Applications that combine Nanoparticles with Stem Cells
Nanotechnology and biomedical treatments using stem cells (such as therapeutic cloning) are among the newest veins of biotechnological research. Even more recently, scientists have begun finding ways to marry the two. Since about 2003, examples of nanotechnology and stem cells combined have been accumulating in scientific journals. While the potential applications for nanotechnology in stem cell research are countless, three main categories can be assigned to their use:
- tracking or labeling
Certain nanoparticles have been in use since the 1990's, for applications such as cosmetic/skin care delivery, drug delivery and labeling. Experimentation with different types of nanoparticles such as quantum dots, carbon nanotubes and magnetic nanoparticles, on somatic cells or microorganisms, has provided the background from which stem cell research has been launched. As a little known fact, the first patent for the preparation of nanofibers was recorded in 1934. These fibers would eventually become the foundation of scaffolds for stem cell culture and transplantation – over 70 years later.
Visualizing Stem Cells Using MRI and SPIO particles
Research on the applications of nanoparticles for magnetic resonance imaging (MRI) has been pushed by the need to track stem cell therapeutics. A common choice for this application are superparamagnetic iron oxide (SPIO) nanoparticles, which enhance the contrast of MRI images. Some iron oxides have already been approved by the FDA. The different types of particles are coated with different polymers on the outside, usually a carbohydrate. MRI labeling can be done by attaching the nanoparticles to the stem cell surface or causing uptake of the particle by the stem cell through endocytosis or phagocytosis. Nanoparticles have helped add to our knowledge of how stem cells migrate in the nervous system.
Labeling using Quantum Dots
Quantum dots (Qdots) are nano-scale crystals that emit light, and are comprised of atoms from groups II-VI of the periodic table, often incorporating cadmium. They are better for visualizing cells than certain other techniques such as dyes, because of their photostability and longevity. This also allows their used for studying cellular dynamics while differentiation of stem cells is in progress.
Qdots have a shorter track record for use with stem cells than SPIO/MRI, and have only been used in vitro so far, because of the requirement for special equipment to track them in whole animals.