Lab-on-a-chip devices are often applied to point-of-care diagnostic solutions as they are low-cost, compact, disposable, and require only small sample volumes. For such devices, various reagents are required for sample preparation and analysis and, for an integrated solution to be realized, on-chip reagent storage and automated introduction are required. This work describes the implementation and characterization of effective liquid reagent storage and release mechanisms utilizing blister pouches applied to various point-of-care diagnostic device applications. The manufacturing aspects as well as performance parameters are evaluated.
A portable analytical system for the characterization of liquid environmental samples and beverages in food control was realized. The key element is the implementation of contactless conductivity detection on lab-on-a-chip basis ensuring the system to be operated in a label free mode. Typical target molecules such as small ionic species like Li+, Na+, K+, SO4 2- or NO3-, organic acids in wine whose concentration and ratio to each other documents the wine quality, or caffeine or phosphate in coke were detected. Results from sample matrices like various beverages as water, cola, tea, wine and milk, water from heaters, environmental samples and blood will be presented.
In case of transplantation or the identification of special metabolic diseases like coeliac disease, HLA typing has to be done
fast and reliably with easy-to-handle devices by using limited amount of sample. Against this background a lab-on-a-chip
device was realized enabling a fast HLA typing via miniaturized Real-time PCR. Hereby, two main process steps were
combined, namely the extraction of DNA from whole blood and the amplification of the target DNA by Real-time PCR
giving rise-to a semi-quantitative analysis. For the implementation of both processes on chip, a sample preparation and a
real-time module were used. Sample preparation was carried out by using magnetic beads that were stored directly on chip
as dry powder, together with all lysis reagents. After purification of the DNA by applying a special buffer regime, the
sample DNA was transferred into the PCR module for amplification and detection. Coping with a massively increased
surface-to-volume ratio, which results in a higher amount of unspecific binding on the chip surface, special additives
needed to be integrated to compensate for this effect. Finally the overall procedure showed a sensitivity comparable to
standard Real-time PCR but reduced the duration of analysis to significantly less than one hour. The presented work
demonstrates that the combination of lab-on-a-chip PCR with direct optical read-out in a real-time fashion is an extremely
promising tool for molecular diagnostics.