2D Visualization of Metabolic Activity: Sample Analysis with a Novel Fluorescent Imaging Technology

摘要

When reading "Fluorescence Imaging" your first thoughts might be labeling cells with fluorescent stains and analyzing cell structures under a fluorescent microscope. The Visisens system not so much aims at giving structural information but enables analyzing functional changes. As this measurement technique is not influencing the investigated system at all even living samples and tissues can be examined and their metabolic activity monitored. It is the only sensor system so far that can visualize gradients, analyte transport and record distribution changes over time. Like in a time lapse movie images recorded can reveal changes and fluctuations that could not be measured and pictured like this before. The Visisens system combines fluorescent optical sensor foils with digital camera technology. The core of this new measurement technique is the sensor foil (Fig. 1). It belongs to the category of so called smart materials reacting to changes in the sample without any intervention from outside - there are no cables or electrodes attached to it. The sensor foil contains special fluorescent dyes which are sensitive to a certain analyte. It acts like a simultaneous interpreter translating concentrations of parameters like O_2, pH, or CO_2 into specific light signals. The sensor works with visible light only, so no electrical signals are needed. Each dye molecule inside the sensor reacts independently and the light signals can be recorded pixel by pixel with the digital camera, so a single image contains the information of a whole array of single sensor points. This way analyte distribution over a whole area can be visualized with high spatial resolution down to μm-scale. The fluorescent dyes incorporated in the sensor foil are non-toxic and cannot escape the foil; therefore the sample will not be contaminated or poisoned.