Komarova N.V.,Scientific and Manufacturing Complex Technological Center |
Andrianova M.S.,Scientific and Manufacturing Complex Technological Center |
Gubanova O.V.,Scientific and Manufacturing Complex Technological Center |
Kuznetsov E.V.,Scientific and Manufacturing Complex Technological Center |
Kuznetsov A.E.,Scientific and Manufacturing Complex Technological Center
Sensors and Actuators, B: Chemical | Year: 2015
A novel ion-selective field effect transistor (ISFET)-based biosensor was developed for the detection of explosives. Escherichia coli nitroreductase (NTR) was used as the recognizing element of the biosensor to afford high specificity and sensitivity toward nitroaromatic compounds. The ISFET-based device demonstrated an analytical response toward the NTR-catalyzed reduction of several nitroaromatic substances, conjugated to the oxidation of the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) to NADP+. Catalytic properties of nitroreductase were characterized by spectrophotometric analysis. Nitroreductase showed maximum activity toward tetryl and trinitrotoluene, and the Michaelis constants were determined to be 70 and 91 μM, respectively. The enzyme was covalently attached to the surface of ISFET using a self-assembly method. Two SiO2-surface immobilization strategies using an asymmetric spacer, 3-maleimidobenzoic acid N-hydroxysuccinimide ester, and a symmetric spacer, glutaric dialdehyde, were compared. The use of the symmetric spacer resulted in higher enzymatic activity of the immobilized nitroreductase. An NTR-functionalized complementary metal-oxide-semiconductor (CMOS)-compatible ISFET chip was combined with a microfluidic system for analyte delivery. The response of the system to several nitroaromatic compounds was examined. The device demonstrated a low detection limit and may be applied for the rapid detection of explosives in various samples. © 2015 Elsevier B.V. All rights reserved.