Nanotechnology
Nanotechnology provides clinical medicine with a range of new diagnostic and therapeutic opportunities such as medical imaging, medical diagnosis, drug delivery, and cancer detection and management. For example manganese, polystyrene, silica, titanium oxide, gold, silver, carbon, quantum dots, and iron oxide and other nanomaterials have made an impact in the development of new analytical tools for biotechnology and life sciences.
Stem cell labeling
The roles of stem cells are under intensive investigation in therapeutic and regenerative medicine, such as regenerating cardiomyocytes, neurons, bone, and cartilage. To track the real-time changes of cell location, viability, and functional status, cell imaging techniques have been introduced during the last few years. Cells of interest are labeled with reporter genes, fluorescent dyes, or other contrast agents that transform the tagged cells into cellular probes or imaging agents. MRI is used for cell tracking with high spatial resolution high anatomic background contrast, but MRI signals cannot indicate whether cells are dead or alive.
Nanoparticles are commercially available as ferro fluids consisting of an aqueous dispersion of magnetic iron oxides with a starch coating. To screen cells in vivo, several techniques have been described using nanoparticles like quantum dots, pebbles and super paramagnetic iron-oxide nanoparticles. The nanoparticle-labeled stem cells for tracking have been found very successful. Nanoparticles are resistant to chemical and metabolic degradation, demonstrating long term photostability. For example Quantum Dots (QDs) offer an alternative to organic dyes and fluorescent proteins to label and track cells in vitro and in vivo.
Labeling of stem cells with nanoparticles overcame the problems in homing and fixing stem cells to their desired site and guiding extension of stem cells to specific directions. Although the biologic effects of some nanoparticles have already been assessed, information on toxicity and possible mechanisms of various particle types remains inadequate.