Nanostructure Science and Technology - World Technology ...

Appendix D. Site Reports—Japan 299
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.
REFERENCES
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.