Inverted Scanning Microwave Microscope for In Vitro Imaging and Characterization of Biological Cells

TL;DR

This paper introduces an inverted scanning microwave microscope (iSMM) capable of noninvasive, label-free imaging of live biological cells at nanometer resolution, sensitive to both surface and subsurface structures.

Contribution

The paper presents the first implementation of an iSMM that can image and characterize live cells without labels, using a simple conversion from existing microscopes.

Findings

iSMM can image intracellular structures in live cells.

The instrument is rugged, compact, and compatible with saline solutions.

It outperforms traditional SMM in sensitivity and dynamic range.

Abstract

This paper presents for the first time an innovative instrument called an inverted scanning microwave microscope (iSMM), which is capable of 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 ectromagnetic properties up to one micrometer below the surface. Conveniently, the iSMM can be constructed through straightforward conversion of any scanning probe microscope, such as the atomic force microscope or the scanning tunneling microscope, with a simple metal probe to outperform traditional SMM in terms of ruggedness, and width, 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 biological cells.