| In order to study structure, function, and dynamics of biological macromolecules and macromolecular assemblies, tools are needed to observe them. Existing atomic force microscopes (AFMs) capable of imaging biological systems are limited in the speed of imaging, which directly limits the time resolution of the instrument. We present several methods to improve the scanning speed limits, resulting in: (1) an order of magnitude increase in speed for tapping mode operation—the mode of imaging most amenable to scanning soft, biological samples and (2) high-speed imaging in liquid environments. This work is enabled by integrating the feedback actuator onto the cantilever in the form of a piezoelectric bimorph, which has a bandwidth 30 times that of a commercial system's piezotube feedback actuator. Furthermore, we design electronics to optimize the cantilever response and improve stability in tapping mode.; Secondly, increasing the area of imaging while maintaining its sensitivity is important to expand the AFM into commercial and clinical applications. We address the problem of limited imaging size with the demonstration of a cantilever array that utilizes an interferometric sensor. The system is capable of angstrom resolution making it the most sensitive cantilever array published.; Thirdly, a cantilever can be used as a sensitive biological sensor. This is done by functionalizing the surface to allow specific binding of biomolecules. Using the same interferometric sensor, we demonstrate a cantilever-based system that is able to detect DNA hybridization.; Finally, microfluidic and micromechanical systems require methods to actuate objects in liquid environments. We demonstrate a method for actuation based on focused acoustic power. A micromachined Fresnel lens provides the means to actuate a cantilever and characterize its physical properties. |
