Nature-inspired Strategy Research Articles

Nature-Inspired Strategy: Novel Borohydride-Based Solid Electrolytes Extracted from Cathode-Electrolyte Interphase.

As the core component of all-solid-state batteries, current solid-state electrolytes fail to simultaneously meet multiple demands, such as their own high performance, the chemical, electrochemical and mechanical compatibility of electrode interface. A fresh perspective is rather desired to guide the development of novel solid electrolytes with comprehensive performance. Herein, this work proposes a novel strategy to synthesize solid electrolytes extracted from cathode-electrolyte interphase (CEI), which is inspired by peach trees secreting peach gum to prevent further damage. A proof-of-concept, using LiBH4-Se and LiBH4-S as prototypes, confirms that as-synthesized electrolytes inherited and improved up the advantages of LiBH4 with unexpected compatibility toward multiple cathodes. It is believed that the family of new electrolytes will be continuously expanded under the guidance of this CEI-derived concept.

Earthworm-Inspired Co/Co3O4/CoF2@NSC Nanofibrous Electrocatalyst with Confined Channels for Enhanced ORR/OER Performance.

The rational construction of highly active and durable oxygen-reactive electrocatalysts for oxygen reduction/evolution reaction (ORR/OER) plays a critical role in rechargeable metal-air batteries. It is pivotal to achieve optimal utilization of electrocatalytically active sites and valid control of the high specific internal surface area. Inspiration for designing electrocatalysts can come from nature, as it is full of precisely manipulated and highly efficient structures. Herein, inspired by earthworms fertilizing soil, a 3D carbon nanofibrous electrocatalyst with multiple interconnected nanoconfined channels, cobalt-based heterojunction active particles and enriched N, S heteroatoms (Co/Co3O4/CoF2@NSC with confined channels) is rationally designed, showing superior bifunctional electrocatalytic activity in alkaline electrolyte, even outperforming that of benchmark Pt/C-RuO2 catalyst. This work demonstrates a new method for porous structural regulation, in which the internal confined channels within the nanofibers are controllably formed by the spontaneous migration of cobalt-based nanoparticles under a CO2 atmosphere. Theoretical analysis reveals that constructing Co/Co3O4/CoF2@NSC electrocatalyst with confined channels can greatly adjust the electron distribution, effectively lower the reaction barrier of inter-mediate and reduce the OER/ORR overpotential. This work introduces a novel and nature-inspired strategy for designing efficient bifunctional electrocatalysts with well-designed architectures.

Polydopamine-Modified Carboxymethyl Cellulose as Advanced Polysulfide Trapping Binder

The search for a high-energy-density alternative to lithium-ion batteries has led to great interest in the lithium sulfur battery (LSB). However, poor cycle lifetimes and coulombic efficiencies (CEs) due to detrimental lithium polysulfide (LiPS) shuttling has hindered its widespread adoption. To address this challenge, a modified sodium carboxymethyl cellulose (CMC) polymer with integrated dopamine moieties and polydopamine nanoparticles was created through a facile one-pot dopamine (DOP) amidation reaction to strengthen noncovalent interactions with LiPSs and mitigate the shuttling effect. The resulting CMC-DOP binder improved electrode wettability, adhesion, and electrochemical performance. Compared to LSBs with a standard CMC binder, CMC-DOP 5:1 (with a 5:1 weight ratio of CMC to dopamine precursor) improves the specific capacity at cycle 100 by 38% to 552 mAh g−1 and CE from 96.8 to 98.9%. LSBs show good stability, even after 500 cycles. Post-mortem electrochemical impedance spectroscopy (EIS) and energy-dispersive spectroscopy (EDS) studies confirmed the effectiveness of the CMC-DOP in confining LiPS in the cathode. This simple but effective nature-inspired strategy promises to enhance the viability of LSBs without using harmful chemicals or adding excess bulk.

Atmosphere-inspired multilayered nanoarmor with modulable protection and delivery of Interleukin-4 for inflammatory microenvironment modulation

Inflammatory bowel disease (IBD) has been closely associated with immune disorders and excessive M1 macrophage activation, which can be reversed by the M2-polarizing effect of interleukin-4 (IL-4). However, maintaining native IL-4 activity with its specific release in the inflammatory microenvironment and efficient biological performance remain a challenge. Inspired by the multilayered defense mechanism of the earth's atmosphere, we constructed a multilayered protective nanoarmor (NA) for IL-4 delivery (termed as IL-4@PEGRA NAs) into an intricate inflammatory microenvironment. The poly(ethylene glycol) (PEG)-ylated phenolic rosmarinic acid (RA)-grafted copolymer contains two protective layers—the intermediate polyphenol (RA molecules) and outermost shield (PEG) layers—to protect the biological activity of IL-4 and prolong its circulation in blood. Moreover, IL-4@PEGRA NAs scavenge reactive oxygen species with the specific release of IL-4 and maximize its biofunction at the site of inflammation, leading to M2 macrophage polarization and downregulation of inflammatory mediators. Simultaneously, gut microbiota dysbiosis can improve to amplify the M2-polarizing effect and inhibit the phosphatidylinositol 3 kinase/Akt signaling pathway, thereby attenuating inflammation and promoting colitis tissue repair. It provides a nature-inspired strategy for constructing an advanced multilayered NA delivery system with protective characteristics and potential for IBD management.

A nature-inspired strategy towards superhydrophobic wood

Plant polyphenols are a type of natural substance widely present in plants, which can form three-dimensional metal-phenolic networks (MPNs) via chelation with metal ions, thereby enabling the construction of functional material coatings.

Mussel-Inspired Adhesive, Antibacterial, and Stretchable Composite Hydrogel for Wound Dressing.

Hydrogels have attracted extensive attention in the field of biomedicine because of their similar structure to extracellular matrix (ECM) and good biocompatibility. However, the adhesiveness, mechanical properties, and antibacterial properties of conventional hydrogels are not satisfactory. In this study, multifunctional chitosan/polydopamine/polyacrylamide (CS/PDA/PAM) hydrogels are prepared through a nature-inspired strategy. The catechol group of polydopamine (PDA) component endows CS/PDA/PAM hydrogels with tissue adhesion and self-healing properties. The introduction of chitosan (CS) not only greatly improves antibacterial ability, but also enhances the mechanical properties of CS/PDA/PAM hydrogels. Skin wound healing experiments show that CS/PDA/PAM hydrogels could accelerate skin tissue regeneration and promote wound healing. Therefore, CS/PDA/PAM hydrogels have great potential in the application of new wound dressings.

Low coefficient of friction hydrogels with fast self-healing properties inspired by articular cartilage

Hydrogels have potential applications in artificial cartilage, soft robotics, and tissue engineering, owing to their excellent wettability, flexibility, and biocompatibility. However, poor lubrication and fragile mechanical properties often limit their applications. In nature, articular cartilage and cornea are coated by brush-like mucous to realize lubrication. Herein, we present a nature-inspired strategy for improving the lubrication properties of hydrogels. A model hydrogel is prepared using poly(vinyl alcohol), borax, and poly(ethylene oxide). The PEO forms a brush-like hydrophilic lubricating layer on the surface of the hydrogel. Thus, the PVA/Borax/PEO hydrogel exhibits a low coefficient of friction (0.08). In addition, after healing for 30 s in the air, the PVA/Borax/PEO hydrogel with a dynamic borate bond exhibit a 93 % cure in strength. Moreover, PVA/Borax/PEO hydrogels also exhibit excellent underwater self-healing ability. With the combination of lubrication and self-healing properties, the PVA/Borax/PEO hydrogels have great potential for use in a wide variety of fields.

Engineering multiphasic heterostructure NiCoP@Co0.5Ni0.5Se2 with optimized electronic structure enabling robust hydrogen evolution

Multiphasic engineering is powerful to improve the performance of hydrogen evolution. Here, NiCoP@Co0.5Ni0.5Se2 heterostructure with a fish-gill-like morphology has been initially prepared via an epitaxial controlled growth strategy. When used as catalyst in the hydrogen evolution, this heterostructure gives low overpotential of 235 mV and long-term durability of 100 h at high current density of 500 mA cm−2 in 1.0 M KOH, showing a superior activity and excellent stability. Such superior performances are achieved by its 3D multiphasic heterostructure and optimized interface electronic structure because extremely porous superhydrophilic and superaerophobic surface of hierarchical morphology enhance kinetic of hydrogen evolution. The findings reported in this work open new occasion for creating novel technologies based on nature-inspired strategy and multiphasic engineering, as evidenced by a superior overall water splitting performance of an assembled NiCoP@Co0.5Ni0.5Se2/NF‖NiFe-LDH/NF cell under industrial condition (30 % KOH, 25 and 60 °C).

Dual-network self-healing hydrogels composed of graphene oxide@nanocellulose and poly(AAm-co-AAc)

A nature-inspired strategy is developed to build dual-network hydrogels made up of rigid graphene oxide-functionalized nanocellulose (GO@NC) network and flexible poly[acrylamide-co-(acrylic acid)] (poly(AAm-co-AAc)) network. A pre-stretching method is used to form a muscle-shape anisotropic architecture. The penetration of poly(AAm-co-AAc) flexible network relieves the stiffness of NC network, thus improving the average elongation at break from 86.2 % to 748.0 %. Compared with the poly(AAm-co-AAc), the average rupture tensile strength rises remarkably by 228.6 %. The dual-crosslinked strategy endows the GO@NC-poly(AAm-co-AAc) hydrogels with a fast, stable and repeatable self-healing ability, which can achieve 85.0 % of healing efficiency after only 600 s of self-healing and maintain 76.2 % of initial strength after 10 cycles of breaking–self-healing. The superb self-healing ability is similar to the muscle function. For potential applications, the hydrogels can achieve real-time, stable, and long-term sensing as smart wearable strain sensors (high gauge factor: 5.13), and can effectively purify Sudan IV wastewater as green recyclable adsorbents.

Nature-inspired preparation of self-adhesive, frost-resistant, and ion-conductive hydrogels for flexible strain sensors.

A nature-inspired strategy has been developed to prepare polyvinyl alcohol (PVA)/catechol-modified quaternized chitosan (QCS-C)/MXene hydrogels with good self-adhesion, frost-resistance, and high ion-conductivity. The PVA/QCS-C/MXene hydrogel shows an ionic conductivity of 8.82 S m−1 and a gauge factor of 33.53 at low strain (0–10%), and remains flexible and conductive at −47 °C. The PVA/QCS-C15/MXene hydrogel displays promising potential as an ionically conductive hydrogel sensor for applications in flexible electronic devices.

Enhancing the Pharmacokinetic Profile of Interleukin 2 through Site-Specific Conjugation to a Selective Small-Molecule Transthyretin Ligand.

Protein drugs hold great promise as therapeutics for a wide range of diseases. Unfortunately, one of the greatest challenges to be addressed during clinical development of protein therapeutics is their short circulation half-life. Several protein conjugation strategies have been developed for half-life extension. However, these strategies have limitations and there remains room for improvement. Here, we report a novel nature-inspired strategy for enhancing the in vivo half-life of proteins. Our strategy involves conjugating proteins to a hydrophilic small molecule that binds reversibly to the plasma protein, transthyretin. We show here that our strategy is effective in enhancing the pharmacokinetic and pharmacodynamic properties of human interleukin 2 in rats, potentially opening the door for more effective and safer cancer immunotherapies. To our knowledge, this is the first example of successful use of a small-molecule that not only extends the half-life but also maintains the smaller size, binding potency, and hydrophilicity of proteins.

Nature-inspired CaCO3 loading TiO2 composites for efficient and durable photocatalytic mineralization of gaseous toluene

The accumulation of intermediates or final products on TiO2 during photocatalytic volatile organic compounds (VOCs) degradation is typically neglected, despite the fact that it could result in the block of active sites and the deactivation of photocatalysts. Inspired from the natural formation of stalactite (CaCO3 + H2O + CO2 ↔ Ca(HCO3)2), we fabricated CaCO3 loading TiO2 composites (CCT21) to realize the spontaneously transfer of accumulated final products (CO2 and H2O). Efficient and durable performance for gaseous toluene removal has been demonstrated and the cost of photocatalyst is greatly reduced by the comparison of specific activity. The introduction of CaCO3 induces the interaction between TiO2 and CaCO3 to stimulate abundant activated electrons for the improvement on the adsorption and activation of reactants and the transformation of photogenerated carriers, and most importantly, facilitates the transfer of final products to release active sites and thus suppress the deactivation of TiO2. Furthermore, we develop a facile method to immobilize CCT21 powder on flexible support, which greatly reduces the loss of photocatalysts and correspondingly enables the practical application of TiO2-based products. Therefore, this work presents a novel nature-inspired strategy to address the challenge of deactivation, and advances the development of photocatalytic technology for environmental remediation.

Lipid engineering combined with systematic metabolic engineering of Saccharomyces cerevisiae for high-yield production of lycopene

Saccharomyces cerevisiae is an efficient host for natural-compound production and preferentially employed in academic studies and bioindustries. However, S. cerevisiae exhibits limited production capacity for lipophilic natural products, especially compounds that accumulate intracellularly, such as polyketides and carotenoids, with some engineered compounds displaying cytotoxicity. In this study, we used a nature-inspired strategy to establish an effective platform to improve lipid oil–triacylglycerol (TAG) metabolism and enable increased lycopene accumulation. Through systematic traditional engineering methods, we achieved relatively high-level production at 56.2 mg lycopene/g cell dry weight (cdw). To focus on TAG metabolism in order to increase lycopene accumulation, we overexpressed key genes associated with fatty acid synthesis and TAG production, followed by modulation of TAG fatty acyl composition by overexpressing a fatty acid desaturase (OLE1) and deletion of Seipin (FLD1), which regulates lipid-droplet size. Results showed that the engineered strain produced 70.5 mg lycopene/g cdw, a 25% increase relative to the original high-yield strain, with lycopene production reaching 2.37 g/L and 73.3 mg/g cdw in fed-batch fermentation and representing the highest lycopene yield in S. cerevisiae reported to date. These findings offer an effective strategy for extended systematic metabolic engineering through lipid engineering.

Nature-inspired engineering of an F-type lectin for increased binding strength.

Individual lectin-carbohydrate interactions are usually of low affinity. However, high avidity is frequently attained by the multivalent presentation of glycans on biological surfaces coupled with the occurrence of high order lectin oligomers or tandem repeats of lectin domains in the polypeptide. F-type lectins are l-fucose binding lectins with a typical sequence motif, HX(26)RXDX(4)R/K, whose residues participate in l-fucose binding. We previously reported the presence of a few eukaryotic F-type lectin domains with partial sequence duplication that results in the presence of two l-fucose-binding sequence motifs. We hypothesized that such partial sequence duplication would result in greater avidity of lectin-ligand interactions. Inspired by this example from Nature, we attempted to engineer a bacterial F-type lectin domain from Streptosporangium roseum to attain avid binding by mimicking partial duplication. The engineered lectin demonstrated 12-fold greater binding strength than the wild-type lectin to multivalent fucosylated glycoconjugates. However, the affinity to the monosaccharide l-fucose in solution was similar and partial sequence duplication did not result in an additional functional l-fucose binding site. We also cloned, expressed and purified a Branchiostoma floridae F-type lectin domain with naturally occurring partial sequence duplication and confirmed that the duplicated region with the F-type lectin sequence motif did not participate in l-fucose binding. We found that the greater binding strength of the engineered lectin from S. roseum was instead due to increased oligomerization. We believe that this Nature-inspired strategy might be useful for engineering lectins to improve binding strength in various applications.

Partial freezing: A nature-inspired strategy for organ banking

Partial freezing: A nature-inspired strategy for organ banking

Nature-Inspired Strategy toward Superhydrophobic Fabrics for Versatile Oil/Water Separation.

Phytic acid, which is a naturally occurring component that is widely found in many plants, can strongly bond toxic mineral elements in the human body, because of its six phosphate groups. Some of the metal ions present the property of bonding with phytic acid to form insoluble coordination complexes aggregations, even at room temperature. Herein, a superhydrophobic cotton fabric was prepared using a novel and facile nature-inspired strategy that introduced phytic acid metal complex aggregations to generate rough hierarchical structures on a fabric surface, followed by PDMS modification. This superhydrophobic surface can be constructed not only on cotton fabric, but also on filter paper, polyethylene terephthalate (PET) fabric, and sponge. AgI, FeIII, CeIII, ZrIV, and SnIV are very commendatory ions in our study. Taking phytic acid-FeIII-based superhydrophobic fabric as an example, it showed excellent resistance to ultraviolet (UV) irradiation, high temperature, and organic solvent immersion, and it has good resistance to mechanical wear and abrasion. The superhydrophobic/superoleophilic fabric was successfully used to separate oil/water mixtures with separation efficiencies as high as 99.5%. We envision that these superantiwetting fabrics, modified with phytic acid-metal complexes and PDMS, are environmentally friendly, low cost, sustainable, and easy to scale up, and thereby exhibit great potentials in practical applications.

Enhanced bioadhesivity of dopamine-functionalized polysaccharidic membranes for general surgery applications.

An emerging strategy to improve adhesiveness of biomaterials in wet conditions takes inspiration from the adhesive features of marine mussel, which reside in the chemical reactivity of catechols. In this work, a catechol-bearing molecule (dopamine) was chemically grafted onto alginate to develop a polysaccharide-based membrane with improved adhesive properties. The dopamine-modified alginates were characterized by NMR, UV spectroscopy and in vitro biocompatibility. Mechanical tests and in vitro adhesion studies pointed out the effects of the grafted dopamine within the membranes. The release of HA from these resorbable membranes was shown to stimulate fibroblasts activities (in vitro). Finally, a preliminary in vivo test was performed to evaluate the adhesiveness of the membrane on porcine intestine (serosa). Overall, this functionalized membrane was shown to be biocompatible and to possess considerable adhesive properties owing to the presence of dopamine residues grafted on the alginate backbone. This article describes the development of a mussels-inspired strategy for the development of an adhesive polysaccharide-based membrane for wound healing applications. Bioadhesion was achieved by grafting dopamine moieties on the structural component on the membrane (alginate): this novel biomaterial showed improved adhesiveness to the intestinal tissue, which was demonstrated by both in vitro and in vivo studies. Overall, this study points out how this nature-inspired strategy may be successfully exploited for the development of novel engineered biomaterials with enhanced bioadhesion, thus opening for novel applications in the field of general surgery.

Bioinspired Carbon/SnO2 Composite Anodes Prepared from a Photonic Hierarchical Structure for Lithium Batteries.

A carbon/SnO2 composite (C-SnO2) with hierarchical photonic structure was fabricated from the templates of butterfly wings. We have investigated for the first time its application as the anode material for lithium-ion batteries. It was demonstrated to have high reversible capacities, good cycling stability, and excellent high-rate discharge performance, as shown by a capacitance of ∼572 mAh g(-1) after 100 cycles, 4.18 times that of commercial SnO2 powder (137 mAh g(-1)); a far better recovery capability of 94.3% was observed after a step-increase and sudden-recovery current. An obvious synergistic effect was found between the porous, hierarchically photonic microstructure and the presence of carbon; the synergy guarantees an effective flow of electrolyte and a short diffusion length of lithium ions, provides considerable buffering room, and prevents aggregation of SnO2 particles in the discharge/charge processes. This nature-inspired strategy points out a new direction for the fabrication of alternative anode materials.