Immunosensor for detection of inhibitory neurotransmitter γ-aminobutyric acid using quartz crystal microbalance

Tingting Wang, Jitendran Muthuswamy

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

A piezoelectric immunosensor for sensing the low molecular weight neurotransmitter γ-aminobutyric acid (GABA), one of two major inhibitory neurotransmitters in the central nervous system, is described. The sensing interface consists of a dextran layer covalentiy attached to a self-assembled monolayer of thiolamine compound on the surface of gold electrodes of the crystals. The dextran layer is further modified with GABA molecules to act as the biosensing layer. The affinity binding of monoclonal anti-GABA antibody on the modified piezoelectric crystals is studied in real time without any additional labels. The equilibrium association constant, Keq for binding between anti-GABA antibody and GABA molecules is 14.5 μg·mL-1. The detection limit for anti-GABA is ∼10 nM. The sensitivity of the sensor at a concentration corresponding to half-maximal response is 13.6 ng/mL·Hz. The functionalized sensor substrate is subsequently used for competitive determination of different concentrations of free GABA (range of 5 μM-50 mM) in PBS-BSA buffer. The detection limit of the immunosensor for sensing GABA with maximum sensitivity is ∼42 μM.

Original languageEnglish (US)
Pages (from-to)8576-8582
Number of pages7
JournalAnalytical chemistry
Volume80
Issue number22
DOIs
StatePublished - Nov 15 2008

ASJC Scopus subject areas

  • Analytical Chemistry

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