Bio-Inspired Strategy for Radiation-Based Thermal Management and Utilization

Abstract

In nature, biological species have evolved unique mechanisms and sophisticated structures for intelligent radiation-based thermal management and utilization over billions of years through natural selection. These adaptive strategies in biological species serve as a significant source of inspiration for the development of advanced thermal engineering materials and systems in modern society, driving innovation in applications such as building heating and cooling, personal thermal management, water acquisition, and next-generation infrared (IR) sensing systems. In this review, advancements in biological and bio-inspired thermal management strategies, including radiative cooling, thermal regulation, and thermal insulation, are comprehensively summarized. Additionally, recent advancements in radiation-based biological and bio-inspired thermal utilization are discussed, focusing on applications such as water harvesting, IR camouflage, and IR detection. Next, various examples of the integration of IR management strategies with electronic and energy systems are introduced, highlighting their potential to enhance efficiency and functionality in thermal management, energy efficiency, and advanced sensing applications. By leveraging these bio-inspired systems, innovative strategies have emerged, encompassing both thermal management and utilization, and enabling efficient heat regulation and energy harvesting across a wide range of technological applications. Finally, a future perspective on the development of radiation-based bio-inspired thermal management and utilization technologies is provided.

Keywords: biological thermal adaptation; bio‐inspired thermal adaptation; thermal management; thermal utilization.

Figure 1

Diversity in thermal management and utilization mechanisms of organisms across different climate habitat. A) Schematic illustration of radiation‐based thermal adaptations in biological systems, illustrating various functions: radiative cooling through thermal emission, thermal regulation via controlled heat exchange, thermal insulation to minimize heat loss, water harvesting mechanisms for survival in arid environments, infrared (IR) camouflage to evade thermal detection, and IR detection for sensing environmental temperature variations. B) Global map showing average ambient temperatures across various climatic regions, highlighting C–J) thermal management and utilization strategies in biological species: (C) A Saharan silver ant (Cataglyphis bombycina) with triangular hairs which enable radiative cooling and minimize heat absorption, facilitating survival in extreme hot and dry Sahara Desert. Reproduced with permission.^{[ 7 ]} Copyright 2015, AAAS. Reproduced with permission.^{[ 8 ]} Copyright 2020, Elsevier. (D) A Bistonina biston butterfly found in South America with scent patch and scent pad on forewings, which shows high emissivity to facilitate radiative cooling. Reproduced with permission.^{[ 9 ]} Copyright 2020, Springer Nature. (E) Zebras (Equus quagga) living in Savanna with black and white stripe patterns to regulate body temperature through convective air eddies induced by temperature gradients. Reproduced with permission.^{[ 12 ]} Copyright 2018, Springer Nature. Reproduced with permission.^{[ 13 ]} Copyright 2020, Elsevier. (F) Emperor penguins (Aptenodytes forsteri) adapted to extreme cold Antarctica with down feathers consisting of aligned long rami and parallel short barbules to minimize heat loss. Reproduced with permission.^{[ 14 ]} Copyright 1999, Academic Press. Reproduced with permission.^{[ 15 ]} Copyright 2013, Royal Society. (G) A reindeer (Rangifer Tarandus) with porous form structure of fur to survive in extremely cold Alaska region. Reproduced with permission.^{[ 19 ]} Copyright 2019, Elsevier Ltd. (H) A Namib sand gecko (Pachydactylus rangei) with ellipsoidal structured on mouth and toes enable fog water collection through droplet formation in the arid Namib Desert of Southern Africa. Reproduced with permission.^{[ 20 ]} Copyright 2024, Wiley‐VCH. (I) A pygmy chameleon (Rhampholeon spectrum) with two superposed layers of iridophores, facilitating dynamic infrared (IR) camouflage. Reproduced with permission.^{[ 21 ]} Copyright 2022, Public Library of Science. Reproduced with permission.^{[ 22 ]} Copyright 2015, Springer Nature. (J) The Australian fire‐beetle (Melanophila atrata) with specialized infrared organs with unique nano architectural structures, enabling efficient detection of forest fires. Reproduced with permission.^{[ 27 ]} Copyright 2014, Emerald Group Publishing Limited.

Figure 2

Overview of biological and bioinspired thermal management and thermal utilization. A) Optical image of a cicada (Cryptotympana atrata) with porous heart shaped structure. B) Illustration of Bio‐PC for radiative cooling, composed of TPU embedded with Al₂O₃ NPs. Reproduced with permission.^{[ 28 ]} Copyright 2021, Wiley‐VCH. C) Photograph of a Siamese cat, Felis catus, showing thermally induced color changes. D) Schematic illustration of reversible thermochromic fiber membrane with temperature‐adaptive dual‐mode thermal management performance utilizing thermochromic microencapsulated phase change material. Reproduced with permission.^{[ 29 ]} Copyright 2024, American Chemical Society. E) Photograph of a polar bear, Ursus maritimus. Reproduced with permission.^{[ 31 ]} Copyright 2025, AAAS. F) Schematic of an EAF for thermal insulation. Reproduced with permission.^{[ 32 ]} Copyright 2023, AAAS. G) Image of a Namib desert beetle (Onymacris unguicularis) with bump microstructures on elytra for fog collection. Reproduced with permission.^{[ 33 ]} Copyright 2010, Springer Nature. H) Schematic diagram of water harvesting device with P(VDF‐HFP) cooling coating embedded with silicon dioxide (SiO₂) and Calcium molybdate (CaMoO₄) nanoparticles for efficient water harvesting, mimicking beetle elytra structures. Reproduced with permission.^{[ 34 ]} Copyright 2020, Wiley‐VCH. I) Photographs of Diaethria clymena butterflies with green scales, showing camouflage and reflection splitting properties. J) Schematic of bioinspired meta‐reflection‐splitter utilizing aluminum (Al)‐polydimethylsiloxane (PDMS) based metasurface for thermal camouflage. Reproduced with permission.^{[ 36 ]} Copyright 2023, Wiley‐VCH. K) Optical image of Morpho sulkowski butterfly with a fractured scale on the wing. L) Illustration of IR detector utilizing Morpho scales structures deposited single‐walled carbon nanotube, resulting in wavelength conversion. Reproduced with permission.^{[ 37 ]} Copyright 2012, Springer Nature. M) Schematic illustration of radiative heat transfer occurring at terrestrial surfaces. P _sun, absorbed power from sunlight; P _rad, radiated power by the emitter; P _atm, absorbed power from the atmosphere; P _non‐rad, non‐radiative heat transfer coefficient. N) Solar spectrum (yellow shaded area) and the sky transmission spectrum (blue shaded area) in the mid‐infrared wavelength range. The solid and dashed line represent the ideal emissivity spectra of the radiative heater and cooler, respectively. O) Net cooling power as the function of the difference between temperature of ambient air (T _air) and sample (T _s). The blue, black, and red correspond to T _air of −20, 20, and 40 °C, respectively. The solid and dashed lines indicate non‐radiative heat transfer coefficients (h _c) of ≈0 and 10 Wm⁻¹K⁻¹, respectively.

Figure 3

Biological organisms and bio‐inspired materials for radiative cooling. A) Optical image of a Saharan silver ant (Cataglyphis bombycina) (left) and scanning electron microscope (SEM) image (right) of the cross‐sectional view of hairs on silver ant, presenting a dense layer of triangularly shaped hairs. Reproduced with permission.^{[ 7 ]} Copyright 2015, AAAS. B) Photograph image of fabricated triangularly shaped PDMS‐SiO₂‐Ag three layered radiative cooler (top) and SEM image of patterned silicon mold. C) Simulation results of averaged emissivity in the ATW of different geometrical structures (triangular, circular, and uniform arrays) with size parameter of 2–15 µm. D) Measured results of emissivity spectra of the 100 µm‐thick uniform PDMS‐SiO₂‐Ag cooler (black line) and the patterned PDMS‐SiO₂‐Ag cooler featuring a triangular prism array with a size parameter of 8 µm (pink line), 9 µm (blue line), and 10 µm (green line) in the wavelength range from 0.25 µm to 2.5 µm and 8 µm to 13 µm (top and bottom, respectively). The red line indicates AM1.5 spectrum. Reproduced with permission.^{[ 8 ]} Copyright 2019, Elsevier. E) Photograph of a male golden longicorn beetle (Neocerambyx gigas) (left), cross‐sectional transmission electron microscope (TEM) of a fluff on the forewing (top right), and SEM image of corrugated facet of the fluff (bottom right). F) SEM image of micro‐pyramid arrayed PDMS polymer matrix containing randomly distributed Al₂O₃ spheres (top) and photograph of Bio‐RC film (bottom). G) Spectral characteristics of fluffs of golden longicorn beetles (top) and a 500‐µm‐thick Bio‐RC film with randomly distributed 100‐nm‐diameter Al₂O₃ particles. In visible wavelength range, the Bio‐RC film shows high reflectivity owing to total internal reflection and Mie scattering. The strong phonon–polariton resonances induced by Al₂O₃ particles and gradual refractive index of pyramid shape, leading to increased IR emissivity. H) Measured temperature of the air (gray line) and Bio‐RC film (blue line) (top) and temperature difference between air and Bio‐RC film (bottom). Reproduced with permission.^{[ 47 ]} Copyright 2020, PNAS. I) Photograph of a male white beetle (Goliathus goliatus) and SEM image of the central part of white scales. Inset: cross‐sectional TEM image of the white scales with exterior shell and interior of packed hollow cylinders, resulting in broadband omnidirectional reflection such as thin‐film interference, Mie scattering, and total internal reflection. Reproduced with permission.^{[ 51 ]} Copyright 2019, Royal Society of Chemistry. J) Photograph of a male Rapala dioetas butterfly (left) and cross‐sectional SEM image (right) of scent patch scales on the hindwing, featuring high IR emissivity due to hierarchical microstructure. Reproduced with permission.^{[ 52 ]} Copyright 2021, AIP Publishing.

Figure 4

Biological and bio‐inspired structures for thermal regulation. A) Photograph of a Himalayan rabbit (Oryctolagus cuniculus), showing visible thermochromism of Himalayan rabbit hairs. B) Optical image of mimosa leaves (Mimosa pudica), presenting covering area variation. C) Schematic illustrations of spectral characteristics of dual‐mode thermal management device combining a thermochromic bottom layer with low IR emissivity and two‐way shape memory polymer top actuating layer with high IR emissivity. D) Optical properties of dual‐mode thermal management device in heating and cooling mode. E) Photograph and thermal images of dual‐mode thermal management device under heating conditions, highlighting visible and IR thermochromism. Reproduced with permission.^{[ 53 ]} Copyright 2024 PNAS. F) Photograph of a camel (Camelus sp.) (top), schematic illustration of double hair coat structure (middle), and porous hollow fiber and double coat structure for radiative cooling and thermal insulation (bottom). Reproduced with permission.^{[ 56 ]} Copyright 2020, Elsevier. Reproduced with permission.^{[ 57 ]} Copyright 2024, Wiley‐VCH. G) Illustration of bioinspired porous fabric (left) and cross‐sectional SEM image of porous elastic TPU fiber (right). H) Solar reflectance and IR emittance of commercial TPU fabric and MEPFT‐d. I) Schematic diagram of heat transfer mechanism of MEPFT‐d. J) Real‐time temperature monitoring of cotton fabric and MEPFT‐d in all weather conditions. Reproduced with permission.^{[ 57 ]} Copyright 2024, Wiley‐VCH.

Figure 5

Biological and bio‐inspired porous structures for thermal insulation. A) Photograph of a polar bear (Ursus maritimus) (top) and cross‐sectional SEM image of a single fur on a polar bear, featuring aligned porous microstructure (bottom). B) Cross‐sectional SEM image of aligned porous structure of single fiber using silk fibroin/chitosan mixed solution by freeze‐spinning technique, combining solution spinning and directional freezing. C) Schematic illustration of heat transfer mechanism and thermal conductivity of the fabricated porous fiber with aligned pores. λ _conv., thermal convection; λ _solid, solid conduction; λ _gas, gas conduction. λ _rad., thermal radiation. D) Optical properties of commercial silk, cotton, polyester, and bio‐inspired textiles. E) Optical image of a bio‐inspired woven porous fiber, showing the potential for large‐scale fabrication. F) Optical and thermal images of rabbits wearing different materials: unworn, commercial polyester, and biomimetic textiles. The biomimetic textile shows thermal stealth property. Reproduced with permission.^{[ 30 ]} Copyright 2018, Wiley‐VCH. G) Photograph of an emperor penguin (Aptenodytes forsteri) (top) and SEM image (bottom) of microstructure of down feathers adapted to extreme cold environments, leading to thermal insulation. The Royal Society. Reproduced with permission.^{[ 14 ]} Copyright 1999, Academic Press. Reproduced with permission.^{[ 15 ]} Copyright 2013, Royal Society. H) Schematic illustrations of theCNT/PLA/MnO₂ (CPMn) membrane. The CPMn membrane consists of three layers of photothermal layer (CNT‐cellulose membrane), insulation layer (PLA membrane), and IR reflection layer (MnO₂ nanowire membrane). I) IR reflectance of cotton, cellulose membrane, CNT/PLA membrane, and CPMn. J) Solar radiation and absorbance spectra of cotton, cellulose membrane, and CPMn membrane in the solar wavelength range. K) Thermal images of (i) CPMn membrane, (ii) CNT/PLA membrane, and (iii) cotton after stabilizing temperature. L) Repeated thermal cyclic test of CPMn (pink line), CNT/PLA membrane (blue line), and cotton (green line). Reproduced with permission.^{[ 61 ]} Copyright 2024, Springer Nature.

Figure 6

Biological and bio‐inspired structures for water harvesting. A) Optical image of a Namib black beetle (Physasterna cribripes) (left) and SEM image of the beetle's elytra, featuring a wax‐free hydrophilic bump and a surrounding wax‐coated hydrophobic/radiative cooling surface (right). B) Cross‐sectional view of the elytra structure. Reproduced with permission.^{[ 64 ]} Copyright 2014, Springer Nature. C) Optical image of a hydrophilic–hydrophobic patterned surface, created by coating Al₂O₃ and TiO₂ powders on an Al sheet. D) High IR emissivity of the other side of the Al sheet, coated with MgHPO₄·0.78H₂O/ P(VDF‐HFP). E,F) Schematic (E) and photograph (F) of dew condensation and growth processes on the patterned surface. G) Comparative graph of water collection efficiencies for various surfaces. Reproduced with permission.^{[ 65 ]} Copyright 2023, Elsevier. H) Optical image of a desert cactus (Copiapoa cinerea) featuring hydrophilic/radiative cooling spines on stems. I) SEM image of the spine mid‐section. Reproduced with permission.^{[ 68 ]} Copyright 2015, IOP Publishing. J) A S‐SLO capable of spontaneous moisture capture and unidirectional water transport. K) Optical image of the S‐SLO made from an Al plate modified with a superhydrophilic reagent, where a Laplace pressure gradient along an asymmetric origami channel induces unidirectional water flow. L) Coating of a ZrC/PDMS composite on the outer surface of S‐SLO for radiative cooling. M) Vapor condensation performances of S‐SLOs with varying channel depths and radiative cooling effect. Reproduced with permission.^{[ 69 ]} Copyright 2023, Wiley‐VCH.

Figure 7

Biological structures for IR modulation and their applications. A,B) Photographs of representative pelagic octopuses (Japetella healthi) (A) and glass squids (Taonius borealis) (B) in their transparent state. Reproduced with permission.^{[ 73 ]} Copyright 2020, Wiley‐VCH. C) Cross‐sectional TEM image of pelagic octopus skin, with labels CP, IP, and LC denoting chromatophore, iridophore, and leucophore, respectively. Reproduced with permission.^{[ 76 ]} Copyright 2001, Wiley‐VCH. D) Schematic of the alternating arrangement of membrane‐enclosed protein layers and extracellular spaces in iridocytes, functioning as biological Bragg stacks for UV–vis and IR reflection. E,F) Illustration (E) and IR spectra with an SEM image (F) of a cephalopod‐inspired adaptive IR‐reflecting device, consisting of an acrylic dielectric elastomer membrane laminated with proton‐conducting electrodes on both top and bottom, and an Al film coating on the top electrode, before and after mechanical actuation. The actuation induced morphology changes and altered IR reflectance. G) Schematic (top), optical images (middle), and thermograms (bottom) of a squid‐shaped device before (left) and after (right) electric field‐induced mechanical actuation under constant thermal flux. Reproduced with permission.^{[ 77 ]} Copyright 2018, AAAS. H) Image of a panther chameleon (Furcifer pardalis). I) Cross‐sectional view of chameleon skin stained with haematoxylin and eosin (H&E) (right), and TEM images of guanine nanocrystals in superficial (S) and deep (D) iridophores, including a 3D FCC lattice model in the insets (left). Reproduced with permission.^{[ 22 ]} Copyright 2015, Springer Nature. J) Schematic and optical images of an IR‐modulating device featuring a bilayer of Ecoflex/EGaIn and Ecoflex before (top) and after (bottom) applying areal strain. The strain transformed the morphology of EGaIn droplets embedded in Ecoflex into a flake‐like shape, thereby enhancing IR reflectance. K) IR reflectance spectra of the device under various areal strains (0%, 137%, 525%, 1011%, and 1500%). L) Demonstration of IR Morse coding through applying predefined areal strains to specifically designed trilayers of Ecoflex/Ecoflex:EGaIn (1:2 and 1:6 in mass ratio)/Au. Reproduced with permission.^{[ 78 ]} Copyright 2024, Springer Nature.

Figure 8

Biological and bio‐inspired structures for IR sensation. A) Facial anatomy of a vampire bat (Desmodus rotundus) with pit organs indicated by red arrowheads. Reproduced with permission.^{[ 80 ]} Copyright 2011, Springer Nature. B) Photograph of a rattlesnake (Crotalus atrox) with a loreal pit organ marked by a red arrow. C) Description of the structure of a pit organ (left), illustrating a pit membrane suspended within a cavity and connected to TG fibers, alongside calcium imaging (right) of heat‐evoked responses of rattlesnake TRPA1 channels) expressed in HEK293 cells. Reproduced with permission.^{[ 81 ]} Copyright 2010, Springer Nature. D) Schematic of a TRP‐inspired biohybrid IR sensor, composed of UCNPs that convert IR to blue light, HEK293 cells expressing ChR2 that generate a blue light‐responsive ion current, and a graphene transistor for recording cellular bioelectricity with ultrahigh carrier mobility and good biocompatibility. E) Demonstration of the photoelectric activity of HEK293‐ChR2 cells upon blue light irradiation. F) Examples of IR letters with a gray gradient (left) and their detection images by the biohybrid IR sensor (right). Reproduced with permission.^{[ 82 ]} Copyright 2023, Elsevier. G) Images of a “fire‐loving” beetle (Melanophila acuminate) (left) and a dome‐shaped sensilla array with small pores (right). Reproduced with permission.^{[ 83 ]} Copyright 2009, SPIE. H) Cross‐sectional description of an IR sensillum. Reproduced with permission.^{[ 84 ]} Copyright 2015, Frontiers. I) Illustration of a “fire‐beetle” pit organ‐inspired IR sensor, consisting of a polyimide (PI)/carbon piezoresistive sensing membrane with extremely high sensitivity and a PDA photothermal transducer, featuring a dendrite‐like tip protruding from a PMMA case. Adjusting the distance (h) between the sensing membrane and the dendrite tip enabled the sensor to operate in either photomechanic or bolometric modes. J,K) IR power‐dependent responses of the sensor in bolometric (J, h = 0 mm) and photomechanic (K, h = 1 mm) modes. Reproduced with permission.^{[ 85 ]} Copyright 2023, Elsevier.

Figure 9

Management of IR radiation for electronic applications. A) Schematic of a stretchable, biodegradable energy harvester consisting of a top black/white patterned layer for generating an in‐plane thermal gradient throughout the day and a Si NMs‐based TEG layer for converting the thermal gradient into electricity. B) Optical images of the device showing the two layers (left) and arrays of n‐ and p‐type TEG legs (right). C) Emissivity spectra of PLCL, PEDOT:PSS, and W foil. (C) IR thermogram and corresponding optical image (inset) of a zebra stripes‐inspired radiative cooling/heating film, where the white PLCL microfibrous membrane exhibits high UV–vis reflectance and IR emissivity, while the dark patterns, made from conductive PEDOT:PSS film or W foil, provide high UV–vis absorption and IR reflectance. E) Real‐time measurements of solar irradiance, △T, and power density for the energy harvester with Si NMs‐ and Bi‐Te‐based TEGs. Reproduced with permission.^{[ 86 ]} Copyright 2023, AAAS. F) Exploded view of a CPV system integrated with two soda lime glass‐based radiative cooling layers. G,H) Measured (solid lines) and simulated (shaded areas and dashed line) temperatures of the CPV system with and without a radiative cooling layer (G), and simultaneous measurements of V_OC, showing the radiative cooler enhanced voltage output by ≈28 mV. Reproduced with permission.^{[ 87 ]} Copyright 2020, Elsevie. I) Photograph of an USRI composed of hollow SiO₂ microspheres, TiO₂ nanoparticles, fluorescent pigments, and polystyrene‐acrylic. J,K) Schematics of the interface coated on a PPG sensing system (J) and its thermal exchange processes (K). L) Temporal measurements of temperatures (left) and PPG signals (middle and right) for the device with and without USRI under various environmental conditions (indoors, in shadow, and in sunlight). Reproduced with permission.^{[ 88 ]} Copyright 2023, AAAS.