Research

Cell Research

The surface of a cell is constantly moving. Techniques that can directly visualize the uptake of nanoscale substances such as viruses, which cannot be captured with an optical microscope, are extremely important, and researchers around the world are working to develop them. We are developing a unique scanning probe microscope that uses an extremely thin glass pipette: the scanning ion conductance microscope (SICM). The video below shows a magnified view of a small part of the cell surface at a resolution beyond the limit of light. We were able to observe the uptake of substances. The image size (2.5 × 2.5 µm) is about 1/50 of the width of a single human hair. The dark areas are depressions, and you can see that the structure changes dynamically. Our current goal is to clarify the mechanism behind these changes.

Biosensors that capture faint cellular responses
Measuring the chemicals consumed and released by a single cell on the spot requires sensors that detect chemicals with extremely high sensitivity. We have been developing electrochemistry-based biosensors for 15 years, including new biosensors built around microelectrodes and the scanning electrochemical microscope (SECM). We also use nanopipettes for local stimulation of cells and for collecting cytoplasm. The video below shows a fluorescent substance being delivered directly from a nanopipette into a single cancer cell. Reagents can be introduced into the cell simply by applying a voltage.

Materials Research

The structure of a catalytic material is closely related to its catalytic activity. Until now, however, visualizing this relationship has been difficult. Visualizing this heterogeneity provides design guidelines for developing higher-performance materials. Takahashi therefore began developing scanning electrochemical cell microscopy (SECCM) in-house in 2012 and succeeded in capturing catalytic activity at the nanoscale. This technique can also be used to evaluate energy storage materials and the corrosion of materials. The image below is an electrochemical image of the hydrogen evolution activity of MoS2, which is attracting attention as a catalyst for hydrogen production. We clearly visualized the difference in reactivity between the edges and terraces of MoS2. We are now also exploring the evaluation of reactions producing species other than hydrogen and oxygen.