Herceptin Research Today is a free monthly online journal that collates and summarizes the latest research about Herceptin, including details on side-effects, breast cancer, treatment, therapy.

Selective probing and imaging of cells with single walled carbon nanotubes as near-infrared fluorescent molecules.

Welsher K, Liu Z, Daranciang D, Dai H

Department of Chemistry, Stanford University, Stanford, California 94305.

Fluorescent molecules emitting in the near-infrared (NIR, wavelength approximately 0.8-2 mum) are relatively scarce and have been actively sought for biological applications because cells and tissues exhibit little auto-fluorescence in this region. Here, we report the use of semiconducting single-walled carbon nanotubes (SWNTs) as near-infrared fluorescent tags for selective probing of cell surface receptors and cell imaging. Biologically inert SWNTs with polyethyleneglycol functionalization are conjugated to antibodies such as Rituxan to selectively recognize CD20 cell surface receptor on B-cells with little nonspecific binding to negative T-cells and Herceptin to recognize HER2/neu positive breast cancer cells. We image selective SWNT-antibody binding to cells by detecting the intrinsic NIR photoluminescence of nanotubes. We observe ultralow NIR autofluorescence for various cells, an advantageous feature over high autofluorescence and large variations between cells lines in the visible. This establishes SWNTs as novel NIR fluorophors for sensitive and selective biological detections and imaging in vitro and potentially in vivo. Further, our results clearly show that the interactions between carbon nanotubes and living cells are strongly dependent on surface functionalization of nanotubes.

Published 14 February 2008 in Nano Lett, 8(2): 586-90.
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