Gold-Based Magneto/Optical Nanostructures: Challenges for In Vivo Applications in Cancer Diagnostics and Therapy
- PDF / 308,772 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 66 Downloads / 191 Views
Magneto/Optical Nanostructures: Challenges for In Vivo Applications in Cancer Diagnostics and Therapy
Marites P. Melancon, Wei Lu, Chun Li Abstract Nanoparticles with a gold shell and iron core have unique optical and magnetic properties that can be utilized for simultaneous detection and treatment strategies. Several nanoparticles have been synthesized and show an ability to mediate a variety of potential applications in biomedicine, including cancer molecular optical and magnetic resonance imaging, controlled drug delivery, and photothermal ablation therapy. However, to be effective, these nanoparticles must be delivered efficiently into their targets. In this review, we will provide an updated summary of the gold-shelled magnetic nanoparticles that have been synthesized, methods for characterization, and their potential for cancer diagnosis and treatment. We will also discuss the biological barriers that need to be overcome for the effective delivery of these nanoparticles. The desired nanoparticle characteristics needed to evade these biological barriers, such as size, shape, surface charge, and surface coating are also explained.
Introduction Gold-shelled core-shell magnetic nanomaterial is composed of a magnetic core, such as magnetite (Fe3O4) or maghemite (γ-Fe2O3), coated with a layer of a gold shell. These unique nanostructures are of special interest not only because gold stabilizes (by preventing aggregation) and reduces the toxicity of the iron oxide core, but also because of these nanostructures’ potential application in diagnostics and therapy.1–3 Gold nanostructures possess unique physical and chemical properties, one of the most fascinating aspects being their strong absorption of light in the visible and near-infrared (NIR) region. The
origin of this absorption is attributed to collective conduction band electron oscillation in response to the electrical field of the electromagnetic radiation of light. Termed “surface plasmon,” this optical absorption is strongly dependent on the shape and size of the nanostructure. By coating gold on the surface of the iron oxide core, it is possible to tune these nanoparticles to absorb light in the NIR region. The tunable optical properties of gold nanostructures are highly desired for many applications that rely on light absorption, including imaging and therapy. Other attractive features of gold-
MRS BULLETIN • VOLUME 34 • JUNE 2009 • www.mrs.org/bulletin
shelled magnetic nanostructures include easy reductive preparation, high chemical stability, biocompatibility, and affinity for binding to amine and thiol terminal groups in organic molecules. While the gold shell offers distinct optical properties, the magnetic iron oxide core provides the potential for noninvasive imaging using magnetic resonance imaging (MRI) (see Lin’s article in this issue) for therapeutic heating in the presence of an alternating magnetic field and for directing nanoparticles to tumors using an external magnetic field. MRI is a noninvasive technique used to obtain anatomic and func
Data Loading...
