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Abstract Positioned within the eye, the lens supports vision by transmitting and focusing light onto the retina. As an adaptive glassy material, the lens is constituted primarily by densely‐packed, polydisperse crystallin proteins that organize to resist aggregation and crystallization at high volume fractions, yet the details of how crystallins coordinate with one another to template and maintain this transparent microstructure remain unclear. The role of individual crystallin subtypes (α, β, and γ) and paired subtype compositions, including how they experience and resist crowding‐induced turbidity in solution, is explored using combinations of spectrophotometry, hard‐sphere simulations, and surface pressure measurements. After assaying crystallin combinations, β‐crystallins emerged as a principal component in all mixtures that enabled dense fluid‐like packing and short‐range order necessary for transparency. These findings helped inform the design of lens‐like hydrogel systems, which are used to monitor and manipulate the loss of transparency under different crowding conditions. When taken together, the findings illustrate the design and characterization of adaptive materials made from lens proteins that can be used to better understand mechanisms regulating transparency. 

Abstract The biological chromophore xanthommatin (Xa) contributes to the yellow, red, and brown colors and hues in cephalopods and arthropods. In many cases, Xa is also present as part of or coupled to supramolecular nanostructures, whose function has yet to be fully explored. To investigate how such structural elements impact the perceived color of these natural chromophores, amorphous photonic assemblies containing Xa chemically coupled to 100 nm polystyrene nanoparticles (PS100‐XA) are fabricated, and blended with pure polystyrene (PS) nanoparticles of varying sizes. Structural colors are observed comprising these bidispersed colloidal assemblies that are tuned by the particle size of PS nanoparticles, the concentration of PS100‐XA, the local environment, and the method of assembly. In all cases, the addition of PS100‐XA regulates the color hue and contrast of the resultant assemblies by increasing light absorption while minimizing incoherent light scattering. Taken together, the results demonstrate how biochromes like Xa can enhance the color intensity and the diversity in colors present in common photonic assemblies. 

The photoexcited charge transfer properties of cephalopod chromatophore granules are examined within a photovoltaic cell. Photoconversion efficiency up to 0.81 ± 0.14% is recorded, highlighting a new function for these unique biomaterials. 

Nature is full of exemplary species that have evolved personalized sensors and actuating systems that interface with and adapt to the world around them. Among them, cephalopods are unique. They employ fast-sensing systems that trigger structural changes to impart color changes through biochemical and optoelectronic controls. These changes occur using specialized optical organs that receive and respond to signals (light, temperature, fragrances, sound, and textures) in their environments. We describe features that enable these functions, highlight engineered systems that mimic them, and discuss strategies to consider for future cephalopod-inspired sensor technologies. 

Crystallins comprise the protein-rich tissue of the eye lens. Of the three most common vertebrate subtypes, β-crystallins exhibit the widest degree of polydispersity due to their complex multimerization properties in situ. While polydispersity enables precise packing densities across the concentration gradient of the lens for vision, it is unclear why there is such a high degree of structural complexity within the β-crystallin subtype and what the role of this feature is in the lens. To investigate this, we first characterized β-crystallin polydispersity and then established a method to dynamically disrupt it in a process that is dependent on isoform composition and the presence of divalent cationic salts (CaCl 2 or MgCl 2 ). We used size-exclusion chromatography together with dynamic light scattering and mass spectrometry to show how high concentrations of divalent cations dissociate β-crystallin oligomers, reduce polydispersity, and shift the overall protein surface charge—properties that can be reversed when salts are removed. While the direct, physiological relevance of these divalent cations in the lens is still under investigation, our results support that specific isoforms of β-crystallin modulate polydispersity through multiple chemical equilibria and that this native state is disrupted by cation binding. This dynamic process may be essential to facilitating the molecular packing and optical function of the lens. 

Synopsis Cephalopods, including squid, octopus, and cuttlefish, can rapidly camouflage in different underwater environments by employing multiple optical effects including light scattering, absorption, reflection, and refraction. They can do so with exquisite control and within a fraction of a second—two features that indicate distributed, intra-dermal sensory, and signaling components. However, the fundamental biochemical, electrical, and mechanical controls that regulate color and color change, from discrete elements to interconnected modules, are still not fully understood despite decades of research in this space. This perspective highlights key advancements in the biochemical analysis of cephalopod skin and discusses compositional connections between cephalopod ocular lenses and skin with features that may also facilitate signal transduction during camouflage.