To ensure effective development and evaluation of our sensor systems, Imego has created a superbly well-equipped laboratory. Projects involving the development of new immuno-assay platforms require measurements with standard techniques for reference measurements and evaluations. We have four different instruments that measure absorbance or fluorescence in couvettes and microtiter plates, respectively. Furthermore, our stereo microscope is also of use in these projects. One of our fluorometers accepts commonly used microtiter plates, microscope slides, etc. It is possible to measure fluorescence variations across a well with sufficient lateral resolution (below 2 mm2). Other more sophisticated equipment allows us to perform time resolved measurements (time resolution of a few nsec). Our equipment also includes two polarisers for the incident and reflected/fluorescent light. Thus we are able to study the effect of polarisation on fluorescence excitation as well as on the emission of fluorescent light. Our laboratory also houses a photon correlation spectroscopy (PCS) instrument for particle measurement below approximately 1 µm. This is extremely useful in all projects involving particles. For magnetic particles, our PCS equipment supplements information on the status of suspensions given by magnetic measurements. We can monitor particle size distributions, follow the kinetics of aggregation as a function of change in particle surface coating and suspension chemistry (pH, salt concentration, etc.) In projects involving particles our viscosimeter and our instrument for measuring the isoelectric point of molecules/particles (Z-potential) are used. Z-potential measurements give an indication of the conditions for suspension stability as well as enabling us to follow changes in particle charge as a function of changed chemistry of the nanoparticles. We have successfully used this equipment to follow the change in charge of molecularly imprinted nanoparticles upon target absorption When working with molecularly imprinted polymers we use electrochemical equipment including a potentiostat/galvanostat and a frequency response analyzer, as well as other instruments. In many, if not all, of our biochemical projects, it is important to measure surface properties and monitor reactions taking place on surfaces. For these projects we use our “multiskop”. This instrument makes ellipsometry, surface plasmon resonance (SPR) and contact angle measurements possible. Our laboratory also has a quartz crystal microbalance with dissipation monitoring (QCM-D) for measuring surface reactions. Both QCM-D and SPR allow us to monitor each step of a chemical reaction in real time. This is of particular importance when optimising the chemistry of multistep assays such as sandwich ELISA's. Standard techniques for measuring for example fluorescence, only give an evaluation of the performance of the whole assay, while these surface techniques allow us to monitor the binding of the capturing antibody, blocking molecules, antigens and detecting antibodies separately (sequentially). In addition, these techniques do not require specific preparation of read-out chemistries such as when using fluorescence or absorbance based detection. |