Site: Tokyo Institute of Technology
Yokohama 226, Japan
Tel: (81) 45-924 5759; Fax: (81) 45-924 5779
Date Visited: 21 July 1997
WTEC: L. Jelinski (report author), E. Hu, M.C. Roco, D. Shaw, C. Uyehara
The Tokyo Institute of Technology has two campuses, one at Tamachi and another at Nagatsuta. The Nagatsuta Campus is about 20 years old, and the Faculty of Bioscience and Biotechnology was put together and moved there about six years ago.
Professor Aizawa, whose laboratory the WTEC team visited at the Tokyo Institute of Technology's Nagatsuta Campus, was the project leader of a ten-year national MITI project on bioelectronic devices. The project, which ended in 1995, involved eight electronics companies and two national labs for its initial five-year period. One of the electronics companies dropped out and did not participate in the second term. An example of the work performed in the project is that by Mitsubishi, which produced an artificial protein that binds an electron acceptor and electron donor.
It appears that much of what was accomplished in the MITI bioelectronics project was accomplished in Aizawa's laboratory (see below). He set out to answer the question, "Are biological systems ideal for molecular electronics or not?" Parts of the project that are being continued appear to be in the form of RIKEN's Brain Research Center. Formulation of ideas for somewhat related work is being carried out by the Intelligent Materials Forum, whose members are working to promote a national project in this area. (The president of the forum is Toshinori Takagi; Aizawa is the vice president.) The idea of intelligent materials is to incorporate sensing and transduction and information processing into the same materials. The idea of forming a "Nanospace Laboratory" was just coming together at the time of the WTEC visit.
Aizawa has been a world leader in bioelectronics. His review on molecular interfacing for protein molecular devices and neurodevices (Aizawa 1994) describes subjects such as the coupling of electron transfer proteins (e.g., glucose oxidase) to solid surfaces, conducting polymer wires that couple the enzyme to the surface, and electrically modulated activity of molecular-interfaced enzymes.
More recent work, not yet published at the time of the WTEC visit, involved developing methodology to orient antibodies on surfaces. The key to making this work was to genetically modify protein A, known to bind the non-antigen binding stalk of the "Y" of the antibody, so its C-terminal carried a cysteine. The modified protein A was then bound to a gold surface via the well-known alkylthiol/gold chemistry. The ability to control the orientation of proteins on the surface is a major step forward in the ability to use these systems for drug targets, biochemical purifications and separations, and for sensing and diagnostic applications.
In other experiments, liposome nanoparticles were engineered by coupling to phosphatidyl choline, a peptide corresponding to one antigen binding domain of an antibody (Kobatake et al. 1997). These nanoparticles were used as the basis for a new fluoroimmunoassay.
Aizawa, M. 1994. Molecular interfacing for protein molecular devices and neurodevices. IEEE Engineering in Medicine and Biology (February/March).
Kobatake, E., H. Sasakura, T. Haruyama, M.-L. Laukkanen, K. Keinänen, and M. Aizawa. 1997. A fluoroimmunoassay based on immunoliposomes containing genetically engineered lipid-tagged antibody. Analytical Chemistry 69(7): 1295-1298.