Ammonia sensing for enzymatic urea detection using organic field effect transistors and a semipermeable membrane. Issue 1 (2nd December 2015)

• Record Type: Journal Article
• Authors: Werkmeister, F. X.; Koide, T.; Nickel, B. A.
• Is Part Of: Journal of materials chemistry. Volume 4:Issue 1(2016)
• Page Start: 162
• Page End: 168
• Publication Date: 2015-12-02
• Subjects: Materials -- Periodicals; Chemistry, Analytic -- Periodicals; Biomedical materials -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c5tb02025e
• Languages: English
• ISSNs: 2050-750X

Abstract

Abstract : Organic transistors detect the enzymatic breakdown of urea via ammonia diffusion into the transistor through a semipermeable parylene-C membrane. Abstract : Organic Field Effect Transistors (OFETs) are used to measure ammonia in solution via ammonia diffusion into the OFET channel. An increase in ammonia concentrations results in a decrease in transistor currents. The regeneration of the OFET current after ammonia uptake is slow, which allows us to read out the maximum ammonia dose which was applied. A 100 nm parylene-C layer serves as a semipermeable top gate dielectric. The parylene layer is functionalized with the covalently attached enzyme urease. The enzyme catalyses the hydrolysis of urea to ammonia and carbon dioxide, i.e. urea can be detected via its hydrolysis product ammonia. The sensitivity covers a range of physiological concentrations of urea, which are several mM.