Plasmon-resonant gold nanorods have been examined as multifunctional agents for imaging and photoactivated therapies. Nanorods can be imaged with single-particle sensitivity by two-photon luminescence (TPL) when excited by fs-pulsed laser irradiation, and have been monitored in vivo while passing through blood vessels at subpicomolar concentrations. TPL imaging can also be used to characterize the targeted delivery of ligand-functionalized nanorods to tumor cells. Nanorods were coated with oligoethyleneglycol (OEG) units using in situ dithiocarbamate formation, a novel and robust method of surface functionalization. Nanorods coated with methyl-terminated OEG chains were shielded from nonspecific cell uptake, whereas nanorods functionalized with folate-terminated OEG chains accumulated on the surface of tumor cells overexpressing their cognate receptor. Cells labeled with folate-functionalized nanorods became highly susceptible to photothermolysis when irradiated at plasmon resonance, often resulting in a dramatic blebbing of the cell membrane. The blebbing was determined not to be directly caused by nanorod-mediated photothermolysis, but rather due to the influx of extracellular Ca2+ following perforation of the cell membrane.
Professor Wei’s research interests are rooted at the interface of organic chemistry and materials science, and their applications to biological systems. His interests include supramolecular surface science, nanoscale self-assembly, nanophotonics and nanomagnetism, cell-surface carbohydrates, and bionanotechnology. He has served on numerous federal and international peer review panels, and is the overseas editor for Science and Technology of Advanced Materials (Elsevier).
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