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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - BISON (Bio-Inspired Self-Assembled Supramolecular Organic Nanostructures)

Teaser

Summary

\"Molecular self-assembly is a key process in the formation of various architectures of ordered nano-materials. Such nano-materials often display unique physical properties, such as mechanical, optical, electrical and piezoelectrical characteristics that are the result of the dimension and ultrastructural properties of the studied assemblies. Moreover, the controllable assembly of simple building blocks into well-ordered structures at the nano-scale has long been envisioned as a key direction towards the realization of a \"\"bottom-up\"\" approach, in which simple building blocks interact with each other in a coordinated fashion to form large and more complex supramolecular assemblies. These strategies can be applied for the development of nano-scale devices and machines for future nanotechnological applications in diverse fields, including material science, energy, biomedical applications and more. The extensive study of inorganic nanostructures is now followed by the exploration of various organic materials as nanotechnological building blocks. Specifically, short peptides show a great promise as the next-generation nanotechnology frontier. The facile production of the peptides, their simple chemical modifications, remarkable efficiency of assembly, biocompatibility and controlled degradability, together with the extraordinary chemical, physical and mechanical properties, make these peptide-based bioinspired structures ideal for various types of applications, as well as open a new field of research into the basic science of molecular recognition, self-assembly and phase organization of these nanostructures.
The BISON project aims to development of a novel class of bio-inspired peptide nanostructures. These bio-inspired assemblies will provide novel and innovative directions for nano-science and nanotechnology, thereby laying the basis for their utilization in diverse applications. Specifically, the research is focused on 3 main objectives: i) Study of the assembly process, (ii) Technological application of the organic nanostructures, and (iii) Engineering of the building blocks.
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Work performed

a. Study of the assembly process: In order to better understand the self-assembly process of short peptides, we have established new methodologies for their analysis as part of the BISON project. These include a microfluidics platform, which allowed us to present the first demonstration of the elongation and shortening of peptide nanostructures, thereby providing key insights into the changes in the physical dimensions of assemblies. We have also established, for the first time, a super-resolution microscopy technique for the study of short peptide building blocks self-assembly, allowing us to analyze the real-time dynamics of the assembly process.
b. Technological application of the organic nanostructures: During the BISON project, we have demonstrated several intriguing applications of peptide-based nanostructures. Thus, we utilized the properties of the self-assembled nanostructures to develop microspheres which serve as sunlight-sensitive antennas for artificial photosynthesis. We were also able to fabricate a self-assembled photonic array with Opal-like multicolor appearance. These arrays display vivid coloration, strongly resembling the appearance of opal gemstones. Moreover, by controlling the solvent evaporation rate, we were able to manipulate the resulting coloration.
c. Engineering of the building blocks: As part of the BISON project, we were able to engineer the most stable emulsions reported so far for peptide and protein emulsifiers. We have established the ability of short heptapeptides to perform the dual functions of emulsifiers and thickeners, a feature that typically requires synergistic effects of surfactants and polysaccharides. We further used our design principles in order to prepare phsopho-peptides that served as phospholipid-like analogues. We could clearly see the organization of the designed building blocks into layer arrangements, highly similar to natural phospholipids, a major component of cell membranes. Finally, we designed a new tri-peptide building block that could form a variety of architectures, including nanowires, nanofibers, nanospheres, and nanotoroids.

Final results

A very important technology that was developed as part of the BISON project is the microfluidics systems for the real-time monitoring of molecular self-assembly. This methodology allowed the precise and rapid adjustment of assembly and disassembly. Direct real-time microscopy analysis revealed that different peptide derivatives showed unidirectional or bidirectional axial dimension variation. This is especially intriguing as the assembly and disassembly is usually monitored indirectly or not in real-time. This novel methodology lays the foundations for the rational control of supramolecular polymer dimensions for applications in material science.
In addition, a very important direction is the definition of the minimal building blocks for the formation of super-helical structures. Our work in progress allowed the identification of peptide elements shorter than 7 amino acids for the formation of stable super-helical structures. The mechanism of formation and utilization of the assemblies are currently being explored.