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Journal of Nanomaterials
Volume 2009, Article ID 620269, 5 pages
http://dx.doi.org/10.1155/2009/620269
Research Article

Asymmetric Composite Nanoparticles with Anisotropic Surface Functionalities

1Nano Biomedicine Research Center, Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
2Department of Chemical and Materials Engineering, University of Cincinnati, Cincinnati, OH 45221, USA
3National Key Laboratory of Nano/Micro Fabrication Technology, Research Institute for Micro/Nano Science and Technology, Shanghai Jiao Tong University, Shanghai 200030, China

Received 28 June 2008; Accepted 17 November 2008

Academic Editor: Jose A. Pomposo

Copyright © 2009 Yilong Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Asymmetric inorganic/organic composite nanoparticles with anisotropic surface functionalities represent a new approach for creating smart materials, requiring the selective introduction of chemical groups to dual components of composite, respectively. Here, we report the synthesis of snowman-like asymmetric silica/polystyrene heterostructure with anisotropic functionalities via a chemical method, creating nanostructure possibly offering two-sided biologic accessibility through the chemical groups. Carboxyl group was introduced to polystyrene component of the snowman-like composites by miniemulsion polymerization of monomer on local surface of silica particles. Moreover, amino group was then grafted to remained silica surface through facile surface modification of the composite nanoparticles. The asymmetric shape of these composites was confirmed by TEM characterization. Moreover, characteristics of anisotropic surface functionalities were indicated by Zeta potential measurement and confocal laser microscopy after being labeled with fluorescent dyes. This structure could find potential use as carriers for biological applications.