Material platforms that exploit the functionalities of both proteins and graphene oxide offer exciting possibilities for the engineering of advanced materials. This study introduces a method to 3D print graphene oxide with a protein that can organise into tubular structures that replicate some properties of vascular tissue.
Self-assembly is the process by which multiple components can organise into larger well-defined structures. Biological systems rely on this process to controllably assemble molecular building-blocks into complex and functional materials exhibiting remarkable properties such as the capacity to grow, replicate, and perform robust functions.
Including graphene as a building-block could lead to the design of new biomaterials that benefit from its distinctive electronic, thermal, and mechanical properties. Graphene oxide is also gaining significant interest as a starting material; being used instead of graphene because its rich oxygen-containing functional groups can facilitate specific interactions with different molecules.
In this study, published in Nature Communications, a new biomaterial is made by the self-assembly of a protein with graphene oxide. The mechanism of assembly enables the flexible (disordered) regions of the protein to order and conform to the graphene oxide, generating a strong interaction between them. By controlling the way in which the two components are mixed, it is possible to guide their assembly at multiple size scales in the presence of cells and into complex robust structures.
"This work offers opportunities in biofabrication by enabling simultaneous top-down 3D bioprinting and bottom-up self-assembly of synthetic and biological components in an orderly manner from the nanoscale," explains researcher Professor Alvaro Mata; “Here, we are biofabricating micro-scale capillary-like fluidic structures that are compatible with cells, exhibit physiologically relevant properties, and have the capacity to withstand flow. This could enable the recreation of vasculature in the lab and have implications in the development of safer and more efficient drugs, meaning treatments could potentially reach patients much more quickly."
By using Small Angle Neutron Scattering (SANS) on Larmor alongside simulations and other experimental techniques, the group was able to describe the key steps of the underlying molecular mechanism. In particular, SANS facilitated the understanding of the unique protein-graphene oxide organization and establishment of the rules for turning these interactions into a supramolecular fabrication process.
The system they produced showed remarkable stability, robust assembly, biocompatibility, and bioactivity. These properties enable its integration with rapid-prototyping techniques to bio-fabricate functional microfluidic devices by directed self-assembly, opening new opportunities for engineering more complex and biologically relevant tissue engineered scaffolds, microfluidic systems, or organ-on-a-chip devices.
The full paper can be found at: https://www.nature.com/articles/s41467-020-14716-z