TY  - JOUR
A1  - Molinnus, Denise
A1  - Sorich, Maren
A1  - Bartz, Alexander
A1  - Siegert, Petra
A1  - Willenberg, Holger S.
A1  - Lisdat, Fred
A1  - Poghossian, Arshak
A1  - Keusgen, Michael
A1  - Schöning, Michael Josef
T1  - Towards an adrenaline biosensor based on substrate recycling amplification in combination with an enzyme logic gate
JF  - Sensors and Actuators B: Chemical
N2  - An amperometric biosensor using a substrate recycling principle was realized for the detection of low adrenaline concentrations (1 nM) by measurements in phosphate buffer and Ringer’s solution at pH 6.5 and pH 7.4, respectively. In proof-of-concept experiments, a Boolean logic-gate principle has been applied to develop a digital adrenaline biosensor based on an enzyme AND logic gate. The obtained results demonstrate that the developed digital biosensor is capable for a rapid qualitative determination of the presence/absence of adrenaline in a YES/NO statement. Such digital biosensor could be used in clinical diagnostics for the control of a correct insertion of a catheter in the adrenal veins during adrenal venous-sampling procedure.
Y1  - 2016
U6  - http://dx.doi.org/10.1016/j.snb.2016.06.064
SN  - 0925-4005
VL  - 237
SP  - 190
EP  - 195
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Riedel, Marc
A1  - Kartchemnik, Julia
A1  - Schöning, Michael Josef
A1  - Lisdat, Fred
T1  - Impedimetric DNA detection – steps forward to sensorial application
JF  - Analytical chemistry
N2  - This study describes a label-free impedimetric sensor based on short ssDNA recognition elements for the detection of hybridization events. We concentrate on the elucidation of the influence of target length and recognition sequence position on the sensorial performance. The impedimetric measurements are performed in the presence of the redox system ferri-/ferrocyanide and show an increase in charge transfer resistance upon hybridization of ssDNA to the sensor surface. Investigations on the impedimetric signal stability demonstrate a clear influence of the buffers used during the sensor preparation and the choice of the passivating mercaptoalcanol compound. A stable sensor system has been developed, enabling a reproducible detection of 25mer target DNA in the low nanomolar range. After hybridization, a sensor regeneration can be reached with deionized water by adjustment of effective convection conditions, ensuring a sensor reusability. By investigations of longer targets with overhangs exposed to the solution, we can demonstrate applicability of the impedimetric detection for longer ssDNA. However, a decreasing charge transfer resistance change (ΔRct) is found by extending the overhang. As a strategy to increase the impedance change for longer target strands, the position of the recognition sequence can be designed in a way that a small overhang is exposed to the electrode surface. This is found to result in an increase in the relative Rct change. These results suggest that DNA and consequently negative charge near the electrode possess a larger impact on the impedimetric signal than DNA further away.
Y1  - 2014
U6  - http://dx.doi.org/10.1021/ac501800q
SN  - 1520-6882 (E-Journal); 0003-2700 (Print); 0096-4484 (Print)
VL  - 86 (2014)
IS  - 15
SP  - 7867
EP  - 7874
PB  - ACS Publications
CY  - Columbus
ER  -