Small multifunctional nanoclusters (nanoroses) for targeted cellular imaging and therapy

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Materials Science

Background:

• Targeted cellular imaging and therapy require nanoparticles with high functionality.
• A key challenge is integrating targeting, imaging, and therapeutic capabilities into small, stable particles.
• Nanoparticle assembly offers a route to create multifunctional nanostructures.

Purpose of the Study:

• To develop stable, uniformly sized, near-infrared (NIR) active, superparamagnetic nanoclusters for cellular imaging and therapy.
• To investigate the optical and magnetic properties of these nanoclusters.
• To evaluate their potential in cancer and atherosclerosis applications.

Main Methods:

• Kinetically controlled self-assembly of gold-coated iron oxide nanoparticles into ~30 nm nanoclusters.
• Characterization of nanocluster size, stability, NIR absorbance, and magnetic relaxivity.
• Evaluation of cellular uptake and imaging capabilities in vitro and in vivo using a rabbit atherosclerosis model.

Main Results:

• Uniformly sized (~30 nm) and stable nanoclusters were successfully synthesized.
• Nanoclusters exhibited intense NIR absorbance (700-850 nm) due to collective electron responses.
• High r(2) spin-spin magnetic relaxivity (219 mM(-1) s(-1)) was achieved with thin gold shells.
• Dextran coating facilitated high macrophage uptake and intense NIR contrast in microscopy.
• Nanoclusters demonstrated stability in deionized water over 8 months.

Conclusions:

• Kinetically controlled assembly of gold-coated iron oxide nanoparticles yields multifunctional nanoclusters.
• These nanoclusters possess significant potential for targeted cellular imaging, therapy, and combined modalities.
• The developed nanoclusters show promise for advancing cancer and atherosclerosis treatment and diagnostics.