Supramolecular Self-assembly of a Model Hydrogelator: Characterization of Fiber Formation and Morphology.

Emilios Dimitriadis,Ryan Nieuwendaal,Ferenc Horkay,Yuan Gao,Bing Xu,Boualem Hammouda,Jack Douglas

doi:10.3390/gels2040027

Abstract

Hydrogels are of intense recent interest in connection with biomedical applications ranging from 3-D cell cultures and stem cell differentiation to regenerative medicine, controlled drug delivery, and tissue engineering. This prototypical form of soft matter has many emerging material science applications outside the medical field. The physical processes underlying this type of solidification are incompletely understood, and this limits design efforts aimed at optimizing these materials for applications. We address this general problem by applying multiple techniques (e.g., NMR, dynamic light scattering, small angle neutron scattering, rheological measurements) to the case of a peptide derivative hydrogelator (molecule 1, NapFFKYp) over a broad range of concentration and temperature to characterize both the formation of individual nanofibers and the fiber network. We believe that a better understanding of the hierarchical self-assembly process and control over the final morphology of this kind of material should have broad significance for biological and medicinal applications utilizing hydrogels.

Highlights

There has been much recent work in synthesizing materials through ‘bonds’ created by molecular association rather than permanent chemical bonds
Transmission Electron Microscopy (TEM) imaging shows a projection of the objects and provides little information about the internal structure of nanofibers [26]
We have studied the thermally reversible gelation of a model peptide by a variety of experimental methods that probe the geometry and relaxation processes of solutions of this gelator molecule over a wide range of spatial and time scales

Summary

Introduction

There has been much recent work in synthesizing materials through ‘bonds’ created by molecular association rather than permanent chemical bonds. Such ”supramolecular” materials [1,2] are the norm in biological systems and this type of material is becoming increasingly important in numerous fields ranging from diverse agricultural products, food additives to drug delivery systems, and separation of biomacromolecules [3,4,5,6]. Supramolecular hydrogel formation has many proven applications [8,9], including cell culture [10], tissue engineering [11,12,13], and regenerative medicine [14,15], there is limited understanding of the factors that control the nanoscale structure and stability of these materials. There have been many previous studies of peptide-based hydrogels and Yan and Pochan [16] and Chow et al [17] have recently reviewed this field

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