Genetic controls, using DNA or siRNA, is emerging as a useful tool for controlling cellular functions in stem cells, particularly for directing their differentiation. Nanoparticles can be used to replace the traditionally used viral vectors, such as retroviruses, which have been implicated in causing complications in whole organisms such as inducing mutations leading to cancer. Nanoparticles offer a less expensive, more easily producible vector for transfection of stem cells, with lower risk of immunogenicity, mutagenicity or toxicity. A popular approach is to use cationic polymers that interact with DNA and RNA molecules. There is also room for development of smart polymers, with features such as targeted delivery or scheduled release. Carbon nanotubes with different functional groups have also been tested for drug and nucleic acid delivery into mammalian cells, but their use in stem cells has not been investigated to a large extent.
Optimizing the Stem Cell Environment
A significant area of study in stem cell research is that of the extracellular environment and how conditions outside the cell send signals for the control of differentiation, migration, adhesion and other activities. The extracellular matrix (ECM), consists of molecules secreted by cells such as collagen, elastin, and proteogylcan. The properties of these excretions and chemistry of the environment they create, provide direction for stem cell activities. Nanoparticles have been used to engineer different patterned topographies that mimic the ECM, for studying their effects on stem cells.
A major complication encountered with stem cell therapies has been the failure of injected cells to engraft to target tissues. Nanoscale scaffolds improve cell survival by aiding the engrafting process. Nanofibers spun from synthetic polymers such as poly(lactic acid) (PLA), or natural polymers of collagen, silk protein or chitosan, provide channels for alignment of stem and progenitor cells. The ultimate goal is to determine what scaffold composition best promotes proper adhesion and proliferation of the stem cells and use this technique for stem cell transplantations. However, it appears the morphology of cells grown on nanofibers may differ from cells grown on other media, and few in vivo studies have been reported.
Optimizing the Stem Cell Environment
A significant area of study in stem cell research is that of the extracellular environment and how conditions outside the cell send signals for the control of differentiation, migration, adhesion and other activities. The extracellular matrix (ECM), consists of molecules secreted by cells such as collagen, elastin, and proteogylcan. The properties of these excretions and chemistry of the environment they create, provide direction for stem cell activities. Nanoparticles have been used to engineer different patterned topographies that mimic the ECM, for studying their effects on stem cells.
A major complication encountered with stem cell therapies has been the failure of injected cells to engraft to target tissues. Nanoscale scaffolds improve cell survival by aiding the engrafting process. Nanofibers spun from synthetic polymers such as poly(lactic acid) (PLA), or natural polymers of collagen, silk protein or chitosan, provide channels for alignment of stem and progenitor cells. The ultimate goal is to determine what scaffold composition best promotes proper adhesion and proliferation of the stem cells and use this technique for stem cell transplantations. However, it appears the morphology of cells grown on nanofibers may differ from cells grown on other media, and few in vivo studies have been reported.