Soft Hydrogels from Nanotubes of Poly(ethylene oxide)−Tetraphenylalanine Conjugates Prepared by Click Chemistry

Abstract

A new poly(ethylene oxide)-tetraphenylalanine polymer-peptide conjugate has been prepared via a "click" reaction between an alkyne-modified peptide and an azide-terminated PEO oligomer. Self-assembled nanotubes are formed after dialysis of a THF solution of this polymer-peptide conjugate against water. The structure of these nanotubes has been probed by circular dichroism, IR, TEM, and SAXS. From these data, it is apparent that self-assembly involves the formation of antiparallel beta-sheets and pi-pi-stacking. Nanotubes are formed at concentrations between 2 and 10 mg mL(-1). Entanglement between adjacent nanotubes occurs at higher concentrations, resulting in the formation of soft hydrogels. Gel strength increases at higher polymer-peptide conjugate concentration, as expected.

A clickable, highly soluble oligopeptide that easily forms organogels

“…Hence, the addition of the poor solvent was the major reason for the formation of well-organised b-sheet structure in gels. This observation was different from the reported pre-organisation of oligopeptides to form b-sheet in solution before the gel was formed (33)(34)(35).…”

Understanding Peptide Oligomeric State in Langmuir Monolayers of Amphiphilic 3-Helix Bundle-Forming Peptide-PEG Conjugates

“…56 Nanotubes were formed by PEGylation of tetraphenylalanine due to formation of antiparallel β -sheets and π – π -stacking. 57 As the PEG chain length increased, the nanotubes were observed to transition into fibrils. 58 The delicate interplay between steric hindrance of the conjugated PEG and inter- and intramolecular interactions of the peptide governs the self-assembly of hybrid peptide-PEG materials.…”

Developing a self-healing supramolecular nucleoside hydrogel

“…Notably there was an order of magnitude between G' and G" which is a characteristic of LMWGs 27 and a maximal G' value of 20 Pa, making it mechanically weaker than previous acyl cytidine derivatives 18 but a comparable magnitude to the guanosine and deoxy-guanosine gelators reported by Adhikari et al 9 The low G' value of this soft hydrogel is more indicative of entanglement of fibres than a crosslinked network. 28 Indeed, entanglement of fibres with transient crosslinks may be responsible for the most interesting behaviour of this N4-octanoyl-2ʹ-deoxycytidine gel as demonstrated by temperature profiling and time dependent-recovery tests. Temperature profiling (Fig.…”