Biopolymeric photonic structures: design, fabrication, and emerging applications

Abstract

Biological photonic structures can precisely control light propagation, scattering, and emission via hierarchical structures and diverse chemistry, enabling biophotonic applications for transparency, camouflaging, protection, mimicking and signaling.

Chiral Cellulose Nanocrystals with Intercalated Amorphous Polysaccharides for Controlled Iridescence and Enhanced Mechanics

“…The polysaccharides, pullulan and dextran, were obtained from Sigma-Aldrich (pullulan is sourced from Aureobasidium pullulans, and dextran is sourced from Leuconostoc spp.). The relative molecular mass (M r ) of pullulan with a linear structure and α (1)(2)(3)(4)(5)(6) linked maltotriose units is ≈75 000 (Scheme 1). [33,34] The dextran from Leuconostoc spp.…”

“…Naturally occurring, vivid colors appear in multiple organisms and plants including butterfly wings, beetle exoskeletons, mollusk shells, pollia fruit, and cellulosic materials. [1][2][3][4] These colors These natural components are capable of strong intermolecular hydrogen bonding with CNC and can potentially promote seamless mixing of the biopolymers with CNC. [18,19,38,39] This combination results in significantly improved mechanical strength, nearly twofold for toughness and ultimate strength (Scheme 1).…”

Hydrogel‐Based Diffractive Optical Elements (hDOEs) Using Rapid Digital Photopatterning

“…[ 15–18 ] These DOEs have become increasingly important in biomedical applications ranging from imaging to diagnostics to sensing. [ 19–22 ] In the past decades, the DOEs are mostly made of conventional optical materials such as glass, semiconductor, and metals. Nonetheless, the inherent lack of mechanical flexibility and biocompatibility of these materials render their use difficult for in vitro and in vivo biophotonics applications.…”

“…Several natural and synthetic hydrogels, such as, silk, chitin, chitosan, bovine serum albumin, polyacrylamide, polyacrylic acid, and PEGDA have been used to make hydrogel based DOEs or hDOEs with optical performance comparable to conventional materials. [ 22–28 ] However, competing challenges such as high resolution, ease/cost of manufacturing, and customization of design based on target applications, prevent its widespread use in the field.…”

Integration of bio-responsive silver in 1D photonic crystals: towards the colorimetric detection of bacteria

“…Photonic crystals (PhCs) exhibit highly pure structural colours that can be engineered nely over the whole visible spectrum, thus offering an easy and recognizable colorimetric read-out while operating in a label-free fashion. [1][2][3] These features can be appealing for the detection of contaminants and pathogenic bacteria in food and water, as the existing detection approaches rely on the use of expensive equipment and specialised personnel due to the complexity of the read-out. 4,5 One-dimensional PhCs, in which the structural colour arises from the alternation of layers with high/low refractive index, have been utilised widely as versatile detection platforms [6][7][8][9] owing to their well-dened optical features, to their relatively easy fabrication and compatibility with a variety of stimuliresponsive functionalities.…”