Journal of Leather Science and Engineering最新文献

Photoaging skin caused by excessive UV radiation has been one of the most common skin diseases, leading to wrinkles, hyperpigmentation, inflammation, and even skin cancer. Oral collagen supplements have emerged as a potential strategy for photoaged skin; however, they suffer from unclear molecular weights and high risk of disease transmission. Herein, we have for the first time developed a series of molecular weight-controllable oral yak skin collagen (OYC) by the molecular weight-directed enzymolysis-chromatography combined strategy. Toxicological studies indicated that OYC displayed good biocompatibility and no organ toxicity. Combo evaluations revealed that OYC contributed to the restoration of photoaged skin to healthy levels. Histological analysis demonstrated that OYC improved the histopathological changes, significantly accelerating the regeneration of collagen fibers. Antioxidant indicators analysis further indicated that OYC alleviated oxidative stress induced by UV irradiation. Notably, OYC with medium molecular weight (MOYC) exhibited the most effective anti-photoaging properties, likely due to its exceptional ability to scavenge reactive oxygen species, improved intestinal absorption, and optimal resistance to degradation. This orally administered yak skin collagen provides a new strategy and theoretical basis for the prevention and treatment of photoaged skin, offering broad prospects in the fields of nutritional supplements and skincare products.

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Enzymatic unhairing is an environmentally friendly and efficient method for leather processing. However, controlling protease hydrolysis remains challenging, leading to incomplete hair removal and potential grain damage. In modern leather manufacturing, the synergistic application of proteases, lime, and sulfide is increasingly employed to achieve satisfactory hair-saving unhairing performance. This study investigated the action mechanism of calcium ions in modulating the hydrolysis of hide proteins by proteases and proposed a balanced enzyme-assisted unhairing process. Enzymological and fluorescence spectroscopy analyses revealed that calcium ions could enhance the enzymatic resistance of hide proteins, including noncollagenous proteins and collagen, by binding to them. This enhancement in enzymatic resistance was more pronounced for globular proteins than for collagen fibers. In detail, following the addition of 20 g/L calcium ions, the hydrolytic activity of neutral and alkaline proteases decreased by 66.7% and 57.9% on bovine serum albumin, and by 40.7% and 48.1% on collagen fibers, respectively. Furthermore, the performance of the five unhairing processes was evaluated by varying the sequence of lime and protease application and type of protease used. Results indicated that while calcium ions exerted a protective effect on hide proteins and reduced damage to collagen fibers, they simultaneously hindered the removal of undesired noncollagenous proteins during unhairing. Consequently, the sequential application of lime followed by proteases resulted in the inadequate removal of interfibrillar substances, leading to unsatisfactory leather quality. Additionally, compared with an alkaline protease, a neutral protease was more easily inhibited under alkaline unhairing conditions, posed a lower risk of damage to the hide grain. Therefore, the neutral protease–lime–sodium sulfide unhairing process was chosen as the optimal strategy. This process involves the addition of neutral protease (50 U/g hide) for 60 min, followed by 1.0% lime for 90 min and 2.0% sodium sulfide for 90 min. These findings provide scientific insights for designing a controlled and efficient approach to enzyme-assisted unhairing processes.

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The practical implementation of lithium–sulfur (Li–S) batteries is hindered by their poor rate performance and rapid capacity fade, primarily due to the sluggish kinetics of polysulfide conversion. To overcome these challenges, a nitrogen-rich fibrous carbon (NFC) material was synthesized using gelatin and g-C₃N₄ as raw materials through a stepwise pyrolysis process. The unique fibrous microstructure of NFC endows it with high ionic and electronic conductivities, facilitating rapid Li ion and electron transports. Furthermore, nitrogen doping increases the electrochemical performance of the Li–S battery by improving polysulfide adsorption and conversion kinetics. Consequently, the Li–S battery incorporated with NFC demonstrates significantly improved rate performance, exhibiting a high discharge specific capacity of 721 mAh g⁻¹ at 4 C. Additionally, the pouch cell incorporating NFC displays a high average capacity of 821.6 mAh g⁻¹ over 40 cycles at 0.1 C, with high cycling stability and a capacity retention rate exceeding 96%. These results highlight the effectiveness of NFC in improving the cycle longevity of Li–S batteries, thereby heralding a significant stride forward in their practical implementation in energy storage systems.

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As consumers prioritize safer and more sustainable skincare ingredients, the traditional facial mask industry faces challenges due to the use of non-biodegradable materials and chemical preservatives that irritate the skin and harm the environment. In the present investigation, an innovative all-biomass solid facial mask was developed using electrospinning technology to incorporate naturally effective ingredients into bio-based fibers made of gelatin and pullulan polysaccharide. This process produced a nanofiber-based, fast-dissolving facial mask with essence uniformly embedded throughout the fibers. Unlike traditional facial masks that rely on preservatives, this solid mask avoids their use while offering excellent water and moisture retention. Owing to its nanostructured architecture and water-soluble fiber materials, it dissolves completely in water within just 7 s. Yak skin collagen peptides incorporated into the nanofiber film demonstrated strong antioxidant activity, scavenging 88.3% of DPPH free radicals. Biocompatibility testing combined with animal skin and eye irritation testing further confirmed the safety of the facial mask. This innovative approach not only supports the sustainable development of environment and resources but also delivers safer, more effective skincare solutions for consumers.

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Uranium plays a pivotal role in nuclear energy production, and extracting it from seawater offers a promising solution to alleviate shortages in land-based uranium resources. However, the marine environment with ultra-low uranium concentrations, high salinity, and microbial activity poses significant extraction challenges, compounded by selectivity and cost limitations in current methods. In the present investigation, an anti-biofouling amino oxime-functionalized collagen/sodium alginate aerogel (CF-AO/SA) was fabricated using leather waste-derived collagen. The dual cross-linked CF-AO/SA network, enhanced by Zn²⁺ incorporation, showed improved structural stability and antibacterial properties, as well as high uranium adsorption capacity, selectivity, and reusability. It achieved 320.7 mg g⁻¹ in 14 ppm uranium solution and maintained 78.6% removal efficiency after five cycles. Additionally, the removal rate of uranium was 89% in simulated seawater. Field tests in Zhuhai's Jinwan District (113.35° E, 21.99° N) showed 5.16 mg g⁻¹ uranium adsorption and excellent mechanical strength after 30 days in seawater. Furthermore, the production cost of CF-AO/SA was estimated at $3.652 per kilogram, which is lower than other reported adsorbents. The newly developed bio-based aerogel beads have substantial potential for practical applications for uranium capture in seawater and provide a novel high-value utilization way for leather wastes.

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Collagen, recognized as the primary structural component of human skin, is essential for preserving dermal integrity and function. Its progressive depletion has been closely associated with structural deterioration of the dermis and the visible signs of skin aging. Among current therapeutic strategies, the injection of exogenous collagen has been established as an effective method for alleviating aging-related skin changes. In the present study, a comprehensive evaluation was conducted to assess the injectability, cellular interactions, and photoaging repair efficacy of recombinant human collagen type III (RHC). The RHC solution was found to demonstrate favorable injectability and support the adhesion and chemotactic behavior of L929 cells, while also upregulating the expression of type I and type III collagen. In co-culture systems with lipopolysaccharide-stimulated macrophages, RHC treatment suppressed macrophage proliferation and reduced the production of proinflammatory cytokines, suggesting notable immunomodulatory properties. Upon intradermal injection of RHC into photoaged rat skin, an increased density of dermal collagen fibers was observed, accompanied by a more organized and uniform fiber arrangement. Additionally, hydroxyproline content and the expressions of collagen I and III were markedly elevated in the RHC group compared with the control and hyaluronic acid groups. Collectively, these findings suggest that RHC holds considerable promise as a therapeutic agent for both medical and cosmetic purposes targeting the restoration and maintenance of youthful skin characteristics.

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Hollow polymer microspheres (HPMs) were synthesized through emulsion polymerization for application in leather retanning, offering a novel approach to lightweight leather processing. Seed emulsion polymerization enabled the controlled synthesis of four distinct HPM sizes ranging from 300 to 650 nm. Comprehensive characterization revealed that HPMs exhibited distinct hollow structures, narrow particle size distributions, and excellent storage stabilities in emulsion form. The retanning performance of HPMs was evaluated in wet-blue. The HPMs demonstrated excellent permeation during the retanning process, selectively filling the gaps among the fibers, particularly larger spaces. The maximum thickening rate of HPM emulsion (solid content of 10%) retanned leathers reached 18.01%, surpassing the 11.32% achieved with the commercial acrylic resin retanning agent (AR, solid content of 30%) at the same dosage. The maximum absorption of HPM (88.31%) closely approached that of AR (90.23%). Furthermore, HPM retanned leathers showed satisfying performances in physical and mechanical properties. These findings demonstrate the potential of HPMs as lightweight and highly selective filling retanning agents with excellent thickening and absorption properties, offering an attractive alternative to traditional retanning agents.

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Mid-facial depression is a key sign of facial aging, primarily caused by the loss of collagen leading to depletion of the extracellular matrix (ECM). However, the existing fillers for soft tissue augmentation have shown certain limitations in repairing mid-facial depression. Therefore, we herein report the development of a novel recombinant humanized type III collagen gel (C3Gel) through rational design and modification of a commercially available recombinant type III humanized collagen lyophilized fiber product. Both biological activity and tissue repair mechanisms of C3Gel were systematically evaluated in vitro and in vivo. C3Gel formed a dense fibrous structure around cells, significantly improving the ECM environment and providing strong support for cells, thereby promoting cell adhesion, migration, and proliferation. After injection of C3Gel into the dorsal region of rats, we observed a significant increase in the expression of type I collagen and elastin that improved tissue mechanical properties and elasticity. High-throughput RNA sequencing analysis revealed that C3Gel activated the integrin signaling pathway to improve binding between cells and ECM, resulting in the increased expression of downstream genes by activating the PI3K-Akt pathway which promoted the production of ECM components, such as collagen and laminin. At the same time, the expression of matrix metalloproteinases was inhibited to maintain ECM stability. Moreover, C3Gel is not carcinogenic in mice. Therefore, C3Gel demonstrates excellent biocompatibility and significant tissue repair ability, offering a safe, efficient, and long-term stable solution for mid-facial soft tissue augmentation, while providing new insights for other applications in regenerative medicine.

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