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Bonn, Germany

Bortolini C.,The Interdisciplinary Center | Bortolini C.,CAS National Center for Nanoscience and Technology | Liu L.,The Interdisciplinary Center | Liu L.,Jiangsu University | And 4 more authors.
Soft Matter | Year: 2014

The final structure and properties of synthetic peptides mainly depend on their sequence composition and experimental conditions. This work demonstrates that a variation in the positions of hydrophobic residues within a peptide sequence can tune the self-assembly. Techniques employed are atomic force microscopy, transmission electron microscopy and an innovative method based on surface acoustic waves. In addition, a systematic investigation on pH dependence was carried out by utilizing constant experimental parameters. © the Partner Organisations 2014. Source


Cavallari M.,University of Basel | Cavallari M.,Whitehead Institute For Biomedical Research | Stallforth P.,Max Planck Institute of Colloids and Interfaces | Stallforth P.,Leibniz Institute for Natural Product Research and Infection Biology | And 11 more authors.
Nature Chemical Biology | Year: 2014

Severe forms of pneumococcal meningitis, bacteraemia and pneumonia result in more than 1 million deaths each year despite the widespread introduction of carbohydrate-protein conjugate vaccines against Streptococcus pneumoniae. Here we describe a new and highly efficient antipneumococcal vaccine design based on synthetic conjugation of S. pneumoniae capsule polysaccharides to the potent lipid antigen a-galactosylceramide, which stimulates invariant natural killer T (iNKT) cells when presented by the nonpolymorphic antigen-presenting molecule CD1d. Mice injected with the new lipid-carbohydrate conjugate vaccine produced high-affinity IgG antibodies specific for pneumococcal polysaccharides. Vaccination stimulated germinal center formation; accumulation of iNKT cells with a T follicular helper cell phenotype; and increased frequency of carbohydrate-specific, long-lived memory B cells and plasmablasts. This new lipid-carbohydrate vaccination strategy induced potent antipolysaccharide immunity that protected against pneumococcal disease in mice and may also prove effective for the design of carbohydrate-based vaccines against other major bacterial pathogens. © 2014 Nature America, Inc. All rights reserved. Source


Slamnoiu S.,University of Konstanz | Vlad C.,University of Konstanz | Vlad C.,SAW Instruments | Stumbaum M.,University of Konstanz | And 13 more authors.
Journal of the American Society for Mass Spectrometry | Year: 2014

Bioaffinity analysis using a variety of biosensors has become an established tool for detection and quantification of biomolecular interactions. Biosensors, however, are generally limited by the lack of chemical structure information of affinity-bound ligands. On-line bioaffinity-mass spectrometry using a surface-acoustic wave biosensor (SAW-MS) is a new combination providing the simultaneous affinity detection, quantification, and mass spectrometric structural characterization of ligands. We describe here an on-line SAW-MS combination for direct identification and affinity determination, using a new interface for MS of the affinity-isolated ligand eluate. Key element of the SAW-MS combination is a microfluidic interface that integrates affinity-isolation on a gold chip, in-situ sample concentration, and desalting with a microcolumn for MS of the ligand eluate from the biosensor. Suitable MS- acquisition software has been developed that provides coupling of the SAW-MS interface to a Bruker Daltonics ion trap-MS, FTICR-MS, and Waters Synapt-QTOF- MS systems. Applications are presented for mass spectrometric identifications and affinity (KD) determinations of the neurodegenerative polypeptides, ß-amyloid (Aß), and pathophysiological and physiological synucleins (α- and ß-synucleins), two key polypeptide systems for Alzheimer's disease and Parkinson's disease, respectively. Moreover, first in vivo applications of αSyn polypeptides from brain homogenate show the feasibility of on-line affinity-MS to the direct analysis of biological material. These results demonstrate on-line SAW-bioaffinity-MS as a powerful tool for structural and quantitative analysis of biopolymer interactions. © 2014 American Society for Mass Spectrometry. Source


Broker P.,University of Potsdam | Lucke K.,GILUPI GmbH | Perpeet M.,SAW Instruments | Gronewold T.M.A.,SAW Instruments
Sensors and Actuators, B: Chemical | Year: 2012

A nanostructured chip surface was fabricated enabling binding via spaced antibodies specifically targeting surface proteins of cancer cells and detection of extremely low numbers of circulating tumor cells (CTC) without labeling using a sam ® 5 biosensor. The antibody surfaces mostly were generated by self assembly of antibodies to gold nanospots on the sensitive SiO 2-surface of a sam ® 5 chip. Compared with a complete gold surface, only 40% of the amount of antibodies was bound to the nanospot surface, but structured such that 15-fold higher sensitivity to vital cancer cells was achieved. Human cancer cell lines JEG-3 (lymphoblastic leukemia) and MOLT-17 (placental choriocarcinoma) from cell cultures were successfully detected. The sensor showed significant responses on less than 10 cells injected in a single run. The extreme increase in sensitivity and its simple regeneration emphasizes the usefulness of its introduction in biomedical applications. © 2012 Elsevier B.V. All rights reserved. Source


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