This proposal was received in response to Nanoscale Science and Engineering initiative, NSF 04-043, category NIRT. In a number of tissues, and particularly muscle and liver cells, stem cells are known to be recruited from their respective niches to repopulate or fuse with existent cells. However, the exact cellular signal and conditions that favor cell targeting and fusion are currently not well understood. This high risk proposal is to develop multimodal Qdot-based nanoprobes that are optically active to track cell delivery and are further acted upon when a labeled stem cell fuses with tissue expressing beta-galactose, to generate MR contrast. The nanoprobe will be engineered to both be excited by and emit in the near infrared, avoiding cell damage caused by higher frequency radiation and providing good transmission through bodily tissues, and to give high contrast during near infrared and magnetic resonance imaging, avoid the leaching of toxic metal ions, and provide flexibility of functionalization. Multimodal Qdots will offer the possibility of a revolutionary, ultra-sensitive (at the level of a single cell) bioimaging capability which will help to unravel the mystery of stem cell homing mechanisms and develop a strong foundation for understanding gene expression mechanisms.
The proposed work will be linked to undergraduate programs, such as the Summer School in Particle Science and Research Experiences for Undergraduates programs, which will provide advanced seminars for experts and graduate students and research experiences for undergraduate students, respectively, based on the proposed work. A monthly seminar series will be started that will be open to the broad community, including professionals.
