Assembly Properties of an Alanine‐Rich, Lysine‐Containing Peptide and the Formation of Peptide/Polymer Hybrid Hydrogels

Abstract

We are interested in developing peptide/polymer hybrid hydrogels that are chemically diverse and structurally complex. Towards this end, an alanine-based peptide doped with charged lysines with a sequence of (AKA 3 KA) 2 (AK2) was selected from the crosslinking regions of the natural elastin. Pluronic ® F127, known to self-assemble into defined micellar structures, was employed as the synthetic building blocks. Fundamental investigations on the environmental effects on the secondary structure and assembly properties of AK2 peptide were carried out with or without the F-127 micelles. At a relatively low peptide concentration (~0.5 mg/mL), the F127 micelles are capable of not only increasing the peptide helicity but also stabilizing it against thermal Correspondence to: Kristi L. Kiick, kiick@udel.edu; Xinqiao Jia, xjia@udel.edu. $ These two authors contributed equally to this work. NIH Public AccessAuthor Manuscript Macromol Chem Phys. Author manuscript; available in PMC 2012 February 1. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript denaturation. At a higher peptide concentration in basic media, the AK2 peptide developed a substantial amount of β-sheet structure that is conducive to the formation of nanofibrils. The fibril formation was confirmed collectively by atomic force microscopy (AFM), small angle neutron scattering (SANS) and transmission electron microscopy (TEM). The assembly kinetics is strongly dependent on solution temperature and pH; an increased temperature and a more basic environment led to faster fibril assembly. The self-assembled nanoscale structures were covalently interlocked via the Michael-type addition reaction between vinyl sulfone-decorated F127 micelles and the lysine amines exposed at the surface of the nanofibers. The crosslinked hybrid hydrogels were viscoelastic, exhibiting an elastic modulus of approximately 17 kPa and a loss tangent of 0.2.

Hybrid Block Copolymers Constituted by Peptides and Synthetic Polymers: An Overview of Synthetic Approaches, Supramolecular Behavior and Potential Applications

“…An alanine (A)-based peptide (AK2) doped with charged lysines (K) with a sequence of (AKA 3 KA) 2 was selected from the crosslinking regions of the natural elastin as a starting point for the hydrogel formation. It was prepared via covalent linkages between the terminal vinyl sulfone groups of the synthetic block copolymer and the lysine amines of the peptide [104]. By heating up to 60 °C the Michael-type addition reaction was accelerated and led to the formation of stable viscoelastic hydrogels.…”

High-Frequency Viscoelastic Shear Properties of Vocal Fold Tissues: Implications for Vocal Fold Tissue Engineering

“…The authors have found that the fit of the frequency dependence of the amplification factor to that obtained from the experiments is very good in the current study and in many others. 13,14,19,26,28,29 Three consecutive repeats of the TWE were performed on each sample.…”

“…Rotation of the upper plate is measured via an optical lever, and the linear viscoelastic shear properties of the specimen are calculated from the frequency dependence of the response. Previous studies have shown the TWE's ability to provide high-frequency viscoelastic shear properties on synthetic gels 13,14,19,26,28 and natural tissues. 29 Additionally, it is important to correlate the viscoelastic properties of the VFs with the histological structure and composition of the tissue, so the structure-property relationship can be understood, and suitable replacement materials can be developed.…”

Modular and orthogonal synthesis of hybrid polymers and networks

“…Our results suggest that the integrin-binding motif incorporated in EMHP is essential not only for cell attachment but also for cell proliferation. 113 …”