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Different orders and life stages of springtails (Collembola) have developed a variety of periodic, hierarchical surface structures with hydrophobic properties. A-A″) Image of Entomobrya intermedia and SEM images showing hexagonal and triangular motifs in P. flavescens. B-B″) Image of Vertagopus arboreus, and SEM images showing irregular square and pentagonal motifs in I. viridus. C-C″) Image of Kalaphorura burmeisteri, and SEM images showing secondary granular structures and hexagonal motifs in S. quadrispina. D-D″) Image of D. ornata, and SEM images showing secondary granular structures and variable elliptical patterns in A. pygmaeus, Scale bars: A′-D′ = 2 µm, A″-D″ = 500 nm. Reproduced with permission. [666] Copyright 2012, Springer.

Different orders and life stages of springtails (Collembola) have developed a variety of periodic, hierarchical surface structures with hydrophobic properties. A-A″) Image of Entomobrya intermedia and SEM images showing hexagonal and triangular motifs in P. flavescens. B-B″) Image of Vertagopus arboreus, and SEM images showing irregular square and pentagonal motifs in I. viridus. C-C″) Image of Kalaphorura burmeisteri, and SEM images showing secondary granular structures and hexagonal motifs in S. quadrispina. D-D″) Image of D. ornata, and SEM images showing secondary granular structures and variable elliptical patterns in A. pygmaeus, Scale bars: A′-D′ = 2 µm, A″-D″ = 500 nm. Reproduced with permission. [666] Copyright 2012, Springer.

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Over the course of their wildly successful proliferation across the earth, the insects as a taxon have evolved enviable adaptations to their diverse habitats, which include adhesives, locomotor systems, hydrophobic surfaces, and sensors and actuators that transduce mechanical, acoustic, optical, thermal, and chemical signals. Insect-inspired design...

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... (i) prevent water (and thus weight) accumulation though antiwetting, (ii) exhibit low adhesion to foreign particles, (iii) promote droplet rolling to encapsulate and remove any contaminants that manage to stick to the surface, (iv) encourage droplet coalescence, which helps protect against the accumulation of water from fine mists, and (v) discourage bacterial growth. [149,154] Broadly, these hydrophobic designs can be generalized into at least four groups: simple (e.g., pillar or dome-shaped) micro- or nanostructures, complex (varied shape) micro-or nanostruc- tures, scales (usually 2-3 µm in one dimension), hairs or setae much longer (typically more than 5 µm in length) than their diameters, and hierarchical organizations including any combi- nation of these elements (Figure 9). [155] Regardless of their design motif, hydrophobicity-inducing structures in insects generally seek to maximize the air-water interface area while minimizing the solid-water contact area. ...
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... research from our group has taken inspiration from the lipid-bilayer-lined pores in the walls of sensilla in moth antennae, which also have the function of detecting and identifying chemicals in small amounts. Moth sensilla provide a nonstick fluid coating (Figure 19C, [430][431][432] ) and selective odorant-binding proteins and neural receptors enable moths to distinguish between odorants as described below. [430,[433][434][435] Similarly, selective conjugation of an analyte to a lipid membrane imparts selectivity to synthetic nanopore sys- tems while minimizing nonspecific adsorption. ...
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... some mechanosensors (see Section 5), the basic chem- oreceptive structures in insects are called sensilla. Sensilla take various shapes involving cuticular projections containing pores or pits ( Figure 19A,B), but the role of each chemoreceptive sen- sillum is the same as in the mechanical sensors: to bring the den- drites of the detecting sensory neurons into direct contact with the outside world while providing them with a protective bar- rier that facilitates chemical transport. The pores on a sensillum mediate access to the sensory neurons. ...
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... to the low concentration of odorant molecules in air and their importance in signaling, many insects have been evolution- arily pressured toward developing incredibly sensitive olfactory systems. For this reason, olfactory sensilla tend to have thou- sands of pores lining their walls ( Figure 19C) to give the sensory dendrites of each sensillum maximum exposure to the environ- ment. Different types of sensilla have evolved to optimally detect different types of analytes; double-walled sensilla are thought to be more sensitive to polar molecules, while single-walled sen- silla have evolved close-packed arrays of pore tubules specialized for the transport of nonpolar odorants. ...
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... types of sensilla have evolved to optimally detect different types of analytes; double-walled sensilla are thought to be more sensitive to polar molecules, while single-walled sen- silla have evolved close-packed arrays of pore tubules specialized for the transport of nonpolar odorants. [430,437] Many insects have multiple types of sensilla decorating their antennae, [438] giving them a wider scope of substrates ( Figure 19A). ...
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... moths in particular have developed spectacular antennae in the shape of combs or feathers. Extensive branching increases the surface area of the antennae of the silkmoth, Bombyx mori, sixfold from 4.8 to 29 mm 2 (Figure 19). [438,439] Adv. ...
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... Less than a millisecond after the valve opens, the explosion resulting from the contact of the fuel with the enzymes displaces a flexible expansion membrane ( Figure 20B) that closes the valve again, giving the jet its pulsed character and automatically regulating the consumption of fuel for longer, less self-destructive pulses than if the fuel were to all enter the chamber at once. [464] The secretion that catalyzes the reaction is dense and sticky and is held to the inner surface of the reaction chamber by an impressively diverse array of microsculp- tures, including branched spines, haired walls, spiny hairs, spiny lobes, small spinules, and a honeycomb-like floor, which mini- mize catalyst loss due to washout between blasts ( Figure 19D). The "turret" at the abdominal apex contains resilin to minimize recoil. ...

Citations

... Insects show a great variety of colors [1] that can have relevant biological functions such as thermoregulation [2], warning (aposematic) coloration [3] or mimicry [4], secondary sexual characters [5], and predator avoidance (crypsis and masquerade) [6]. Coloration can be due to structural colors (forms of surface and epidermal structures) or pigments (outer body layers) that selectively absorb, reflect, or scatter the light. ...
... Coloration can be due to structural colors (forms of surface and epidermal structures) or pigments (outer body layers) that selectively absorb, reflect, or scatter the light. Orange, red, yellow, and brown-black colors of the body observed in insects derive from pigments, while blue or green colors are often due to structural features [1]. Either the colors or the way they are arranged into patterns often vary among individuals of a species. ...
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As part of the studies on the morphological color variation of insects, a case study on the seasonal body color variation of Cirrospilus pictus (Nees) (Hymenoptera: Eulophidae: Eulophinae) parasitoid of leafminers is reported. Observations were made from January 2000 to December 2003 in north-western Sicily (Italy), in relation to sex, body regions of adults and seasonal periods. Wasps parasitizing Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) were collected from organic citrus orchards (Citrus limon L., var. “Femminello zagara bianca” and “Femminello comune”). Adults were grouped in classes: yellow males, black males, yellow females, yellow–black females and black females. The results highlighted a phenotypic pigmentation variation in the head, thorax, gaster and legs of individuals influenced by the season of sampling. Adults were yellow–green in summer months, whereas individuals with dark pigmentation were found in autumn and winter months. A correlation between color patterns and seasonal temperatures was found for both females and males. This work provides a contribution to the description of the intraspecific variability of this species, improving its identification.
... Wettability characterizes a surface's ability to get wet or the ability of a liquid to spread across a surface. This is impacted by both surface morphology and chemistry [1]. However, surface-structure-induced hydrophobicity is the more powerful mechanism. ...
... Insect cuticle is a remarkable material that has long captured the attention of scientists. The cuticle can be thin and flexible, thick and rigid, smooth or rough, and can provide various functionalities such as adhesion, chemical sensing and defense, color manipulation, locomotion, mechanosensation, sound production, thermoregulation, (anti)reflectivity, and (anti)wetting [1]. It can also vary between sexes, life stages and body parts, and can change based on the environment in which the insect lives [27,28]. ...
... Terrestrial beetles with hydrophobic microstructures include darkling beetles (Lagria hirta, Zophobas morio), the flower chafer beetle (Mimela testaceipes), poplar leaf beetle (Chrysomela populi), terrestrial leaf beetle (Gastrophysa viridula), and the Namib desert beetle (Onymacris unguicularis). The cuticular features of these beetles resemble hair-like setae which promote hydrophobicity [1,54,55,58,59]. Examination of a terrestrial leaf beetle (G. ...
Article
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Insects demonstrate a wide diversity of microscopic cuticular and extra-cuticular features. These features often produce multifunctional surfaces which are greatly desired in engineering and material science fields. Among these functionalities, hydrophobicity is of particular interest and has gained recent attention as it often results in other properties such as self-cleaning, anti-biofouling, and anti-corrosion. We reviewed the historical and contemporary scientific literature to create an extensive review of known hydrophobic and superhydrophobic structures in insects. We found that numerous insects across at least fourteen taxonomic orders possess a wide variety of cuticular surface chemicals and physical structures that promote hydrophobicity. We discuss a few bioinspired design examples of how insects have already inspired new technologies. Moving forward, the use of a bioinspiration framework will help us gain insight into how and why these systems work in nature. Undoubtedly, our fundamental understanding of the physical and chemical principles that result in functional insect surfaces will continue to facilitate the design and production of novel materials.
... The designs developed by engineers can perform only one function, however, designs formed by biological traits may show various functions. Schroeder et al. reported that wings of butterfly have stimulated for the generation of structurally colored substances [22]. The wings must be thermally efficient, flexible, hydrophobic and durable for flight besides light manipulation function [23,24]. ...
Article
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Nature has always inspired innovative minds for development of new designs. Animals and plants provide various structures with lower density, more strength and high energy sorption abilities that can incite the development of new designs with significant properties. By observing the important functions of biological structures found in nature, scientists have fabricated structures by bio-inspiration that have been proved to exhibit a significant improvement over traditional structures for their applications in the environmental and energy sector. Bio-fabricated materials have shown many advantages due to their easy synthesis, flexible nature, high performance and multiple functions as these can be used in light harvesting systems, batteries, biofuels, catalysis, purification of water, air and environmental monitoring. However, there is an urgent need for sensitive fabrication instruments that can synthesize bio-inspired structures and convert laboratory scale synthesis into large scale production. The present review highlights recent advances in synthesis of bio-inspired materials and use of hierarchical nanomaterials generated through biomolecular self-assembly for their use in removal of environmental contaminants and sustainable development.
... It also prevents the deformation of the hair base and acts as an elastic spring for restoring the hair to its normal position. These stimuli over the dendrite by the hair shaft are known as coupling [54]. This dendrite with dendrite sheath and a tubular body is tightly packed with microtubules, and any pressure applied on the dendrite sheath due to deformation of the hair will generate ion currents, which is considered a transduction process. ...
... These induced ion currents, also known as receptor potentials, pass through microtubules and flow into the axon of the central nervous system, which delivers information to the insect brain [14,55]. Schroeder et al. [54] claimed that the joint membrane should be elastic and flexible enough to deflect the hair. The action potential was most substantial when the hair was bent toward the dendrite's tip connected to the hair base [35,52]. ...
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Simple Summary: Nabis rugosus is a representative of the Nabidae family belonging to the heterop-teran group. It is a predator of tiny insects and has different sensory receptors that detect environmental changes. The present study focuses on the antennal sensilla of N. rugosus, mainly on the trichoideum sensillum as mechanoreceptors for detecting various tactile factors surrounding the insect. The morphology of trichoideum mechanosensillum in N. rugosus was modelled as a three-dimensional structure from the derived data sets using SEM and TEM. Specific inner features of the sensillum are also presented, which will be useful to build a biosensor for detecting physical environmental parameters. Abstract: The present study aims to investigate the morphological features of the antennal sensilla by using SEM and TEM. The construction of a 3D model of trichoideum sensillum using Amira software is presented in this paper. Five sensillum types, namely trichoideum, chaeticum, campa-niformium, coeloconicum, and basiconicum, were recorded. This model exhibits the mechanosen-sillum components, including the embedded hair in a socket attached by the joint membrane and the dendrite connected to the hair base passing through the cuticle layers. TEM images present the dendrite way, micro-tubules inside the dendritic sheath, and terminal structure of the tubular den-drite body and so-called companion cells included in the receptor, e.g., tormogen and trichogen. The parameters noted for the external structure and ultrastructure of the mechano-receptor indicate that they are specific to a particular type of sensillum and would be useful in developing the model for a biosensor. Results show that bio-inspired sensors can be developed based on morphological and ultrastructural studies and to conduct mechanical studies on their components.
... The resonator is made up of two structures, the tympana (membranous structures) and the air sac [2,4]. After sound is produced by the tymbal, it is transferred to the air sac, which then creates resonant vibrations, which are in turn radiated to the environment through the tympana [2,3], analogous in many ways to how loudspeakers are built up [5,6]. Bennet-Clark [7] reported that, as a primary resonator [3], the tymbal has the components of a resonant system (mass and compliance). ...
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This paper focusses on the morphological and viscoelastic properties of the cicada tymbal from the species Dundubia rufivena. Morphological details were determined by scanning electron and fluorescence microscopy, while the viscoelastic properties were determined by dynamic mechanical thermal analysis, and further supported by differential scanning calorimetry. We find that water evaporation from the tymbal begins at 71.1 °C and the glass transition for the tymbal, which is a chitin–resilin composite, is on average 150 °C, though there is considerable heterogeneity in the material of the tymbal, as indicated by the half height peak width of the tymbal (35.3 °C) and the shoulder peak indicative of a second phase and hence glass transition at on average, 168 °C. This second phase is assumed to reflect the effects of large-scale molecular pinning and restructuring at resilin–chitin interfaces (possibly via specific binding domains). In addition, we elucidate that the predominantly resilin regions of the tymbal of Dundubia rufivena is reinforced by a polygonal mesh of chitin, a morphological feature that has not been described in any previous research on the cicada tymbal. We provide evidence for nonlinear elasticity in the tymbal by comparing the storage modulus of the tymbal at different frequencies and loading amplitudes.
... Similar phenomena have also been observed on some insect surfaces, such as planthoppers and springtails [33]. Planthoppers' hindwings feature topographical and functional similarities to lotus leaves, thus exhibiting non-wetting behavior and low adhesion to pollutants [34,35]. Springtail skin is another kind of superhydrophobic surface consisting of a microcolumnar with a double nanoreentrant ( Figure 2C) [36][37][38]. ...
Article
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Surface bacterial fouling has become an urgent global challenge that calls for resilient solu- tions. Despite the effectiveness in combating bacterial invasion, antibiotics are susceptible to causing microbial antibiotic resistance that threatens human health and compromises the medication efficacy. In nature, many organisms have evolved a myriad of surfaces with specific physicochemical proper- ties to combat bacteria in diverse environments, providing important inspirations for implementing bioinspired approaches. This review highlights representative natural antibacterial surfaces and discusses their corresponding mechanisms, including repelling adherent bacteria through tailoring surface wettability and mechanically killing bacteria via engineering surface textures. Following this, we present the recent progress in bioinspired active and passive antibacterial strategies. Finally, the biomedical applications and the prospects of these antibacterial surfaces are discussed.
... Similar phenomena have also been observed on some insect surfaces, such as planthoppers and springtails [33]. Planthoppers' hindwings feature topographical and functional similarities to lotus leaves, thus exhibiting non-wetting behavior and low adhesion to pollutants [34,35]. Springtail skin is another kind of superhydrophobic surface consisting of a microcolumnar with a double nanoreentrant ( Figure 2C) [36][37][38]. ...
Article
Full-text available
Surface bacterial fouling has become an urgent global challenge that calls for resilient solutions. Despite the effectiveness in combating bacterial invasion, antibiotics are susceptible to causing microbial antibiotic resistance that threatens human health and compromises the medication efficacy. In nature, many organisms have evolved a myriad of surfaces with specific physicochemical properties to combat bacteria in diverse environments, providing important inspirations for implementing bioinspired approaches. This review highlights representative natural antibacterial surfaces and discusses their corresponding mechanisms, including repelling adherent bacteria through tailoring surface wettability and mechanically killing bacteria via engineering surface textures. Following this, we present the recent progress in bioinspired active and passive antibacterial strategies. Finally, the biomedical applications and the prospects of these antibacterial surfaces are discussed.
... [7][8][9][10][11] Across the range of applications, biomimetic approaches aiming to replicate nature's functionally-evolved motifs have been a consistent muse for the development of novel patterned coatings. [12][13][14][15] Among these, the striking array of circular epicuticular impressions on the wings of the cicada insect has become particularly attractive in recent years due to its supreme wetting and antimicrobial functionalities. [16][17][18][19][20][21] The surface of cicada wings manifest self-organised hexagonally-packed features of circular footprints, with diameters spanning from several hundreds to thousands of nanometers, at a typically high surface coverage of 50-70% (Fig. 1). ...
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Since its original conception as a tool for manufacturing porous materials, the breath figure method (BF) and its variations have been frequently used for the fabrication of numerous micro- and nanopatterned functional surfaces. In classical BF, reliable design of the final pattern has been hindered by the dual role of solvent evaporation to initiate/control the dropwise condensation and induce polymerization, alongside the complex effects of local humidity and temperature influence. Herein, we provide a deterministic method for reliable control of BF pore diameters over a wide range of length scales and environmental conditions. To this end, we employ an adapted methodology that decouples cooling from polymerization by using a combination of initiative cooling and quasi-instantaneous UV curing to deliberately arrest the desired BF patterns in time. Through in situ real-time optical microscopy analysis of the condensation kinetics, we demonstrate that an analytically predictable self-similar regime is the predominant arrangement from early to late times O(10-100 s), when high-density condensation nucleation is initially achieved on the polymer films. In this regime, the temporal growth of condensation droplets follows a unified power law of D ∝ t. Identification and quantitative characterization of the scale-invariant self-similar BF regime allow fabrication of programmed pore size, ranging from hundreds of nanometers to tens of micrometers, at high surface coverage of around 40%. Finally, we show that temporal arresting of BF patterns can be further extended for selective surface patterning and/or pore size modulation by spatially masking the UV curing illumination source. Our findings bridge the gap between fundamental knowledge of dropwise condensation and applied breath figure patterning techniques, thus enabling mechanistic design and fabrication of porous materials and interfaces.
... 81 Beyond color, adhesion, and structural mechanics, one should note that chitinous architectures have been considered in other roles. 82 For instance, the antibacterial activity of chitin has been used in material science. Protection from pathogens is associated with the biological activity of chitin, for instance, for application in healthcare. ...
... Spindlelike chitinous structures can serve as vibration sensors or defense tool against predators. 82,83 The latter urticating structures are typically observed in caterpillars, 84 and longer extraction devices can be found in mosquitoes and butterflies, where the mechanical properties of theses constructs are optimized as a function of the target . Other examples include hydrophilicity and mostly superhydrophobicity at the interface, 35 motion-generating structures, 85,86 and vibrating structures used for sound generation. ...
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Chitin, a fascinating biopolymer found in living organisms, fulfills current demands of availability, sustainability, biocompatibility, biodegradability, functionality, and renewability. A feature of chitin is its ability to structure into hierarchical assemblies, spanning the nano- and macroscales, imparting toughness and resistance (chemical, biological, among others) to multicomponent materials as well as adding adaptability, tunability, and versatility. Retaining the inherent structural characteristics of chitin and its colloidal features in dispersed media has been central to its use, considering it as a building block for the construction of emerging materials. Top-down chitin designs have been reported and differentiate from the traditional molecular-level, bottom-up synthesis and assembly for material development. Such topics are the focus of this Review, which also covers the origins and biological characteristics of chitin and their influence on the morphological and physical-chemical properties. We discuss recent achievements in the isolation, deconstruction, and fractionation of chitin nanostructures of varying axial aspects (nanofibrils and nanorods) along with methods for their modification and assembly into functional materials. We highlight the role of nanochitin in its native architecture and as a component of materials subjected to multiscale interactions, leading to highly dynamic and functional structures. We introduce the most recent advances in the applications of nanochitin-derived materials and industrialization efforts, following green manufacturing principles. Finally, we offer a critical perspective about the adoption of nanochitin in the context of advanced, sustainable materials.
... Insects also contain unique nanostructures implicated in specific physical and physiological functions ( Figure 17). Adhesion, chemical sensing, and response, color vision and manipulation, movement, mechano-sensation, and thermoregulation are the mentioned functions [255,256]. For instance, in fairyflies, wings have very thin hairs (300 nm-2.5 μm in diameter) that allow them to move freely at different speeds because hair spacing influences the force produced by moving. ...
... Insects also contain unique nanostructures implicated in specific physical and physiological functions ( Figure 17). Adhesion, chemical sensing, and response, color vision and manipulation, movement, mechano-sensation, and thermoregulation are the mentioned functions [255,256]. For instance, in fairyflies, wings have very thin hairs (300 nm-2.5 µm in diameter) that allow them to move freely at different speeds because hair spacing influences the force produced by moving. ...
Article
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Nanomaterials are becoming important materials in several fields and industries thanks to their very reduced size and shape-related features. Scientists think that nanoparticles and nanostructured materials originated during the Big Bang process from meteorites leading to the formation of the universe and Earth. Since 1990, the term nanotechnology became very popular due to advances in imaging technologies that paved the way to specific industrial applications. Currently, nanoparticles and nanostructured materials are synthesized on a large scale and are indispensable for many industries. This fact fosters and supports research in biochemistry, biophysics, and biochemical engineering applications. Recently, nanotechnology has been combined with other sciences to fabricate new forms of nanomaterials that could be used, for instance, for diagnostic tools, drug delivery systems, energy generation/storage, environmental remediation as well as agriculture and food processing. In contrast with traditional materials, specific features can be integrated into nanoparticles, nanostructures, and nanosystems by simply modifying their scale, shape, and composition. This article first summarizes the history of nanomaterials and nanotechnology. Followed by the progress that led to improved synthesis processes to produce different nanoparticles and nanostructures characterized by specific features. The content finally presents various origins and sources of nanomaterials, synthesis strategies, their toxicity, risks, regulations, and self-aggregation.