Selective Perchlorate Sensing Using Electrochemical Impedance Spectroscopy with Self-Assembled Monolayers of semiaza-Bambusurils

In the last two decades, perchlorate salts have been identified as environmental pollutants and recognized as potential substances affecting human health. We describe self-assembled monolayers (SAMs) of novel semiaza-bambus[6]urils (semiaza-BUs) equipped with thioethers or disulfide (dithiolane) functionalities as surface-anchoring groups on gold electrodes. Cyclic voltammetry (CV) with Fe(CN)63−/4− as a redox probe, together with X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and ellipsometry, were employed to characterize the interactions at the interface between the anchoring groups and the metal substrate. Data showed that the anion receptors′ packing on the gold strongly depends on the anchoring group. As a result, SAMs of BUs with lipoic amide side chains show a concentration-dependent layer thickness. The BU SAMs are extremely stable on repeated electrochemical potential scans and can selectively recognize perchlorate anions. Our electrochemical impedance spectroscopy (EIS) studies indicated that semiaza-BU equipped with the lipoic amide side chains binds perchlorate (2–100 mM) preferentially over other anions such as F−, Cl−, I−, AcO−, H2PO4−, HPO42−, SO42−, NO2−, NO3−, or CO32−. The resistance performance is 10 to 100 times more efficient than SAMs containing all other tested anions.</p

The ND2 subunit is labeled by a photoaffinity analogue of asimicin, a potent complex I inhibitor

AbstractNADH:ubiquinone oxidoreductase (complex I) is the entry enzyme of mitochondrial oxidative phosphorylation. To obtain the structural information on inhibitor/quinone binding sites, we synthesized [3H]benzophenone-asimicin ([3H]BPA), a photoaffinity analogue of asimicin, which belongs to the acetogenin family known as the most potent complex I inhibitor. We found that [3H]BPA was photo-crosslinked to ND2, ND1 and ND5 subunits, by the three dimensional separation (blue-native/doubled SDS–PAGE) of [3H]BPA-treated bovine heart submitochondrial particles. The cross-linking was blocked by rotenone. This is the first finding that ND2 was photo-crosslinked with a potent complex I inhibitor, suggesting its involvement in the inhibitor/quinone-binding

Biologically Relevant Molecular Transducer with Increased Computing Power and Iterative Abilities

SummaryAs computing devices, which process data and interconvert information, transducers can encode new information and use their output for subsequent computing, offering high computational power that may be equivalent to a universal Turing machine. We report on an experimental DNA-based molecular transducer that computes iteratively and produces biologically relevant outputs. As a proof of concept, the transducer accomplished division of numbers by 3. The iterative power was demonstrated by a recursive application on an obtained output. This device reads plasmids as input and processes the information according to a predetermined algorithm, which is represented by molecular software. The device writes new information on the plasmid using hardware that comprises DNA-manipulating enzymes. The computation produces dual output: a quotient, represented by newly encoded DNA, and a remainder, represented by E. coli phenotypes. This device algorithmically manipulates genetic codes