Polyaniline (PANI) is a conducting polymer with good long-term stability, high conductivity, and good biocompatibility, making it a promising candidate for chemical and biological sensors. Additionally, it can be used as a template for the facile growth of well-ordered metal nanoparticles. We have recently developed a method for the fabrication of PANI-Au nanocomposites with interesting optical properties, in particular strong and reproducible surface plasmon resonance, which can be applied towards surface enhanced Raman spectroscopy measurements. Due to their good electrochemical stability and their surface enhanced Raman capability, we are developing these nanocomposite materials as substrates for possible bimodal biosensors. In this work, we further advance the electrochemical behavior of these nanocomposites by extending PANI’s useful pH range to physiologically relevant ranges, i.e., around pH 7. PANI’s conductivity strongly depends on its protonation state and is highly conducting only when fully protonated (pH &lt; 2.5). This poses particular drawbacks for biosensing applications, which would typically be carried out in neutral buffered solutions. To alleviate this problem and improve the electroactivity of PANI films, we examine the electrochemical incorporation of ferricyanide ions (FeCN) into PANI and PANI-Au films via cyclic voltammetry from neutral pH solutions. The resulting PANI-FeCN-Au films show enhanced electroactivity in buffered solutions at pH 7. We present the mechanistic details of this doping process and the properties of the resulting films as characterized by UV-Vis absorption spectroscopy, Raman spectroscopy, cyclic voltammetry, and electrochemical quartz crystal microbalance. These PANI-FeCN-Au nanocomposites have the stability and biocompatibility characteristic of PANI but with additional electroactivity in neutral solutions.

Polyaniline-gold nanocomposites doped with ferricyanide for electrochemical and optical biosensing measurements

253rd National Meeting (2017)

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