Page 436 - Book Hosokawa Nanoparticle Technology Handbook

FUNDAMENTALS CH. 7 ENVIRONMENTAL AND SAFETY ISSUES WITH NANOPARTICLES
conducted with quantum dots conjugated with MUA, [13] H. Hoffmann, G. Speit: Mutat. Res. 581(1–2),
and quantum dots-NH with an amino group. DNA 105–114 (2005).
2
damage was not observed in either case. The results [14] S. Lemiere, C. Cossu-Leguille, A.M. Charissou and
indicate that as far as particles themselves do not P. Vasseur: Biomarkers, 10(1), 41–57 (2005).
break down, the cyto-toxicity of quantum dots is [15] F. Mattiolo, A. Martelli, C. Garbero, M. Gosmar,
derived from the chemical properties of the materials V. Manfredi, F.P. Mattiolo, G. Torre and G. Brambilla:
covering the quantum dots. Toxicol. Appl. Pharmacol., 203(2), 99–105 (2005).
The safety evaluation of nanoparticles has not been
conducted sufficiently. As indicated above, the pro- [16] F. Mouchet, L. Gauthier, C. Mailhes, M.J. Jourdain,
cedure for surface-conjugation could apply not only V. Ferrier and A. Devaux: J. Toxicol. Environ. Health
to Cd/Se nanoparticles but also to other nanoparti- A, 68(10), 811–832 (2005).
cles. Today, various kinds of techniques for surface- [17] A. Hoshino, K. Fujioka, T. Oku, M. Suga, Y. F. Sasaki,
conjugations have been available in academic papers, T. Ohta, M. Yasuhara, K. Suzuki and K. Yamamoto:
proceedings, and on the Internet. Some of them are Nano Lett., 4(11), 2163–2169 (2004).
widely known and others are patented. Those tech-
niques are all shared among the human race.
Even at this moment, the human beings are making
breakthroughs in various fields and developing differ- 7.4 Removal of nanoparticles
ent kinds of technologies. Sharing these technologies
will lead to still more speedy developments of yet 7.4.1 Principle of particle removal
more advanced technologies. To achieve it, these tech-
nologies should be so structured that different fields, In order to prevent nanoparticles release from a sys-
for example, bioimaging and biotechnology, struc- tem so as to maintain environmental safety, the
tured on their own, can be linked to each other. Such removal technique of nanoparticles must be estab-
structured knowledge will play an essential part in lished. In this section, separation techniques of parti-
merging different fields. cles from exhausted or suspended gas and liquid are
described focusing on particles less than 100 nm.
Generally, as shown in Fig. 7.4.1, all particle sepa-
References rators for a dispersed system employ either one of
three basic forms of particle separation. On the left
[1] S. Coe, W.K. Woo, M. Bawendi and V. Bulovic:
hand side of the figure lie the separation methods in
Nature, 420, 800–803 (2002).
which particles are collected only by force field (elec-
[2] T.C. Harman, P.J. Taylor, M.P. Walsh and B.E. LaForge:
trostatic force, centrifugal force, gravity force, etc.),
Science, 297, 2229–2232 (2002). and the representative separator is electrostatic pre-
[3] C. Santori, D. Fattal, J. Vuckovic, G.S. Solomon and cipitator (ESP). If some obstacles (collectors) are
Y. Yamamoto: Nature, 419, 594–597 (2002). placed into the particle laden stream, particle separa-
[4] X. Li, Y. Wu, D.Y. Steel, D. Gammon, T.H. Stievater, tion is facilitated because particles are collected on
D.S. Katzer, D. Park, C. Piermarocchi and L.J. Sham: obstacles with a smaller deviation from the fluid flow
Science, 301, 809–811 (2003). by the force exerting on the particles compared to the
case without obstacles. Typical collectors of this form
[5] A. Zrenner, E. Beham, S. Stufler, F. Findeis, M. Bichler
are air filter, deep bed filter, etc. On the right hand
and G. Abstreiter: Nature, 418, 612–614 (2002).
side of the figure lie separators that collect particles
[6] W.C. Chan, S. Nie: Science, 281, 2016–2018 (1998).
utilizing only sieving effect of obstacles without any
[7] K. Hanaki, A. Momo, T. Oku, A. Komoto, S.
force field. In this case, geometrical size of channel
Maenosono, Y. Yamaguchi and K. Yamamoto: Biochem. between the obstacles must be smaller than that of
Biophy. Res. Commun., 302, 496–501 (2003). particles. Membrane filter, fabric filter, etc. belong to
[8] M. Ishiyama, Y. Miyazono, K. Sasamoto, Y. Ohkura this group.
and K. Ueno: Talanta, 44, 1299 (1997). When we apply the above collection forms to
[9] T. Mosman: Rapid colorimetric assay for cellular nanoparticles, the major collection mechanisms are
growth and survival: J. Immunol. Method., 65, 55–63 Brownian diffusion and electrostatic force for particles
in gas, while sieving effect and interception/adhesion
(1983).
forces for those in liquid.
[10] H. Tominaga, M. Ishiyama, F. Ohseto, K. Sasamoto,
T. Hamamoto, K. Suzuki and M. Watanabe: Anal.
7.4.2 Removal of nanoparticles suspended in gas
Commun., 36, 47 (1999).
[11] A. Shiohara, A. Hoshino, K. Hanaki, K. Suzuki and K. As mentioned above, most airborne particles are col-
Yamamoto: Microbiol. Immunol., 48, 669–675 (2004). lected by separators utilizing various kinds of forces
[12] A.N. Shatrova, N.D. Aksenov, A.I. Poletaev, V.V. such as gravity, centrifugal force, electrostatic
Zenin: Tsitologiia, 45(1), 59–68 (2003). forces, inertia, Brownian diffusion force, and so on.
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