TY  - JOUR
A1  - Liu, Songqin
A1  - Wollenberger, Ursula
A1  - Halamek, Jan
A1  - Leupold, Eik
A1  - Stöcklein, Walter F. M.
A1  - Warsinke, Axel
A1  - Scheller, Frieder W.
T1  - Affinity interaction betwen phenylboronic acid-carrying self-assembled monolayers and FAD or HRP
N2  - A method is provided for the recognition of glycated molecules based on their binding affinities to boronate- carrying monolayers. The affinity interaction of flavin adenine dinucleotide (FAD) and horseradish peroxidase (HRP) with phenylboronic acid monolayers on gold was investigated by using voltammetric and microgravimetric methods. Conjugates of 3-aminopherrylboronic acid and 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester) or 11-mercaptoundecanoic acid were prepared and self-assembled on gold surfaces to generate monolayers. FAD is bound to this modified sur-face and recognized by a pair of redox peaks with a formal potential of -0.433 V in a 0.1 m phosphate buffer solution, pH 6.5. Upon addition of a sugar to the buffer, the bound FAD could be replaced, indicating that the binding is reversible. Voltammetric, mass measurements, and photometric activity assays show that the HRP can also be bound to the interface. This binding is reversible, and HRP can be replaced by sorbitol or removed in acidic solution. The effects of pH, incubation time, and concentration of H2O2 were studied by comparing the catalytic reduction of H2O2 in the presence of the electron-donor thionine. The catalytic current of the HRP-loaded electrode was proportional to HRP concentrations in the incubation solution in the range between 5 mu g mL(-1) and 0.4 mg mL(-1) with a linear slope of 3.34 mu A mL mg(-1) and a correlation coefficient of 0.9945
Y1  - 2005
ER  - 
TY  - JOUR
A1  - Halámek, Jan
A1  - Wollenberger, Ursula
A1  - Stöcklein, Walter F. M.
A1  - Warsinke, Axel
A1  - Scheller, Frieder W.
T1  - Signal amplification in immunoassays using labeling via boronic acid binding to the sugar moiety of immunoglobulin G : proof of concept for glycated hemoglobin
N2  - A novel electrochemical immunoassay based on the multiple affinity labeling of the indicator antibody with an electro-active tag is presented. The concept is illustrated for the determination of the glycated hemoglobin HbA1c in hemoglobin samples. Hemoglobin is adsorbed to the surfactant-modified surface of a piezoelectric quartz crystal. Whereas the quartz crystal nanobalance is used to validate the total Hb binding, the HbA1c on the sensor surface is recognized by an antibody and quantified electrochemically after the sugar moieties of the antibody have been labeled in-situ with ferroceneboronic acid. The sensitivity of this sensor is about threefold higher than the sensitivity of a hemoglobin sensor, where the ferroceneboronic acid is bound directly to HbA1c.
Y1  - 2007
UR  - http://www.informaworld.com/openurl?genre=journal&issn=0003-2719
U6  - https://doi.org/10.1080/00032710701327096
SN  - 0003-2719
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Wollenberger, Ursula
A1  - Warsinke, Axel
A1  - Lisdat, Fred
T1  - Research and development in biosensors
Y1  - 2001
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Bauer, Christian G.
A1  - Makower, Alexander
A1  - Wollenberger, Ursula
A1  - Warsinke, Axel
A1  - Bier, Frank Fabian
T1  - Immunoassays using enzymatic amplification electrodes
Y1  - 2002
SN  - 0-7484-0791-X
ER  - 
TY  - JOUR
A1  - Scheller, Frieder W.
A1  - Bauer, Christian G.
A1  - Markower, Alexander
A1  - Wollenberger, Ursula
A1  - Warsinke, Axel
A1  - Bier, Frank Fabian
T1  - Coupling of immunoassays with enzymatic recycling electrodes
Y1  - 2001
ER  -