TY  - JOUR
A1  - Rabehi, Amine
A1  - Garlan, Benjamin
A1  - Achtsnicht, Stefan
A1  - Krause, Hans-Joachim
A1  - Offenhäusser, Andreas
A1  - Ngo, Kieu
A1  - Neveu, Sophie
A1  - Graff-Dubois, Stephanie
A1  - Kokabi, Hamid
T1  - Magnetic detection structure for Lab-on-Chip applications based on the frequency mixing technique
JF  - Sensors
N2  - A magnetic frequency mixing technique with a set of miniaturized planar coils was investigated for use with a completely integrated Lab-on-Chip (LoC) pathogen sensing system. The system allows the detection and quantification of superparamagnetic beads. Additionally, in terms of magnetic nanoparticle characterization ability, the system can be used for immunoassays using the beads as markers. Analytical calculations and simulations for both excitation and pick-up coils are presented; the goal was to investigate the miniaturization of simple and cost-effective planar spiral coils. Following these calculations, a Printed Circuit Board (PCB) prototype was designed, manufactured, and tested for limit of detection, linear response, and validation of theoretical concepts. Using the magnetic frequency mixing technique, a limit of detection of 15 µg/mL of 20 nm core-sized nanoparticles was achieved without any shielding.
KW  - Lab-on-Chip
KW  - magnetic sensing
KW  - frequency mixing
KW  - superparamagnetic nanoparticles
KW  - magnetic beads
Y1  - 2018
U6  - https://doi.org/10.3390/s18061747
SN  - 1424-8220
VL  - 18
IS  - 6
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Poghossian, Arshak
A1  - Jablonski, Melanie
A1  - Koch, Claudia
A1  - Bronder, Thomas
A1  - Rolka, David
A1  - Wege, Christina
A1  - Schöning, Michael Josef
T1  - Field-effect biosensor using virus particles as scaffolds for enzyme immobilization
JF  - Biosensors and Bioelectronics
N2  - A field-effect biosensor employing tobacco mosaic virus (TMV) particles as scaffolds for enzyme immobilization is presented. Nanotubular TMV scaffolds allow a dense immobilization of precisely positioned enzymes with retained activity. To demonstrate feasibility of this new strategy, a penicillin sensor has been developed by coupling a penicillinase with virus particles as a model system. The developed field-effect penicillin biosensor consists of an Al-p-Si-SiO₂-Ta₂O₅-TMV structure and has been electrochemically characterized in buffer solutions containing different concentrations of penicillin G. In addition, the morphology of the biosensor surface with virus particles was characterized by scanning electron microscopy and atomic force microscopy methods. The sensors possessed a high penicillin sensitivity of ~ 92 mV/dec in a nearly-linear range from 0.1 mM to 10 mM, and a low detection limit of about 50 µM. The long-term stability of the penicillin biosensor was periodically tested over a time period of about one year without any significant loss of sensitivity. The biosensor has also been successfully applied for penicillin detection in bovine milk samples.
Y1  - 2018
U6  - https://doi.org/10.1016/j.bios.2018.03.036
SN  - 0956-5663
VL  - 110
SP  - 168
EP  - 174
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Aboulnaga, Elhussiny A.
A1  - Zou, Huibin
A1  - Selmer, Thorsten
A1  - Xian, Mo
T1  - Development of a plasmid-based, tunable, tolC-derived expression system for application in Cupriavidus necator H16
JF  - Journal of Biotechnology
N2  - Cupriavidus necator H16 gains increasing attention in microbial research and biotechnological application due to its diverse metabolic features. Here we present a tightly controlled gene expression system for C. necator including the pBBR1-vector that contains hybrid promoters originating from C. necator native tolC-promoter in combination with a synthetic tetO-operator. The expression of the reporter gene from these plasmids relies on the addition of the exogenous inducer doxycycline (dc). The novel expression system offers a combination of advantageous features as; (i) high and dose-dependent recombinant protein production, (ii) tight control with a high dynamic range (On/Off ratio), which makes it applicable for harmful pathways or for toxic protein production, (iii) comparable cheap inducer (doxycycline, dc), (iv) effective at low inducer concentration, that makes it useful for large scale application, (v) rapid, diffusion controlled induction, and (vi) the inducer does not interfere within the cell metabolism. As applications of the expression system in C. necator H16, the growth ability on glycerol was enhanced by constitutively expressing the E. coli glpk gene-encoding for glycerol kinase. Likewise, we used the system to overcome the expression toxicity of mevalonate pathway in C. necator H16. With this system, the mevalonate-genes were successfully introduced in the host and the recombinant strains could produce about 200 mg/l mevalonate.
Y1  - 2018
U6  - https://doi.org/10.1016/j.jbiotec.2018.03.007
SN  - 0168-1656
VL  - 274
SP  - 15
EP  - 27
PB  - Elsevier
CY  - Amsterdam
ER  -