SIC-BIO, Bioelectronics and Nanobioengineering Group, Departament d'Electrònica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona, Spain.
Colloids Surf B Biointerfaces. 2013 Feb 1;102:117-23. doi: 10.1016/j.colsurfb.2012.08.013. Epub 2012 Aug 19.
Scanning probe microscopy techniques are powerful tools for studying the nanoscale surface properties of biofilms, such as their morphology and mechanical behavior. Typically, these studies are conducted using atomic force microscopy probes, which are force nanosensors based on microfabricated cantilevers. In recent years, quartz tuning fork (QTF) probes have been used in morphological studies due to their better performance in certain experiments with respect to standard AFM probes. In the present work QTF probes were used to measure not only the morphology but also the nanomechanical properties of Pseudomonas aeruginosa during early stages of biofilm formation. Changes in bacterium size and the membrane spring constant were determined in biofilms grown for 20, 24 and 28 h on gold with and without glucose in the culture media. The results obtained using the standard AFM and QTF probes were compared. Both probes showed that the bacteria forming the biofilm increased in size over time, but that there was no dependence on the presence of glucose in the culture media. On the other hand, the spring constant increased over time and there was a clear difference between biofilms grown with and without glucose. This is the first time that QTF probes have been used to measure the nanomechanical properties of microbial cell surfaces and the results obtained highlight their potential for studying biological samples beyond topographic measurements.
扫描探针显微镜技术是研究生物膜纳米表面特性的有力工具，例如它们的形态和机械行为。通常，这些研究使用原子力显微镜探针进行，原子力显微镜探针是基于微制造悬臂梁的力纳米传感器。近年来，由于石英音叉 (QTF) 探针在某些相对于标准 AFM 探针的实验中具有更好的性能，因此在形态研究中已被使用。在本工作中，QTF 探针不仅用于测量生物膜形成早期铜绿假单胞菌的形态，还用于测量其纳米力学特性。在有和没有葡萄糖的培养基中培养 20、24 和 28 小时后，在金上形成的生物膜中测定了细菌大小和膜弹簧常数的变化。比较了使用标准 AFM 和 QTF 探针获得的结果。两种探针都表明，随着时间的推移，形成生物膜的细菌会增大，但培养基中葡萄糖的存在没有依赖性。另一方面，弹簧常数随时间增加，并且有葡萄糖存在和不存在的生物膜之间存在明显差异。这是首次使用 QTF 探针测量微生物细胞表面的纳米力学特性，并且所获得的结果突出了它们在除形貌测量之外的生物样品研究中的潜力。
