Biomedical Engineering Reference
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Fig. 13 From designer self-assembling peptides to nanofi bers to scaffolds to tissues. ( a) Active
synapses on the peptide surface. Primary rat hippocampal neurons form active synapses on peptide
scaffolds. The confocal images shown in bright discrete green dot labeling are indicative of synap-
tically active sites after incubation of neurons with the fl uorescent lipophilic probe FM1-43. The
active synapses on the peptide scaffold are fully functional, indicating that the peptide scaffold is
a permissible material for neurite outgrowth and active synapse formation. ( b) Adult mouse neural
stem cells embedded in 3-D scaffold. ( c) Brain damage repair in hamster. The peptide scaffold was
injected into the optical nerve area of brain that was fi rst severed with a knife. The cut was sealed
by the migrating cells after 2 days. A great number of neurons form synapses (image courtesy of
Rutledge Ellis-Behnke). ( d) Chondrocytes in the peptide KLD12 (KLDLKLDLKLDL) scaffold
and cartilage formation. The trypan blue-stained chondrocytes show abundant glycosaminoglycan
production ( left panel ), while antibody to type II collagen demonstrates abundant Type II collagen
production ( right panel ). A piece of pre-molded cartilage with encapsulated chondrocytes in the
peptide nanofi ber scaffold. The cartilage formed over a 3-4 week period after the initial seeding of
the chondrocytes (image courtesy of John Kisiday). ( e ) Von Kossa staining showing transverse
sections of primary osteoblast cells on HA-PHP-RADA16-I self-assembling peptide nanofi ber
scaffold. Scale bar = 0.1 mm. The intensely stained black areas represent bone nodules forming
(image courtesy of Maria Bokhari et al. 2005 )
engineering, such as poly- (DL-lactic acid), poly- (lactide-co-glycolide acid) and
poly- (capro-lactone acid) (Gelain et al. 2007a, b ) . While natural-derived substrates
showed the best performances, RADA16-I scaffold coaxed neural stem cell differ-
entiation and survival to a similar degree of the other synthetic biomaterials.
Although self-assembling peptides are promising scaffolds, they show no spe-
cifi c cell interaction because their sequences are not naturally found in living
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