Hans Börner - Academia.edu (original) (raw)

Papers by Hans Börner

Chemical Communications, 2014

The existence of multi-phonon vibrational states is once again the focus of a lively debate in nu... more The existence of multi-phonon vibrational states is once again the focus of a lively debate in nuclear structure physics. Theoretically, two-phonon vibrational bands were expected to occur at approximately twice the energy of the single vibrational phonons. Recently, there have been several reported observations of two-phonon vibrational bands where the ratio of excitation energies for the two and one phonon

Macromolecular Bioscience, 2014

Polymer-block-peptide conjugates are tailored to render hydrophobic small molecule drugs water so... more Polymer-block-peptide conjugates are tailored to render hydrophobic small molecule drugs water soluble. The combinatorial strategy selects for bioconjugates that exhibit sequencespecific solubilization and switchable release profiles of the cargo through incorporation of a disulfide linker moiety into the peptide-library design. While the study focused on the photosensitizer m-THPC and reductive carrier cleavage, the approach is generic and might be expanded toward a broad range of poorly soluble smallmolecule drugs and other selective cleavage mechanisms to disassemble a peptide binding domain of the bioconjugatebased solubilizer.

ACS Symposium Series, 2014

Soft Matter, 2008

... CO 2 -switchable oligoamine patches based on amino acids and their use to build polyelectroly... more ... CO 2 -switchable oligoamine patches based on amino acids and their use to build polyelectrolyte containers with intelligent gating. Laura Hartmann, Matthieu Bedard, Hans G. Börner, Helmut Möhwald, Gleb B. Sukhorukov and Markus Antonietti Soft Matter, 2008, 4, 534-539. ...

Progress in Polymer Science, 2008

... these novel class of macromolecules have been shown to be useful in many other emerging areas... more ... these novel class of macromolecules have been shown to be useful in many other emerging areas of ... These novel synthetic trends are discussed in details in the present manuscript ... gained increased attention in materials science [5], [6] and [7]. For instance, the modern range of ...

Macromolecules, 2008

... Bulmus, V.; Herlambang, DL; Barner-Kowollik, C.; Stenzel, MH; Davis, TR Angew. Chem., Int. Ed... more ... Bulmus, V.; Herlambang, DL; Barner-Kowollik, C.; Stenzel, MH; Davis, TR Angew. Chem., Int. Ed. ... Peptide/Protein−Synthetic Polymer Conjugates: Quo Vadis. Harm-Anton Klok. Macromolecules 2009 42 (21), 7990-8000. Peptide/Protein−Synthetic Polymer Conjugates: Quo Vadis. ...

Macromolecules, 2006

The synthesis of peptide-polymer conjugates comprising (D-alt-L)-cyclopeptides as aggregator doma... more The synthesis of peptide-polymer conjugates comprising (D-alt-L)-cyclopeptides as aggregator domains and their self-assembly into tubelike structures is described. By coupling two well-defined poly(n-butyl acrylate) blocks to opposite sides of a preformed cyclic (D-alt-L)-R-octapeptide, a coil-ring-coil bioconjugate was accessed. The applied solution-phase coupling route allowed a multigram scale synthesis of the conjugate and assured both a controlled synthesis and ease of analysis. The controlled self-assembly of the conjugate leads to uniform tube structures. Atomic force microscopy (AFM) of these aggregates deposited on mica revealed a height of 1.4 (0.2 nm, a width of 5 nm, and roughly estimated lengths of up to 200-300 nm. A model is proposed, explaining the structure dimensions. This includes the formation of a tubular peptide core build via stacking of the cyclopeptides and a poly(n-butyl acrylate) shell wrapping around the peptide tube. The model is consistent with infrared spectroscopy and electron diffraction measurements, verifying that the peptide segment of the conjugate adopts a-sheet structure, similar to unsubstituted (D-alt-L)-cyclopeptides. Hence, the stacks of peptide rings are stabilized along the fiber axis via interring sheet H-bonding. The tube structures are capable to interact laterally, organizing further into weak networks as was evidenced by AFM and transmission electron microscopy.

Macromolecular Rapid Communications, 2010

The readers of Macromolecular Rapid Communications will probably be surprised by the title of thi... more The readers of Macromolecular Rapid Communications will probably be surprised by the title of this special issue. Indeed, Precision Macromolecular Chemistry does not correspond yet to a known sub-discipline in the field of polymer science. However, the adjective ‘‘precision’’ has been frequently used in recent years to describe certain aspects of polymer synthesis. In fact, it implicitly underlines a certain degree of accuracy in synthesizing macromolecules. Indeed, ‘‘precision’’ evokes immediately the skills of a traditional watchmaker. Thus, this term has been associated to certain aspects of polymer synthesis,which are generally difficult to control without accurate and adequate chemical tools. For instance, crucial macromolecular parameters such as polydispersity, tacticity, monomer sequences, and folding are still not fully mastered in current polymer science. Yet, very interesting approaches for controlling these molecular features have been reported during the past few years. These emerging trends are describe under the label Precision Macromolecular Chemistry in this special issue. In fact, the research topics presented herein differ in some ways from mainstream polymer science. During the past twenty years, polymer chemists developed unprecedented ways to control the architecture of synthetic polymers. Since the introduction of controlled radical polymerization techniques, such as atom transfer radical polymerization or reversible additionfragmentation chain-transfer polymerization, andafterwardof ‘‘click’’ ligation tools, such as copper-catalyzed azidealkyne cycloadditions or thiol-ene chemistry, the possibilities of macromolecular engineering have exploded. For instance, macromolecular architectures such as block copolymers, graft copolymers, star polymers, or macrocycles can nowadays be routinely synthesized. In addition, new types of

Macromolecular Rapid Communications, 2008

Macroscopic networks of oriented polymer-silica composite fibers can be accessed via a convenient... more Macroscopic networks of oriented polymer-silica composite fibers can be accessed via a convenient 2D-plotting process. By using self-assembled PEO-peptide nanotapes as an ink to draw the composite fibers, the macroscopic form of the fiber networks, the line width, and both network orientation as well as network anisotropy can be defined. The plotting process relies on a biomimetic silicification route, which combines self-assembly and peptide-directed silicification in a cooperative manner. The local injection of PEO-peptide nanotapes into a thin layer of a dilute solution of pre-hydrolyzed TMOS leads to the rapid formation of the composite fibers, which exhibit several levels of hierarchical order. It was shown, that the rate of plotting is a parameter, enabling one to control the line width and the orientation of the nano-and sub-micrometer structure elements in the network. Moreover, the plotted composite fibers can be used as precursors for networks of oriented, mesoporous silica-fibers. After calcination procedures, nonwoven silica fabrics can be obtained with high surface areas and cylindrical pores aligned in plot direction.

Angewandte Chemie International Edition, 2011

ABSTRACT A photoconjugation strategy based on light-triggered Diels-Alder addition of o-quinodime... more ABSTRACT A photoconjugation strategy based on light-triggered Diels-Alder addition of o-quinodimethanes is described. This method is compatible with biomolecules and proceeds rapidly at ambient temperature without the need of a catalyst. Spatial control was confirmed by photopatterning of a small-molecule ATRP initiator, a polymer, and a peptide in a time-of-flight secondary-ion mass spectrometry investigation.

ACS Nano, 2011

We report herein the synthesis of a novel type of hybrid compound that consists of a poly(ethylen... more We report herein the synthesis of a novel type of hybrid compound that consists of a poly(ethylene oxide) (PEO) functionalized β-sheet peptide sequence covalently linked to an alkylated quaterthiophene moiety. Compounds of this class are highly promising for technological applications because their self-assembly and stimuli-responsive behavior, which is mainly caused by the peptide moieties, combined with the potential semiconducting properties of oligothiophenes provides unprecedented opportunities for the design of advanced materials at the nanoscale in such areas as, for example, organic electronics and sensor design for chemical and biomedical applications. The compound presented herein is experimentally shown to form stable fibrillar aggregates that are visualized by both transmission electron and atomic force microscopy. We developed a theoretical methodology to study the possible intermolecular arrangements and their characteristic features with the help of all-atom MD simulations, while simultaneously incorporating available experimental data into the model. Large-scale atomistic simulations of several fibrillar aggregates with different molecular arrangements were performed. The results of the simulations are compared with experimental data, which leads to the proposition of a likely model for the arrangement of the individual molecules within the observed aggregates.

Angewandte Chemie International Edition, 2007

Biological inorganic-bioorganic hybrid materials, from bones [1] to filaments of glass sponges [2... more Biological inorganic-bioorganic hybrid materials, from bones [1] to filaments of glass sponges [2, 3] to shells of mollusks, [4] are high-performance composites with properties welladapted to their purpose and frequently superior to synthetic mimics. [5, 6] This is a result of defined hierarchical structures that are formed by self-assembly and templating processes facilitated by proteins, peptides, or polysaccharides. [7] Marine glass sponges, for instance the hexactinellid sponge Euplectella sp., are considered to be one of the most primitive animals in existence. However, they produce integrated composite materials with outstanding mechanical properties. [2, 8] This material exhibits a rather complex design, thus ensuring the control of both mechanical and chemical interfaces between the different components to overcome the brittleness of the main constituent material, glass. [2] Inspired by the formation of bioglass filaments, [9] we report the peptide-directed silicification of self-assembled peptidepolymer nanotapes. The spontaneously formed reinforced silica fibers exhibit a distinct inner structure with six distinguishable levels of hierarchical order. Proteins such as silaffin [10] from diatoms or silicatein [11] from glass sponges catalyze and guide the formation of silica from dilute silicic acid solution at neutral pH in vivo and in vitro. [12] Deming et al. pioneered the mimicking of the functions of such proteins by using poly(cysteine-blocklysine). [13] This approach was further broadened by applying other polypeptides and polypeptide derivatives. [14] In addition, several low-molecular-weight compounds containing aamino acids were used to create chiral, mesoporous silica through sol-gel templating routes. [15] In analogy to the formation of biological glass fibers, we encoded the structural and functional information in a fiberlike nanostructure, which was particularly designed to direct the silicification process (Figure 1). To access these functional nanotapes (Figure 1 a), a peptide-polymer conjugate, which combines polyethylene oxide (PEO) with an oligopeptide segment, was synthesized and assembled as

Drug Testing and Analysis, 2018

Exposure to the vesicant sulfur mustard (SM) may lead to erythema and blistering. Toxicity of SM ... more Exposure to the vesicant sulfur mustard (SM) may lead to erythema and blistering. Toxicity of SM is hypothesized to be due to the alkylation of DNA bases and nucleophilic amino acid side chains in proteins (adducts) by forming the hydroxyethylthioethyl (HETE) moiety. Despite of its prohibition by the chemical weapons convention, SM still represents a serious threat to military personnel and civilians. Therefore, development and improvement of forensic analytical methods for the verification of SM exposure is of high interest. Protein adducts have been shown to be highly suitable and beneficial biomarkers of poisoning. Herein we present methionine 329 in human serum albumin (HSA) as a novel target of SM forming a HETE-methionyl sulfonium ion. The alkylated tetrapeptide LeuGlyMet 329 (-HETE)Phe, LGM(-HETE)F, was detected after pepsin mediated proteolysis and subsequent analysis by microbore liquid chromatography-electrospray ionization highresolution tandem-mass spectrometry. Compound identity was confirmed by a synthetic reference. Proteolysis conditions for HSA were optimized towards maximum yield of LGM(-HETE)F and its limit of identification (32.3 nM SM in serum) was similar to those of the established HSA-derived biomarkers HETE-CysPro and HETE-CysProPhe (15.6 nM SM in serum). Stability of the alkylated Met 329 in vitro and in vivo was limited to 5 days making this modification a beneficial short-time biomarker. Furthermore, it was found that the HETE-methionyl sulfonium ion can transfer its HETE moiety to the side chain of cysteine and glutamic acid as well as to the N-terminus of peptides and proteins in vitro thus revealing novel insights into the molecular toxicity of SM.

Polymers, 2014

Thermoresponsive polymer coatings allow the control of adhesion of cells on synthetic substrates.... more Thermoresponsive polymer coatings allow the control of adhesion of cells on synthetic substrates. In particular, decreasing the temperature below the lower critical solution temperature (LCST) of the polymer triggers the non-invasive detachment of cells from their cultivation substrate. Widening the range of applications of these coatings in cellular biotechnology requires a better understanding of their interaction with cells. By monitoring the morphological changes of cells during their detachment at various temperatures, we provide evidence that cell detachment is an active process. Analyses of cell residues that are left behind by the cells on the substrate during their detachment, further support this notion. In the second part of this work, we show that the kinetics of adhesion and the efficiency of detachment of cells can be controlled through the coadsorption of molecules bearing the peptide motif RGD (arginine-glycine-aspartic acid) with the polymers.

Langmuir, 2004

Individual molecules of multiarm starlike molecular brushes were visualized by atomic force micro... more Individual molecules of multiarm starlike molecular brushes were visualized by atomic force microscopy. In the studied series of brushes, the number of arms varied from one for a linear chain to four, while the length of the side chains was kept approximately constant. Molecular visualization provided a unique opportunity for independent size characterization of the brush arms separately from that of the entire molecule. In agreement with the Schulz-Flory theory for chain coupling, the polydispersity of the total length was significantly lower than that of the arm length. The variation in polydispersity had an effect on molecular ordering. Lateral compression of the starlike brushes caused a transition from an extended dendritic-like conformation to a compact disklike conformation. In contrast to one-, two-, and three-arm brushes, the four-arm molecules with a lower polydispersity index of 1.04 demonstrated local hexagonal order.

ACS Macro Letters, 2012

Aldrich and used as received. Tyrosinase was stored at-20°C. Human full blood serum (Sigma) was d... more Aldrich and used as received. Tyrosinase was stored at-20°C. Human full blood serum (Sigma) was diluted with millipore MQ, filtered prior to use and stored at-20°C. N-α-Fmoc protected amino acids Fmoc-Ala OH, Fmoc-Lys(Boc) OH, Fmoc-Pro OH, Fmoc-Ser(tBu) OH, Fmoc-Thr(tBu) OH, Fmoc-Tyr(Boc) OH, scavenger tri-methyl silylbromide (TMSBr) as well as coupling reagents 2-(1Hbenzotriazole-1-yl)-1,1,3,3-tertamethyluroniumhexafluorophosphate (HBTU), (benzotriazol-1yloxyl)tripyrrolidino-phosphoniumhexa-fluorophosphate (PyBOP), and N-methyl-2-pyrrolidone (NMP, 99.9+ %, peptide synthesis grade) were used as received from IRIS Biotech GmbH (Marktredwitz, Germany). TentaGel PAP resin (PEG attached peptide resin, loading: 0.27 mmol/g; Mw = 3200, PDI = 1.04) and TentaGel S RAM resin (loading: 0.24 mmol/g) were obtained from Rapp Polymere GmbH (Tübingen, Germany). N,N-diisopropylethylamine (DIPEA; peptide grade), piperidine (peptide grade) and L-3-(3,4-Dihydroxyphenyl)alanine (99%) were purchased from Acros and used without further purification. Triethylsilane (TES; Alfa Aesar, Karlsruhe, Germany, 98+ %), sodium chloride (NaCl, J.T. Baker), L(+)-ascorbic acid (≥99%, Roth, Karlsruhe, Germany) and guanidine hydrochloride (99.5%, Roth, Karlsruhe, Germany) have been applied as received. Trifluoroacetic acid (TFA; Acros, peptide grade) was distilled prior to use. Dichloromethane (DCM, IRIS Biotech GmbH, peptide grade) was distilled from CaH 2 prior to use.

J. Mater. Chem. B, 2014

The aggregation of amyloid-b peptide (Ab) has been linked to the formation of neuritic plaques, w... more The aggregation of amyloid-b peptide (Ab) has been linked to the formation of neuritic plaques, which are pathological hallmarks of Alzheimer's disease. We synthesized peptides containing fluorinated amino acids and studied their effect on the Ab aggregation. The peptides were based on the sequence LVFFD, in which valine was substituted by either 4,4,4-trifluorovaline or 4-fluoroproline, or the phenylalanine at position 3 was replaced by 3,4,5-trifluorophenylalanine. Our results demonstrate that fluorination of the hydrophobic residue valine or phenylalanine is effective in preventing the Ab aggregation. This study opens up the possibility of using new sequences based on fluorinated amino acids to inhibit the amyloid-fibril formation.