Peptidic Hydrogels - In-Situ Gelling Polymers: For Biomedical Applications - page 128

be discussed in greater detail further on with quaternary structures. Figure 2 is an
example from the Hartgerink group, showing fibril formation and hydrogel forma-
tion [ 50 ]. First, the primary order peptide structures assembled into fibrous qua-
ternary structures. Gelation is triggered with the introduction of multivalent ions,
inducing interfibrillar assembly. The barely entangled or branched fibril structures
between the short sequence peptide hydrogels of Fig. 1 is visibly different from
the longer sequence fibrils after gelation in Fig. 2 .

Fig. 1 Top dipeptide structure (I) and bottom peptide structure (II) and a combination of the two
shown with TEM and with inset to better show local fibril structure. The scale bar is 200 nm. a I
alone, b II alone, c combination of I and II [ 80 ]

Fig. 2 Dimers and folding mechanism of primary peptide sequences. TEM images show
E(QL) 6 E from the Hartgerink group a before gelation and b after gelation with Mg 2 + [ 50 ]