Biomimetic confined self-assembly of chitin nanocrystals

Nanochitin for sustainable and advanced manufacturing

“…To better understand the natural photonic observations, Liu et al investigated the self-assembly of chitin nanocrystals in capillaries and found that the chitin nanocrystals form a continuous orderly anisotropic phase depending on the phase boundary growth. 111 The air-liquid interface confined at the end of capillaries allowed the concurrent evaporation and deposition of chitin nanocrystals, which self-assemble into nested paraboloid Bouligand structures with a density gradient. Continuous birefringent layers were observed as a result of directional evaporation.…”

Modulating of Bouligand Structure and Chirality Constructed Bionically Based on the Self-Assembly of Chitin Whiskers

“…Chitin whiskers (CHWs), usually obtained from chitin by acid treatment, morphologically exhibit rigid needle-rod nanostructures and have a large aspect ratio and specific surface area . Motivated by the Bouligand structure formed by the self-assembly of natural chitin molecules in shrimp and crab shells, numerous researchers have been attempting to replicate such a microscopic topology in vitro based on CHWs by a variety of methods such as biomimetic mineralization, , self-assembly, and evaporation-induced self-assembly (EISA), and some progress has been made in the related research. In the earlier study, it was found that following self-assembly by sonication generates lyotropic crystals at certain concentrations .…”

“…In subsequent studies, this unique fingerprint weave of anisotropic phases of CHWs was reported to be a chiral nematic liquid crystal weave and exhibited a left-handed helical structure. , Vignolini’s team tried to deacetylate chitin to achieve the structural coloration of self-assembled chitin nanocrystal films . Zhang et al self-assembled of CHWs in restricted geometric capillaries by the biomimetic means of EISA, resulting in a well-defined Bouligand structure . Further, bioinspired Bouligand structure is used as chiral templates to guide the process of mineralization and thus the preparation of biophotonic structural materials with advanced functions. ,, …”

“…The Bouligand structure created by CHWs can offer some directions for the development of bionic materials. Nevertheless, in in vitro reproduction, it is not easy to achieve this structure because the self-assembly behavior of CHWs can be influenced by many factors with instability, , on the one hand, intrinsic factors such as different sources of CHWs, whiskers’ size, chargeability, and the concentration of the CHWs, and on the other hand, external environmental factors such as pH, ionic strength of the CHWs suspensions, − temperature, sonication treatment, and geometric space limitation. , These factors vary the strength of the interaction forces between the CHWs, which changes how the self-assembly process behaves. As reported by Gray, altering the acid hydrolysis conditions (time, temperature, acid concentration, etc.)…”

Toward High Sensitivity: Perspective on Colorimetric Photonic Crystal Sensors

“…Photonic crystals (PCs) are characterized with ordered structures, which endow PCs with striking structural colors arising from Bragg diffraction. − PCs based colorimetric sensors stand out for their unfading and readable sensing signals without any equipment and power sources, which are ideal candidates for the point-of-care (POC) sensing devices. The advances in newly developed synthetic polymers − and natural products (e.g., cellulose, − chitin nanocrystals, and proteins , ) as structural color materials offer colorimetric PC sensors with facilely tunable responsiveness and extending properties (e.g., self-healing , and adhesive , properties). On the other hand, the fabrication strategies of PCs such as magnetic assembly, − polymers assembly by solvent treatment, , microfluidics, spray coating, printing, − etc., provide opportunities for preparing sensors with diverse materials and structures as well as low-cost and large-scale manufacturing.…”