High performance, easy to fabricate, composite microheater for life sciences and biomedical applications

Abstract

Micro-heaters, are used in a number of applications including medical diagnostics , synthesis, environmental monitoring and actuation. Conventional micro-heaters rely on thin films electrodes microfabricated in clean-room environment. However, low-cost alternatives based on conductive paste electrodes fabricated using printing techniques have started to emerge over the years. Compared to thin film electrodes, such “thick” electrodes typically suffer from lower heating efficacy and poorer mechanical properties. Here we present a solution that addresses both issues simultaneously. Mixing silver ink and PVA results in the solubilization of performance-hindering organic compound that gets eliminated after heating. The new electrodes, which reach a temperature of 80 ºC within 5 minutes using a voltage of 1.0 V, display an overall 42% and 35% improvement of the mechanical (hardness) and electrical (resistivity) properties compared to pristine silver ink electrodes. To validate our results, we use the composite microheater to amplify and detect parasite DNA from Trypanosoma brucei, associated with African sleeping sickness. Our LAMP test compares well with commercially available systems, confirming the excellent performance of our microheaters. Since their fabrication relies on well-established techniques, we anticipate they will find use in a range of applications.