This contribution describes first results concerning the overall and especially optical system design of microfluidic skin
patches for drug detection based on fluorescence analysis of sweat samples. This work has been carried out within the
European project LABONFOIL which aims to develop low-cost lab-on-chip systems for four different applications, one
of them for the detection of cocaine abuse by professional drivers. To date work has focused on the integrated design of
the skin patch itself including methods for sweat collection as well as studies concerning the feasibility of OLEDs for
optical excitation of the fluorescence signal.
A new concept of the fabrication process for glass microlenses (external diameter ED<1 mm, focal length a few millimeters), based on the silicon master mask-less anisotropic wet etching in KOH, vacuum anodic bonding and re-flow of borosilicate glass, followed by the precise wafer-scale polishing and DRIE has been presented. A single spherical microlens as well as an array of spherical microlenses with focal length between 44.8 and 8.6 mm and external diameter 0.35 to 0.985 mm have been repeatable manufactured.
A new microwave enhanced anisotropic wet method of etching of silicon (External Etching Microwave Silicon - E2Msi), has been presented. In the method an etchant is irradiated by microwave and then flows to an external reaction chamber where etching is performed. The reaction chamber is situated outside of area of microwave irradiation. The main characteristics of E2Msi etching has been presented. It has been shown that the new process utilizes a memory effect of high chemical reactivity observed in water and water-based solution irradiated by microwave.