Natural Biological Systems Research Articles

Structurally Colored Photonic Crystal Biomimetic Microstructures for Daytime Radiative Cooling.

Daytime radiative cooling offers a novel solution to the energy crisis, enabling green and efficient thermal management in space. High reflectance in the solar spectrum is essential for passive radiative cooling, rendering dye coloring and similar methods unsuitable for colored coolers. This paper presents a structurally colored photonic crystal biomimetic microstructured radiative cooler. Inspired by natural biological systems, this cooler features a dual-layered microtruncated-cone array structure on the surface and bottom membrane layers. The silver reflector and 3D micrograting surface structure produce continuous iridescent colors through multiple interference effects. Optimized lithographic process enable the fabrication of the ordered dual-layer surface microstructure arrays with precise angular combinations. The dual-layered microtruncated-cone introduces a gradient refractive index, reducing impedance mismatch at the interface. As a result, the radiative cooler achieves high solar spectral reflectance (0.95) and high mid-infrared emissivity (0.95). Notably, the net theoretical cooling power and the subambient temperature drop are 106.9 W m-2 and 7.4 °C, respectively, at an ambient temperature of 40 °C, with a measured average temperature reduction of 6.1 °C under direct sunlight. This performance matches that of advanced radiative coolers, striking a balance between aesthetics and radiative cooling capability.

Response Surface Methodology for Optimisation of Parameter on Water Absorption of Natural Fibre Hybrid Composite in Boat Construction

Today, the utilisation of natural or green fibre has supplanted engineered fibre as fibreglass has become a pattern in composite boat producing and other gears because of its lightweight, excellent relative mechanical properties, and more significant elements. For example, it is eco-accommodating, has manageable materials, and has lower costs compared to fibreglass. The utilisation of fibreglass is costly and has a high effect on the natural biological system. It also gets over the area of ecological contamination, word-related well-being, and security concerns. This study used the Woven Kenaf/fibreglass as reinforcement and polyester as matric to fabricate hybrid composite coupons. Response Surface Methodology (RSM) of Box-Behnken Design (BBD) was applied to optimise fibre contents (35 to 75 wt%) and water absorption performance for the development of Woven Kenaf/fibreglass to polyester hybrid composite material based on the parameters. The BBD revealed that 45% Woven Kenaf/fibreglass to polyester performed the optimum fibre content and water absorption. Analyses of variance (ANOVA) showed that the model satisfactorily correlated the parameters. After immersion, 45% Woven Kenaf/fibreglass to polyester composite also gained 9.48% weight.

Development of Controllable Hetero-Pauson-Khand Polymerization to Functional Stimuli-Responsive Poly(γ-lactam)s.

Polymers containing lactam structures play a crucial role in both natural biological systems and human life, and their synthesis, functions and applications are of utmost importance for biomimetics and the creation of new materials. In this study, we developed an efficient heterogeneous Pauson-Khand polymerization (h-PKP) method for the controlled synthesis of main-chain poly(γ-lactam)s containing α, β-unsaturated γ-lactam functionalities using readily available internal alkynes and imines. The molecular weights of the resulting poly(N-Ts/γ-lactam)s can be precisely controlled by adjusting the ratio of phenyl formate and nickel. These polymers exhibit high solid-state luminescence and demonstrate rapid and sensitive dual responsiveness to light and acid stimuli. They further demonstrate strong reactive oxygen species (ROS) generation capability. The unique dual-emission peaks observed in poly(N-H/γ-lactam)s obtained through post-treatment under acidic conditions demonstrate a mechanism of aggregation-induced intermolecular excited-state proton transfer specific to lactam structures. The efficient one-pot synthetic method for poly(γ-lactam) provides a novel strategy for constructing polymers with γ-lactam structures in the main chain and the simple and efficient post-modification method offer a versatile toolbox for functionalizing poly(γ-lactam)s to expand their potential applications.

Nitrogen-Oxidized Tröger's Base Macrocyclic Arenes: Unprecedented Enantioselective Recognition in Water.

Achieving high enantioselectivity with synthetic receptors, particularly in water, remains a significant challenge despite the success seen in natural biological systems. In this study, we introduce a facile synthesis of Tröger's base (TB)-containing macrocyclic arenes (TBn), where TB units are linked via methylene bridges, providing the macrocycles with a rigid framework. Oxidation of enantiopure TBn yields corresponding chiral nitrogen oxides (TBnNO) with excellent water solubility, attributed to the high polarity of the N-O bond, surpassing the pH limitations of traditional ion-functionalized approaches. Remarkably, TBnNO exhibits exceptional enantioselective recognition toward a wide range of chiral guests in aqueous solution, achieving enantioselectivities as high as 41.0. The underlying mechanism involves a combination of hydrophobic interactions and steric effects caused by rigid chiral cavities. These findings highlight the potential of nitrogen-oxidized macrocycles as a transformative tool for supramolecular application in water.

Nitrogen‐Oxidized Tröger's Base Macrocyclic Arenes: Unprecedented Enantioselective Recognition in Water

Achieving high enantioselectivity with synthetic receptors, particularly in water, remains a significant challenge despite the success seen in natural biological systems. In this study, we introduce a facile synthesis of Tröger's base (TB)‐containing macrocyclic arenes (TBn), where TB units are linked via methylene bridges, providing the macrocycles with a rigid framework. Oxidation of enantiopure TBn yields corresponding chiral nitrogen oxides (TBnNO) with excellent water solubility, attributed to the high polarity of the N‐O bond, surpassing the pH limitations of traditional ion‐functionalized approaches. Remarkably, TBnNO exhibits exceptional enantioselective recognition toward a wide range of chiral guests in aqueous solution, achieving enantioselectivities as high as 41.0. The underlying mechanism involves a combination of hydrophobic interactions and steric effects caused by rigid chiral cavities. These findings highlight the potential of nitrogen‐oxidized macrocycles as a transformative tool for supramolecular application in water.

Recent progress of chiral metal-organic frameworks in enantioselective separation and detection.

Chiral compounds are abundantly distributed in both the natural world and biological systems. It is crucial to identify and detect chiral compounds in living systems or to separate and determinethem in the natural environment. Many researchers have developed a range of chiral materials with different functionalizations to separate and detect chiral substances. Chiral metal-organic frameworks (CMOFs) have the potential to be used in enantioselective separation and detection due to their large surface areas, regulated framework topologies, particular substrate interactions, and accessible chiral sites. CMOFs contribute significantly to the development of enantiomer separation and detection in medicine, agriculture, food, environment, and other fields. This review focuses on four synthesis methods of CMOFs and their applications in chiral separation and chiral sensing in the past five years, mainly including chromatographic separation, membrane separation, optical sensing, electrochemical sensing, and other sensingmethods. Finally, the challenges and potential growth direction of CMOFs in enantiomer separation and detection are discussed and prospected.

Development of Controllable Hetero‐Pauson‐Khand Polymerization to Functional Stimuli‐Responsive Poly(γ‐lactam)s

Polymers containing lactam structures play a crucial role in both natural biological systems and human life, and their synthesis, functions and applications are of utmost importance for biomimetics and the creation of new materials. In this study, we developed an efficient heterogeneous Pauson‐Khand polymerization (h‐PKP) method for the controlled synthesis of main‐chain poly(γ‐lactam)s containing α, β‐unsaturated γ‐lactam functionalities using readily available internal alkynes and imines. The molecular weights of the resulting poly(N‐Ts/γ‐lactam)s can be precisely controlled by adjusting the ratio of phenyl formate and nickel. These polymers exhibit high solid‐state luminescence and demonstrate rapid and sensitive dual responsiveness to light and acid stimuli. They further demonstrate strong reactive oxygen species (ROS) generation capability. The unique dual‐emission peaks observed in poly(N‐H/γ‐lactam)s obtained through post‐treatment under acidic conditions demonstrate a mechanism of aggregation‐induced intermolecular excited‐state proton transfer specific to lactam structures. The efficient one‐pot synthetic method for poly(γ‐lactam) provides a novel strategy for constructing polymers with γ‐lactam structures in the main chain and the simple and efficient post‐modification method offer a versatile toolbox for functionalizing poly(γ‐lactam)s to expand their potential applications.

Flow field characteristics and drag reduction performance of high–low velocity stripes on the biomimetic imbricated fish scale surfaces

AbstractImproving energy efficiency and cost reduction is a perennial challenge in engineering. Natural biological systems have evolved unique functional surfaces or special physiological functions over centuries to adapt to their complex environments. Among these biological wonders, fish, one of the oldest vertebrate groups, has garnered significant attention due to its exceptional fluid dynamics capabilities. Researchers are actively exploring the potential of fish skin's distinctive structural and material characteristics in reducing resistance. In this study, models of biomimetic imbricated fish scale are established, and the evolution characteristics of the flow field and drag reduction performance on these bionic surfaces are investigated. The results showed a close relationship between the high–low velocity stripes generated and the fluid motion by the imbricated fish scale surface. The stripes' prominence increases with the spacing of the adjacent scales and tilt angle of the fish scale, and the velocity amplitude of the stripes decreases as the exposed length of the imbricated fish scale surface increases. Moreover, the biomimetic imbricated fish scale surface can decrease the velocity gradient and thereby reduce the wall shear stress. The insights gained from the fish skin‐inspired imbricated fish surface provide valuable perspectives for an in‐depth analysis of fish hydrodynamics and offer fresh inspiration for drag reduction and antifouling strategies in engineering applications.

Thermoregulatory integration in hand prostheses and humanoid robots through blood vessel simulation

In this paper, we introduce an innovative approach for generating robotic faces with a thermal signature similar to that of humans and equipping prosthetic or robotic hands with a lifelike temperature distribution. This approach enhances their detection via infrared cameras and promotes more natural interactions between humans and robots. This method integrates a temperature regulation system into artificial skin, drawing inspiration from the human body’s natural temperature control via blood flow. Central to this technique is a fiber network simulating blood vessels within the artificial skin. Water flows through these fibers under specific temperature and flow conditions, forming a controlled heat release system. The heat emission can be adjusted by changing the dilation of these fibers, primarily by modulating the frequency of circulation. Our findings indicate that this approach can replicate the varied thermal characteristics of different human faces and hand areas. Consequently, the robotic faces appear more human-like in infrared images, aiding their identification by infrared cameras. At the same time, the prosthetic hands achieve a more natural temperature, reducing the discomfort typically felt in direct contact with synthetic limbs. The aim of this study was to address the challenges faced by the users of prosthetic hands. The results from this study show a promising direction in humanoid robotics, fostering improved tactile interactions and redefining human–robot relationships. This innovative technique facilitates further advancements, blurring the lines between artificial aids and natural biological systems.

Injectable Biomimetic Gels for Biomedical Applications.

Biomimetic gels are synthetic materials designed to mimic the properties and functions of natural biological systems, such as tissues and cellular environments. This manuscript explores the advancements and future directions of injectable biomimetic gels in biomedical applications and highlights the significant potential of hydrogels in wound healing, tissue regeneration, and controlled drug delivery due to their enhanced biocompatibility, multifunctionality, and mechanical properties. Despite these advancements, challenges such as mechanical resilience, controlled degradation rates, and scalable manufacturing remain. This manuscript discusses ongoing research to optimize these properties, develop cost-effective production techniques, and integrate emerging technologies like 3D bioprinting and nanotechnology. Addressing these challenges through collaborative efforts is essential for unlocking the full potential of injectable biomimetic gels in tissue engineering and regenerative medicine.

Laser Ablating Biomimetic Periodic Array Fish Scale Surface for Drag Reduction.

Reducing resistance to surface friction is challenging in the field of engineering. Natural biological systems have evolved unique functional surfaces or special physiological functions to adapt to their complex environments over centuries. Among these biological wonders, fish, one of the oldest in the vertebrate group, have garnered attention due to their exceptional fluid dynamics capabilities. Fish skin has inspired innovation in reducing surface friction due to its unique structures and material properties. Herein, drawing inspiration from the unique properties of fish scales, a periodic array of fish scales was fabricated by laser ablation on a polished aluminum template. The morphology of the biomimetic fish scale surface was characterized using scanning electron microscopy and a white-light interfering profilometer. Drag reduction performance was measured in a closed circulating water tunnel. The maximum drag reduction was 10.26% at a Reynolds number of 39,532, and the drag reduction performance gradually decreased with an increase in the distance between fish scales. The mechanism of the biomimetic drag reduction surface was analyzed using computational fluid dynamics. Streamwise vortices were generated at the valley of the biomimetic fish scale, replacing sliding friction with rolling friction. These results are expected to provide a foundation for in-depth analysis of the hydrodynamic performance of fish and serve as new inspiration for drag reduction and antifouling.

Biomimetic Hydrogel Strategies for Cancer Therapy.

Recent developments in biomimetic hydrogel research have expanded the scope of biomedical technologies that can be used to model, diagnose, and treat a wide range of medical conditions. Cancer presents one of the most intractable challenges in this arena due to the surreptitious mechanisms that it employs to evade detection and treatment. In order to address these challenges, biomimetic design principles can be adapted to beat cancer at its own game. Biomimetic design strategies are inspired by natural biological systems and offer promising opportunities for developing life-changing methods to model, detect, diagnose, treat, and cure various types of static and metastatic cancers. In particular, focusing on the cellular and subcellular phenomena that serve as fundamental drivers for the peculiar behavioral traits of cancer can provide rich insights into eradicating cancer in all of its manifestations. This review highlights promising developments in biomimetic nanocomposite hydrogels that contribute to cancer therapies via enhanced drug delivery strategies and modeling cancer mechanobiology phenomena in relation to metastasis and synergistic sensing systems. Creative efforts to amplify biomimetic design research to advance the development of more effective cancer therapies will be discussed in alignment with international collaborative goals to cure cancer.

Dynamic Near‐Infrared Circularly Polarized Luminescence Encoded by Transient Supramolecular Chiral Assemblies

AbstractCircularly polarized luminescence (CPL) is promising for applications in many fields. However, most systems involving CPL are within the visible range; near‐infrared (NIR) CPL‐active materials, especially those that exhibit high glum values and can be controlled spatially and temporally, are rare. Herein, dynamic NIR‐CPL with a glum value of 2.5×10−2 was achieved through supramolecular coassembly and energy‐transfer strategies. The chiral assemblies formed by the coassembly between adenosine triphosphate (ATP) and a pyrene derivative exhibited a red CPL signal (glum of 10−3). The further introduction of sulfo‐cyanine5 resulted in a energy‐transfer process, which not only led to the NIR CPL but also increased the glum value to 10−2. Temporal control of these chiral assemblies was realized by introducing alkaline phosphatase to fabricate a biomimetic enzyme‐catalyzed network, allowing the dynamic NIR CPL signal to be turned on. Based on these enzyme‐regulated temporally controllable dynamic CPL‐active chiral assemblies, a multilevel information encryption system was further developed. This study provides a pioneering example for the construction of dynamic NIR CPL materials with the ability to perform temporal control via the supramolecular assembly strategy, which is expected to aid in the design of supramolecular complex systems that more closely resemble natural biological systems.

Dynamic Near-Infrared Circularly Polarized Luminescence Encoded by Transient Supramolecular Chiral Assemblies.

Circularly polarized luminescence (CPL) is promising for applications in many fields. However, most systems involving CPL are within the visible range; near-infrared (NIR) CPL-active materials, especially those that exhibit high glum values and can be controlled spatially and temporally, are rare. Herein, dynamic NIR-CPL with a glum value of 2.5×10-2 was achieved through supramolecular coassembly and energy-transfer strategies. The chiral assemblies formed by the coassembly between adenosine triphosphate (ATP) and a pyrene derivative exhibited a red CPL signal (glum of 10-3). The further introduction of sulfo-cyanine5 resulted in a energy-transfer process, which not only led to the NIR CPL but also increased the glum value to 10-2. Temporal control of these chiral assemblies was realized by introducing alkaline phosphatase to fabricate a biomimetic enzyme-catalyzed network, allowing the dynamic NIR CPL signal to be turned on. Based on these enzyme-regulated temporally controllable dynamic CPL-active chiral assemblies, a multilevel information encryption system was further developed. This study provides a pioneering example for the construction of dynamic NIR CPL materials with the ability to perform temporal control via the supramolecular assembly strategy, which is expected to aid in the design of supramolecular complex systems that more closely resemble natural biological systems.

Adaptive dynamic programming for the optimal liver regeneration control

Every living organism interacts with an environment and uses that interaction for an improvement of its own adaptability, and, as a result, one’s survival and overall development. The process of evolution shows us that different species change methods of interaction with an environment with passage of time, which leads to natural selection and survival of the most adaptive ones. This learning, which based on actions, or reinforcement learning may embrace the idea of optimal behavior occurring in environmental systems. We describe mathematical formulas for reinforcement learning and the practical integration method also known as adaptive dynamic programming. That gives us the overall concept of controllers for artificial biological systems that both learn and show the optimal behavior. This paper reviews the formulation of the upper optimality problem, for which the optimal regulation strategy is guaranteed to be better or equivalent to objective regulation rules that can be observed in natural biological systems. In cases of optimal reinforcement learning algorithms the learning process itself moves from the analysis of the item take on system dynamics to the much higher level. The object of interest now is not the details of the system dynamics, but the quantity efficiency index, which clearly represents how optimally the control system works. Such scheme of reinforcement learning is learning technique of optimal behavior in order to monitor the response to non-optimal control strategies. The purpose of this article is to show the possibility of using of reinforcement learning methods, the adaptive dynamic programming (ADP) in particular, to control biological systems using feedback. This article shows the on-line methods for solving the problem of searching the upper optimality estimate with adaptive dynamic programming.

Emergent digital bio-computation through spatial diffusion and engineered bacteria

Biological computing is a promising field with potential applications in biosafety, environmental monitoring, and personalized medicine. Here we present work on the design of bacterial computers using spatial patterning to process information in the form of diffusible morphogen-like signals. We demonstrate, mathematically and experimentally, that single, modular, colonies can perform simple digital logic, and that complex functions can be built by combining multiple colonies, removing the need for further genetic engineering. We extend our experimental system to incorporate sender colonies as morphogen sources, demonstrating how one might integrate different biochemical inputs. Our approach will open up ways to perform biological computation, with applications in bioengineering, biomaterials and biosensing. Ultimately, these computational bacterial communities will help us explore information processing in natural biological systems.

Multiscale analysis of hierarchical flax-epoxy biocomposites with nanostructured interphase by xyloglucan and cellulose nanocrystals

Natural biological systems feature hierarchical nanostructured architectures achieving high strength and toughness. In this work, the spontaneous adsorption of xyloglucan (XG) and cellulose nanocrystals (CNC) onto flax fabrics is considered to develop hierarchical interphases with improved interfacial adhesion in epoxy-based biocomposites. A multi-scale analysis is carried out, from the nano & micrometric scale with the characterization of fibre surface topography, work of adhesion and interfacial shear strength (IFSS) between flax fibres and epoxy resin, to the macroscopic scale with the transverse mechanical properties of biocomposites. At the fibre scale, XG and CNC increase the surface roughness of flax fibres, as well as their adhesion to epoxy resin with IFSS improved by 60 %, up to 22.3 MPa. At the composite scale, the treatments have a major influence on the cohesion of flax cell walls and microstructure of the biocomposites. Transverse tensile tests reveal both cohesive and adhesive interfacial failure.

Collective queuing motion of self-propelled particles with leadership and experience

The coordinated and ordered collective behavior arising from dispersed and local self-organizing interactions among individuals is widely observed in many biological communities. For populations engaging in group foraging or migration, complex societies with multiple hierarchical levels are common. A prevalent scenario involves two dominant levels, one corresponding to leaders and the other composed of followers. In this paper, we explore how a group can be influenced by a set of leaders to organize and move in a coordinated manner towards a preferred direction. Specifically, we balance social interactions among group members through two weighted factors, corresponding to the leadership and experience of leaders. Through computer simulations, we observe a linear relationship between the proportion of leaders guiding group movement and the group size, with larger groups requiring a higher proportion of leaders while maintaining initial density. Additionally, we identify an optimal leadership interval where group movement performance enhances with increasing leadership up to a certain point, beyond which it starts to decline. Similar patterns are observed concerning individual visual field, indicating the existence of an optimal interval for visual angle. Our findings not only contribute to understanding collective motion in natural biological systems but also provide new insights into effective leadership mechanisms in artificial swarm systems.

A preassembled framework nanocellulose hydrogel inspired by biological systems in nature and ion-imprinted polymers for efficient removal of Cu(II)

Hydrogels can effectively address various adsorption requirements as a multifunctional adsorbent material with a three-dimensional spatial network. However, conventional hydrogels, typically synthesized using the one-pot method, often exhibit a heterogeneous internal structural arrangement, leading to non-uniform stress distribution when interacting with heavy metal ions. This has resulted in the structural disruption of conventional hydrogels in the adsorption of heavy metal ions, and they exhibit low adsorption performance, low cycling performance, and non-selective adsorption. Herein, a preassembled framework structure hydrogel (Cu2+-CNF hydrogel) was developed by introducing template ions (Cu2+), which have been coordinated with monomers (Acrylic acid and Acrylamide), into a network of cellulose nanofibrils (CNFs) polymers. The obtained Cu2+-CNF hydrogel exhibited excellent adsorption properties(Cu2+-CNF hydrogel, 402 mg/g) compared to those prepared by the one-pot method(CNF hydrogel, 129 mg/g). In addition, the Cu2+-CNF hydrogel has superior selective adsorption property and tensile strain properties (CNF hydrogel: 20 % to Cu2+-CNF hydrogel: 100 %) at higher swelling ratios (CNF hydrogel: 2313 wt% to Cu2+-CNF hydrogel: 8379 wt%). Even after multiple folding or repeated adsorption–desorption cycles, the integrity of the structure and adsorption function can still be maintained. This work provides a general strategy for preparing a new type of nanocellulose hydrogel.

Monolithic 2D Perovskites Enabled Artificial Photonic Synapses for Neuromorphic Vision Sensors.

Neuromorphic visual sensors (NVS) based on photonic synapses hold a significant promise to emulate the human visual system. However, current photonic synapses rely on exquisite engineering of the complex heterogeneous interface to realize learning and memory functions, resulting in high fabrication cost, reduced reliability, high energy consumption and uncompact architecture, severely limiting the up-scaled manufacture, and on-chip integration. Here a photo-memory fundamental based on ion-exciton coupling is innovated to simplify synaptic structure and minimize energy consumption. Due to the intrinsic organic/inorganic interface within the crystal, the photodetector based on monolithic 2D perovskite exhibits a persistent photocurrent lasting about 90s, enabling versatile synaptic functions. The electrical power consumption per synaptic event is estimated to be≈1.45×10-16J, one order of magnitude lower than that in a natural biological system. Proof-of-concept image preprocessing using the neuromorphic vision sensors enabled by photonic synapse demonstrates 4 times enhancement of classification accuracy. Furthermore, getting rid of the artificial neural network, an expectation-based thresholding model is put forward to mimic the human visual system for facial recognition. This conceptual device unveils a new mechanism to simplify synaptic structure, promising the transformation of the NVS and fostering the emergence of next generation neural networks.