Tailored Carbon Nanotubes for Tissue Engineering Applications
Tailored Carbon Nanotubes for Tissue Engineering Applications
Tissue engineering has always excited me because of its novelty and innovation. However, the study of biomaterials has also sparked my interest since I have been taking organic chemistry. I currently plan to follow the tissue engineering and biomaterials track for biomedical engineering. This particular article addresses the use of biomaterials in engineering various types of tissue, including nervous tissue which is relevant to our current focus in class.
Carbon nanotubes (CNTs) are graphite sheets that are rolled into tubes of nanoscale diameter and length. While a CNT is not a biomaterial itself, surface modifications make it biocompatible. The have a large surface area, are strong, and have high thermal conductivity. One particular downfall is the fact that CNTs are hydrophobic and thus insoluble, making them difficult to integrate into biosystems. A solution to this issue is surface modification to make the CNTs soluble.
The various applications of CNTs are extensive, but they have not been proven completely successful, especially in vivo. Of particular interest to me is the application in tissue scaffolding. The properties of CNTs, along with cell viability, have been shown to improve with the collagen in the extracellular matrix. In addition, most current bone scaffolds are made of materials that have low strength and provoke immunorejection while CNTs have high strength and have not been shown to cause a major inflammatory reaction. In bone graft, CNTs improve cell adhesion and the ability of the scaffold to attract calcium ions which is important in mineralizing the bone matrix. In blood contact environments, most biomaterials cause thrombosis (clotting), but CNTs are chemically inert, allowing for a lower level of adhesion and reactivity with blood.
Another impressive application is in neuron regeneration since CNTs are electrically conductive and have diameters close to that of nerve fibers. CNTs may be used as devices to improve neural signal transfer as CNT substrates increase the spontaneous synaptic activity. Drug and gene delivery systems, as well as protein transportation, can make use of CNTs. An example of an application of selective drug delivery is the ability of drugs to be targeted at cancer cells.
In spite of the many potential benefits of carbon nanotubes, investigations into their safety in the human body are contradictory at best. CNTs, like most nanoparticles, can create reactive oxygen species, contributing to cytotoxicity, and severe DNA damage has also occurred in certain stem cells. Furthermore, production and treatment quality are not perfect, so contaminants, along with dispersant agents, can affect the safety of CNT use. It seems that solubilized and functionalized CNTs are less toxic. However, these modified CNTs convert into insoluble forms while in the organism and are released into the environment.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2700190/
Tissue engineering has always excited me because of its novelty and innovation. However, the study of biomaterials has also sparked my interest since I have been taking organic chemistry. I currently plan to follow the tissue engineering and biomaterials track for biomedical engineering. This particular article addresses the use of biomaterials in engineering various types of tissue, including nervous tissue which is relevant to our current focus in class.
Carbon nanotubes (CNTs) are graphite sheets that are rolled into tubes of nanoscale diameter and length. While a CNT is not a biomaterial itself, surface modifications make it biocompatible. The have a large surface area, are strong, and have high thermal conductivity. One particular downfall is the fact that CNTs are hydrophobic and thus insoluble, making them difficult to integrate into biosystems. A solution to this issue is surface modification to make the CNTs soluble.
The various applications of CNTs are extensive, but they have not been proven completely successful, especially in vivo. Of particular interest to me is the application in tissue scaffolding. The properties of CNTs, along with cell viability, have been shown to improve with the collagen in the extracellular matrix. In addition, most current bone scaffolds are made of materials that have low strength and provoke immunorejection while CNTs have high strength and have not been shown to cause a major inflammatory reaction. In bone graft, CNTs improve cell adhesion and the ability of the scaffold to attract calcium ions which is important in mineralizing the bone matrix. In blood contact environments, most biomaterials cause thrombosis (clotting), but CNTs are chemically inert, allowing for a lower level of adhesion and reactivity with blood.
Another impressive application is in neuron regeneration since CNTs are electrically conductive and have diameters close to that of nerve fibers. CNTs may be used as devices to improve neural signal transfer as CNT substrates increase the spontaneous synaptic activity. Drug and gene delivery systems, as well as protein transportation, can make use of CNTs. An example of an application of selective drug delivery is the ability of drugs to be targeted at cancer cells.
In spite of the many potential benefits of carbon nanotubes, investigations into their safety in the human body are contradictory at best. CNTs, like most nanoparticles, can create reactive oxygen species, contributing to cytotoxicity, and severe DNA damage has also occurred in certain stem cells. Furthermore, production and treatment quality are not perfect, so contaminants, along with dispersant agents, can affect the safety of CNT use. It seems that solubilized and functionalized CNTs are less toxic. However, these modified CNTs convert into insoluble forms while in the organism and are released into the environment.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2700190/
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