Formaldehyde assay by capacitance versus voltage and impedance measurements using bi-layer bio-recognition membrane

Formaldehyde-sensitive sensor based on recombinant formaldehyde dehydrogenase using capacitance versus voltage measurements

“…On the contrary to bacterial FDH from Pseudomonas putida (Tanaka et al, 2003;Fujii et al, 2004), yeast FDH is dependent on two low molecular negatively charged compounds-NAD and glutathione (Schutte et al, 1976;Demkiv et al, 2005). To solve the cofactors problem, NAD + and reduced glutathione (GSH) were non-covalently incorporated into a bio-selective sensor membrane in high concentrations (Ben Ali et al, 2006), which supply the sufficient levels of the cofactors for a great number of assays. The high levels of the cofactors in biomembrane have been supported by using an additional negatively charged "Nafion" membrane covering the enzyme-and cofactors-containing one, which creates a diffusion barrier preventing a leakage of the cofactor from the bioactive zone of biosensors.…”

Direct fabrication of 3D graphene on nanoporous anodic alumina by plasma-enhanced chemical vapor deposition

“…Table 1 compares the specific capacitance and the overall capacitance of G-AAO (1 cm × 1 cm × 0.1 mm) with the same-sized gold electrode 45 46 , which is a commonly used bio-capacitor. The G-AAO and gold electrodes were tested in solution and biased at −1 V. It can be seen from the table that although the specific capacitance of G-AAO is smaller than that of gold, the overall capacitance is much larger for the G-AAO electrode due to its much larger surface area.…”

Formaldehyde Oxidizing Enzymes and Genetically Modified Yeast Hansenula polymorpha Cells in Monitoring and Removal of Formaldehyde

“…A similar FA sensitive biosensor based on commercial preparation of bacterial FdDH as recognizing element has been also described (Ben Ali et al, 2006). As transducers, gold electrodes SiO 2 /Si/SiO 2 /Ti/Au and electrolyte-insulator-semiconductor Si/SiO 2 structures (EIS) have been used.…”

“…FA can also be found in the air and enter the one carbon pool for incorporation into the cells constituents (CasanovaSchmitz, 1984). At the moment, three different FdDHes, bacterial NAD + -dependent, yeast NAD + -and GSH-dependent and bacterial dye-linked NAD + and GSH-independent, are widely used for bioanalytical purposes (Ben Ali et al, 2006Winter and Cammann, 1989;Vastarella and Nicastri, 2005;Herschkovitz et al, 2000;Korpan et al, 1993;Gonchar et al, 2002;Korpan et al, 2010;Achmann et al, 2008;Kawamura et al, 2005). Besides FdDH, FA can be easily oxidized by alcohol oxidase (AOX) (EC 1.1.3.13), an enzyme which is responsible in vivo for the first reaction of methanol metabolism in methylotrophic yeast (Klei van der et al, 1990).…”