Confinement-induced liquid crystalline transitions in amyloid fibril cholesteric tactoids

Abstract

Chirality is ubiquitous in nature and plays crucial roles in biology, medicine, physics and materials science. Understanding and controlling chirality is therefore an important research challenge with broad implications. Unlike other chiral colloids, such as nanocellulose or filamentous viruses, amyloid fibrils form nematic phases but appear to miss their twisted form, the cholesteric or chiral nematic phases, despite a well-defined chirality at the single fibril level. Here we report the discovery of cholesteric phases in amyloids, using β-lactoglobulin fibrils shortened by shear stresses. The physical behaviour of these new cholesteric materials exhibits unprecedented structural complexity, with confinement-driven ordering transitions between at least three types of nematic and cholesteric tactoids. We use energy functional theory to rationalize these results and observe a chirality inversion from the left-handed amyloids to right-handed cholesteric droplets. These findings deepen our understanding of cholesteric phases, advancing their use in soft nanotechnology, nanomaterial templating and self-assembly.

Effect of Size Polydispersity on the Pitch of Nanorod Cholesterics

“…The helical twist of the local nematic director defines a typical mesoscopic lengthscale, referred to as the pitch, whose controllability is of key importance in the manifold examples of chiral nematics involved in technological applications (e.g., displays), as well as in nature [19]. Cholesteric materials * Electronic address: wensink@lps.u-psud.fr based on nanorods commonly consist of rigid, fibrillar units, composed of some biological component such as cellulose (CNCs) [20][21][22], chitin [23,24], collagen [25], or amyloid [26,27]. These fibrils are inherently sizepolydisperse and the effect of size disparity on the sensitivity of the pitch remains an important outstanding issue.…”

Effect of the concentration of protein and nanoparticles on the structure of biohybrid nanocomposites

“…Additionally, such ordered structures are of particular scientific interest because of their insolubility at physiological conditions, as well as their excellent nanomechanical properties; one example of nanogels made of amyloidal fibrils has a potential use as a drug delivery systems . Until now, these fibrillary materials are increasingly used as components for nanotechnology, as templates for the fabrication of conductive nanowires, and as matrix ingredient of graphene‐doped composite materials . Particularly in the field of biotechnology, these fibrils represent a significant number of biomaterials for many applications, of which reducing microcapsules composed of a fibrillary structure‐reinforced nanocomposite shell is one of the examples …”

Theoretical Platform for Liquid-Crystalline Self-Assembly of Collagen-Based Biomaterials

“…This evolution has two steps: (i) emergence of a cholesteric nucleus in a continuous isotropic phase, (ii) followed by the formation of a stable chiral nematic tactoid coexisting with the isotropic phase. In this work we restrict simulations to a single collagen tactoid with the aim of contributing to the evolving understanding of chiral phase ordering [24,25,41]. The simulations are also restricted to 2D.…”