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

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 organise 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 organisation 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/GOmembranes compared to the ELR5/PA membranes. Lastly, we investigated biocompatibility of the ELR5/PA/GO membrane via various cell culture methods

Peptide-Protein Coassemblies into Hierarchical and Bioactive Tubular Membranes

Multicomponent self-assembly offers opportunities for the design of complex and functional biomaterials with tunable properties. Here, we demonstrate how minor modifications in the molecular structures of peptide amphiphiles (PAs) and elastin-like recombinamers (ELs) can be used to generate coassembling tubular membranes with distinct structures, properties, and bioactivity. First, by introducing minor modifications in the charge density of PA molecules (PAK2, PAK3, PAK4), different diffusion-reaction processes can be triggered, resulting in distinct membrane microstructures. Second, by combining different types of these PAs prior to their coassembly with ELs, further modifications can be achieved, tuning the structures and properties of the tubular membranes. Finally, by introducing the cell adhesive peptide RGDS in either the PA or EL molecules, it is possible to harness the different diffusion-reaction processes to generate tubular membranes with distinct bioactivities. The study demonstrates the possibility to trigger and achieve minor but crucial differences in coassembling processes and tune material structure and bioactivity. The study demonstrates the possibility to use minor, yet crucial, differences in coassembling processes to tune material structure and bioactivity

Cross-linking of a biopolymer-peptide co-assembling system

Producción CientíficaThe ability to guide molecular self-assembly at the nanoscale into complex macroscopic structures could enable the development of functional synthetic materials that exhibit properties of natural tissues such as hierarchy, adaptability, and self-healing. However, the stability and structural integrity of these kinds of materials remains a challenge for many practical applications. We have recently developed a dynamic biopolymer-peptide co-assembly system with the capacity to grow and undergo morphogenesis into complex shapes. Here we explored the potential of different synthetic (succinimidyl carboxymethyl ester, poly (ethylene glycol) ether tetrasuccinimidyl glutarate and glutaraldehyde) and natural (genipin) cross-linking agents to stabilize membranes made from these biopolymer-peptide co-assemblies. We investigated the cross-linking efficiency, resistance to enzymatic degradation, and mechanical properties of the different cross-linked membranes. We also compared their biocompatibility by assessing the metabolic activity and morphology of adipose-derived stem cells (ADSC) cultured on the different membranes. While all cross-linkers successfully stabilized the system under physiological conditions, membranes cross-linked with genipin exhibited better resistance in physiological environments, improved stability under enzymatic degradation, and a higher degree of in vitro cytocompatibility compared to the other cross-linking agents. The results demonstrated that genipin is an attractive candidate to provide functional structural stability to complex self-assembling structures for potential tissue engineering or in vitro model applications.Ministerio de Economía, Industria y Competitividad (Project MAT2013-42473-R and MAT2015-68901R)Junta de Castilla y León (programa de apoyo a proyectos de investigación – Ref. VA244U13, VA313U14 and VA015U

Co-assembly, spatiotemporal control and morphogenesis of a hybrid protein-peptide system

Controlling molecular interactions between bioinspired molecules can enable the development of new materials with higher complexity and innovative properties. Here we report on a dynamic system that emerges from the conformational modification of an elastin-like protein by peptide amphiphiles and with the capacity to access, and be maintained in, non-equilibrium for substantial periods of time. The system enables the formation of a robust membrane that displays controlled assembly and disassembly capabilities, adhesion and sealing to surfaces, self-healing and the capability to undergo morphogenesis into tubular structures with high spatiotemporal control. We use advanced microscopy along with turbidity and spectroscopic measurements to investigate the mechanism of assembly and its relation to the distinctive membrane architecture and the resulting dynamic properties. Using cell-culture experiments with endothelial and adipose-derived stem cells, we demonstrate the potential of this system to generate complex bioactive scaffolds for applications such as tissue engineering.The work was supported by the European Research Council Starting Grant (STROFUNSCAFF), the European Commission under FP7 and H2020 programs ((NMP3- LA-2011-263363, HEALTH-F4-2011-278557, PITN-GA-2012-317304, MSCA-ITN-2014- ETN- 642687, 642687 H2020-NMP-2014-646075), the Ministry of Economy and Competitiveness (Spain) (MAT2012-38043-C02-01, MAT2013-41723-R, MAT2013- 42473-R) the Junta de Castilla y Leon (VA244U13, VA313U14) and the Portuguese Foundation for Science and Technology, grants PTDC/EBB-BIO/114523/2009 and SFRH/ BD/44977/2008. Additional support was obtained from the Bilateral Program Portugal– Spain Integrated Actions 2011 (E-50/11) and Marie Curie Career Integration Grant 618335. The authors thank the European Synchrotron Research Facility for access to synchrotron beamline BM29 and P. Pernot for support during the experiments, and C. López (Centres Científics i Tecnològics University of Barcelona), C. Semino (Institut Químic de Sarrià), E. Rebollo (Advanced Fluorescence Microscopy Unit in the Molecular Biology Institute of Barcelona), J. P. Aguilar, R. Doodkorte, A. Amzour and the technical staff of the Material Characterization Laboratory and Nanovision Laboratory at the Queen Mary University of London for the constructive discussions and contributions in this study