Study of low Rayleigh heaters for biomedical diagnostic tools

D. Gosselin, J. Berthier, A. Delon, D. Chaussy, N. Belgacem, G. Delapierre

Keywords: microheaters, low Rayleigh number, point-of-care, biomedical device, screen-printing, conductive inks


Microfluidic is a very promising technology to improve biomedical devices and to provide diagnostic tools for the developing world. The World Health Organization has introduced a list of requirements that an ideal diagnostic tool for the developing world must meet. It can be abbreviated with the acronym ASSURED: Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free, Delivered. In order to comply with these criteria the diagnostic tools should be as portable as possible. This work presents an experimental study of microheaters which can be easily integrated within such a device because of their small dimension and their low-power consumption. These microheaters have been made by screen-printing of conductive carbon ink on PET substrate. Thanks to its resistivity, this carbon ink will heat up by Joule effect. To study the physics of such heaters 36 different square and rectangle shapes have been designed with dimensions ranging from 5mm to 20mm. Due to the small dimensions of these elements, their Rayleigh numbers are small too (