Inverted scanning microwave microscope for in vitro imaging and characterization of biological cells

This paper presents an instrument called an inverted scanning microwave microscope (iSMM), which is capable of performing noninvasive and label-free imaging and characterization of intracellular structures of a live cell on the nanometer scale. In particular, the iSMM is sensitive to not only surface structures but also electromagnetic properties up to one micrometer below the surface. Conveniently, the iSMM can be constructed through straightforward conversion of any scanning probe microscope, such as an atomic force microscope and a scanning tunneling microscope, with a simple metal probe to outperform a traditional SMM in terms of ruggedness, bandwidth, sensitivity, and dynamic range. By contrast, the application of the traditional SMM to date has been limited to mainly surface physics and semiconductor technology because the traditional SMM requires a fragile and expensive probe and is incompatible with saline solution or live cells.