Self-assembled monolayers of supramolecular compounds for chemical sensors

We have studied the application of self-assembled resorcin[4]arene monolayers as chemically sensitive coating of quartz microalance sensors. Resorcin[4]arenes are typical supramolecular compounds with a molecular cavity formed by an aromatic ring system. The latter provides lipophilic binding sites and acts therefore as a molecular recognition structure for organic molecules. Reosrcinarenes are of particular interest for the selective detection of organic molecules in the gas and liquid phase. A high level of molecular order can be achieved by using modified cage compounds: dialkylsulfide-substituted resorcin[4]arene derivatives (with 4 aromatic rings) form well-ordered monolayers at Au surfaces by a self-assembling process which occurs spontaneously in ethanol/chloroform solutions of thes resorcin[4]arene derivatives. The driving force is the formation of very stable AuS bonds and the van der Waals interaction between the alkyl chains. We present results on the structure of resorcin[4]arene monolayers and their interactions with organic molecules. These results were obtained from angle-resolved X-ray photoelectron spectroscopy (AR-XPS) and thermal desorption spectroscopy (TDS). The latter techniques makes it possible to determine binding energies of the molecule/resorcin[4]arene ‘key-lock’ interaction. The binding energies are then compared with mass changes Δm which are obtained from quartz microbalance oscillators with their Au electrodes coated with resorcin[4]arene monolayers. We tested different organic molecules in the gas and liquid phase such as tetrachloroethane (C2Cl4), Trichloroethylene (HClCCCl2), tetrachloromethane (CCl4), chloroform (CHCl3) and toluene (H3C-C6H5). By far the most pronounced sensor response and hence highest selectivity was observed to tetrachloroethene (C2Cl4)

Duennschichttechnologische Erforschung und physikalisch-chemische Charakterisierung organischer und metallorganischer Schichten in Wechselwirkung mit technischen Gasen Teilprojekt: Grenzflaechenanalytik zur Optimierung organischer Schichtsysteme. Abschlussbericht

SIGLEAvailable from TIB Hannover: F94B1221+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Genetic Variants in ARHGEF6 Cause Congenital Anomalies of the Kidneys and Urinary Tract in Humans, Mice, and Frogs.

BACKGROUND: About 40 disease genes have been described to date for isolated CAKUT, the most common cause of childhood CKD. However, these genes account for only 20% of cases. ARHGEF6, a guanine nucleotide exchange factor that is implicated in biologic processes such as cell migration and focal adhesion, acts downstream of integrin-linked kinase (ILK) and parvin proteins. A genetic variant of ILK that causes murine renal agenesis abrogates the interaction of ILK with a murine focal adhesion protein encoded by Parva , leading to CAKUT in mice with this variant. METHODS: To identify novel genes that, when mutated, result in CAKUT, we performed exome sequencing in an international cohort of 1265 families with CAKUT. We also assessed the effects in vitro of wild-type and mutant ARHGEF6 proteins, and the effects of Arhgef6 deficiency in mouse and frog models. RESULTS: We detected six different hemizygous variants in the gene ARHGEF6 (which is located on the X chromosome in humans) in eight individuals from six families with CAKUT. In kidney cells, overexpression of wild-type ARHGEF6 -but not proband-derived mutant ARHGEF6 -increased active levels of CDC42/RAC1, induced lamellipodia formation, and stimulated PARVA-dependent cell spreading. ARHGEF6-mutant proteins showed loss of interaction with PARVA. Three-dimensional Madin-Darby canine kidney cell cultures expressing ARHGEF6-mutant proteins exhibited reduced lumen formation and polarity defects. Arhgef6 deficiency in mouse and frog models recapitulated features of human CAKUT. CONCLUSIONS: Deleterious variants in ARHGEF6 may cause dysregulation of integrin-parvin-RAC1/CDC42 signaling, thereby leading to X-linked CAKUT