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Title: 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 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.
Authors:
; ;  [1] ; ; ;  [2]
  1. Department of Physics, Faculty of Sciences - UNESP, Bauru, SP (Brazil)
  2. Department of Physics, Faculty of Philosophy, Science and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP (Brazil)
Publication Date:
OSTI Identifier:
22250789
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Advances; Journal Volume: 4; Journal Issue: 3; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ATOMIC FORCE MICROSCOPY; BENZOQUINONES; DEPOSITS; DETECTION; FIELD EFFECT TRANSISTORS; GOLD; MELANIN; SENSITIVITY; SENSORS; SPECTROSCOPY; SUBSTRATES; THIN FILMS; TIN OXIDES