Label-free protein detection based on the heat-transfer method-a case study with the peanut allergen Ara h 1 and aptamer-based synthetic receptors

© 2015 American Chemical Society. Aptamers are an emerging class of molecules that, because of the development of the systematic evolution of ligands by exponential enrichment (SELEX) process, can recognize virtually every target ranging from ions, to proteins, and even whole cells. Although there are many techniques capable of detecting template molecules with aptamer-based systems with high specificity and selectivity, they lack the possibility of integrating them into a compact and portable biosensor setup. Therefore, we will present the heat-transfer method (HTM) as an interesting alternative because this offers detection in a fast and low-cost manner and has the possibility of performing experiments with a fully integrated device. This concept has been demonstrated for a variety of applications including DNA mutation analysis and screening of cancer cells. To the best our knowledge, this is the first report on HTM-based detection of proteins, in this case specifically with aptamer-type receptors. For proof-of-principle purposes, measurements will be performed with the peanut allergen Ara h 1 and results indicate detection limits in the lower nanomolar regime in buffer liquid. As a first proof-of-application, spiked Ara h 1 solutions will be studied in a food matrix of dissolved peanut butter. Reference experiments with the quartz-crystal microbalance will allow for an estimate of the areal density of aptamer molecules on the sensor-chip surface

Soft X ray spectroscopy of light elements in energy storage materials

The increasing demand for electrochemical energy storage devices continuously promotes the development of new electrode materials and electrolytes. As a result, understanding their structural and electronic properties affecting electrochemical performance becomes crucial. The role of light elements, which are found in anode and cathode materials, in electrolytes and hence in the solid-electrolyte interphases, requires a special attention. Soft X-ray spectroscopies are particularly relevant to probe selectively light elements in complex environment. Here, the recent advances in the characterization of light elements in energy storage materials by soft X-ray spectroscopy and microscopy techniques are reviewed. After introducing the main X-ray spectroscopic methods and their application to ex situ/in situ/operando characterization of electrochemical processes, the role of light elements in the electrode for supercapacitors and Li/Na-ion storage applications is described. The characterization of electrolytes and related ion solvation is then briefly reviewed before describing how the formation and evolution of solid-electrolyte interphases can be monitored with these methods. Finally, major challenges and future opportunities for soft X-rays spectroscopy in the context of electrochemical energy storage are highlighted

Catalytic oxidation of ascorbic acid via copper polypyridyl complex immobilized on glass

A monolayer of redox-active copper–polypyridyl complexes on glass support was utilized for catalytic oxidation of ascorbic acid showing high performance.</p

(3aR,8bR)-3a,8b-Dihydroxy-2-methylsulfanyl-3-nitro-1-phenyl-1,8b-dihydroindeno[1,2-b]pyrrol-4(3aH)-one

In the title compound, C18H14N2O5, the pyrrolidine ring adopts a shallow envelope conformation, with the C atom bearing the OH group (and remote from the N atom) displaced by 0.257&#8197;(2)&#8197;&#197; from the other atoms. The cyclopentane ring has a twisted conformation about the C&#8212;C bond bearing one =O and one &#8212;OH grouping. The dihedral angle between the five-membered rings (all atoms) is 65.54&#8197;(9)&#176; and the OH groups lie to the same side of the ring-junction. The molecular structure features a weak intramolecular O&#8212;H...O bond and a possible C&#8212;H...&#960; interaction. In the crystal, the molecules are linked into [010] chains by O&#8212;H...O hydrogen bonds. Weak C&#8212;H...O bonds connect the chains into (100) sheets

(3aR*,8bR*)-3a,8b-Dihydroxy-1-(4-methylphenyl)-2-methylsulfanyl-3-nitro-1,8b-dihydroindeno[1,2-b]pyrrol-4(3aH)-one

The asymmetric unit of the title compound, C19H16N2O5S, contains four independent molecules (A, B, C and D), with two molecules (B and D) displaying disorder in their methylsulfanyl groups [occupancy ratios of 0.797 (11):0.203 (11) and 0.85 (2):0.15 (2)]. The nitro groups are twisted slightly out of the planes of the 2-pyrroline rings to which they are bonded with dihedral angles of 10.17 (1), 8.01 (1), 9.44 (1) and 8.87 (1)° in molecules A, B, C and D, respectively. The 2-pyrroline rings are almost orthogonal to the attached tolyl rings, forming dihedral angles of 73.44 (1), 81.21 (1), 88.18 (8) and 73.94 (1)° for molecules A, B, C and D, respectively. A weak intramolecular O—H...O interaction is observed in molecules B and C. The two hydroxy groups in each molecule are involved in intermolecular O—H...O hydrogen bonding. In the crystal, molecules are connected via O—H...O and C—H...O hydrogen bonds, forming a complex three-dimensional network

Unusual cause of crystalline nephropathy

Adenine phosphoribosyltransferase deficiency is a rare, inherited autosomal recessive disease presenting with 2,8-dihydroxyadenine (DHA) urolithiasis, DHA nephropathy, and chronic kidney disease. The presence of DHA crystals in urine and renal biopsy is pathognomonic of the disease. We report a 23-year-old female with acute renal failure and nephrotic proteinuria. Urinalysis showed reddish brown, round crystals with dark outline, and central spicules consistent with 2,8-DHA crystals. Renal biopsy showed membranous nephropathy and 2,8-DHA nephropathy. Our patient improved with liberal fluid intake, restriction of high adenine content foods, and oral xanthine dehydrogenase inhibitor febuxostat. Early diagnosis and initiation of treatment prevent renal complications

Hepatocurative potential of sesquiterpene lactones of Taraxacum officinale on carbon tetrachloride induced liver toxicity in mice

The hepatocurative potential of ethanolic extract (ETO) and sesquiterpene lactones enriched fraction (SL) of Taraxacum officinale roots was evaluated against carbon tetrachloride (CCl4) induced hepatotoxicity in mice. The diagnostic markers such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and total bilirubin contents were significantly elevated, whereas significant reduction in the level of reduced glutathione (GSH) and enhanced hepatic lipid peroxidation, liver weight and liver protein were observed in CCl4 induced hepatotoxicity in mice. Post-treatment with ETO and SL significantly protected the hepatotoxicity as evident from the lower levels of hepatic enzyme markers, such as serum transaminase (ALT, AST), ALP and total bilirubin. Further, significant reduction in the liver weight and liver protein in drug-treated hepatotoxic mice and also reduced oxidative stress by increasing reduced glutathione content and decreasing lipid peroxidation level has been noticed. The histopathological evaluation of the liver also revealed that ETO and SL reduced the incidence of liver lesions induced by CCl4. The results indicate that sesquiterpene lactones have a protective effect against acute hepatotoxicity induced by the administration of CCl4 in mice. Furthermore, observed activity of SL may be due to the synergistic action of two sesquiterpene lactones identified from enriched ethyl acetate fraction by HPLC method