Biomedical Engineering Reference
In-Depth Information
10.6
Self-assembling peptide scaffolds
Self-assembling peptide scaffolds (sapeptides) are another class of matrices for
tissue engineering applications (Fig. 10.3). Although not yet approved by the
FDA, as are other biomaterials mentioned in this chapter, sapeptides are a
unique solution to the problem of construction of tissue engineering matrices.
Instead of using synthetic polymers or natural decellularized matrices,
sapeptides are peptide monomers that spontaneously aggregate into -sheets
due to the arrangement of ionic hydrophobic and hydrophilic amino acids. These
-sheets structures then assemble further to create larger matrix constructs.
Sapeptides have similar cellular ingrowth characteristics as other matrices used
for tissue engineering (PLLA, PLGA, PCLA, collagen and Matrigel), but they
offer the benefit of having no detectable immune response (DÂgano et al., 2009)
and their degradation products are digestible amino acid monomers that can be
reused by the body (Kyle et al., 2009).
Some of the common sequences used for sapeptide scaffolds are named based
on their constituent amino acids. For example EAK16-II has the sequence
AEAEAKAKAEAEAKAK, and RADA16-I has the sequence AcN-
RADARADARADARADA-CNH
2
, with the letters referring to the amino acid
code A for alanine, E for glutamic acid, K for lysine, R for arginine and D for
aspartic acid. Sapeptide monomers can be produced by chemical synthesis or
with the use of transgenic organisms. Chemically synthesizing sapetides works
in a laboratory setting, but is not suited for scaling up for clinical applications.
10.3 Example of designer self-assembling peptide nanofiber scaffold (Gelain et
al., 2007b).
