@article{BronderPoghossianSchejaetal.2015,
  author    = {Bronder, Thomas and Poghossian, Arshak and Scheja, Sabrina and Wu, Chunsheng and Keusgen, Michael and Mewes, Dieter and Sch{\"o}ning, Michael Josef},
  title     = {DNA Immobilization and Hybridization Detection by the Intrinsic Molecular Charge Using Capacitive Field-Effect Sensors Modified with a Charged Weak Polyelectrolyte Layer},
  series = {Applied Materials \& Interfaces},
  volume    = {36},
  journal   = {Applied Materials \& Interfaces},
  number    = {7},
  publisher = {American Chemical Society},
  address   = {Washington, DC},
  doi       = {10.1021/acsami.5b05146},
  pages     = {20068 -- 20075},
  year      = {2015},
  abstract  = {Miniaturized setup, compatibility with advanced micro- and nanotechnologies, and ability to detect biomolecules by their intrinsic molecular charge favor the semiconductor field-effect platform as one of the most attractive approaches for the development of label-free DNA chips. In this work, a capacitive field-effect EIS (electrolyte-insulator-semiconductor) sensor covered with a layer-by-layer prepared, positively charged weak polyelectrolyte layer of PAH (poly(allylamine hydrochloride)) was used for the label-free electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization. The negatively charged probe single-stranded DNA (ssDNA) molecules were electrostatically adsorbed onto the positively charged PAH layer, resulting in a preferentially flat orientation of the ssDNA molecules within the Debye length, thus yielding a reduced charge-screening effect and a higher sensor signal. Each sensor-surface modification step (PAH adsorption, probe ssDNA immobilization, hybridization with complementary target DNA (cDNA), reducing an unspecific adsorption by a blocking agent, incubation with noncomplementary DNA (ncDNA) solution) was monitored by means of capacitance-voltage and constant-capacitance measurements. In addition, the surface morphology of the PAH layer was studied by atomic force microscopy and contact-angle measurements. High hybridization signals of 34 and 43 mV were recorded in low-ionic strength solutions of 10 and 1 mM, respectively. In contrast, a small signal of 4 mV was recorded in the case of unspecific adsorption of fully mismatched ncDNA. The density of probe ssDNA and dsDNA molecules as well as the hybridization efficiency was estimated using the experimentally measured DNA immobilization and hybridization signals and a simplified double-layer capacitor model. The results of field-effect experiments were supported by fluorescence measurements, verifying the DNA-immobilization and hybridization event.},
  language  = {en}
}
@inproceedings{PoghossianBronderWuetal.2015,
  author    = {Poghossian, Arshak and Bronder, Thomas and Wu, Chunsheng and Sch{\"o}ning, Michael Josef},
  title     = {Label-free sensing of biomolecules by their intrinsic molecular charge using field-effect devices},
  series = {Semiconductor Micro- and Nanoelectonics : Proceedings of the tenth international conference, Yerevan, Armenia, September 11-13},
  booktitle = {Semiconductor Micro- and Nanoelectonics : Proceedings of the tenth international conference, Yerevan, Armenia, September 11-13},
  isbn      = {978-5-8084-1991-9},
  pages     = {61 -- 63},
  year      = {2015},
  language  = {en}
}
@article{WuBronderPoghossianetal.2014,
  author    = {Wu, Chunsheng and Bronder, Thomas and Poghossian, Arshak and Werner, Frederik and B{\"a}cker, Matthias and Sch{\"o}ning, Michael Josef},
  title     = {Label-free electrical detection of DNA with a multi-spot LAPS: First step towards light-addressable DNA chips},
  series = {Physica status solidi A : Applications and materials science},
  volume    = {211},
  journal   = {Physica status solidi A : Applications and materials science},
  number    = {6},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-396X (E-Journal); 1862-6319 (E-Journal); 0031-8965 (Print); 1862-6300 (Print)},
  doi       = {10.1002/pssa.201330442},
  pages     = {1423 -- 1428},
  year      = {2014},
  abstract  = {A multi-spot (4 × 4 spots) light-addressable potentiometric sensor (MLAPS) consisting of an Al-p-Si-SiO2 structure has been applied for the label-free electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization by the intrinsic molecular charge for the first time. Single-stranded probe ssDNA molecules (20 bases) were covalently immobilized onto the silanized SiO2 gate surface. The unspecific adsorption of mismatch ssDNA on the MLAPS gate surface was blocked by bovine serum albumin molecules. To reduce the screening effect and to achieve a high sensor signal, the measurements were performed in a low ionic-strength solution. The photocurrent-voltage (I-V) curves were simultaneously recorded on all 16 spots after each surface functionalization step. Large shifts of I-V curves of 25 mV were registered after the DNA immobilization and hybridization event. In contrast, a small potential shift (∼5 mV) was observed in case of mismatch ssDNA, revealing good specificity of the sensor. The obtained results demonstrate the potential of the MLAPS as promising transducer platform for the multi-spot label-free electrical detection of DNA molecules by their intrinsic molecular charge.},
  language  = {en}
}
@inproceedings{WuBronderPoghossianetal.2014,
  author    = {Wu, Chunsheng and Bronder, Thomas and Poghossian, Arshak and Sch{\"o}ning, Michael Josef},
  title     = {DNA-hybridization detection using light-addressable potentiometric sensor modified with gold layer},
  series = {Sensoren und Messsysteme 2014 ; Beitr{\"a}ge der 17. GMA/ITG-Fachtagung vom 3. bis 4. Juni 2014 in N{\"u}rnberg. (ITG-Fachbericht ; 250)},
  booktitle = {Sensoren und Messsysteme 2014 ; Beitr{\"a}ge der 17. GMA/ITG-Fachtagung vom 3. bis 4. Juni 2014 in N{\"u}rnberg. (ITG-Fachbericht ; 250)},
  publisher = {VDE-Verl.},
  address   = {D{\"u}sseldorf},
  organization    = {VDI/VDE-Gesellschaft Mess- und Automatisierungstechnik},
  isbn      = {978-3-8007-3622-5},
  pages     = {1 -- 4},
  year      = {2014},
  language  = {en}
}
@article{BronderWuPoghossianetal.2014,
  author    = {Bronder, Thomas and Wu, Chunsheng and Poghossian, Arshak and Werner, Frederik and Keusgen, M. and Sch{\"o}ning, Michael Josef},
  title     = {Label-free detection of DNA hybridization with light-addressable potentiometric sensors: comparison of various DNA-immobilization strategies},
  series = {Procedia Engineering},
  volume    = {87},
  journal   = {Procedia Engineering},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1877-7058},
  doi       = {10.1016/j.proeng.2014.11.647},
  pages     = {755 -- 758},
  year      = {2014},
  abstract  = {Light-addressable potentiometric sensors (LAPS) consisting of a p-Si-SiO2 and p-Si-SiO2-Au structure, respectively, have been tested for a label-free electrical detection of DNA (deoxyribonucleic acid) hybridization. Three different strategies for immobilizing single-stranded probe DNA (ssDNA) molecules on a LAPS surface have been studied and compared: (a) immobilization of thiol-modified ssDNA on the patterned Au surface via gold-thiol bond, (b) covalent immobilization of amino-modified ssDNA onto the SiO2 surface functionalized with 3-aminopropyltriethoxysilane and (c) layer-by-layer adsorption of negatively charged ssDNA on a positively charged weak polyelectrolyte layer of poly(allylamine hydrochloride).},
  language  = {en}
}
@inproceedings{WuPoghossianWerneretal.2013,
  author    = {Wu, Chunsheng and Poghossian, Arshak and Werner, Frederik and Bronder, Thomas and B{\"a}cker, Matthias and Wang, Ping and Sch{\"o}ning, Michael Josef},
  title     = {An application of a scanning light-addressable potentiometric sensor for label-free DNA detection},
  series = {11. Dresdner Sensor-Symposium : 9.-11.12.2013},
  booktitle = {11. Dresdner Sensor-Symposium : 9.-11.12.2013},
  organization    = {Dresdner Sensor-Symposium <11, 2013>},
  isbn      = {978-3-9813484-5-3},
  pages     = {164 -- 168},
  year      = {2013},
  language  = {en}
}