Scaffold for Tissue Engineering


Natural Bioscaffold

What are some examples of natural scaffolds currently under investigation?

                In the previous section, the topic of silk bioscaffolds was touched upon.  Silk has already been implemented as a degradable suture due to its mechanical strength and biocompatibility.  These two characteristics are key to making a feasible bioscaffold.  With some slight modifications, natural silk cultivated from silk worms can be made to have the ideal properties for bioscaffold construction.  One of the most important modifications involves a slight change to the protein arrangement.  This causes the silk to be biodegradable, which is very important for implantable bioscaffolds.  Other modifications include heating the silk to separate out proteins and also changing the crystallinity of the silk.  Each of these procedures can be manipulated to produce an ideal silk structure.  Another development is the genetic engineerins of silk worms to produce stronger silk.  This has been recently accomplished by Kraig Biocraft Laboratories.  Two recent accomplishments made using silk bioscaffolds were the regeneration of a ligament and the regeneration of an artery section.  The scaffold was constructed to mimic the native tissue properties in order to provide support until the tissue was regenerated.  Prior to implantation, cells were seeded on and into the scaffold.  Both procedures resulted in successful tissue regeneration using natural silk fibers.

                Another bioscaffold derived from natural materials is currently being investigated in liver replacement.  One of the largest obstacles of liver disease treatment is that healthy transplantable livers are difficult to locate and replacement is generally the only method which experiences success.  However, researchers have recently designed a way to use old livers, which have dead or dying cells, as natural scaffolds.  Using a special procedure, all cells and cell debris are removed from the liver.  Next, healthy stem cells are seeded to the empty tissue and vasculature is restored to promote growth.  So far, the replacement of livers with "refurbished" livers has shown great success in preliminary studies.  Two obstacles currently being investigated are circulation issues and cell supply.  However, the results still are very promising.  A similar technique is being investigated to treat diabetic patients using pig islets. 

                Lungs have also been successfully replaced using the technique previously mentioned.  A group of researchers at Yale University successfully replaced the lungs in a mouse using lungs from another mouse.  The lungs were stripped of their cells and then seeded with viable cells, which were allowed to grow for eight days.  Finally they were transplanted to the receiving mouse, where they functioned properly.  This technology is expected to be appropriate for human beings by around 2030.  The greatest hurdle encountered by each of these examples is the human immune response.  Because the cells being used are not native to the body, the transplanted lungs cause an immune reaction.  Therefore, a technique of culturing the patients cells must be developed before any of the cell replacement technology can be utilized successfully. 




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