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Name (Title):
Keisuke Sato (MANA Research Associate)
Affiliation:
International Center for Materials Nanoarchitectonics
(MANA), NIMS
Address:
1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
Email: SATO.Keisuke@nims.go.jp
Home Page:
Presentation Title:
Silicon nanoparticles as fluorescent labeling of living cells
Abstract:
Fluorescent cadmium-based nanoparticles (NPs) have been
developed as bio-imaging material in vitro and/or in vivo.
However, concerns have been raised about the toxicological
issue of cadmium in biological systems under ultraviolet (UV)exposure
although the material has excellent optical properties,
such as size-dependent tunable fluorescence color and high
quantum yield of fluorescence for bio-imaging in vivo. Because
of the problem, the development of new NPs consisting of nontoxic
and more reliable elements is required. Silicon (Si)-NPs are
candidate materials for the elimination of any potential
toxicology problems. In this study, cytotoxicity of human
cervical carcinoma cell line (HeLa) cells labeled with Si-NPs
before and after UV-exposure, and the fluorescent imaging of Si-
NPs in vivo is discussed. The cytotoxicity examined the viability
of HeLa cells having Si-NPs as a function of the concentration
using the mitochondrial activity assay. The UV-exposed Si-NPs
exhibited a remarkably stable survival curve although the
viability decreased only slight with increasing the concentration
to 1.12 mg/ml, as shown in Fig. 1. This result substantiated the
low toxicity of Si-NPs. Moreover, the fluorescent imaging using
Si-NPs was investigated by the circulation from the lymphatic
vessel to the lymph node of a mouse. The transfer pathway of Si-
NPs could be satisfactorily recognized with the naked eye by
detecting the strong red light from Si-NPs, as shown in Fig. 2.
Therefore, these features demonstrate the usefulness of Si-NPs as
the biological labels for living cell imaging in vitro and/or in
vivo.
References:
[1] K. Sato, N. Kishimoto and K. Hirakuri, J. Appl. Phys. Vol.102 (2007) 104305.
[2] K. Sato, N. Kishimoto and K. Hirakuri, J. Nanosci. Nanotechnol. Vol.8 (2008) 374.
Viability ( % )
100
50
0
Unexposed
UV-exposed
Control
10 -2
Lymphatic vessel
Poster Session PS-15
10 -1
10 0
Concentration ( mg/ml )
Fig. 1 Viability of HeLa cells having
unexposed and UV-exposed Si-NPs
as a function of the concentration.
Lymph node
Fig. 2 Fluorescence image of Si-NPs
flowing into lymph node.
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