Introduction Rapid characterization methods are in demand for bacteria, which are simple to use and reliable, in a variety of fields such as clinical diagnosis, food inspection, and in environmental energy industries. Bacterial characterization methods can be divided into two categories: analysis of phenotype and genotype. Phenotype analysis includes a morphological study and chemotaxonomy where analysis of bacterial cell components such as proteins and lipids are analyzed. Genotype analysis includes gel electrophoresis and DNA sequencing using a sequencer. In many cases, a skilled operator can identify the species of bacteria using an optical microscope combined with supplemental information. However, optical microscope (OM) has limited resolution and with bacterial size typically smaller than a few micrometers, detailed structural information cannot be obtained. The use of scanning electron microscope (SEM) overcomes this resolution limitation but often requires long sample pretreatment such as dehydration and fixation that can take a day or even longer.