FastScan atomic force microscope for rapid imaging and property measurement of biological systems under natural conditions.

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Atomic force microscopy (AFM) is now starting to deliver its potential for biology, allowing us to follow biological dynamics at the molecular scale in their natural (liquid) environment, to monitor the forces that drive biological processes and locally measure mechanical properties from the sub-protein level to entire tissues. Over recent years in Sheffield we have pioneered the use of this technology to answer questions from protein organisation in photosynthetic membranes, to the architecture of bacterial cell walls and we are expanding into entirely new applications such as the measurement of local mechanical properties in the walls of individual plant cells that are important in enabling their function. However, a new generation of AFMs is now commercially available that provides capabilities that are vital for understanding many of the most pressing problems. Processes at molecular length scales are inherently fast, while AFM, because each pixel of an image is collected consecutively, has traditionally had limited imaging rate. The new fast scanning systems have tackled this problem and are able to follow processes with sub-second image rates. Similarly, single proteins typically operate with very small forces, at the picoNewton level, and the properties of structures such as bacterial cell walls vary subtly over tiny, nanometre, length scales in a way that is important for their function. The new AFMs are able to use smaller cantilevers that are inherently more sensitive to force and less susceptible to noise than those used in conventional microscopes, allowing us to really start to unravel the molecular scale properties of living systems. The purpose of this project is to purchase a fast scanning AFM system and to use it to tackle a diverse range of questions including biological solar energy harvesting, bacterial cell division, dynamic changes as plant epidermal cells respond to environmental changes, and membrane protein function. As well as these initial applications, the Principal Investigator has an excellent track record of building successful collaborations using AFM to tackle biological problems, and the new machine will be vital in further expanding the questions that can be broached. Beyond this, the new microscope will form a vital component of a new centre at the University of Sheffield that will bring together state-of-the-art techniques for AFM, super-resolution optics and cryo-electron microscopy, in combination with internationally leading biology, to really understand living systems from individual molecules to entire cells and tissue. This ambition will occur within an extensive portfolio of BBSRC funded research providing an underpinning facility, vital for our future success.