An atomic force microscope or AFM, is a high resolution surface profiling instrument that can produce topographical images of biological specimens. It can be operated in aqueous liquid and humid enviornments making it adept at probing biological materials and tissue without fixation and/or addition of contrast agents. It measures force through the use of a micro-cantilever sensor, so as well as imaging specimens it can measure their local mechanical properties. The AFM feels the specimen surface through a sharp tip at the end of the force sensor, which can have a radius less than 10nm. This gives the AFM the capability of measuring the nanoscale properties of materials and to acquire images of biological processes in situ.