Browsing by Subject "mikroskopia"

The aim of this thesis was to investigate the potential of label-free CARS microscopy as a new method for chemically-specific imaging of live cells and particle-cell interactions in a drug delivery context. Cells used to mimic the intestinal epithelium, Caco-2 cells and HT-29 cells and nano-/ microcrystal particle interactions with macrophages were studied. More information about drug absorption from intestinal and particle cell interactions are needed, since many novel drugs lack properties needed for good bioavailability. It would be beneficial if these events could be visualized without labels. CARS microscopy was found to be well suited to imaging live Caco-2 and HT-29 cells that were grown on PTFE Transwell inserts. CARS microscopy revealed lipid droplets inside these cells. The size of lipid droplets increased in Caco-2 cells a lot during a three week period so that at the end a large part of the inner part of the cell was filled with lipid droplets. It was also observed that Caco-2 cells and HT-29 cells can grow on top of each other on Transwell inserts and not just as a monolayer. These two facts could cause variations in drug absorption studies based on Caco-2 cell monolayers. CARS microscopy was able to detect nanocrystals as small as about 500 nm with label-free, molecular-specific CARS microscope inside RAW 264.7 macrophages after incubation of 120 min. This observation was important, since nanocrystal drug formulations are gaining interest in the field of pharmacy. Nanocrystals can be used in parenteral drug formulations as well as in oral dosage forms. In suspensions, nanocrystals can be used to cause long lasting drug release. Nanocrystals can be also used to enhance poor bioavailability of drugs. Whether these nanocrystals are used in parenteral formulations or in oral drug formulations it is evident that imaging techniques are needed to image interactions between these nanocrystals and cells. CARS microscopy could be one of those techniques, since it is suitable for live cell imaging and it can be used to image nanocrystals that are not labeled. The results in this thesis suggest that CARS microscopy could be used as fast imaging technique for nanocrystal particle cell interactions. Overall, CARS microscopy is a relatively new imaging method that shows much promise as a label-free chemically specific imaging technique for imaging cells and cell-particle interactions in a drug delivery context. As the technique becomes more widely available and undergoes some technical developments, it will become much more widespread imaging method in the future.

The Finnsheep and the Finnish Grey Landrace have recently been identified as two different breeds of sheep (Ovis aries). As this was achieved by genetical analyses and as many important characteristics of the wool are heritable it is possible that there are differences within the wool qualities of the Finnsheep and the Finnish Grey Landrace. The aim of this study was to find out if the Finnsheep wool fibres and the Finnish Grey Landrace wool fibres can be identified by breed when compared using stereomicroscopy techniques, and if the Finnsheep wool fibres and the Finnish Grey Landrace wool fibres have structural differences that might affect their usage as textile material. Wool fibres of two white and two brown Finnsheep ewes and two pale grey and two black Finnish Grey Landrace ewes were examined by microscopic methods. The longitudinal structures, cross sections and scale casts of fibres were examined. The scale patterns of the cuticula, the shape and structure of the medulla and the cross sections were examined by qualitative methods as well as the shape of the edges of the scales. The diameter of the fibres, the height and the rate of the scales were measured by using Motic Images Plus 2.0 ML software. The examined traits were compared between individuals, colours and breeds. No such trait was found that would have been characteristic for only one breed as there were no differences between the breeds. Most of the traits were similar between two colours instead of breeds. The results suggest that the wool fibres of the Finnsheep and the Finnish Grey Landrace can be used together as textile material. According to the results the wool fibres can’t be used to tell the two breeds apart. For future research, it might be more relevant to compare wool fibres between colours than breeds.