AbstractA bundle of conducting polymer tubules was employed to build a biosensor of improved sensitivity. The tubule structure was able to provide larger enzyme encapsulating space per unit area of the sensor electrode compared to other immobilizing methods. The bundle structure was prepared by using electrochemical polymerization of EDOT into the template on ITO. After dosing of enzyme into the tubule, it was covered with PPDA channels. The amperometric response of the sensor to galactose showed linear behavior in the range of 0.1–1 mM with an average sensitivity of 6.37 µA/mM cm2. The response time was 30–40 s. After keeping the sensor in phosphate buffer solution at 4 °C for a week, it showed about 82 % of its original sensitivity. The detection limit was 0.01 mM based on S/N=3.