TY  - JOUR
A1  - Yarman, Aysu
A1  - Badalyan, Artavazd
A1  - Gajovic-Eichelmann, Nenad
A1  - Wollenberger, Ursula
A1  - Scheller, Frieder W.
T1  - Enzyme electrode for aromatic compounds exploiting the catalytic activities of microperoxidase-11
JF  - Biosensors and bioelectronics : the principal international journal devoted to research, design development and application of biosensors and bioelectronics
N2  - Microperoxidase-11 (MR-11) which has been immobilised in a matrix of chitosan-embedded gold nanoparticles on the surface of a glassy carbon electrode catalyzes the conversion of aromatic substances. This peroxide-dependent catalysis of microperoxidase has been applied in an enzyme electrode for the first time to indicate aromatic compounds such as aniline. 4-fluoroaniline, catechol and p-aminophenol. The electrode signal is generated by the cathodic reduction of the quinone or quinoneimine which is formed in the presence of both MP-II and peroxide from the substrate. The same sensor principle will be extended to aromatic drugs.
KW  - Microperoxidase-11
KW  - Nanoparticles
KW  - p-Aminophenol
KW  - Aniline
KW  - Catechol
KW  - 4-Fluoroaniline
KW  - Biosensors
Y1  - 2011
U6  - https://doi.org/10.1016/j.bios.2011.09.004
SN  - 0956-5663
VL  - 30
IS  - 1
SP  - 320
EP  - 323
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Yildirim-Semerci, Cigdem
A1  - Benayahu, Dafna
A1  - Adamovski, Miriam
A1  - Wollenberger, Ursula
T1  - An Electrochemical Assay for Monitoring Differentiation of the Osteoblastic Cell Line (MBA-15) on the Sensor Chip
JF  - Electroanalysis : an international journal devoted to fundamental and practical aspects of electroanalysis
N2  - An electrochemical assay for the indication of the activity of the cell bound differentiation marker alkaline phosphatase (ALP) is proposed using voltammetry on an in-vitro cell culture. The basis of the assay is cultivation of cells on gold microelectrodes in wells of a microplate, catalytic hydrolysis of p-aminophenyl phosphate by ALP and indication of p-aminophenol oxidation by square wave voltammetry (SWV) with the sensors onto which the cells attached. The morphology of the bone marrow stromal cell line (MBA-15) on the electrode surface was investigated and it exhibited in vitro osteogenic characteristics. Since ALP is expressed on the cell surface in early differentiation stage of osteoblastic cells, its activity was followed after different culture times over a period of 144 h by recording repetitive voltammograms at different time points upon addition of the substrate p-aminophenyl phosphate. The ALP activity was estimated from the signal increase related to formation rate of p-aminophenol and the number of cells. The highest value was measured at 120 h, when the cells reached confluence. The results of the electrochemical activity assay are consistent with the colorimetric acquired value from p-nitrophenol formation rate.
KW  - Alkaline phosphatase
KW  - Osteoblast
KW  - Voltammetry
KW  - Biomarker
KW  - p-Aminophenol
Y1  - 2015
U6  - https://doi.org/10.1002/elan.201400684
SN  - 1040-0397
SN  - 1521-4109
VL  - 27
IS  - 6
SP  - 1350
EP  - 1358
PB  - Wiley-VCH
CY  - Weinheim
ER  -