Abstract

The development of biocompatible nanoparticles for in-vivo molecular imaging and targeted therapy is an area of considerable current interest. The basic rationale is that nanometer-sized particles have functional and structural properties that are not available from either discrete molecules or bulk materials. When conjugated with biomolecular targeting ligands such as monoclonal antibodies, peptides or small molecules, these nanoparticles can be used to target malignant tumors with high specificity and affinity. In the “mesoscopic” size range of 10-100 nm diameter, nanoparticles also have large surface areas for conjugating to multiple diagnostic (e.g., optical, radioisotopic, or magnetic) and therapeutic (e.g., anticancer) agents. Recent advances have led to the development of biodegradable nanostructures for drug delivery, iron oxide nanocrystals for magnetic resonance imaging (MRI), quantum dots (QDs) for multiplexed molecular diagnosis and in-vivo imaging, and nanoscale carriers for short-interfering RNA (siRNA) delivery. We have developed a new class of biocompatible and nontoxic nanoparticles for in-vivo tumor targeting and detection based on self-assembled nanostrucrures and pegylated colloidal gold. These pegylated gold nanoparticles are considerably brighter than semiconductor quantum dots with light emission in the near-infrared window. When conjugated to tumor targeting ligands such as single chain variable fragment (ScFv) antibodies, the conjugated nanoparticles are able to target tumor biomarkers such as epidermal growth factor receptors (EGFR) on human cancer cells and in xenograft tumor models.

© 2010 Optical Society of America