Analysis of Molecular Processes at Biointerfaces
How many interfaces between your body and artificial materials or devices can you find? Ranging from cosmetics, cloths to contact lenses, there are a variety of biointerfaces around us. When cells or living tissues are in contact with materials, cell membrane proteins interact the material surfaces generating signal cascades inside the cells. This signalings determine cell behaviors: adhesion, extension, movement, cell death. These lead to macroscopic response of our body, blood clotting, rejection response, etc.
We are trying to understand the signalings using our original techniques based on analyses of bio-surfaces and interfaces to discuss
1. What is the physics and chemistry behind biocompatibility?
2. What kinds of molecular processes occur between artificial materials and cells or living tissues.?
- Ligand recepter interactions involved in processes of molecular recognition (we are interested in structure, fluctuation, and dynamics of molecules)
- Identification and structural analysis of protein molecules adsorbed on solid surfaces
- Water molecules in the vicinity of biocompatible materials and relevance to biocompatibility
- Molecular events at cell-material interfaces
Development of Original Analytical Tools
To observe molecular processes at biointerfaces, we try to develop our original analytical tools. So far, we developed the following techniques to investigate biointerfaces.
Atomic Force Microscopy for Imagings of Biointerfaces
Initially, an AFM was used to image nanostructures of materials in vacuum. Now AFM has evolved as a strong tool to visualize behavior of biomolecules at biointerfaces. In addition to conventional piezo-driving of cantilevers, we developed the original photo-thermal excitation system to oscillate the cantilever with high stability in water.
Optical microscopes combined with an atomic force microscope
TERS enables us to measure local chemical properties of samples with nanoscale resolution from Raman spectra obtained from the area just under the metallized probe.
Our target samples are not limited to normal inorganic and organic nanomaterials and surfaces. We try to perform diagnostics of single protein molecules, which work as a “bed” for the adhering cells (so-called “ECM”: extra-cellular matrix)
Single-molecule Force Spectroscopy
AFM makes it possible to perform adhesion tests at a single-molecule level. Molecular interactions at a pN (pico Newton) level can be revealed by our special force measurements. With this method, we can get the picture of molecular recognition processes of biomolecules.
Surface Force Analysis Using an Atomic Force Microscope
We have revealed the behavior of water at biointerfaces by surface force analysis. Thus far, we have clarified that the physical barrier of water in the vicinity of bioinert surfaces prevent proteins and cells from adsorption and adhesion in case of highly non fouling surfaces.
Material informatics for design of biomaterial
In 2016, we started a completely new project to design biomaterials using a technique of material informatics. After 10 years we have worked on understanding of
Keywords for Our Techniques and Materials
Scanning probe microscopy
Atomic force microscopy
Single-molecule force measurements of peptides, proteins, ligand-receptor, antibody-antigen molecules, etc