Infiltration of Proteins in Cholesteric Cellulose Structures

Abstract

Cellulose nanocrystals (CNCs) can spontaneously self-assemble into chiral nematic (cn) structures, similar to natural cholesteric organizations. The latter display highly dissipative fracture propagation mechanisms given their “brick” (particles) and “mortar” (soft matrix) architecture. Unfortunately, CNCs in liquid media have strong supramolecular interactions with most macromolecules, leading to aggregated suspensions. Herein, we describe a method to prepare nanocomposite materials from chiral nematic CNCs (cn-CNCs) with strongly interacting secondary components. Films of cn-CNCs were infiltrated at various loadings with strongly interacting silk proteins and bovine serum albumin. For comparison and to determine the molecular weight range of macromolecules that can infiltrate cn-CNC films, they were also infiltrated with a range of poly(ethylene glycol) polymers that do not interact strongly with CNCs. The extent and impact of infiltration were evaluated by studying the optical reflection properties of the resulting hybrid materials (UV–vis spectroscopy), while fracture dissipation mechanisms were observed via electron microscopy. We propose that infiltration of cn-CNCs enables the introduction of virtually any secondary phase for nanocomposite formation that is otherwise not possible using simple mixing or other conventional approaches.

The Colloidal Properties of Nanocellulose

“…While colloidal composites, including lysozyme amyloids, did not show a distinct effect on the chiral nematic pitch but rather limited the formation of a well‐ordered chiral phase, the native lysozyme showed a clear blue shift of the resulting chiral nematic pitch with increasing protein concentration. In contrast to these bottom‐up CNC–protein liquid crystals, Bast and co‐workers successfully infiltrated pre‐dried chiral nematic CNC films with bovine serum albumin (BSA), silk fibroin, and silk sericin [159] . In all cases, the presence of protein in the CNC films caused a redshift originating in an increased chiral nematic pitch.…”

Isolation of Mixed Compositions of Cellulose Nanocrystals, Microcrystalline Cellulose, and Lignin Nanoparticles from Wood Pulps

“…However, UBSK 64 had no chiral nematic reflection by UV–vis (Figure c), perhaps because its pitch is obscured by lignin absorbance. Indeed, others have observed protein adsorption bands that overlapped with the short-wavelength reflection bands of chiral nematic structures . BSK 64 has a parabolic focal conic liquid crystalline texture (Figure d), a structure that was first reported in CNC films by Roman and Gray .…”

Adsorption Process of Various Antimicrobial Peptides on Different Surfaces of Cellulose

“…The cellulose chain axis turns by 180° due to the chemical bonds of involved units which cause extensive H-bonds . Over the last few decades, many attempts have been dedicated to novel biopolymers-based cellulose synthesis for papermaking technology to meet environmental compliance goals. − Today, producing new materials based on cellulose for specific applications is of importance, however the cellulose surface needs to be modified to achieve antimicrobial properties in order to meet the high-level hygiene standards necessary in places like hospitals, pharmaceutical production units, food factories, etc. − For instance, antimicrobial papers offer promising properties for food packaging materials, medical wipes, bank notes, and air filters. The number of bacterial species showing resistance to commercially used antibiotics is increasing, which causes a global public health challenge .…”