Interfacial Self-Assembly to Spatially Organize Graphene Oxide Into Hierarchical and Bioactive Structures

Abstract

Multicomponent self-assembly holds great promise for the generation of complex and functional biomaterials with hierarchical microstructure. Here, we describe the use of supramolecular co-assembly between an elastin-like recombinamer (ELR5) and a peptide amphiphile (PA) to organize graphene oxide (GO) flakes into bioactive structures across multiple scales. The process takes advantage of a reaction-diffusion mechanism to enable the incorporation and spatial organization of GO within multiple ELR5/PA layers. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and ImageJ software were used to demonstrate the hierarchical organization of GO flakes within the ELR5/PA layers and the distribution profiles of GO throughout the ELR5/PA membranes. Furthermore, atomic force microscopy (AFM) revealed improved Young's Moduli of the ELR5/PA/GO membranes compared to the ELR5/PA membranes. Lastly, we investigated biocompatibility of the ELR5/PA/GO membrane via various cell culture methods.

Engineering Smart Composite Hydrogels for Wearable Disease Monitoring

“…One method to realize mass fabrication, miniaturization and integration of hydrogel-based sensors is to combine photocurable hydrogel with photolithography technology to prepare micropatterned hydrogel through specific mask exposure [ 217 – 219 ]. In addition, microfluidics [ 220 , 221 ], 3D printing [ 221 , 222 ], and non-contact forces [ 223 , 224 ] (i.e., electric, magnetic, or acoustic fields and self-assembly) are also competitive to be exploited in fabricating hydrogel-based devices with complex structures.…”

Synthetic extracellular matrices with function-encoding peptides

“…Furthermore, co-assembling peptides with structural proteins or inorganic fillers may enable the engineering of hydrogel nanocomposites; for example, co-assembly of short self-assembling peptides with macromolecules, such as resilin-like polypeptides 160 , elastin-like proteins 154 , 156 , or hyaluronic acid 88 , 153 , 177 , increases the mechanical properties and bioactivity of the peptides. Similarly, peptides can be co-assembled with rigid 2D nanomaterials, such as graphene oxide 226 and the synthetic clay Laponite 88 , to formulate peptide-based constructs for load-bearing applications.…”

“…Similar co-assembling approaches by non-specific interactions can be applied to organize proteins into hierarchical ensembles; for example, by tuning the charge of PAs (K2, K3, K4), the conformation of disordered elastin-like polypeptides (ELPs) can be modulated to trigger co-assembly mechanisms that result in different hierarchical material structures and properties, including the capacity to grow and heal 154 . This approach enables the use of hydrodynamic forces to hierarchically guide assembly 155 , organize exogenous components, such as graphene oxide 156 , or tune peptide structures (Fmoc-FFK) to increase material stability 157 . Further modulation of the charge density and epitope presentation of PAs allows co-assembly with multiple ECM components to generate complex, yet controlled, cell-instructive matrices; for example, to model the tumour microenvironment (TME) of ovarian cancer, keratin can be co-assembled with multiple peptides (VPGIGH 2 K for hydrogel stability, RGDS for cell adhesion, GHK for angiogenesis) 158 , and to recreate the TME of pancreatic cancer, fibronectin, collagen, laminin and hyaluronan can be integrated in an EEE-containing PA 159 .…”

3D Patterning within Hydrogels for the Recreation of Functional Biological Environments

“…H) Peptide amphiphile (PA)‐protein interfacial self‐assembly based on a diffusion–reaction process used to create graphene oxide patterns. [ 284 ] Copyright 2020, Frontiers Media. I) PA‐protein hydrodynamically guided co‐assembly to form patterned hydrogels with distinct geometries.…”

“…This approach has been used to generate hydrogel structures with intricate geometries with internal patterns such as peptide–protein layers [ 62 ] or be used to incorporate the components such as graphene oxide (Figure 9H). [ 63,284 ] Furthermore, hydrodynamic fluid forces can also be used as extrinsic forces to guide self‐assembly to further enhance geometrical and pattern complexity (Figure 9I). [ 285 ]…”