Characterization of Silver Resistive Electrode as Heating Module for Portable Thermocycler Device

Medical devices such as in-vitro diagnostic, micro total analysis system, cell-on-chip, lab-on-chip, bio-microelectromechanical system are products of miniaturization technology. These micro/mini products enable us to run similar process as the macro products with the same result but deliver it faster with portability as main benefit. Several processes that have been introduced such as cell/tissue culture, polymerase chain reaction, drug screening etc. These devices commonly require heating module in performing their task. This study focuses on developing heating modules by utilizing Joule heating effect on a silver electrode. The silver electrode was casted from silver paste that was chosen due to its good heating properties with relatively low price. The specific objective of this research is to carry out initial characterization of the resistive electrode that realized using doctor blade techniques. Doctor blade has been known as technique that realized thick layer with some castable materials in form of paste. The silver electrode was then applied with 0.1-1.6 VDC. The accumulated heat can be observed in the temperature reading system. Our measurement showed that the electrode with a dimension of 1 mm wide, 0.03 mm thick and 20 mm length can generate heat at around $160^{\circ} \mathrm{C}$ in 60 seconds at the applied 1.0 VDC. Our characterization showed that the electrode has conductivity at around 6x10⁵ S/m. this study also reported a break down if the electrode was applied above 1.5 VDC as showed by endurance testing. This finding convinced us to move forward in realizing portable device with extra low energy and compact in size.