Semiconductor Quantum Dots for Cell Imaging

Nanotechnology is currently undergoing unprecedented development in various fields. There has been a widespread interest in the application of nanomaterials in medicine with its promise of improving imaging, diagnostics, and therapy. The recent advances in engineering and technology have led to the development of new nanoscale platforms such as quantum dots, gold nanocrystals, superparamagnetic nanocrystals, and other semiconductor nanoparticles. Literature on the applications of quantum dots in life sciences has recently increased in number. This may have led to predictions that nanotechnology in life sciences research will contribute $3.4 billion by 2010 while institutions have predicted that the market for nanotechnology and corresponding products will reach $1 trillion in 2012 (1). Ocean NanoTech is at the height of developmental stages of nanoparticle production for biological applications. Ocean’s high quantum-yield quantum dots (QDs) is currently being tested and used for cell imaging, as wells as for the detection of proteins, DNA, whole cells, and whole organisms. Imaging of cells involves conjugation of QDs to highly sensitive and specific antibody to form QD˜Ab conjugates that attach to specific protein target on the cell surface. Attachment of the QD˜Ab on the cell surface allows imaging of the cell under a fluorescence microscope. QD based imaging can be used in a multiplex immunoassay detection of several types of cells (or microorganisms) in a single sample when several size tunable quantum dots are used as reporter probes. We report the QD imaging of breast cancer cells. Using the breast cancer cell line SK-BR3, which expresses high levels of her2 antigens on the cell surface, anti-her2 were conjugated to Ocean’s quantum dots, QSH620. To eliminate non-specific binding of the QD˜20Ab Ocean’s super blocking buffer BBB and BBG were used. Preliminary results of in vitro studies indicated that QD based systems can be used to image cells. We anticipate that this system can be transferred to in vivo detection.