A. Naber, and W. Nahm. Video magnification for intraoperative assessment of vascular function. In Current Directions in Biomedical Engineering, vol. 3(2) , pp. 175-178, 2017
In neurovascular surgery the intraoperative fluorescence angiography has been proven to be a reliable contact-free optical imaging technique to visualize vascular blood-flow. This angiography is obtained by injecting a fluorescence dye e.g. indocyanine green and using an infrared camera system to visualize the fluorescence inside the vessel. Obviously this requires a medical approved dye and an additional camera setup and therefore generating risks and costs. Hence, the aim of our research is to develop a comparable technique for assessing the vascular function. This approach would not require dye nor an additional infrared camera setup. It is achieved by first preprocessing the video data of a camera that records only the visible spectrum and then filter it spatially as well as temporally. The prepared data is again processed to extract information about the vascular function and visualize it. This method would provide an option to compute and visualize the vascular function using the data recorded in the visible spectrum by the surgical microscopes. Given this contact-free optical imaging system, physiological information can be easily provided to the surgeon without an additional setup. In the case of comparable results with the state-of-the-art, this technique provides a straightforward optical intraoperative angiography. Further no drug approval is needed since no dye is injected.
A miniaturized ceramic atmospheric plasma source for the utilization in life sciences has been developed. It is manufactured in LTCC-technology (low temperature cofired ceramic). The plasma generation is based on buried electrodes which lead to a Dielectric Barrier Discharge (DBD). The employed technology allows small feature sizes (electrode width 150 μm, barrier thickness 40μm etc.) as well as precision in the μm range, resulting in a very low power consumption of the system (approx. 5 W). Thus, the maximum temperature at the point of use can be kept below 40 °C. The flexibility of the manufacturing process (layer lamination, screen printing, patterning with picosecond laser etc.) offers additional features like robust fluidic structures (channels, chambers, gas distribution etc.) as well as the direct implementation of electronic components. The technology concept as well as the design of the ceramic parts and the handhold matched to the multi-well plate format is demonstrated. The plasma of the system can be tuned depending on the assembly of the system and the electric excitation. To prove the biocompatibility and the experimental compatibility with cell cultures (low temperature at the point of use), a method for temperature measurements on the bottom of a multi-well plate was developed. First results of the impact of the plasma source on cell cultures are presented. The effects occurring in the plasma, as well as their effects on the cell cultures (ozone formation, ultraviolet radiation etc.) are separately considered. Furthermore, the cell tolerability of the treatment with the micro-plasma source is investigated with L929 fibroblast cells.