Size-Tunable Magnetofluorescent Nanoparticles as In Vivo Imaging
- PDF / 1,182,471 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 65 Downloads / 176 Views
Size-Tunable Magnetofluorescent Nanoparticles as In Vivo Imaging Keisuke Sato1,2, Kenji Hirakuri1, Kouki Fujioka3, Yoshinobu Manome3, Hiroaki Sukegawa4, Hideo Iwai5 and Naoki Fukata2 1 Department of Electrical and Electronic Engineering, Tokyo Denki University, 5 Senju-Asahi-cho, Adachi-ku, Tokyo 120-8551, JAPAN. 2 International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, JAPAN. 3 Department of Molecular Cell Biology, Jikei University School of Medicine, 3-25-8 Nishi-shimbashi, Minato-ku, Tokyo 105-8461, JAPAN. 4 Magnetic Materials Center, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, JAPAN. 5 Materials Analysis Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, JAPAN. ABSTRACT Magnetic/fluorescent (magnetofluorescent) materials have become one of the most important tools in the imaging modality in vivo using magnetic resonance imaging (MRI) and fluorescence imaging. We succeeded in fabricating magnetofluorescent nanoparticles (MFNPs) consisting of silicon/magnetite composite nanoparticles. Our unique synthetic approach can control simultaneously the magnetic and fluorescence behaviors by varying the particle size, demonstrating the superparamagnetic behavior and green fluorescence for the MFNPs having mean diameter of 3.0 nm, and the ferromagnetic behavior without fluorescence for the MFNPs having mean diameter more than 5.0 nm. More intriguingly, the MFNPs with superparamagnetism can detect green fluorescence even after the magnetic guidance of MFNPs by the commercial neodymium magnet. Additionally, the MFNPs having two magnetic behaviors also possess good biocompatibility. INTRODUCTION The rapid development of noninvasive diagnostic imaging modalities, such as magnetic resonance imaging (MRI) and florescence imaging, has revolutionized biomedical research [1-3]. Recently, magnetofluorescent nanoparticles (MFNPs) that combine magnetic materials and fluorescent materials have been developed as contrast agent of both MRI and fluorescence imaging. In the design of such NPs, the selection of materials is absolutely critical. Fluorescent silicon (Si) NPs are well-known to be one of the safest materials in biomedicine applications, because they are composed of nontoxic elements and have little environmental impact [4,5]. We have fabricated the fluorescent SiNPs by the combination of radio-frequency (rf) magnetron sputtering process and subsequent annealing process. Such synthetic approach enables the formation of a variety of SiNPs by changing target materials, which use during sputtering process. Actually, we have succeeded in fabricating impurity doped SiNPs [6] and surfacemodified SiNPs [7]. Thus, our synthetic approach is also effective technique for the growth of MFNPs. We report herein on a simplified procedure to synthesize MFNPs that combine Si and magnetic materials by the utilization of Si and magnetic materials as target materials. We selected magnetic iro
Data Loading...
