1. Technical Field
The invention relates to an apparatus for arranging at least one sample container in an optical measuring device, an optical measuring device including such an apparatus, and the use of such an optical measuring device.
2. Related Art
In the biological and pharmaceutical research field, methods for measuring the fluorescence and luminescence have been used successfully for many years. For this, transfected or transgenic animals or plants are used, where at least one gene of the respective plant or the respective animal can code a protein that shows luminescence or fluorescence. If the gene is active, this protein is formed and conclusions can be reached relating to the activity of the respective gene by observing its luminescence or fluorescence. For example, conclusions also can be reached concerning the effect which specific substances have on the animal/the plant. Measuring the luminescence and/or the fluorescence activity can be realized integrally or with a local resolution.
In particular, in plants, the expression of many of these genes is subject to a circadian rhythm or is dependent on growth phases. Both can in turn be influenced through external influences of natural or artificial origin. The gene expressions are therefore tracked over longer periods of time (ranging from several hours to several weeks).
The sample containers, for example, Petri dishes, are at least sealed and at times also sterilized and sealed to prevent unintended contamination of the sample material, meaning the plants or seedlings. This is normally achieved with transparent lids which are additionally secured with adhesive tape or a layer of paraffin wax. The samples inside the sample containers are normally positioned in or on top of an aqueous liquid or a solid medium.
At least one sample container is positioned on a carrier which can be a simple plate or board. A carrier of this type is provided with depressions or the like to always ensure the same measuring positions, especially if several sample containers are used, so that the carrier determines a geometric arrangement of the sample containers. For the sake of simplicity, we always refer to several sample containers in the following, but it is clear that only a single sample container may exist.
The luminescence or fluorescence is usually measured with the aid of an optical sensor unit—at least one photomultiplier or a sensitive CCD (charge-coupled device) camera—which is located above the sample container.
It is an object of the present invention to improve the state of the technology in such a way that the reproducibility of the luminescence and fluorescence measurements is improved.
It has turned out that during the operation of the optical measuring device, condensate can form on the lids of the sample containers. Condensation forming larger droplets will falsify the obtained measuring values as a result of scattering and/or absorption (refers to at least a fluorescence or luminescence measurement, but can also relate to a photographic recording). That is a serious problem for several reasons, specifically in long-term experiments where a sample container or a set of sample containers remain for several days or weeks inside the optical measuring device. If luminescence or fluorescence recordings are made, the optical sensor unit “does not see” the condensation droplets that have formed, especially if the unit operates without a local resolution. These droplets can also not be observed from the outside because a light-impermeable housing must exist for fluorescence and luminescence measuring operations. This means that a complete series of the measuring can be worthless and the measuring time is lost. What is even worse is if the condensate that forms evaporates again prior to the end of the series of the measuring because of changes in the conditions, especially a change in the temperature. In that case, it may not be noticed and a falsified measuring result will be used further.