Page 210 - Book Hosokawa Nanoparticle Technology Handbook

FUNDAMENTALS CH. 4 CONTROL OF NANOSTRUCTURE OF MATERIALS
patterning method on the substrate of heat-labile or pH-
sensitive organic compounds.
For mineralization, the ZnO-binding peptide with
a cysteine residue at the C-terminus was added into
a sol solution of zinc hydrate (Zn(OH) ). In the absence
2
of peptide, the Zn(OH) sol solution was stable during
2
the time course of the experiment; in fact, no change
was observed after a month. In contrast, ZnO-binding
peptide appeared to immediately interact with the
Zn(OH) sol phase, so that the sol state became more
2
condensed and finally ZnO particles were precipitated
in the solution after 3 days (Fig. 4.2.11). The addition
of a mixture of free amino acids found in the ZnO-
binding peptide shows no condensation of Zn(OH) nor
2
deposition of ZnO. The mineralization function is
expressed by making the peptide with amino acids
ordered according to the ZnO-binding peptide. In addi-
tion, a scanning electron microscope (SEM) and trans-
mission electron microscope (TEM) images for
synthesized ZnO showed a flower-type anisotropic
morphology composed of ZnO nanoparticles with a
diameter of 10–20 nm (Fig. 4.2.12). Our results show
the potential that the peptide with the capability to syn-
thesize inorganic materials can assist in the formation
of inorganic matter with unique structures.
In order to pattern inorganic nanoparticles on
organic substrates, selection of appropriate adhesion
between organic and inorganic materials is necessary.
When various different inorganic nanoparticles are
arranged on an organic substrate, specific organic–
inorganic adhesions for each combination should be
required; however, the number of possible covalent
bonding between organic and inorganic materials is
not sufficient for the requirement. Whereas, peptide
can supply various organic–inorganic adhesions, uti-
lizing a numerous combination number of amino acids
order. In addition, biomineralization has the potential
of the production of hybrid materials, because of the
mineralization at room temperature in neutral solution.
The advance in peptide/protein engineering will open
the way to a novel inorganic nanoparticle assembly.

References
[1] http://www.ndu.ac.jp/~t-nagumo/
[2] R.P. Blakemore: Annu. Rev. Microbiol., 36, 217–238
(1982).
[3] K. Shimizu, J. Cha, G.D. Stucky: Proc. Natl. Acad. Sci.
USA, 95, 6234–6238 (1998).
[4] D.E. Morse: Trend. Biotechnol., 17, 230–232 (1999).
[5] S. Brown: Proc. Natl. Acad. Sci. USA, 89, 8651–8655
(1992).
[6] S.R. Whaley, D.S. English, E.L. Hu, P.F. Barbara,
A.M. Belcher: Nature, 405, 665–668 (2000).
Figure 4.2.12 [7] S. Brown: Nat. Biotechnol., 15, 269–272 (1997).
SEM and TEM images of the ZnO particles synthesized by [8] M.A. Schembri, K. Kjaergaard, P. Klemm: FEMS
ZnO-binding peptide. Microbiol. Lett., 170, 363–371 (1999).

186