Biomimetic self-templating supramolecular structures

Abstract

In nature, helical macromolecules such as collagen, chitin and cellulose are critical to the morphogenesis and functionality of various hierarchically structured materials. During tissue formation, these chiral macromolecules are secreted and undergo self-templating assembly, a process whereby multiple kinetic factors influence the assembly of the incoming building blocks to produce non-equilibrium structures. A single macromolecule can form diverse functional structures when self-templated under different conditions. Collagen type I, for instance, forms transparent corneal tissues from orthogonally aligned nematic fibres, distinctively coloured skin tissues from cholesteric phase fibre bundles, and mineralized tissues from hierarchically organized fibres. Nature's self-templated materials surpass the functional and structural complexity achievable by current top-down and bottom-up fabrication methods. However, self-templating has not been thoroughly explored for engineering synthetic materials. Here we demonstrate the biomimetic, self-templating assembly of chiral colloidal particles (M13 phage) into functional materials. A single-step process produces long-range-ordered, supramolecular films showing multiple levels of hierarchical organization and helical twist. Three distinct supramolecular structures are created by this approach: nematic orthogonal twists, cholesteric helical ribbons and smectic helicolidal nanofilaments. Both chiral liquid crystalline phase transitions and competing interfacial forces at the interface are found to be critical factors in determining the morphology of the templated structures during assembly. The resulting materials show distinctive optical and photonic properties, functioning as chiral reflector/filters and structural colour matrices. In addition, M13 phages with genetically incorporated bioactive peptide ligands direct both soft and hard tissue growth in a hierarchically organized manner. Our assembly approach provides insight into the complexities of hierarchical assembly in nature and could be expanded to other chiral molecules to engineer sophisticated functional helical-twisted structures.

Biomimetic virus-based colourimetric sensors

“…2b) 25 . By controlling the phage deposition process, we could easily fabricate distinct and tunable structurally coloured nanostructures, in which colours do not appear to be strongly angle dependent.…”

“…We created the phage self-assembled colour band patterns using a simple pulling method 25 . The colours of the assembled structures were varied by controlling the pulling speed between 20 and 80 mm min À 1 .…”

“…1. Tunable phage-based structures fabricated using a self-templating assembly process are composed of quasiordered phage-bundle nanostructures and exhibit viewing-angle independent colours 25 . These films mimic the structure of turkey skins (Meleagris gallopavo, Pitman Farms, Sanger, CA, USA), which are structurally coloured blue due to coherent scattering of light from collagen bundle-based nanostructures (Fig.…”

The energy components of stacked chromatin layers explain the morphology, dimensions and mechanical properties of metaphase chromosomes

“…Fortunately, however, cutting-edge nanotechnology research has demonstrated that self-assembly of different structures of biological origin produces extremely complex micrometrescale materials that can be modelled using basic concepts of supramolecular chemistry [38][39][40][41]. In this context, recent research has revealed that multilayer plates (identical to those found in metaphase chromosomes) can be self-assembled from chromatin fragments obtained by micrococcal nuclease digestion of metaphase chromosomes [18].…”

The transformation of chiral signals into macroscopic properties of materials using chirality-responsive polymers

“…Recently, Chung et al 79 advanced this research and explained these phenomena from a new perspective. They also chose a single type of bacterial virus, the M13 phage, as the building block and constructed a Transformation of chiral signals G Qing and T Sun Transformation of chiral signals G Qing and T Sun series of LCs with distinct supramolecular structures by using a selftemplating assembly approach.…”