Scanning force microscope and force spectroscope

全面了解微生物生物膜形成的初始过程是我们研究的主要目标。具体来说，我们的目标是了解细胞粘附结合蛋白质吸附在许多不同的情况下。我们特别感兴趣的是口腔或体内特定的感染部位。参与研究小组的专业知识，（生物）物理学，医学微生物学和牙科学，使我们能够从字面上研究“从实验台到床边和背部”的现象：例如，可以使用单个活细菌的力光谱来确定其对不同材料和不同环境的粘附性（例如与唾液或血液接触）。材料范围从精确表征的模型表面到临床植入物，其中一些已经植入人体。可以从病原体方面研究不同类型的细菌/酵母菌。对于个别物种，我们可以获得野生型以及转基因细菌。然而，我们不仅想确定粘附力，还想使用单个细菌探针记录详细的力-距离曲线，因为这些曲线可以更深入地了解相互作用的性质、相互作用分子的数量、它们的长度和刚度，以及细菌与表面接触的区域的大小。这里应用的原子力显微镜装置还旨在解决了现有设备无法解决的新问题，例如，由于信噪比比现有设备高一个数量级，Z轴上的移动受到太多限制，或者由于没有合适的光学控制。例如，我们想阐明为什么相同细胞群的单个细菌有时在其粘附行为上表现出非常大的差异。假设是细胞分裂后新合成的区域在粘附方面不同于旧的细胞壁区域。由于可以通过荧光标记区分年龄，因此也应用了荧光显微镜。该装置在Z轴上的扩展工作范围也使我们能够通过单细胞力谱法记录力-距离曲线，即使是在粗糙的表面上，如细胞培养单层、组织样本或宿主或动物模型中植入物上产生的真实生物膜。（在非常低的接触力下），它还将使我们能够研究蛋白质聚集、使用蛋白质囊泡的材料运输或分子通过膜或在膜中的扩散性。对于后者，将开发一个可以内置到原子力显微镜中的微流体平台，以便可以在那里形成膜和囊泡并立即进行表征。

A comprehensive understanding of the initial processes of microbial biofilm formation is the major goal of our research. Specifically, we aim to understand cell adhesion in combination with protein adsorption in many different situations. We are particularly interested in the oral cavity or specific sites of infection in the body. The expertise of the participating research groups, (bio-) physics, medical microbiology and dentistry, allows us to study the phenomenon literally "from bench to bedside and back": For example, force spectroscopy with a single, living bacterium can be used to determine its adhesion to different materials and in different environments (e.g. in contact with saliva or blood). The material spectrum ranges from precisely characterized model surfaces to clinical implants, some of which have already been implanted in the human body. Different types of bacteria/yeasts can be investigated from the pathogen side. For individual species we have access to wild types as well as genetically specifically modified bacteria. However, we do not only want to determine the adhesive force, but also record detailed force-distance curves using individual bacterial probes, as these curves allow deeper insights into the nature of the interactions, the number of interacting molecules, their length and stiffness, and the size of the area with which the bacterium comes into contact with the surface.The atomic force microscope setup applied for here is also intended to answer new questions that could not be dealt with with the existing devices so far, e.g. because the signal/noise ratio is an order of magnitude higher than with current devices, the movement in the Z-axis is too restricted, or because no suitable optical control is available. For example, we would like to elucidate why individual bacteria of the identical cell population sometimes exhibit very large differences in their adhesion behavior. The hypothesis is that the newly synthesized areas after cell division differ from older cell wall areas in terms of adhesion. Since it is possible to differentiate age by fluorescent labelling, a fluorescence microscope has also been applied for. The extended working range of the proposed setup in the Z-axis also enables us to record force-distance curves by single cell force spectroscopy even on rougher surfaces such as cell culture monolayers, tissue samples or authentic biofilms generated on implants in the host or animal model.Since the device applied for can also scan faster than the devices available to us (at very low contact forces), it will also enable us to investigate protein aggregation, material transport using vesicles of proteins or the diffusivity of molecules through or in membranes. For the latter, a microfluidics platform is to be developed that can be built into the atomic force microscope, so that membranes and vesicles can be formed and immediately characterized there.