a passive targeting mechanism. Here, using the transparent zebrafish model infected with Mycobacterium marinum we show that an EPR-like process also occurs allowing different types of NPs to extravasate from the vasculature to reach granulomas that assemble during tuberculosis (TB) infection. PEGylated liposomes and other NP types cross endothelial barriers near infection sites within minutes after injection and accumulate close to granulomas.

Oligomerisation of Synaptobrevin-2 Studied by Native Mass Spectrometry and Chemical Cross-Linking.

Synaptobrevin-2 is a key player in signal transmission in neurons. It forms, together with SNAP25 and Syntaxin-1A, the neuronal soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex and mediates exocytosis of synaptic vesicles with the pre-synaptic membrane. While Synaptobrevin-2 is part of a four-helix bundle in this SNARE complex, it is natively unstructured in the absence of lipids or other SNARE proteins.

Dendritic polyglycerol nanoparticles show charge dependent bio-distribution in early human placental explants and reduce hCG secretion.

A thorough understanding of nanoparticle bio-distribution at the feto-maternal interface will be a prerequisite for their diagnostic or therapeutic application in women of childbearing age and for teratologic risk assessment. Therefore, the tissue interaction of biocompatible dendritic polyglycerol nanoparticles (dPG-NPs) with first- trimester human placental explants were analyzed and compared to less sophisticated trophoblast-cell based models. First-trimester human placental explants, BeWo cells and primary trophoblast cells from human term placenta were exposed to fluorescence labeled, ∼5 nm dPG-NPs, with differently charged surfaces, at concentrations of 1 µM and 10 nM, for 6 and 24 h.

NFGAIL Amyloid Oligomers: The Onset of Beta-Sheet Formation and the Mechanism for Fibril Formation.

The hexapeptide NFGAIL is a highly amyloidogenic peptide, derived from the human islet amyloid polypeptide (hIAPP). Recent investigations indicate that presumably soluble hIAPP oligomers are one of the cytotoxic species in type II diabetes. Here we use thioflavin T staining, transmission electron microscopy, as well as ion mobility-mass spectrometry coupled to infrared (IR) spectroscopy to study the amyloid formation mechanism and the quaternary and secondary structure of soluble NFGAIL oligomers.

Hybrid Silicon-Based Organic/Inorganic Block Copolymers with Sol-Gel Active Moieties: Synthetic Advances, Self-Assembly and Applications in Biomedicine and Materials Science.

Hybrid silicon-based organic/inorganic (multi)block copolymers are promising polymeric precursors to create robust nano-objects and nanomaterials due to their sol-gel active moieties via self-assembly in solution or in bulk. Such nano-objects and nanomaterials have great potential in biomedicine as nanocarriers or scaffolds for bone regeneration as well as in materials science as Pickering emulsifiers, photonic crystals or coatings/films with antibiofouling, antibacterial or water- and oil-repellent properties. Thus, this Review outlines recent synthetic efforts in the preparation of these hybrid inorganic/organic block copolymers, gives an overview of their self-assembled structures and finally presents recent examples of their use in the biomedical field and material science.

Global substitution of hemeproteins with noncanonical amino acids in Escherichia coli with intact cofactor maturation machinery.

Global substitution of canonical amino acids (cAAs) with noncanonical (ncAAs) counterparts in proteins whose function is dependent on post-translational events such as cofactor binding is still a methodically challenging and difficult task as ncAA insertion generally interferes with the cofactor biosynthesis machinery. Here, we report a technology for the expression of fully substituted and functionally active cofactor-containing hemeproteins. The maturation process which yields an intact cofactor is timely separated from cAA→ncAA substitutions.

Deciphering the Fluorine Code-The Many Hats Fluorine Wears in a Protein Environment.

Deciphering the fluorine code is how we describe not only the focus of this Account, but also the systematic approach to studying the impact of fluorine's incorporation on the properties of peptides and proteins used by our groups and others. The introduction of fluorine has been shown to impart favorable, but seldom predictable, properties to peptides and proteins, but up until about two decades ago the outcomes of fluorine modification of peptides and proteins were largely left to chance. Driven by the motivation to extend the application of the unique properties of the element fluorine from medicinal and agro chemistry to peptide and protein engineering we have established extensive research programs that enable the systematic investigation of effects that accompany the introduction of fluorine into this class of biopolymers.

Dielectric analysis of the upper critical solution temperature behaviour of a poly(acrylamide-co-acrylonitrile) copolymer system in water.

A copolymer consisting of acrylamide (AAm) and acrylonitrile (AN) in aqueous solution was investigated using broadband dielectric spectroscopy at frequencies between 10 Hz and 10 Hz in the temperature range from 2 °C to 60 °C. This system shows an UCST phase behavior. The phase transition and aggregation behavior is monitored by both the temperature and frequency dependence of the complex conductivity σ*(f, T), where the AN fraction and the concentration of the solution were varied.

Discovery and Investigation of Natural Editing Function against Artificial Amino Acids in Protein Translation.

Fluorine being not substantially present in the chemistry of living beings is an attractive element in tailoring novel chemical, biophysical, and pharmacokinetic properties of peptides and proteins. The hallmark of ribosome-mediated artificial amino acid incorporation into peptides and proteins is a broad substrate tolerance, which is assumed to rely on the absence of evolutionary pressure for efficient editing of artificial amino acids. We used the well-characterized editing proficient isoleucyl-tRNA synthetase (IleRS) from to investigate the crosstalk of aminoacylation and editing activities against fluorinated amino acids.

Biocatalysis with Unnatural Amino Acids: Enzymology Meets Xenobiology.

The goal of xenobiology is to design biological systems endowed with unusual biochemical functions, whereas enzymology concerns the study of enzymes, the workhorses of biocatalysis. Biocatalysis employs enzymes and organisms to perform useful biotransformations in synthetic chemistry and biotechnology. During the past few years, the effects of incorporating noncanonical amino acids (ncAAs) into enzymes with potential applications in biocatalysis have been increasingly investigated.

Phase transition and aggregation behaviour of an UCST-type copolymer poly(acrylamide-co-acrylonitrile) in water: effect of acrylonitrile content, concentration in solution, copolymer chain length and presence of electrolyte.

An UCST-type copolymer of acrylamide (AAm) and acrylonitrile (AN) (poly(AAm-co-AN)) was prepared by reversible addition fragmentation chain transfer (RAFT) polymerization and its temperature-induced phase transition and aggregation behaviour studied by turbidimetry, static and dynamic light scattering, small angle neutron scattering (SANS) and cryo-transmission electron microscopy (cryo-TEM) measurements. The phase transition temperature was found to increase with increasing AN content in the copolymer, concentration of the solutions and copolymer chain length. A significant effect was observed onto the phase transition temperature by addition of different electrolytes into the copolymer solution.

Tuning the Surface of Nanoparticles: Impact of Poly(2-ethyl-2-oxazoline) on Protein Adsorption in Serum and Cellular Uptake.

Due to the adsorption of biomolecules, the control of the biodistribution of nanoparticles is still one of the major challenges of nanomedicine. Poly(2-ethyl-2-oxazoline) (PEtOx) for surface modification of nanoparticles is applied and both protein adsorption and cellular uptake of PEtOxylated nanoparticles versus nanoparticles coated with poly(ethylene glycol) (PEG) and non-coated positively and negatively charged nanoparticles are compared. Therefore, fluorescent poly(organosiloxane) nanoparticles of 15 nm radius are synthesized, which are used as a scaffold for surface modification in a grafting onto approach.

Temperature-Triggered Protein Adsorption on Polymer-Coated Nanoparticles in Serum.

The protein corona, which forms on the nanoparticle's surface in most biological media, determines the nanoparticle's physicochemical characteristics. The formation of the protein corona has a significant impact on the biodistribution and clearance of nanoparticles in vivo. Therefore, the ability to influence the formation of the protein corona is essential to most biomedical applications, including drug delivery and imaging.

Time-Resolved Electron Paramagnetic Resonance Study of Photoinduced Electron Transfer in Pd Porphyrin-Quinone and Zn Porphyrin-Quinone Dyads with a Cyclohexylene Spacer.

Peculiarities of the light induced intramolecular electron transfer processes in two ensembles where Pd porphyrin and Zn porphyrin donors with similar peripheral substituents are covalently linked via cyclohexylene spacer with a quinone acceptor, were studied by time-resolved electron paramagnetic resonance spectroscopy in different phases of the magnetically oriented nematic liquid crystal E-7. In the photoexcited PdP-Q the net absorptive signal was observed and ascribed to the thermally equilibrated spectrum of (3)*(PdP(•+)-Q(•-)). In ZnP-Q photoinduced intramolecular electron transfer was also found.

Impact of multivalent charge presentation on peptide-nanoparticle aggregation.

Strategies to achieve controlled nanoparticle aggregation have gained much interest, due to the versatility of such systems and their applications in materials science and medicine. In this article we demonstrate that coiled-coil peptide-induced aggregation based on electrostatic interactions is highly sensitive to the length of the peptide as well as the number of presented charges. The quaternary structure of the peptide was found to play an important role in aggregation kinetics.

Protomers of benzocaine: solvent and permittivity dependence.

The immediate environment of a molecule can have a profound influence on its properties. Benzocaine, the ethyl ester of para-aminobenzoic acid that finds an application as a local anesthetic, is found to adopt in its protonated form at least two populations of distinct structures in the gas phase, and their relative intensities strongly depend on the properties of the solvent used in the electrospray ionization process. Here, we combine IR-vibrational spectroscopy with ion mobility-mass spectrometry to yield gas-phase IR spectra of simultaneously m/z and drift-time-resolved species of benzocaine.

Functionalized polyglycerol amine nanogels as nanocarriers for DNA.

Polyglycerol based nanogels (nPG) can function as cellular delivery systems. These nPGs are synthesized with different amine densities (nPG amines) by acid-catalyzed epoxide-opening polymerization using a mini-emulsion approach and surface modification. All the synthesized nanogels are characterized by NMR, dynamic light scattering, and ζ-potential, showing slightly positive surface charge and a homogeneous size of ≈100 nm.

Penetration of normal, damaged and diseased skin--an in vitro study on dendritic core-multishell nanotransporters.

A growing intended or accidental exposure to nanoparticles asks for the elucidation of potential toxicity linked to the penetration of normal and lesional skin. We studied the skin penetration of dye-tagged dendritic core-multishell (CMS) nanotransporters and of Nile red loaded CMS nanotransporters using fluorescence microscopy. Normal and stripped human skin ex vivo as well as normal reconstructed human skin and in vitro skin disease models served as test platforms.

Chemical aminoacylation of tRNAs with fluorinated amino acids for in vitro protein mutagenesis.

This article describes the chemical aminoacylation of the yeast phenylalanine suppressor tRNA with a series of amino acids bearing fluorinated side chains via the hybrid dinucleotide pdCpA and ligation to the corresponding truncated tRNA species. Aminoacyl-tRNAs can be used to synthesize biologically relevant proteins which contain fluorinated amino acids at specific sites by means of a cell-free translation system. Such engineered proteins are expected to contribute to our understanding of discrete fluorines' interaction with canonical amino acids in a native protein environment and to enable the design of fluorinated proteins with arbitrary desired properties.

Towards identifying preferred interaction partners of fluorinated amino acids within the hydrophobic environment of a dimeric coiled coil peptide.

Phage display technology has been applied to screen for preferred interaction partners of fluoroalkyl-substituted amino acids from the pool of the 20 canonical amino acids. A parallel, heterodimeric alpha-helical coiled coil was designed such that one peptide strand contained one of three different fluorinated amino acids within the hydrophobic core. The direct interaction partners within the second strand of the dimer were randomized and coiled coil pairing selectivity was used as a parameter to screen for the best binding partners within the peptide library.