Melanin as an active layer in biosensors

The development of pH sensors is of great interest due to its extensive application in several areas such as industrial processes, biochemistry and particularly medical diagnostics. In this study, the pH sensing properties of an extended gate field effect transistor (EGFET) based on melanin thin fil...

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Bibliographic Details
Published in:AIP advances 2014-03, Vol.4 (3), p.037120-037120-8
Main Authors: Piacenti da Silva, Marina, Fernandes, Jéssica Colnaghi, de Figueiredo, Natália Biziak, Congiu, Mirko, Mulato, Marcelo, de Oliveira Graeff, Carlos Frederico
Format: Article
Language:English
Subjects:
ATOMIC FORCE MICROSCOPY
BENZOQUINONES
Binding sites
Biosensors
DEPOSITS
DETECTION
Electrochemical impedance spectroscopy
FIELD EFFECT TRANSISTORS
GOLD
Hydroxyl groups
Indium tin oxides
MATERIALS SCIENCE
MELANIN
Precursors
Semiconductor devices
SENSITIVITY
SENSORS
SPECTROSCOPY
SUBSTRATES
THIN FILMS
TIN OXIDES
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Summary:The development of pH sensors is of great interest due to its extensive application in several areas such as industrial processes, biochemistry and particularly medical diagnostics. In this study, the pH sensing properties of an extended gate field effect transistor (EGFET) based on melanin thin films as active layer are investigated and the physical mechanisms related to the device operation are discussed. Thin films were produced from different melanin precursors on indium tin oxide (ITO) and gold substrates and were investigated by Atomic Force Microscopy and Electrochemical Impedance Spectroscopy. Experiments were performed in the pH range from 2 to 12. EGFETs with melanin deposited on ITO and on gold substrates showed sensitivities ranging from 31.3 mV/pH to 48.9 mV/pH, depending on the melanin precursor and the substrate used. The pH detection is associated with specific binding sites in its structure, hydroxyl groups and quinone imine.
ISSN:2158-3226
2158-3226
DOI:10.1063/1.4869638