Wounds caused by trauma, burns, diabetes, and surgery have threatened human health, and wound management has become a serious clinical challenge and economic burden. Collagen-based hydrogels have good biological activity, biocompatibility, and biodegradability, which make them have broad application prospects as wound dressings in different stages of wound healing and different types of wound healing. In this paper, the advantages and composition characteristics of collagen-based hydrogel dressings and their function mechanism in different wound healing processes such as hemostasis, inflammatory, proliferation, and remodeling are systematically reviewed. To summarize, the main molecular mechanisms of collagen-based hydrogel dressings include the provision of abundant nutrients at various stages, modulation of related cytokines (e.g., CD34, bFGF, and CTGF), inducement of signaling pathways (such as TGF-β/Smad, PI3K/Akt/mTOR), and promotion of the synthesis of ECM components, especially collagen. Thus, throughout the wound healing process, collagen-based hydrogel dressings can accelerate wound hemostasis, reduce inflammation, promote cell proliferation (especially of fibroblasts), aid in angiogenesis, enhance collagen synthesis, accelerate granulation tissue formation and re-epithelialization, and remodel the cytoplasmic matrix, ultimately leading to wound closure. Furthermore, this review discusses the existing problems in clinical application and scale production and outlines the future of development directions in the researches of collagen-based hydrogel dressings combining innovative wound treatment technologies, preparation technologies, and structural design methods, in order to inspire more new advancement and progress.

Mycelium has emerged as a promising bio-based material for the development of sustainable leather alternatives, driven by the increasing demand for eco-friendly materials. This work explores the crosslinking mechanism of mycelial leather alternatives treated with genipin tanning, focusing on the interactions between genipin and mycelium fibers. Genipin tanning agent interacts with nitrogen-containing groups and carboxyl groups in mycelial polysaccharides, inducing conformational changes in glycosides and increasing the thermal and structural stability of the mycelial leather alternative. Moreover, the synergistic effect of genipin tanning and glycerol fatliquoring resulted in a more organized and compact structure, with mycelial fibers tightly interwoven. The mycelial leather alternative demonstrated a tensile strength of 6.1 MPa, an elongation at break of 73.1%, as well as excellent thermal stability. The observed improved physical properties were attributed to the crosslinking of genipin with mycelial fibers and hydrogen bond formation between glycerol molecules and the hydroxyl groups on the fibers. Furthermore, the mycelial leather alternative demonstrated strong environmental performance, with more than 50% biodegradation in soil within 50 days. Its incineration produces fewer waste gases compared with traditional sheep leather. This work demonstrates the feasibility of using tanning methods to treat mycelial materials, providing valuable insights for advancing the development of leather alternatives.

Thyroid diseases, encompassing both thyroid dysfunction and benign or malignant thyroid nodules, are among the most prevalent disorders within the endocrine system. However, in some cases, current diagnostic approaches for different thyroid diseases lack precision, and therapeutic strategies for advanced tumors remain suboptimal in terms of efficacy. The recent emergence of nanomaterials and collagen have introduced novel paradigms for advancing the clinical diagnosis and management of thyroid disorders. Nanomaterials engineered with tailored designs enable exceptional precision in lesion targeting and ultra-sensitive detection of serum biomarkers. Furthermore, their superior biocompatibility and robust stability have been harnessed to optimize targeted drug delivery and controlled release systems, thereby enhancing therapeutic value while minimizing off-target damage to healthy tissues. As a primary constituent of the natural extracellular matrix, collagen serves as an innate biopolymer nanomaterial. Its nanostructured forms (including fibers, particles, and hydrogels) demonstrate extensive biomedical applicability, facilitating thyroid cell adhesion and functional regeneration while offering an optimal substrate for implantable diagnostic and therapeutic devices. This review highlights nanomaterials’ diagnostic/therapeutic advancements for thyroid diseases, discusses clinical challenges, and outlines future directions. Collagen, beyond being a nanomaterial adjunct, shows standalone promise in regenerative medicine, potentially enabling novel precision approaches.

Tannic acid (TA) is a widely available plant-derived polyphenol with a long history of use in the leather industry due to its strong affinity for collagen. This long-standing application stems from the ability of TA to form stable complexes with collagen and gelatin via multiple interactions, making it not only a natural tanning agent but also a valuable crosslinker in modern biomaterials. In recent years, TA has garnered increasing attention in wound healing applications because of its multifunctional bioactivities, including antibacterial, antioxidant, anti-inflammatory, and hemostatic effects. The abundant phenolic hydroxyl groups enable various covalent and noncovalent interactions (such as hydrogen bonding, metal coordination, π–π stacking, and oxidative coupling) with biomacromolecules and inorganic components, thereby enhancing the mechanical properties and biological functions of the hydrogel. This review summarizes the historical background and physicochemical properties of TA, introduces current hydrogel construction strategies (e.g., polymer blending and postfabrication immersion), and highlights the roles of TA in modulating the wound microenvironment by combating infection, scavenging reactive oxygen species, regulating inflammation, and promoting tissue regeneration. Advances in the use of TA-based hydrogels for treating acute, infected, and chronic wounds and other types of tissue injury are discussed. Furthermore, this review addresses the significant challenges—namely, stability, mechanistic understanding, and biosafety—in the clinical translation of TA-based hydrogels and discusses potential strategies for future development.

This work was conducted to prepare the transglutaminase (TGase) cross-linked collagen gel (CGL) by using pork skin as raw material, and to systematically investigate its digestive and absorptive properties and serum metabolism regulation in mice. The analysis of peptidomics revealed that CGL exhibited a lower average molecular weight of peptides (803.78 Da) and a higher proportion of small molecular peptides (11.22% of <500 Da) in the gastric digestion stage, indicating that the crosslinked structure significantly enhanced the hydrolysis efficiency of pepsin. After entering the small intestine, the proportion of small peptides (<500 Da) in the CGL group decreased compared to the gastric stage, and the number of small peptides in the CGL group decreased compared to the collagen sol (CSL) group, indicating that small peptides in the CGL group were rapidly absorbed in the small intestine stage. Meanwhile, the proportion of peptides in the 500–1000 Da range in the CGL group (53.42%) was higher than that in the CSL group (35.50%), suggesting that intestinal proteases can continuously degrade the large-molecule peptides in the CGL group. This also resulted in the CGL group maintaining a high number of characteristic peptides (161 unique peptides) in the cecum stage. The serum analysis revealed obviously increased collagen peptide counts (205 peptides) and hydroxyproline peptide ratios (93.66%) in the CGL group, with specific peptide segments primarily originating from the cross-linking active sites (Lys644, Gln972). These findings confirm the absorption advantage of the CGL group. In addition, CGL optimized the amino acid absorption pattern by cross-linking modification while maintaining the basic nutritional properties of collagen. The metabolomics results showed that CGL regulated key metabolic pathways such as steroid hormone synthesis, glutathione metabolism and tryptophan metabolic pathway. This study reveals the progressive “gastric degradation - intestinal absorption” mechanism of crosslinked collagen gel. Its unique peptide release pattern and metabolic regulation provide a theoretical basis for developing functional collagen-based products targeting intestinal absorption.

Leather cultural relics are valuable materials for reconstructing and understanding human civilization. However, identifying the tanning agents used in their manufacture remains challenging due to the absence of rapid, non-destructive analytical techniques. This work presents a pioneering non-destructive approach, based on synchrotron small-angle X-ray scattering (SAXS), for identifying vegetable tanned ancient leathers. To validate the method, six simulated ancient leather samples (produced by vegetable, oil, smoke, aluminum, iron, and mirabilite-flour tanning) were analyzed using SAXS, in combination with attenuated total reflectance Fourier transform infrared spectroscopy, X-ray fluorescence, and pyrolysis–gas chromatography-mass spectrometry. SAXS analysis revealed distinctive diffraction patterns: vegetable tanned leathers exhibited minimal or absent peaks due to masking of the collagen fibril D-periodic structure by vegetable tannins, whereas non-vegetable tanned leathers displayed clear periodic diffraction peaks. Application of this method to seven cultural relic samples identified two as vegetable tanned leathers, a result further corroborated by phenolic pyrolysis products detected via pyrolysis–gas chromatography-mass spectrometry. This SAXS-based strategy enables rapid and non-destructive identification of vegetable tanned leather cultural relics.

In recent years, chromium-free tanning agents have gained widespread attention as eco-friendly and non-toxic alternatives in the leather industry. However, most commercially available options still suffer from poor stability under wet and heat conditions, lack of antimicrobial properties, and susceptibility to yellowing. Herein, pectin (P) was oxidized by sodium periodate (NaIO₄), green ethylene glycol diglycidyl ether (EGDE) was then used for graft modification, resulting in the successful synthesis of a multifunctional, green oxidized pectin-EGDE (OPE) as a chromium-free tanning agent. Characterization by FTIR, XPS, XRD, and ¹H NMR indicates that OPE has an oxidation value of 68%, epoxide value of 0.34 mol/100 g. Leather tanned with OPE demonstrates remarkably improved properties compared to traditional chromium-free tanning agents (F-90 and TWS), including high thermal stability (shrinkage temperature of 80.5 °C), superior softness (6.3 mm), tensile strength (13.3 MPa), and tear strength (57.3 N/mm). Moreover, the leather tanned with OPE also exhibits significant antimicrobial properties (inhibition zone diameters of 15 mm against S. aureus and 18 mm against E. coli), resistance to yellowing, and biocompatibility. Notably, the biodegradability of the wastewater from OPE tanned leather (BOD₅/COD ≥ 0.3) and its life cycle assessment confirm its unique environmental advantages. Overall, this work uses natural polysaccharides as the raw material to develop a green functional tanning agent, offering an innovative and sustainable solution for advancing the leather industry toward greener development.

The next-generation on-skin devices are expected to provide identical textural characteristics to skin for accomplishing comfortable long-term wearability. Cattle hide is mainly consisted of type I collagen, which is therefore an ideal collagenous-matrix platform for developing skin-like on-skin devices. However, the raw cattle hide has a high water content that leads to poor wearability. Herein, we developed the skin-like wearable (SW) platform via a brand-new inter-fiber spacer-aided (IFS-aided) drying of cattle hide, where an amphiphilic nonionic surfactant that was capable of thoroughly infiltrating into the 3D hierarchical network of collagen fibers (CFs) was employed to work as the inter-fiber spacer to avoid the sticking of CFs during drying. Moreover, the inter-fiber spacer was easily eluted after drying for obtaining the collagenous matrix with highly dispersed fiber structure. The as-developed SW-platform exhibited ideal wearability by exhibiting full-protein nature, outstanding softness (6.808 mm), exceptional water-vapor permeability (5950 g·m^-2·d^-1) and high thermal stability. The hierarchical fiber structure with sufficient inter-fiber space endowed the SW-platform with reversible cross-scale deformations of CFs at both the nanoscale and microscale, which demonstrated its promising application in developing the skin-like and eco-friendly e-skins with outstanding sensing capability and flexible display function.

Collagenous derivatives (collagen, gelatin, and collagenous hydrolysate (CH)) are extensively used across the food, biomedical, and pharmaceutical industries. Traditionally, these have been sourced from porcine, bovine, and fish due to their ready availability and biocompatibility. However, conventional collagenous derivatives face ongoing challenges regarding sustainability, resource intensity, and socio-cultural perceptions. This has led to the exploration of alternative collagenous derivatives from unconventional sources, with a primary focus on evaluating their potential for yields, extractability, and functional properties, all of which are fundamental for future scale-up and alternative applications. This review summarizes alternative collagenous derivatives from unconventional animals, including amphibians, mollusks, echinoderms, insects, unconventional fish and byproducts, and reptiles. Their structures, extraction techniques, functional properties, and potential applications are comprehensively summarized, showcasing their ability to complement or even surpass conventional sources in specific uses. Additionally, the challenges and prospects for industrial application, emphasizing the sustainability of meeting growing collagen demand and encouraging further research into these promising alternative sources, were discussed. Unconventional collagenous derivatives demonstrate excellent and unique characteristics as alternatives to conventional ones. Type I collagen from amphibians, reptiles, and mollusks had superior thermal stability. Unconventional gelatin and CH also possess various bio-functionalities that can enhance their potential applications. The relatively low extraction yield could be addressed by increasing the concentration of chemicals or extraction time and incorporating green technology without causing an adverse impact on the quality. These findings indicate the potential applications of unconventional collagenous derivatives as food ingredients and supplements.

Environmental and health concerns related to mineral and synthetic tanning agents in leather production are prompting a shift toward sustainable, plant-based alternatives. One group of plant-based tanning agents are the secoiridoids from plants of the Oleaceae family (olive, privet). When their leaves are damaged, secoiridoids are enzymatically deglycosylated to produce aglycones containing aldehyde groups, which are able to cross-link collagen covalently. However, a reliable method to quantify these active aldehyde compounds has been lacking, hindering the application of such tannins. Here, secoiridoid aglycones with aldehyde groups in Olea europaea and Ligustrum vulgare leaf extracts were measured using HPLC-DAD after derivation with 2,4-dinitrophenylhydrazine. Low-temperature extractions (≤40 °C) yielded high aldehyde content (up to 17 mg/g extract), attributed to enzymatic activity, while high-temperature extractions (≥60 °C) preserved the inactive, glycosylated precursors but contained negligible aldehydes due to enzyme denaturation. The cross-linking potential of the extracts was quantified by testing the denaturation temperature and proportion of covalently bound lysine groups of the hide powder treated with endogenously activated Oleaceae extracts. A strong linear relationship was found between aldehyde content and tanning capacity. The most essential aldehyde-containing substances in the extracts as well as the key parameters for efficient extraction were identified. In conclusion, we introduce a new method to accurately measure aldehyde content and assess the cross-linking potential of Oleaceae plant extracts, and expect to support the development of safer, plant-based tannins for the leather industry.

Cellular senescence significantly impairs tissue repair through disrupting tissue homeostasis and limiting regenerative capacity. Biomaterial based microenvironment modulation has emerged as a promising strategy to counteract senescence and promote tissue regeneration. While mechanical properties such as matrix stiffness are known to influence cell fate, whether different tissue-derived cells exhibit distinct mechanical requirements for senescence resistance remains poorly understood. Here, we used stiffness-tunable polyacrylamide hydrogels spanning physiologically relevant elastic moduli and systematically evaluated senescence responses in neuronal (SH-SY5Y), dermal fibroblast (NIH3T3), and osteoblast precursor (MC3T3-E1) cells. Our results revealed tissue-specific stiffness windows that maximally suppressed senescence, with optimal senescence resistance responses observed at 1 kPa, 10 kPa, and 250 kPa for SH-SY5Y, NIH3T3, and MC3T3-E1 cells, respectively. Mechanistically, integrin α1, a collagen-binding integrin, was identified as a key mechanosensor mediating these effects. Optimal stiffness conditions enhanced integrin α1-mediated mechanotransduction, cytoskeletal remodeling, and activation of PI3K–Akt and YAP signaling pathways, leading to the downregulation of senescence markers (p16, p21) and upregulation of proliferation related genes. These findings provide a mechanistic framework for the design of stiffness-matched biomaterials to counteract senescence and enhance tissue regeneration.

The reliance on fossil-derived compounds in most conventional retanning agents faces a challenge to the sustainable development of the leather industry. Consequently, the development of environmentally friendly biomass-based retanning agents is urgently needed. In this research, a novel sucrose-based amphoteric retanning agent (GLS) was synthesized with a weight-average molecular weight of 3.48 × 10⁴ g/mol. The molecular structure of GLS was determined using FT-IR, ¹³C-NMR, XPS, and EA. The GLS exhibited a favorable isoelectric point (pI = 4.68) as a retanning agent. At a 10% dosage, GLS retanning of wet-blue resulted in a 14.42% thickness increase, substantially greater than that achieved with commercial amino resin (CML, 6.77%) and acrylic resin (LP, 10.8%) retanning agents. GLS also exhibited superior absorption (87.13%) compared to CML (75.27%) and absorption comparable to LP (89.2%). Notably, GLS improved the uptake of subsequent anionic fatliquoring agents compared to CML and LP. Moreover, GLS-retanned leather displayed good thermal stability and commendable physical and mechanical properties. The BOD₅/COD value of the GLS retanning wastewater was 0.48, indicating its excellent biodegradability. Life cycle assessment further highlighted the environmental benefits of GLS compared to LP and CML. These findings position GLS as a promising biomass-derived amphoteric retanning agent with the potential to displace conventional fossil-derived alternatives.

In pursuit of environmentally sustainable leather processing, this study reports a novel amphoteric copolymeric fatliquor synthesized from allyltrimethylammonium bromide (ATMA) and dimethylaminoethyl methacrylate (DMAEMA) through free radical copolymerization. The copolymer exhibits a dual ionic character that ensures compatibility with both chrome-tanned and chrome-free leather systems. Structural characterizations using FTIR, NMR, GPC, and ESI-MS confirmed the successful incorporation of cationic, anionic, and hydrophobic functionalities. The amphoteric architecture facilitated pH-responsive interactions with collagen, promoting uniform penetration and efficient fixation. In chrome-tanned leather, the copolymer achieved a substantially higher fatliquor uptake (85.2%) compared to conventional systems (68.7%), along with an improved shrinkage temperature (112 °C vs. 103 °C) and tensile strength (32.25 N/mm², making a 46.7% increase). Enhanced softness and fullness were also observed, with a softness index of 8.3 compared to 6.1 for the control. Notably, the effluent chemical oxygen demand decreased from ~ 42,000 mg/L to ~ 32,000 mg/L, indicating a lower environmental burden. Comparable improvements were observed in chrome-free leather, demonstrating the copolymer’s versatility across tanning systems. This work not only presents a scalable and eco-efficient fatliquoring technology, but also provides a fundamental advancement in understanding collagen-copolymer interactions that significantly contributes to the goals of sustainable leather manufacturing.

Conventional leather manufacturing converts only ~ 20% of raw animal hides into finished products, leaving the majority underutilized and generating substantial waste. To improve resource valorization and realize the high-value potential of leather waste, we propose an innovative "waste upgrading-function integration" strategy, transforming discarded leather into high-value carbon dots via a one-pot hydrothermal process. The resulting waste leather-based carbon quantum dots (W-CQDs) exhibited uniform particle size (~ 8.26 nm), high fluorescence quantum yield (66.3%), semiconductor-like behavior (band gap: 4.25 eV), and a positively charged surface (ζ-potential: +16.6 mV). These physicochemical properties endowed W-CQDs with remarkable antibacterial activity (most effective against E. coli and S. aureus at 6 mg/mL), strong antioxidant capability, and low biotoxicity. By integrating W-CQDs into a polyacrylamide (PAM) network and engineering a biomimetic hair-like microstructure, we developed a W-CQDs/PAM hydrogel sensor with excellent mechanosensitivity (gauge factor: 2.67), rapid response (468–476 ms), and long-term stability (> 1000 cycles). Furthermore, the W-CQDs/PAM hydrogel exhibited pH-responsive fluorescence (pH 3 ~ 11) through intramolecular charge transfer (ICT) and aggregation-induced emission (AIE) mechanisms. Incorporation of LiBr further enhanced water retention and antifreeze performance, significantly expanding its potential for real-world sensing applications.

The ideal wound care materials for wilderness first aid should be convenient for storage, easy to use, adhesive, antibacterial, anti-inflammatory, pro-angiogenic, wound-closure promoting, and simple for clinical translation. To meet all requirements, we developed a supramolecular FPC hydrogel by simply co-assembling 2-amino-2′-fluoro-2′-deoxyadenosine (FA), polydeoxyribonucleotide (PDRN), and collagen III (COL-III)-fully active pharmaceutical ingredients. Based on the abundant hydrogen bonding interactions among FA, PDRN, and COL-III, this hydrogel exhibited sprayability, tissue adhesiveness, and superior biological performance. In vivo studies showed that due to synergistic effects among FA, PDRN, and COL-III, FPC hydrogels offered significant anti-inflammatory benefits and angiogenic capabilities, which promoted granulation tissue formation, collagen deposition, wound tissue epithelialization, and effectively sped up wound healing. Furthermore, the FPC hydrogel could be conveniently stored in a bottle and sterilized through boiling, making it well-suited for wilderness first aid applications. This hydrogel has the potential to transform wound care by offering a versatile solution for both outdoor and everyday wound management needs.

Fish-based collagen supplements have potential health benefits, including antioxidant, ACE inhibitory, and DPP-IV inhibitory properties, which are expressed upon their digestion in the gastrointestinal system, thus releasing bioactive peptides (BPs). This study evaluated the pre-digestion of fish collagen using papain as a pre-digestive enzyme, which has broad specificity to enhance collagen breakdown and BPs release. Fish skin collagen was extracted via acid solubilisation, confirmed as type-I, and subsequently hydrolysed using two methods: pepsin-trypsin digestion (PTD) and pre-digestion with papain followed by PTD (PDPTD). The PDPTD–fish collagen hydrolysates (FCH) exhibited IC50 values (mg/mL) of 0.088 for ACE, 1.67 for DPP-IV, as well as 2.38 and 0.026 for antioxidant activities including DPPH and ABTS radicals scavenging, respectively, which were significantly lower than that of PTD-FCH. The FCH (PTD and PDPTD) were identified using LC-MS/MS analysis, and molecular docking studies showed lower binding energies for PDPTD–FCH peptides, particularly IGFPGFPG, against ACE (-11.2 kcal/mol) and DPP-IV (-9.1 kcal/mol), suggesting better inhibitory ability exhibited by BPs. This study highlighted fish collagen as a valuable source of BPs with enhanced bioactivity when pre-digested with papain, indicating its potential for functional foods and nutraceutical industries.

Human amniotic membrane (AM), a valuable natural biomaterial, is increasingly used in clinical applications. However, its limited mechanical strength and rapid degradation restrict broader use. To address these limitations, we developed a spray-applied crosslinking method for dry AM. A spray delivery of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) with N-hydroxysuccinimide (NHS), combined with a hydrogen-bond-supplementing solution (oxygen-containing compounds), produced a crosslinked dry AM with improved mechanical strength and enhanced resistance to enzymatic degradation in vitro. The EDC/NHS chemistry promoted the formation of covalent bonds within the collagen network, increasing tensile strength and enzymatic stability, while the hydrogen-bond supplement preserved the membrane’s native flexibility after rehydration. The maximum uniaxial tensile fracture stress of the crosslinked AM increased by 156.1%, and the weight loss ratio of enzymatic degradation decreased from 100% to 63.6%. These results indicated that the spray crosslinking protocol yielde a mechanically robust, enzymatically stabilized AM without compromising flexibility, and might expand the membrane’s clinical applicability.

Conventional immunotoxicological approaches are often insufficient to comprehensively elucidate the complex immune responses that may arise during the degradation, metabolite generation, and tissue integration of protein-based medical devices. To address this limitation, we established and applied a six-tiered, stepwise immunological evaluation framework in an appropriate murine model, aiming to systematically characterize the immunological risks of proteinaceous biomaterials. This framework sequentially incorporates baseline immune screening, marketed product comparison, interspecies differentiation, dose–response validation, temporal dynamics assessment, and delayed response detection. By integrating multiple dimensions of readouts, including antibody levels (IgG, IgM, IgA), cytokine profiles (IL-2, IL-6, IL-12p70, IFN-γ, TNF-α), complement activation (C3, C4, C5), immune cell phenotyping, and splenic lymphocyte functionality, the framework establishes a structured, quantifiable, and scalable evaluation pathway. Using recombinant human collagen for injectable fillers as a model material, we demonstrated that this strategy effectively distinguishes diverse immune response types and differentiates material-intrinsic effects from interspecies artifacts, thereby confirming its applicability and interpretive strength in immunological safety assessment of protein-based biomaterials. Collectively, the proposed six-tiered evaluation strategy not only overcomes the limitations of traditional single-parameter or short-term assessments, but also provides a scientifically rigorous and systematic methodology that can serve as a versatile tool for both immunological evaluation and design validation of protein-based and other complex biomacromaterials.

This comprehensive review examines the application of life cycle assessment (LCA) in the leather industry, emphasizing its pivotal role in advancing circular economy integration. Through literature analysis and case studies, this review demonstrates how LCA facilitates animal by-product valorization, waste minimization, and material circularity, transforming traditional leather production into a paradigm of resource efficiency. Key environmental hotspots are identified across system boundaries: animal husbandry dominates Cradle-to-Grave impacts, while chemical usage (e.g., chrome agents) and energy-intensive processes prevail in leather processing, modulated by regional energy mixes. Emerging sustainable technologies and waste valorization innovations show promise in curbing ecological footprints. However, challenges persist, including methodological inconsistencies, data shortages, and regional disparities. To overcome these challenges, the review advocates for unified sector-specific databases, multidimensional assessment frameworks, and AI-driven modeling. Ultimately, LCA emerges as an essential tool for impact quantification, circular transitions, and sustainable industry evolution.

Dehairing proteases are eco-friendly alternatives to chemical dehairing process. Yet, their widespread industrial adoption requires focused research on key factors influencing their efficacy. Earlier research on two microbial proteases, SP01 (from Bacillus cereus VITSP01) and SP02 (from Brevibacterium luteolum VITSP02), revealed a correlation between substrate specificity for proteoglycans and dehairing efficacy. Herein, a comprehensive comparative analysis of their biochemical, thermodynamic, and molecular characteristics was performed to elucidate the determinants of their performance. In comparison to SP01, SP02 could cleave skin proteoglycans and dehair goat skins efficiently at lower temperatures (15 °C and 37 °C). Additionally, it exhibited thermolability, lower activation energy (Ea = 27.003 kJ mol⁻¹) and tolerance to 10% SDS, non-ionic detergents, and 20% NaCl, while Ca²⁺ had a stabilizing effect on its structure. The protease genes of SP01 and SP02 were identified to be trypsin-like peptidase domain-containing protein and S8 family peptidase, respectively. The docking and molecular dynamics simulation revealed stabler interactions between proteoglycans and SP02 compared to SP01. The penetration of SP02 was faster than that of SP01 through skin matrix, probably due to its lower molecular weight (around 30 kDa), pI (about 4.6), proteoglycan degrading property, and smaller Rg and Rh. In silico structural analyses suggested some salient structural features responsible for the cold tolerance of SP02, and the resultant structural flexibility along with a larger catalytic pocket and longer multiple substrate-interacting tunnels could enable better substrate accommodation. In conclusion, SP02 was demonstrated as a potential dehairing enzyme with cold tolerant structural features. This study revealed some key determinants influencing its efficacy and stability, thereby implying improvements for process optimization.

Collagen-based fillers are increasingly recognized as versatile biomaterials for soft-tissue augmentation, yet evidence guiding the enzymatic management of collagen-associated complications remains limited. Here, we performed a systematic characterization of two National Medical Products Administration-approved porcine type I collagen fillers (PCFs), glutaraldehyde cross-linked PCF (CL-PCF) and uncross-linked PCF (UCL-PCF), using hyaluronic acid (HA) filler as a clinical benchmark. CL-PCF exhibited superior mechanical robustness and markedly enhanced resistance to collagenase degradation relative to UCL-PCF. In a rabbit ear embolization model, both PCFs induced significantly milder vascular ischemic manifestations than HA. In vivo enzymolysis assessment in SD rats demonstrated that collagenase concentrations ≤ 300 IU/mL effectively facilitated the controlled degradation of PCFs without inducing notable tissue injury, whereas higher concentrations resulted in extensive matrix loss, hemorrhage, and focal skeletal muscle lysis with inflammatory infiltration. This study provides the first integrated mechanistic and safety-oriented framework for understanding the enzymolysis of collagen fillers and optimizing collagenase-based interventions. These findings offer clinical guidance for complication management and inform evidence-based decision-making in collagen filler applications.

The residual issue of 2,4,5-trichlorophenol (2,4,5-TriCP) affects the leather industry because excessive 2,4,5-TriCP levels are detected in several finished leather products. This study reports the feasibility of using ecofriendly cyclodextrins (CDs) for 2,4,5-TriCP removal from pickled hide via host-guest interactions. Molecular docking, fluorescence spectroscopy, and quartz crystal microbalance with dissipation monitoring results confirmed that β-CD was suitable for 2,4,5-TriCP removal owing to its appropriate cavity structure. Batch elution experiments were performed to evaluate the influence of key parameters on the removal efficiency of β-CD, including time, temperature, sodium chloride (NaCl), β-CD concentrations, and the number of elution cycles. The mentioned optimal elution conditions were identified: 8% (w/v) NaCl, 120 min duration, 5 g·L^− 1 β-CD, 298.15 K, and five elution cycles. 2,4,5-TriCP (40.55–116.39 mg·kg^− 1) was completely removed, meeting the international ecotextile standard limit for chlorophenol (0.05 mg·kg^− 1). Finally, the physical properties of the β-CD eluted pickled hide samples were barely affected compared to the samples treated using the conventional process, confirming that β-CD could be used as a green eluting agent for sustainable leather production.

Ultraviolet (UV) irradiation is a major cause of photoaging, driving oxidative stress, inflammation, and extracellular matrix (ECM) degradation. Collagen is central to dermal integrity, yet animal-derived sources pose immunogenic and pathogen risks, while recombinant collagens reported to date often lack the stable triple-helical architecture required for bioactivity. Here, we present a triple-helical recombinant humanized type I collagen (THRCI) that combines native-like conformation with excellent biosafety and regenerative efficacy. THRCI supported fibroblast adhesion, proliferation, migration, and collagen synthesis, while suppressing intracellular reactive oxygen species and pro-inflammatory cytokines. In zebrafish, THRCI reduced oxidative stress and alleviated UV-induced caudal fin atrophy. In a murine model of acute UV photodamage, topical THRCI accelerated epidermal recovery, restored hydration and barrier function, increased dermal density, and promoted collagen fiber remodeling, while downregulating IL-6, IL-1β, MMP-1, and MMP-9. Collectively, these findings indicate that THRCI exhibits effective photodamage-repair properties in our established models and represents a promising animal-free collagen biomaterial for skin regeneration.

Electronic skin (e-skin) holds significant potential for applications in health monitoring and human-machine interaction. However, conventional materials are often limited by poor biocompatibility and mechanical mismatch with biological tissues. Collagen and its derivatives, as naturally derived biopolymers, have emerged as an ideal matrix for constructing high-performance e-skin due to their exceptional biocompatibility, tunable biodegradability, mechanical properties that closely match human skin, and bioactivity endowed by abundant cell-recognition motifs. This review systematically presents the biomimetic design principles and advanced fabrication strategies of collagen-derived e-skins (CDE-Skins), including structural biomimicry, diversified manufacturing techniques, and conductive functionalization. It further examines their performance and underlying mechanisms in multimodal sensing, such as tactile, thermal, humidity, and biochemical sensing, elucidating the origins of their high sensitivity and stable signal response. The article also highlights representative applications in personalized telehealth monitoring, wound protection and therapy, and human-machine teleoperation. Concurrently, it outlines current challenges and offers perspectives on future research directions. This work aims to provide a comprehensive theoretical foundation to advance technological innovation and accelerate the practical translation of biocompatible e-skin technologies.

With the depletion of petroleum resources, biomass has been widely applied as an alternative to petroleum-based feedstocks. In this work, a lightweight tannin-lignin-phenolic carbon foam (TLCF_5−ME) with excellent smoke suppression was developed. The foam precursor was prepared by substituting 30 wt% of phenol with modified lignin, and tannin was used as a framework filler to reinforce the samples. The effects of lignin, tannin type, including myrica extract (ME), wattle extract (WE), and tannic acid (TA), and addition amount of tannin on the mechanical behavior and smoke suppression of carbon foam were determined, and the mechanism was illustrated. Surprisingly, it was found that the total smoke release of TLCF_5−ME was only 0.39 m²/m², which was 97.62% lower than that of pure phenolic carbon foam (CF), and the compressive strength of TLCF_5−ME was 0.32 MPa, which was 33.33% higher than that of CF. In summary, adding modified lignin and ME not only reduced the use of phenol, but also increased the number of aromatic rings and improved the graphitization degree of carbon foam, thereby promoting the formation of compact char layers under combustion, and further effectively inhibiting the smoke production of samples.

This study explores the potential of upcycling wet-white leather shavings as a filler in thermoplastic polyurethane (TPU) composites for fused filament fabrication (FFF). Leather waste was chemically analyzed to ensure compliance with environmental and safety regulations before being incorporated into TPU at varying concentrations (10 wt% to 40 wt%). Morphological, thermal, rheological, and mechanical characterizations were performed to assess the feasibility of composites for filament production and 3D printing. Results indicated that composites containing up to 30 wt% leather waste maintained good printability, with a speed of 50 mm/s at 220–225 °C identified as optimal printing parameters. Higher filler concentrations (40 wt%) caused severe embrittlement due to material breakage during spool preparation for printing and during filament handling in the FFF feeding system, rendering the material unusable. Despite these limitations, the material demonstrated a promising potential for sustainable additive manufacturing applications in fashion, automotive interiors, and design, offering an eco-friendly alternative for repurposing industrial leather waste.

This study aimed to identify anti-photoaging peptides in porcine skin and to elucidate their bioactive mechanisms using physicochemical property prediction, molecular docking, cell experiments, and network pharmacology. Four collagen peptides were identified from porcine skin hydrolysates via ultrafiltration, gel chromatography, and multi-pathway molecular docking. Among them, FGPYGF and GPPSGGFG exhibited superior photoprotective efficacy which increased the viability of UVB-damaged HaCaT cells to 72.15% and 66.36% at 400 µM, respectively, while effectively suppressing cellular senescence at 200 µM. Molecular docking revealed that synergetic and stronger binding was mediated by hydrogen bonding, ionic interactions, and π-π stacking in forming complexes between both bioactive peptides and four target enzymes (MMP-1, MMP-9, NF-κB, and IL-1β), with binding energies ranging from − 8.34 to -18.37 kcal/mol. FGPYGF inhibited MMP-1 expression and promoted type I collagen synthesis, while GPPSGGFG significantly reduced ROS levels. FGPYGF blocked inflammation and matrix degradation by targeting the TNF signaling pathway and collagen catabolic processes (IL1B/MMP9/2), while GPPSGGFG delayed cell cycle progression and enhanced antioxidant capacity via the FoxO/PI3K-Akt pathway (CCND1/SIRT1). This study confirms that multi-target intervention through cross-pathway modulation significantly enhances photoprotection, providing a theoretical basis for the rational design and precision application of anti-photoaging peptides.

Chronic wounds are marked by persistent inflammation that disrupts normal tissue repair. Growing attention is being directed toward dietary supplements as non-pharmacological strategies to support wound healing. This study evaluated the therapeutic potential of a specific formulation of bioactive fish-derived collagen peptides, Naticol^®, in promoting cutaneous repair. The results demonstrated that oral supplementation with Naticol^® accelerated excisional wound closure in type 2 diabetic mice by restoring essential histological features of healthy skin and enhancing collagen production. This effect is achieved through the establishment of an antioxidant and anti-inflammatory wound microenvironment, the enhancement of scavenger-dependent efferocytosis, and the modulation of MMP9/TIMP1 ratio in favor of tissue remodeling. Notably, Naticol^® drove transcriptional reprogramming of human dermal fibroblasts and monocytes toward antioxidant, anti-inflammatory, and pro-repair phenotypes. In human keratinocytes, Naticol^® increased migratory capacity, further contributing to tissue regeneration. Consistent with in vivo findings, Naticol^® treatment improved wound healing in human skin explants by reinforcing an antioxidant, anti-inflammatory, and pro-reparative microenvironment. These results highlight Naticol^®, a fish-derived bioactive collagen peptide preparation, as a promising functional food component, providing an innovative complementary approach for the management of chronic wounds.

Meniscus possesses weak self-repairability once getting hurt due to heterogeneity, particularly “white region” of avascular parts. However, the effect of conventional therapies in restoring structure and function of the meniscus isn’t ideal. Collagen, a key part of the extracellular matrix, is quite promising. Its excellent biocompatibility and biological activity enable collagen-based tissue-engineered meniscus scaffolds to be safely implanted in the body, effectively improving the pathological and physiological state of cells at the meniscus injury site and the surrounding microenvironment. This review describes the application of different implantable medical collagen-based materials used for meniscal regeneration and repair. Firstly, the structure and physiological function of meniscus are described briefly. Then, different collagen-based materials for meniscal repair are introduced emphatically. Last but not least, some current challenges and issues regarding collagen-based strategies on meniscus repair are analyzed so as to provide strategies for future studies.

Emerging carbonized polymer dots (CPDs) from natural aromatic-like lignin biopolymer have ignited the renaissance of sustainable nanoscale biomass valorization but are hindered by structural instability and functionality barriers. Herein, we report an interfacial heterostructure engineering that immobilizes lignin-based dual-emissive CPDs onto Fe, Co layered double hydroxides (LDHs), with the function of a recyclable electrode. The CPDs deliver a stable metal-ion binding behavior via rapid light-quenching with a low limit-of-detection, which are fixed into FeCo-LDH to improve the electrical conductivity, available reactive site, structural stability, and charge storage. The reconstructed FeCo-LDH@CPDs electrode outputs an ultrahigh specific capacitance of 1842.0 F g^− 1 at 1 A g^− 1. When assembled into a symmetrical supercapacitor (SSCs), it also achieves a superior energy density of 33.79 Wh kg^− 1 at 375 W kg^− 1, excellent rate performance and long-term cycling lifespan (100% retention after 10,000 cycles even at 20 A g^− 1). To validate a closed-loop upcycling of end-of-life electrode, we demonstrate that the recycled FeCo-LDH@CPDs offer a robust Fenton-like catalytic reactivity to fulfill a rapid, reversible and ionic anti-interfering antibiotics elimination. We confirm the participation of singlet oxygen ¹O₂-dominated reactive oxygen species and persistent electron shuttling in tetracycline oxidation. Towards achieving renewable resource technologies, our work sheds an insight on designing high-performance CPDs-hybrid electrode from biomass, ranging from lignin to collagen and/or leather, with the reusable catalytic capabilities to exert a bifunctional energy-water footprint.

Biodegradability of finished leather is crucial for the sustainable development of the leather industry. Herein, the biodegradability evaluation system of finished leather was engineered using soil burial degradation, microbial community dynamics, and biogeochemical cycles. The protein content of chrome grain leather (CGL), chrome-free grain leather (FGL) and chrome-free suede leather (FSL) exceeded 60%, indicating their inherent biodegradation potential during soil burial. After 6 months of soil burial, the biodegradation rate of FGL was around 2.16-fold that of CGL, demonstrating higher biodegradability of chrome-free finished leather. Besides, total nitrogen contents in FSL and CGL soils at 9 months were 2.45- and 1.07- fold those in the initial soil, respectively. These results suggested that organic matter from the finished leathers, particularly chrome-free finished leathers, was gradually released during soil burial degradation. Metagenome sequencing revealed that the diversity of the soil microbial community was considerably enhanced by the soil burial degradation of finished leather. Pseudomonadota, Actinomycetota, and Chloroflexota are the dominant bacteria phyla driving the soil burial biodegradation of finished leather. Accordingly, the degradation of finished leather can change the relative abundance of genes encoding enzymes involved in amino acid metabolism. The degradation of finished leather may continuously release nitrogen-containing substrates, supporting key nitrogen cycling processes including organic nitrogen metabolism, nitrification, assimilation, and nitrate reduction. These results diversify the evaluation systems for finished leather biodegradability, and demonstrate that chrome-free finished leather holds significant promise for the sustainable development of the leather industry.

Osteoarthritis (OA), a prevalent chronic degenerative joint disorder, affects hundreds of millions of people worldwide and has become a leading cause of joint pain and functional impairment in middle-aged and elderly populations. It not only severely compromises patients’ quality of life but also imposes a significant socioeconomic burden on public health systems. Targeting key pathological processes in OA, such as inflammatory responses, chondrocyte apoptosis, and dysregulated autophagy, an injectable liposomal system named RAPA@Lipo/rhCol Ⅲ were developed in this study. This system consisted of rapamycin-loaded liposomes surface-modified with recombinant human collagen type Ⅲ (rhCol Ⅲ). It enabled sustained release of rapamycin to precisely inhibit the mTOR pathway, thereby exerting synergistic biological effects including anti-inflammation, inhibition of chondrocyte apoptosis, and promotion of autophagy. Moreover, the surface collagen modification enhanced the system’s biocompatibility and provided essential matrix microenvironment cues and bioactive signals for cartilage repair. Experimental results demonstrated that RAPA@Lipo/rhCol Ⅲ effectively scavenged reactive oxygen species in chondrocytes, promoted cell proliferation and cartilage matrix synthesis, and modulated the expression of autophagy- and inflammation-related genes, thereby synergistically achieving structural and functional restoration of OA cartilage across multiple dimensions. The integrated “disease modulation-tissue repair” strategy proposed in this study offerd a novel approach and experimental evidence for targeted therapy and functional regeneration in osteoarthritis.