A novel ISFET-based NAD+-dependent enzyme sensor for lactate

Andrei B. Kharitonov, Maya Zayats, Lital Alfonta, Eugenii Katz, Itamar Willner

Research output: Contribution to journalConference articlepeer-review

49 Scopus citations


An integrated NAD+-dependent enzyme field-effect transistor (ENFET) device for the biosensing of lactate is described. The aminosiloxane-functionalized gate interface is modified with pyrroloquinoline quinone (PQQ) that acts as a catalyst for the oxidation of NADH. A synthetic amino-derivative of NAD+ is covalently linked to the PQQ monolayer. Faradaic impedance spectroscopy and chronopotentiometry are used as electrochemical methods for probing in situ bioaffinity interaction between NAD+-dependent enzyme, lactate dehydrogenase (LDH) (E.C., and the NAD+-functionalized Au-electrode surface. The association constant of 1.5 × 105 M-1 was found by both techniques. The affinity complex formed between the NAD+/PQQ-assembly and the LDH is cross-linked and yields an integrated biosensor ENFET-device for the analysis of lactate. The device reveals the lower detection limit of 1 × 10-4 M for lactate and the sensitivity of 24 ± 2 mV dec-1. The response time of the device is as low as 15 s.

Original languageEnglish
Pages (from-to)203-210
Number of pages8
JournalSensors and Actuators, B: Chemical
Issue number1-3
StatePublished - 1 Jun 2001
Externally publishedYes
EventProceeding of the 8th International Meeting on Chemical Sensors - Basel, Switzerland
Duration: 2 Jul 20005 Jul 2000


  • Biosensor
  • Chronopotentiometry
  • Field-effect transistor
  • Impedance spectroscopy
  • Lactate
  • NAD-dependent enzyme
  • PQQ
  • Pyrroloquinoline quinone

ASJC Scopus subject areas

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


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