Effects of biomedical macromolecules on the structure of chitin liquid crystals

The chitin whiskers (CHWs) form liquid crystals in colloidal suspensions due to their unique anisotropic structure, showing enormous potential for applications in optical materials, biomedical materials and other fields. Chitin liquid crystal (CLC) usually requires the introduction of a macromolecular system to form thin films or hydrogels to achieve the purpose of fixing the anisotropic liquid crystal texture. This study aims to systematically explore the interaction between macromolecules and CHWs, clarify the influence of macromolecules on the behavior of CLC. Herein, polyethylene glycol (PEG), chitosan (CS), hyaluronic acid (HA) were selected as model macromolecules. When uncharged macromolecule (PEG) is introduced, the increase in the concentration and molecular weight of the macromolecule increases the effective attraction between CHWs, thereby affecting the arrangement of CHWs and the structure of CLC. When positively charged macromolecule (CS) is introduced, the macromolecule affects CLC through electrostatic interactions and hydrogen bonding interactions with CHWs; when negatively charged macromolecule (HA) is introduced, the macromolecule affects CLC through electrostatic interactions with CHWs. When the interaction between the macromolecules and CHWs is greater than the driving force for self-assembly of CHWs, it is difficult for CLC to self-assemble into a cholesteric phase, thereby maintaining a nematic liquid crystal texture.