Ngamna, O;Morrin, A;Moulton, SE;Killard, AJ;Smyth, MR;Wallace, GG

2005

September

Synthetic Metals

SYNTHETIC METALS

Published

35 ()

IMMUNOSENSOR ELECTRODE

153

185

188

The properties of poly (2-methoxyaniline-5-sulfonic acid) (PMAS), a water-soluble polymer, has been investigated as a potential mediator for biosensors. Addition of poly (L-Lysine) (PLL) to the PMAS renders this material water-insoluble; an important feature for aqueous based biosensors. Characterisation of various PMAS/PLL mixtures showed that a uniform and stable film could reproducibly be fabricated on ITO coated Mylar using 0.1% (w/v) PMAS and 0.05% (w/v) PLL. Immobilisation of enzyme horseradish peroxidase (HRP) onto the PMAS/PLL film was also investigated. Amperometric detection (-0.1 V vs. Ag/AgCl reference electrode) of hydrogen peroxide was investigated using the PMAS/PLL/HRP electrode as the working electrode in a three electrode cell containing phosphate buffer saline (pH 6.4) solution. Amperometric responses were observed upon the addition of hydrogen peroxide. HRP immobilised concentration was optimised to be 0.35% (w/v) at 35 mu L. Loading volume was also studied and optimised to be 35 mu L. The optimal condition for amperometric test was using constant applied potential at -100 mV. Detection limit of the sensor in PBS solution was 0.01 mM H2O2. Calibration curve in PBS pH 6.4 shows a linear response range between 0.01 and 0.1 mM H2O2 with a sensitivity of 24.91 mu A/cm(2) mM(-1) and correlation coefficient of 0.9966.

LAUSANNE

0379-6779

10.1016/j.synthmet.2005.07.259