A lab-on-a-chip microsystem with new conductometric detection

Aim of project
The aim of the project is the development of a cheap and simple in construction microsystem with conductometric detection. Up to now such constructions utilised metallic electrodes placed under a microchannel. This required a few steps in technology in order to insulate the electrodes both electrically and hydrodynamically. Our new idea is to implement side microchannels and use them as electrodes. One such electrode is connected to a function generator and the second to a current to voltage converter. Then the obtained signal is amplified and measured. The electrodes create a kind of capacitor whose capacitance depends on the conductance of the fl owing medium. The measurements are quite diffi cult because the impedance of the capacitor is quite high and the frequency as well as the amplitude of the generation have to be optimised. Initial work carried out in the laboratory proved that such a construction could be used in the measurements. The microchannels were filled with a concentrate electrolyte. However, it is necessary to cover the microchannel walls with a metallic conductor in order to increase its conductivity. The microstructures will be prepared based on the use of various materials. First of all, poly(dimethylsiloxane) PDMS will be used. These microsystems will be prepared in technology designed in our laboratory (this technology was submitted to the Polish Patent Office). It is also planned to use glass as a substrate with wet etching of the microchannels. Finally, a hybrid structure will be prepared.

Expected results
A new construction of conductometer will be designed. The results will be presented on an international conference (mTAS series) as well as will be included in D.Sc., Ph.D., and M.Sc. theses.