Biomedical Engineering Reference
In-Depth Information
magnetic nanoparticles, when their size is below 30±50 nm, they have super-
paramagnetism properties (a phenomena when the clusters of magnetic particles
are so small that they can randomly flip direction under thermal fluctuations;
thus, the material as a whole is not magnetized except in an externally applied
magnetic field), which can enhance their sensitivity. Therefore, magnetic
nanoparticles are excellent MRI enhancers to identify tumors with higher
sensitivity than conventional imaging techniques [22].
Generally speaking, adult nerves are very difficult to self-repair and
regenerate, so stem cell therapy has been highly illuminated recently to treat
nervous system diseases or damage. For cell therapy, one of the critical concerns
is how to promote stem cell differentiation to the desired cell type at the
appropriate region for treatment. Nano-based 3D matrices made by various
nanotechniques can mimic the natural nervous system extracellular matrices to
induce cell differentiation for therapeutic applications (Fig. 9.15). Carbon
nanotubes/carbon nanofibers have been found to improve neuron differentiation
from human embryonic stem cells to more quickly return motor function
9.15 Neuronal cells grown on polypyrrole (PPy)/polystyrenesulfonate (PSS)
coated carbon nanofiber (CNF)/carbon nanotube (CNT) arrays. (Adapted
from Andrews [112].)