Gold Boom In Nanotechnology Continues; Iron Oxide Nanoparticle-Containing Gold Nanocages Target and Destroy Cancer Cells

Korea Research Institute of Bioscience and Biotechnology (Daejeon, KR) disclosed gold nanocages containing magnetic nanoparticles for medical applications and a preparation method in U.S. Patent Application 20100228237.  One of the key and growing uses for nanogold is in medical applications, especially in imaging and cancer treatment.   

According to inventors Bong Hyun Chung, Yong Taik Lim and Jin Kyeong Kim, hollow-type gold nanocage particles contain iron oxide nanoparticles having a magnetic property and have an optical property of strongly absorbing or scattering light in the near-infrared (NIR) region.  Due to their optical property and magnetic property, the magnetic nanoparticle-containing gold nanocages can be used in various applications, including analysis in a turbid medium with light, cancer therapy or biomolecular manipulation using light, contrast agents for magnetic resonance imaging, magnetic hyperthermia treatment and drug delivery guide, etc.

FIG. 1 schematically shows a process for preparing gold nanocages containing iron oxide nanoparticles

FIG. 2 illustrates electron microscope photographs of iron oxide nanoparticles (1), gold-coated iron oxide nanoparticles (2), iron oxide nanoparticles (3) comprising silver coated on the nanoparticles (2), and iron oxide nanoparticle-containing gold nanocages (4), prepared through the process shown in FIG. 1

The optical property of the magnetic nanoparticle-containing gold nanocages of the present invention enables the gold nanocages to be used as contrast agents for magnetic resonance imaging (MRI) as shown in FIG. 6. 

FIG. 5 shows an MRI image of gold-coated iron oxide nanoparticles. 

FIG. 6 shows an MRI image of gold nanocage particles containing iron oxide nanoparticles.

Also, the magnetic property of the magnetic nanoparticle-containing gold nanocages can guide the gold nanocage particles to the desired site in the human body and enables the gold nanocages to be used in various applications such as magnetic hyperthermia treatment.

Also, the magnetic property and optical property of the magnetic nanoparticle-containing gold nanocages according to the present invention can be applied such that the gold nanocages target specific cells or tissue, and then selectively kill only specific cells and biomolecules.

FIG. 7 is a photograph showing that breast cancer cells (SKBR-3) were killed with a near-infrared laser (810 nm) using antibody-coated, iron oxide nanoparticle-containing gold nanocages. The gold nanocages that strongly absorb near-infrared light serve to selectively destroy tissues such as skin cancer around the skin using near-infrared light that can penetrate deep into the skin. The gold nanocages have an advantage in that they can greatly reduce side effects or pain, because the gold nanocages absorb near-infrared light, convert the absorbed light into thermal energy, and then selectively kill only target cancer cells (see FIG. 7).

Gold or silver nanoparticles exhibit strong surface plasmon resonances (light absorption or scattering) at specific wavelengths based on the sizes and shapes thereof. Also, these nanoparticles have very excellent optical stability compared to that of common organic dyes, and the surface plasmon resonance frequency thereof can also be controlled by changing the size, shape or structure thereof (Jin, R. et al., Science, 294:1901, 2000).

Using such properties of metal nanoparticles, studies on metal nanoparticles are being actively conducted in various fields, including biosensors for sensing biomaterials such as DNA or proteins, metal nanoparticle-containing detectors for detecting biomaterials (WO 2005/047864), surgical prosthetic biomaterials containing metal nanoparticles (U.S. 60/458,227), and chemical sensors comprising encapsulated metal nanoparticles (KR 10-2005-0065904). 

Recently, biosensors containing gold nanoparticles have been reported. For example, WO 2006/021091 discloses a biosensor for targeting specific DNA depending on the size of gold nanoparticles. Meanwhile, although metal nanoparticles may be used as test nanoparticle colloidal solutions, they can be used as tools for surface enhanced Raman scattering (SERS) after being coated onto a specific substrate or can be used as various biological and chemical sensors by forming an array thereof or coating them on colloidal particles (Taton, T. A. et al., Science, 289:1757, 2000).