Bacterial infection, excessive inflammation and damaging blood vessels network are the major factors to delay the healing of diabetic ulcer. At present, most of wound repair materials are passive and ...can't response to the wound microenvironment, resulting in a low utilization of bioactive substances and hence a poor therapeutic effect. Therefore, it's essential to design an intelligent wound dressing responsive to the wound microenvironment to achieve the release of drugs on-demand on the basis of multifunctionality. In this work, metformin-laden CuPDA NPs composite hydrogel (Met@ CuPDA NPs/HG) was fabricated by dynamic phenylborate bonding of gelatin modified by dopamine (Gel-DA), Cu-loaded polydopamine nanoparticles (CuPDA NPs) with hyaluronic acid modified by phenyl boronate acid (HA-PBA), which possessed good injectability, self-healing, adhesive and DPPH scavenging performance. The slow release of metformin was achieved by the interaction with CuPDA NPs, boric groups (B–N coordination) and the constraint of hydrogel network. Metformin had a pH and glucose responsive release behavior to treat different wound microenvironment intelligently. Moreover, CuPDA NPs endowed the hydrogel excellent photothermal responsiveness to kill bacteria of >95% within 10 min and also the slow release of Cu2+ to protect wound from infection for a long time. Met@ CuPDA NPs/HG also recruited cells to a certain direction and promoted vascularization by releasing Cu2+. More importantly, Met@CuPDA NPs/HG effectively decreased the inflammation by eliminating ROS and inhibiting the activation of NF-κB pathway. Animal experiments demonstrated that Met@CuPDA NPs/HG significantly promoted wound healing of diabetic SD rats by killing bacteria, inhibiting inflammation, improving angiogenesis and accelerating the deposition of ECM and collagen. Therefore, Met@CuPDA NPs/HG had a great application potential for diabetic wound healing.
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•A metformin-laden CuPDA NPs composite hydrogel (Met@ CuPDA NPs/HG) was fabricated.•The hydrogel had a microenvironment response to release metformin intelligently.•The hydrogel eradicated bacteria by photothermal responsiveness and the slow release of Cu2+.•The hydrogel promoted vascularization and decreased the inflammation.•Met@ CuPDA NPs/HG had a significant promotion on diabetic infected wound healing.
Diabetic wounds suffer from bacterial infections, reactive oxygen species, and inflammatory reactions. Curcumin (Cur) is a natural diketone with antibacterial, anti‐inflammatory, antioxidant ...activities, but poor water solubility and toxicity at high local concentration. Herein, inspired by the oxygen transport process of red blood cells via the dynamic interaction of hemoglobin and oxygen, phenylboronic acid (PBA)‐anchored hydrogel (GOHA‐PBA) is utilized to achieve active enrichment and smart release of Cur, which can reverse the inflammatory microenvironment and promote wound healing. First, PBA‐modified gelatin (Gel‐PBA) and oxidized hyaluronic acid (OHA) crosslink and form GOHA‐PBA by borate ester reaction and Schiff base reaction. GOHA‐PBA possesses excellent curcumin loading efficiency with 130 000 times than that in water and forms Cur‐laden GOHA‐PBA (GOHA‐Cur). GOHA‐Cur has injectability, self‐healing, and self‐adaptive properties, which are conducive to surgical procedure. GOHA‐Cur owns reversible adhesion properties, facilitating it be peeled off and remove harmful substances, including excess glucose, acids, bacteria, and ROS at the wounds. GOHA‐Cur can pH and glucose responsively release Cur; hence, it shows excellent antibacterial, antioxidant, anti‐inflammatory effects in vitro. Animal experiments show that GOHA‐Cur can inhibit inflammation and promote wound regeneration. This study can provide a valuable concept for Cur delivery and diabetic wound healing.
Inspired by the oxygen transport process of red blood cells, active enrichment and smart release of curcumin via dynamic crosslinked hydrogel that hangs PBAs are realized. The hydrogel has excellent curcumin loading efficiency, injectability, and reversible adhesion properties. Meanwhile, the hydrogel can responsively release curcumin according to the pathological environment and eventually shows excellent antibacterial, antioxidant, anti‐inflammatory effects.
Abstract
Flexible hydrogels containing various osteogenic inorganic constituents, which can accommodate complicated shape variations, are considered as ideal grafts for craniofacial bone defect ...reconstruction. However, in most hybrid hydrogels, poor interaction between the polymer network and particles has detrimental effects on hydrogel rheological and structural properties, clinical manipulation and repair efficacy. In this article, we designed and prepared a series of hyaluronic acid composite hydrogel containing Cu-doped bioactive glass (CuBG) and phosphoserine (PS), in which hyaluronic acid was modified by methacrylate groups and phenylboronic acid groups to form a double crosslinked network. PS acted as an interaction bridge of CuBG particles and HAMA-PBA network to improve the mechanical properties of the composite hydrogels. The CuBG/PS hydrogels exhibited suitable rheological properties (injectable, self-healing, shape-adaptable), bone tissue integrating ability and anti-bacterial property. Meanwhile, we found that CuBG and PS have synergistic effect on improving osteogenic efficiency both in vitro and in vivo, particularly when the ratio of CuBG to PS is lower than 3 (9CB/3PS). This work provided a versatile and scalable approach to enhanced the interaction within inorganic particles and polymer network in hydrogels without extra modification on components.
Graphical abstract
In polycrystalline bismuth telluride-based thermoelectric materials, mechanical-deformation-induced donor-like effects can introduce a high concentration of electrons to change the thermoelectric ...properties through the evolution of intrinsic point defects. However, the evolution law of these point defects during sample preparation remains elusive. Herein, we systematically investigate the evolution of intrinsic point defects in n-type Bi2Te3-based materials from the perspective of thermodynamics and kinetics, in combination with positron annihilation measurement. It is found that not only the mechanical deformation but also the sintering temperature is vital to the donor-like effect. The mechanical deformation can promote the formation of cation vacancies and facilitate the donor-like effect, and the sintering process can provide excess energy for Bi antisite atoms to surmount the diffusion potential barrier. This work provides us a better understanding of the evolution law of intrinsic point defects in Bi2Te3-based alloys and guides us to control the carrier concentration by manipulating intrinsic point defects.
The development of amidoxime-based polymeric (ABP) fibers offers a solution for uranium extraction from seawater (UES) and provides an alternative solution to the uranium resource shortage. However, ...ABP adsorbents prepared by existing methods cannot meet the requirements of high adsorption capacity, high selectivity, good mechanical strength and long service life. Herein, we fabricated a 3D hierarchical porous, high specific surface area ABP (H-ABP) fiber
via
self-assembly of axial grafting chains. A high adsorption capacity of 11.50 mg-U per g-adsorbents was achieved in natural seawater, which is a significant breakthrough in UES. Meanwhile, the adsorption capacity of uranium was higher than its major competing element vanadium, which overturned the U/V mass ratio of the ABP fiber. The H-ABP fiber also exhibited good mechanical strength and a long service life of at least 10 adsorption-desorption cycles. The well-designed structure resulted in groundbreaking properties, which completely meet the requirements for the economic evaluation of UES. This work presents a new technology for the synthesis of highly efficient adsorbents for UES, thus opening a whole new means of nuclear fuel production from the ocean.
The development of high specific surface area amidoxime-based polymeric (H-ABP) fibers presents a new technology for the synthesis of highly efficient adsorbents for uranium extraction from seawater (UES), thus opening a whole new means of nuclear fuel production from the ocean.
Crystalline SnSe has been revealed as an efficient thermoelectric candidate with outstanding performance. Herein, record-high thermoelectric performance is achieved among SnSe crystals via simply ...introducing a small amount of SnSe2 as a kind of extrinsic defect dopant. This excellent performance mainly arises from the largely enhanced power factor by increasing the carrier concentration high as 6.55 × 1019 cm–3, which was surprisingly promoted by introducing extrinsic SnSe2 even though pristine SnSe2 is an n-type conductor. The optimized carrier concentration promotes a deeper Fermi level and activates more valence bands, leading to an extraordinary room-temperature power factor ∼54 μW cm–1 K–2 through enlarging the band effective mass and Seebeck coefficient. As a result, on the basis of simultaneously depressed thermal conductivity induced from both Sn vacancies and SnSe2 microdomains, maximum ZT values ∼0.9–2.2 and excellent average ZT > 1.7 among the working temperature range are achieved in Na doped SnSe crystals with 2% extrinsic SnSe2. Our investigation illustrates new approaches on improving thermoelectric performance through introducing defect dopants, which might be well-implemented in other thermoelectric systems.
Thermosetting polymer materials with excellent mechanical properties are highly promising in cryogenic engineering applications. However, the research on the toughening mechanism of thermosetting ...materials at cryogenic temperatures is always difficult. Herein, one type of high strength hyperbranched epoxy composite was successfully fabricated, and the correlation between microstructure (free volume) and mechanical properties of the HPB/epoxy composites was studied. To disclose the correlations between mechanical properties and microstructures for these composites, positron annihilation lifetime (PAL) measurements were carried out. Thereafter, better impact and compression properties were observed for composites with smaller free volume holes. Meanwhile, the impact and tensile properties of the composites are positively correlated with the free volume holes fraction at 77 K. The correlation between microstructure and mechanical properties provide valuable information for regulating the cryogenic mechanical properties of thermosetting materials in the future.
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•One type of high strength hyperbranched epoxy composite was successfully fabricated.•The positron annihilation lifetime (PAL) measurements were carried out to detected the microstructure of hyperbranched epoxy composite.•The effect of free volume holes on mechanical properties provide valuable information for improving the cryogenic mechanical properties of epoxy resins in future.
Since the rise of two-dimensional (2D) semiconductors, it seems that the electronic devices will soon be upgraded with spintronics, in which the manipulation of spin degree of freedom endows it ...obvious advantages over conventional charge-based electronics. However, as the most crucial prerequisite for the above-mentioned expectation, 2D semiconductors with adjustable magnetic interaction are still rare which has greatly hampered the promotion of spintronics. Recently, the transition metal phosphates have attracted tremendous interest due to their intrinsic antiferromagnetism and potential applications in spintronics. Herein, the parasitic ferromagnetism is achieved for the first time by exfoliating the antiferromagnetic chalcogenophosphate to few layers. Taking transition-metal chalcogenophosphate Mn2P2S6 as an example, the antiferromagnetic transition at Néel temperature is completely suppressed and the magnetic behaviors of the as-obtained few-layered Mn2P2S6 are dominated by parasitic ferromagnetism. We experimentally verify an electron redistribution that part of Mn 3d electrons migrate and redistribute on P atoms in few-layered Mn2P2S6 due to the introduced Mn vacancies. The results demonstrated here broaden the tunability of the material's magnetic properties and open up a new strategy to rationally design the magnetic behaviors of 2D semiconductors, which could accelerate the applications of spintronics.
Membranes of high ion permselectivity are significant for the separation of ion species at the subnanometer scale. Here, we report porous organic cage (i.e., CC3) membranes with hierarchical channels ...including discrete internal cavities and cage-aligned external cavities connected by subnanometer-sized windows. The windows of CC3 sieve monovalent ions from divalent ones and the dual nanometer-sized cavities provide pathways for fast ion transport with a flux of 1.0 mol m–2 h–1 and a mono-/divalent ion selectivity (e.g., K+/Mg2+) up to 103, several orders of magnitude higher than the permselectivities of reported membranes. Molecular dynamics simulations illustrate the ion transport trajectory from the external to internal cavity via the CC3 window, where ions migrate in diverse hydration states following the energy barrier sequence of K+ < Na+ < Li+ ≪ Mg2+. This work sheds light on ion transport properties in porous organic cage channels of discrete frameworks and offers guidelines for developing membranes with hierarchical channels for efficient ion separation.
The structure-property relationship of the interlamellar amorphous phase in semicrystalline polymers has been a fundamental yet controversial topic in polymer physics for several decades. The ...intricate hierarchical structure and limited availability of experimental techniques pose significant challenges in quantitatively characterizing the evolution of the amorphous structure and establishing its connection to the mechanical behavior. In this work, the unannealed and annealed isotactic polypropylene hard-elastic films composed of idealized series-arranged lamellar stacks are studied to simplify the mechanical coupling between the two phases. By utilizing the synchrotron-based in-situ small and wide-angle X-ray scattering (SAXS/WAXS) techniques, the apparent modulus and overall volumetric strain of the amorphous phase are estimated. Moreover, with our significant progress in the counting rate of positron annihilation lifetime spectroscopy (PALS), the minute-scale structure evolution of amorphous phase (free-volume pores) during the tensile process is now feasible to be captured. Combing in-situ X-ray scattering and in-situ PALS results, in the elastic regime, it is found that triaxial stress in the amorphous phase leads to the expansion of free-volume pores (about 23% volume increase for the annealed sample, 35% volumetric strain for the unannealed one) and density decrement within occupied volume by overcoming Van Der Waals force. Our quantitative analysis also reveals that the annealing process not only enhances the crystallinity and aspect ratio of lamellae but also weakens the intrinsic modulus and chain packing density of amorphous phase.
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•The structure-property relationship of interlamellar amorphous phase is investigated based on a model structure composed of highly oriented lamellar stacks instead of spherulite on the scale of micrometers.•The significantly improved counting rate of PALS enables us to observe the minute-scale evolution of free-volume pores during the continuous tensile process.•By combining in-situ PALS and in-situ X-ray scattering, the structure evolution and intrinsic properties of interlamellar amorphous phase are feasible to be analyzed quantitatively and profoundly.•Our quantitative analysis reveals that the annealing process not only enhances the aspect ratio of lamellae but also weakens the intrinsic modulus and chain packing density of amorphous phase.
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