Biopolymer Nanoscale Assemblies as Building Blocks for New Materials: A Review

Abstract

Biopolymers, a class of fascinating polymers from biomass provide sustainability, biodegradability, availability, biocompatibility, and unique properties. A ubiquitous feature of biopolymers is their hierarchical structure, with the presence of well‐organized structures from the nanoscale to macroscopic dimensions. This structural organization endows biopolymers with toughness, defect resistance, and bucking adaptability. To retain these inherent structural features, nano‐structural assemblies isolated from biomass have been applied as building blocks to construct new biopolymer‐based materials. This top‐down processing strategy is distinct from the more traditional molecular‐level bottom‐up design and assembly approach for new materials. In this review, the hierarchical structures of several representative biopolymers (cellulose, chitin, silk, collagen) are introduced with a focus on these nanoscale building blocks, as well as highlighting the similarities and differences in the respective chemistries and structures. Recent progress in production strategies of these natural building blocks are summarized, covering methods and treatments used for isolations. Finally, approaches and emerging applications of biopolymer‐based materials using these natural nano‐ and meso‐scale building blocks are demonstrated in areas of biomedicine, electronics, environmental, packaging, sensing, foods, and cosmetics.

Biopolymer‐Templated Deposition of Ordered and Polymorph Titanium Dioxide Thin Films for Improved Surface‐Enhanced Raman Scattering Sensitivity

“…A few biotemplates including the proteins in tobacco mosaic virus, ferritin, [19] and butterfly wings [20] have been successfully exploited to prepare porous TiO 2 thin films. Being engineered from the most abundant biopolymers, [21] nanocellulose represents another type of biotemplates, [22] which typically includes cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial cellulose. [23] Although CNCs [24] and bacterial cellulose [25] have demonstrated promising possibilities for fabricating 3D templates of TiO 2 thin films, the progress over CNF-templated TiO 2 thin films is still very limited.…”

Electro-assembly of a dynamically adaptive molten fibril state for collagen

“…Collagen is also an important technical material with various potential applications in tissue engineering, regeneration medicine, and implantable medical devices (23)(24)(25)(26). For instance, collagenbased membranes have been used in periodontal and implant therapy in clinic to promote the growth of specific types of cells.…”

Fiber‐Based Biopolymer Processing as a Route toward Sustainability

“…This topic has been extensively reviewed elsewhere. [19,20,212] The direct thermoplastic molding of pure chitin or its derivatives without plasticizers has not been reported, while the chemical modification of chitin through acylation has been extensively explored to improve processibility. [213] However, it remains challenging to thermally mold acylated chitin alone due to the closeness of the decomposition and flow temperatures, resulting in a narrow processing window for thermoplastic molding.…”

“…Alternatively, solution-based methods, [15][16][17][18] where biopolymers dissolve at the molecular level, have traditionally been used for fibrous biopolymer processing to overcome or embrace the inherent structural stability of these native materials. The unique hierarchical organization of their fibrous structures prompts the use of fibrillation-based methods more recently developed for processing, [19,20] where the native building blocks of the fibrous biopolymers are retained during processing. This gap between synthetic plastic processing (thermal) and fibrous biopolymer (solution and fibrillation based) processing approaches invariably results in major gaps in process utility, complexity, costs, and consistency in polymer outcome; thermoplastics are preferred.…”