Convergence Nanoparticles for Multi-Modal Biomedical Imaging
- Friday, 01 May 2009
This technique enables detection, sensing, navigation, and actuation in a single nanosystem.
A project is underway to develop a novel, versatile, multi-functional convergence nanoparticle system that utilizes inorganic nanoparticles for advanced biomedical applications. Inorganic nanoparticles exhibit improved optical, magnetic, and electronic properties compared to classical bulk materials, making them useful as key components for futuristic nano-device applications.
The approach being used to develop multi-functional convergence nanoparticles involves three stages: 1) Fabrication of magnetic nanoparticles for simultaneous diagnosis and hyperthermia treatments; 2) fabrication of a convergence nanoparticle system; and 3) multi-modal utilization of convergence nanoparticles.
Magnetic nanoparticles have novel magnetic properties arising from nanoscale phenomena. For example, magnetic nanoparticles have been widely used as a diagnostic agent for MRI. Therefore, the heat-generation efficiency of magnetic nanoparticles, which make them ideal for both cancer diagnosis and therapy, have been investigated.
For the project’s purposes MnFe2O4 (MnMEIO, manganese doped magnetism engineered iron oxide) was used. MnFe2O4 is synthesized via high- temperature decomposition of MnCl2 and Fe(acac)3 in the presence of oleylamine and oleic acid as capping molecules following known methods.
The synthesized nanoparticles [1 mg/ml (Mn+Fe)] were mixed with cancer cells (MCF7) and heat-generation efficacy was measured with the cell viability under the alternating current (AC) magnetic fields (500 kHz). Live cells were stained with Calcein-acetoxymethyl (AM). The MnMEIO nanoparticles displayed significant cancer-cell killing effect with the AC magnetic-field irradiation compared to the case without AC magnetic field (see figure).
In the next stage, prototype convergence nanoparticles (Co@Pt-Au) are fabricated through epitaxial growth on the seed. Convergence nanoparticles can be fabricated through self-assembly of nanoparticles using molecular assemblers or selective secondary nucleation on top of the seed nanoparticles.
Since the chemical/biological molecules can be designed and synthesized to have high symmetry and have the ability of self-recognition and assembly, the use of these molecular assemblers enables the systematic construction of multi-component convergence nano - particles. In the case of the formation of convergence nanoparticles through secondary nucleation on the seed, modulation of similarity of the lattice geometry between seeds and secondary materials; affinity between two materials such as alloying, electrochemical potential differences; activity of a specific surface; and catalytic activity is important.
Lastly, the multi-component convergence nanoparticle system can enable multimodal multiplexing imaging and detection of biological processes by conjugating with bio-active materials. Conventional detection systems are operated independently and each detection system has its own advantages and disadvantages. However, convergence nanoparticles can overcome the many shortcomings that are present for single-imaging modality methods. As a model case study, magnetic-optical convergence nanoparticles for the dual-mode detection of proteins (amyloid protein) or lymph node is planned.
This work was done by Jinwoo Cheon of Yonsei University, Seoul, Korea, for the Air Force Research Laboratory. AFRL-0109
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