Label-free electrical detection of DNA with a multi-spot LAPS: First step towards light-addressable DNA chips

Chunsheng Wu, Thomas Bronder, Arshak Poghossian, Carl Frederik Werner, Matthias Bäcker, Michael J. Schöning

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)


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.

Original languageEnglish
Pages (from-to)1423-1428
Number of pages6
JournalPhysica Status Solidi (A) Applications and Materials Science
Issue number6
Publication statusPublished - 2014 Jun
Externally publishedYes


  • DNA hybridization
  • biosensors
  • field-effect transistors
  • label-free biosensing
  • light-addressable potentiometric sensors

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Electrical and Electronic Engineering
  • Materials Chemistry


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