Subsurface imaging of magnetic nanoparticles and quantification of nanomechanical properties of polymeric and biological materials by bimodal atomic force microscopy

点击翻译按钮获取中文摘要

The main purpose of targeted drug delivery is to release the active substance directly at the target location. The exact diffusion mechanisms of the drug carrier, e.g. the motion processes of functionalized nanoparticles within the human body, however, are mainly unexplored. This demands a tool that enables the observation of diffusion processes in real-time and the correlation of the mechanical and biological properties of cellular tissue with the diffusion locations. For this purpose, the suggested project addresses the high-resolution characterization of mechanical properties of polymeric and biological materials, the diffusion processes of magnetic nanoparticles and their subsurface detection. Advanced atomic force microscopy (AFM) methods, such as frequency modulation combined with a simultaneous excitation of two or more cantilever eigenmodes are to be improved. To enhance the lateral resolution, the imaging rate and the sensitivity of the method, short cantilevers will be used, whose applicability should be demonstrated in the liquid environment. A photo thermal excitation of the cantilever prevents the stimulation of undesired resonances in the AFM setup. An improvement of the electronics of the system for faster imaging rates will allow the in situ observation of biological processes. To this end, a subsurface detection of magnetic nanoparticles in polymeric and biological materials will be realized. The combination of fast imaging rates with the quantification of the mechanical sample properties and structural and magnetic detection on the nanoscale, allows for the observation of diffusion processes of magnetic nanoparticles into cellular tissue. To visualize the penetration of nanoparticles through the cell membranes helps to gain new knowledge about the targeted drug delivery. The main goal of the project is to correlate the diffusion locations of the nanoparticles with the nanomechanical properties of endothelial cells.