Analysis of dopamine and tyrosinase activity on ion-sensitive field-effect transistor (ISFET) devices.
Dopamine (1) and tyrosinase (TR) activities were analyzed by using chemically modified ion-sensitive field-effect transistor (ISFET) devices. In one configuration, a phenylboronic acid functionalized ISFET was used to analyze 1 or TR. The formation of the boronate-1 complex on the surface of the gate altered the electrical potential associated with the gate, and thus enabled 1 to be analyzed with a detection limit of 7x10(-5) M. Similarly, the TR-induced formation of 1, and its association with the boronic acid ligand allowed a quantitative assay of TR to be performed. In another configuration, the surface of the ISFET gate was modified with tyramine or 1 to form functional surfaces for analyzing TR activities. The TR-induced oxidation of the tyramine- or 1-functionalized ISFETs resulted in the formation of the redox-active dopaquinone units. The control of the gate potential by the redox-active dopaquinone units allowed a quantitative assay of TR to be performed. The dopaquinone-functionalized ISFETs could be regenerated to give the 1-modified sensing devices by treatment with ascorbic acid.
Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Ronit
R
Freeman
Johann
J
Elbaz
Ron
R
Gill
Maya
M
Zayats
Itamar
I
Willner
D000537:Aluminum Oxide / Q000737:chemistry; D016227:Benzoquinones / Q000737:chemistry; D015374:Biosensing Techniques; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives / Q000737:chemistry; D004298:Dopamine / Q000032:analysis*; D005453:Fluorescence; D007202:Indicators and Reagents; D014442:Monophenol Monooxygenase / Q000032:analysis*; D010084:Oxidation-Reduction; D011199:Potentiometry; D045663:Quantum Dots; D014173:Transistors, Electronic; D014443:Tyrosine / Q000032:analysis
D016227:Benzoquinones; D007202:Indicators and Reagents; D014443:Tyrosine; D004295:Dihydroxyphenylalanine; C035157:dopaquinone; D014442:Monophenol Monooxygenase; D000537:Aluminum Oxide; D004298:Dopamine