Assembly of Cellulose Nanocrystal–Lysozyme Composite Films with Varied Lysozyme Morphology

Abstract

In modern society, there is a constant need for developing reliable, sustainable and costeffective antibacterial materials. Here, we investigate the preparation of cellulose nanocrystallysozyme composite films via the well-established method of evaporation-induced self-assembly.We consider the effects of lysozyme concentration and aggregation state (native lysozyme , lysozyme amyloid fibers, and sonicated lysozyme amyloid fibers) on suspension aggregation and film-forming ability. Although at higher lysozyme loading levels (ca. 10 wt%), composite films lost their characteristic chiral nematic structuring, these films demonstrated improved mechanical properties and antibacterial activity with respect to CNC-only films, regardless of lysozyme aggregation state. We anticipate that the results presented herein could also contribute to the preparation of other CNC/protein-based materials, including films, hydrogels and aerogels, with improved mechanical performance and antibacterial activity.

Biohybrid Nanocellulose–Lysozyme Amyloid Aerogels via Electrostatic Complexation

“… 50 − 53 The deconvolution of AMY-FL and AMY-S aerogel spectra was performed in order to evaluate the effects of sonication on the protein secondary structure ( Supporting Information , Table S3). 54 In both cases, a high content of the β-sheet structure, as expected for protein amyloids, 40 , 55 − 57 was evidenced, with almost no variation before and after sonication. This suggests that sonication is an effective method for tuning amyloid fibril length without affecting its protein conformational state.…”

“… 38 , 39 Similarly, work in our group previously investigated the preparation of structured composite films from CNCs and lysozyme amyloids via an evaporation-induced self-assembly. 40 Although the electrostatic complexation between negatively charged CNCs and positively charged lysozyme amyloids led to films with a decreased structural order, the incorporation of lysozyme amyloids improved the film’s antimicrobial properties against Gram-positive S. aureus , again with relatively small effects on film mechanics. Taken together, these results suggest that the incorporation of protein amyloids into nanocellulose-based materials is an effective method to add functionality based on the amyloid component, with the nanocellulose component providing structural integrity.…”

Chitin–amyloid synergism and their use as sustainable structural adhesives

“…3(a3) ). 25 Monomeric HEWL (M), amyloid fibrils (A), and short amyloids (SA) were all used to produce lap shear specimens through the C-EISA of 40 μL of individual suspensions (2 wt% and pH 2).…”

“…S3 † ). This was likely caused by the higher charge density 25 of the amyloids or by their slower diffusion relative to ChNCs. Either one of these effects, or the combination of both, may have led to an earlier onset of gelation, preventing the organization of the particles towards the edges.…”

“…The suspension was placed in a thermomixer (Eppendorf AG) at 90 °C and 400 rpm for 24 h. Short amyloids were prepared by subsequently tip-sonicating (Digital Sonifier 450, Branson Ultrasonics) the fully grown amyloid suspension for 20 min (2 second pulses) at 20% amplitude. 25 Samples were stored at 4 °C prior to use.…”