Self-assembly of a peptide amphiphile: transition from nanotape fibrils to micelles

Abstract

A thermal transition is observed in the peptide amphiphile C 16-KTTKS (TFA salt) from nanotapes at 20 C to micelles at higher temperature (the transition temperature depending on concentration). The formation of extended nanotapes by the acetate salt of this peptide amphiphile, which incorporates a pentapeptide from type I procollagen, has been studied previously [V. Castelletto et al., Chem. Commun., 2010, 46, 9185]. Here, proton NMR and SAXS provide evidence for the TFA salt spherical micelles at high temperature. The phase behavior, with a Krafft temperature separating insoluble aggregates (extended nanotapes) at low temperature from the high temperature micellar phase resembles that for conventional surfactants, however this has not previously been reported for peptide amphiphiles.

Structural behaviour and gene delivery in complexes formed between DNA and arginine-containing peptide amphiphiles

“…37 The cylinder-shell form factor was also used for fitting data from samples prepared with the lipopeptide PRW-C 16 dissolved in buffered solutions (middle curve in Figure 2A). The fitting parameters were as follows: L = 187.4 nm, R = 1.61 nm and R = 1.33 nm, consistent with cylindrical micelles with cores built up from C16:0 alkyl chains 38 and outer shells made up from a tripeptide functional group (3  0.34 = 1.02 nm) plus a counter ion layer. 39 SAXS profiles from solutions containing the bolaamphiphile RFL 4 FR (middle curve in Figure 2B) were consistent with nanosheets as previously described.…”

Investigation of perfluorosulfonic acid ionomer solutions by 19 f NMR and DLS: Establishment of an accurate quantification protocol

“…Concerned larger particles should exhibit a very slow motion regime and thus will give very broad NMR signals (solid‐like). “NMR silent aggregates” have already been described in liquid‐NMR spectroscopy of molecules or polymers solutions . In the present study, the measurements on the same samples of both DLS and NMR signals (Figs.…”

Molecular simulations of peptide amphiphiles

“…Experimentally these PAs have been found to self-assemble into nanostructures ranging from spherical micelles to vesicles, bilayers, nanofibers, nanotubes, as well as nanoribbons. 11–15 In particular, cylindrical nanofibers have gained recognition for their biomedical applications such as nerve regeneration, 16 wound healing, 17 cartilage regeneration, 18 as well as drug delivery devices 19 . In the last decade, an increasing number of computational groups have provided major insights into the structure and self-assembly of PA nanofibers as shown in Table 1 and in discussed within the context of this review.…”