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Open Access Highly Accessed Research

Quantum dots incorporated magnetic nanoparticles for imaging colon carcinoma cells

Syed Rahin Ahmed12, Jinhua Dong1, Megumi Yui3, Tatsuya Kato34, Jaebeom Lee25* and Enoch Y Park134*

Author Affiliations

1 Department of Bioscience, Graduate School of Science and Technology, Shizuoka University, 836 Ohya Suruga- ku, Shizuoka 422-8529, Japan

2 Department of Nano Fusion Technology, College of Nanoscience and Nanotechnology, Pusan National University, Miryang 627-706, Korea

3 Department of Applied Biological Chemistry, Shizuoka University, 836 Ohya Suruga- ku, Shizuoka 422-8529, Japan

4 Green Chemistry Research Division, Research Institute of Green Science and Technology, Shizuoka University, 836 Ohya Suruga- ku, Shizuoka 422-8529, Japan

5 Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 609-735, Korea

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Journal of Nanobiotechnology 2013, 11:28  doi:10.1186/1477-3155-11-28

Published: 17 August 2013

Abstract

Background

Engineered multifunctional nanoparticles (NPs) have made a tremendous impact on the biomedical sciences, with advances in imaging, sensing and bioseparation. In particular, the combination of optical and magnetic responses through a single particle system allows us to serve as novel multimodal molecular imaging contrast agents in clinical settings. Despite of essential medical imaging modalities and of significant clinical application, only few nanocomposites have been developed with dual imaging contrast. A new method for preparing quantum dots (QDs) incorporated magnetic nanoparticles (MNPs) based on layer-by-layer (LbL) self-assembly techniques have developed and used for cancer cells imaging.

Methods

Here, citrate - capped negatively charged Fe3O4 NPs were prepared and coated with positively - charged hexadecyltrimethyl ammonium bromide (CTAB). Then, thiol - capped negatively charged CdTe QDs were electrostatically bound with CTAB. Morphological, optical and magnetic properties of the fluorescent magnetic nanoparticles (FMNPs) were characterized. Prepared FMNPs were additionally conjugated with hCC49 antibodies fragment antigen binding (Fab) having binding affinity to sialylated sugar chain of TAG-72 region of LS174T cancer cells, which was prepared silkworm expression system, and then were used for imaging colon carcinoma cells.

Results

The prepared nanocomposites were magnetically responsive and fluorescent, simultaneously that are useful for efficient cellular imaging, optical sensing and magnetic separation. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) revealed that the particle size is around 50 nm in diameter with inner magnetic core and outer CdTe QDs core-shell structure. Cytotoxicity test of prepared FMNPs indicates high viability in Vero cells. NPs conjugated with anti cancer antibodies were successfully labeled on colon carcinoma cells (LS174) in vitro and showed significant specificity to target cells.

Conclusion

The present report demonstrates a simple synthesis of CdTe QDs-Fe3O4 NPs. The surface of the prepared FMNPs was enabled simple conjugation to monoclonal antibodies by electrostatic interaction. This property further extended their in vitro applications as cellular imaging contrast agents. Such labeling of cells with new fluorescent-magneto nanoprobes for living detection is of interest to various biomedical applications and has demonstrated the potential for future medical use.

Keywords:
Core-shell structure; Magnetic nanoparticles; Quantum dots; Fluorescent nanoparticles; Cell imaging