The article describes the research of Professor Jiro Usukura and his team at Nagoya University EcoTopia Science Institute (Japan). Using ultrasonication, the researchers unroofed a cell membrane (removed the top layer) to expose the inner side or cytoplasmic membrane. Once exposed, the Park XE-Bio atomic force microscope was able to image the very soft and high-resolution details of the underlying intracellular cytoskeleton and the cytoplasmic surface of the cell membrane. The XE-Bio can do this very delicate imaging, even in an aqueous environment, thanks to its True Non-Contact Mode™ where the tip of the AFM probe can collect extremely accurate imagery data without making contact with the surface of the sample. This mode preserves the physical integrity of the sample while extending the life of the AFM probe tip.
According to Usukura, “The measurement capabilities of Park XE-Bio and True Non-Contact Mode™ imaging in a more biologically relevant condition demonstrate that it is an important tool for imaging intracellular structures and cell surfaces in the native, aqueous state.”
With the XE-Bio images, the researchers were able to see the details of actin filaments that form a complex meshwork on the cytoplasmic surface of the membrane. Examining the filaments at higher magnification, they noted characteristic periodic striations of about 5 nm formed by the assembly of G-actin. They also detected microtubules, often tethered to the membrane surface by fine filaments. For the first time in a water environment, they were even able to see clathrin coats on the membrane. While electron micrographs of freeze-etched samples can yield somewhat higher resolution, the Park XE-Bio provides nanoscale images in the more biologically relevant – wet – state. This makes the atomic force microscopy of the XE-Bio an important tool for imaging intracellular structures and cell surfaces.
As Dr. Sang-joon Cho, Chief Scientist at Park Systems put it, “AFM has not yet been used for the intracellular measurement of membrane cytoskeletons in vivo. Professor Usukura and his team successfully imaged various types of intracellular actin filaments directly at higher resolution by using Park XE-Bio with unroofing techniques. They enabled a new and important application of AFM in biology.” He noted that True Non-Contact ModeTM is ideal for imaging soft biological samples because it provides a method for measuring sample topography with minimal or no contact between the tip and the sample surface.
Park XE-Bio is a powerful 3-in-1 nanoscience research tool that uniquely combines Ion Conductance Microscope (ICM) with True Non-Contact mode AFM and inverted optical microscope on the same platform. The modular design of Park XE-Bio allows easy exchange between ICM and non-contact AFM. Designed for single live cell imaging, the combined imaging capability of ICM, AFM, and inverted optical microscope makes Park XE-Bio ideal for imaging biological samples, such as single living cells, in dynamic conditions. Moreover, ICM can be adapted to enable a host of powerful applications in nanoscale electrophysiology.
About Park Systems
Park Systems serves its customers by providing a complete range of AFM solutions including AFM systems, options and software, along with global service and support. Park Systems is the leading nanotechnology solutions partner for nanoscale measurements and systems for both research and industry. The product line of Park Systems reflects its focused strength to help customers achieve the metrology performance that meets the needs and requirements of present and future applications. Since improvements in nanometrology are key to enabling tomorrow's research, analysis, processing and product manufacturing, the innovative technology and market leadership of Park Systems in the field of nanometrology will remain as the core competence and market driving force of its future business. Park Systems' manufacturing and engineering facilities are located in Suwon, South Korea. Global sales and service offices are located throughout the U.S., Japan, and Singapore. For more information, visit www.parkAFM.com.