Label-free detection of DNA using light-addressable potentiometric sensor modified with a positively charged polyelectrolyte layer
- A multi-spot (16 spots) light-addressable potentiometric sensor (MLAPS) consisting of an Al–p-Si–SiO2 structure modified with a weak polyelectrolyte layer of PAH (poly(allylamine hydrochloride)) was applied for the label-free electrical detection of DNA (deoxyribonucleic acid) immobilization and hybridization by the intrinsic molecular charge for the first time. To achieve a preferentially flat orientation of DNA strands and thus, to reduce the distance between the DNA charge and MLAPS surface, the negatively charged probe single-stranded DNAs (ssDNA) were electrostatically adsorbed onto the positively charged PAH layer using a simple layer-by-layer (LbL) technique. In this way, more DNA charge can be positioned within the Debye length, yielding a higher sensor signal. The surface potential changes in each spot induced due to the surface modification steps (PAH adsorption, probe ssDNA immobilization, hybridization with complementary target DNA (cDNA), non-specific adsorption of mismatched ssDNA) were determined from the shifts of photocurrent–voltage curves along the voltage axis. A high sensor signal of 83 mV was registered after immobilization of probe ssDNA onto the PAH layer. The hybridization signal increases from 5 mV to 32 mV with increasing the concentration of cDNA from 0.1 nM to 5 μM. In contrast, a small signal of 5 mV was recorded in the case of non-specific adsorption of fully mismatched ssDNA (5 μM). The obtained results demonstrate the potential of the MLAPS in combination with the simple and rapid LbL immobilization technique as a promising platform for the future development of multi-spot light-addressable label-free DNA chips with direct electrical readout.
Author: | Chunsheng WuORCiD, Thomas BronderORCiD, Arshak PoghossianORCiD, Frederik WernerORCiD, Michael Josef SchöningORCiD |
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DOI: | https://doi.org/10.1039/C4NR07225A |
Parent Title (English): | Nanoscale |
Publisher: | Royal Society of Chemistry (RSC) |
Place of publication: | Cambridge |
Document Type: | Article |
Language: | English |
Year of Completion: | 2015 |
Volume: | 14 |
Issue: | 7 |
First Page: | 6143 |
Last Page: | 6150 |
Link: | https://doi.org/10.1039/C4NR07225A |
Zugriffsart: | campus |
Institutes: | FH Aachen / Fachbereich Medizintechnik und Technomathematik |
FH Aachen / INB - Institut für Nano- und Biotechnologien | |
Verlag / Royal Society of Chemistry (RSC) |