Sprayable Zwitterionic Antibacterial Hydrogel With High Mechanical Resilience and Robust Adhesion for Joint Wound Treatment.

Wound healing in movable parts, including the joints and neck, remains a critical challenge due to frequent motions and poor flexibility of dressings, which may lead to mismatching of mechanical properties and poor fitting between dressings and wounds; thus, increasing the risk of bacterial infection. This study proposes a sprayable zwitterionic antibacterial hydrogel with outstanding flexibility and desirable adhesion. This hydrogel precursor is fabricated by combining zwitterionic sulfobetaine methacrylate (SBMA) with poly(sulfobetaine methacrylate-co-dopamine methacrylamide)-modified silver nanoparticles (PSBDA@AgNPs) through robust electrostatic interactions. About 150 s of exposure to UV light, the SBMA monomer polymerizes to form PSB chains entangled with PSBDA@AgNPs, transformed into a stable and adhesion PSB-PSB@Ag hydrogel at the wound site. The resulting hydrogel has adhesive strength (15-38 kPa), large tensile strain (>400%), suitable shape adaptation, and excellent mechanical resilience. Moreover, the hydrogel displays pH-responsive behavior; the acidic microenvironment at the infected wound sites prompts the hydrogel to rapidly release AgNPs and kill bacteria. Further, the healing effect of the hydrogel is demonstrated on the rat neck skin wound, showing improved wound closing rate due to reduced inflammation and enhanced angiogenesis. Overall, the sprayable zwitterionic antibacterial hydrogel has significant potential to promote joint skin wound healing.

Injectable hydrogel with antimicrobial and anti-inflammatory properties for postoperative tumor wound care.

Clinically, tumor removal surgery leaves irregularly shaped wounds that are susceptible to bacterial infection and further lead to excessive inflammation. Injectable hydrogel dressings with antimicrobial and anti-inflammatory properties have been recognized as an effective strategy to care for postoperative tumor wounds and prevent recurrence in recent years. In this work, we constructed a hydrogel network by ionic bonding interactions between quaternized chitosan (QCS) and epigallocatechin gallate (EGCG)-Zn complexes which were coordinated by EGCG and zinc ions. Because of the synergistic effect of QCS and EGCG-Zn, the hydrogel exhibited outstanding antimicrobial capacity (>99.9% inhibition), which could prevent infections caused byEscherichia coli and Staphylococcus aureus. In addition, the hydrogel was able to inhibit the growth of mice breast cancer cells (56.81% survival rate within 72 h) and reduce inflammation, which was attributed to the sustained release of EGCG. The results showed that the hydrogel was effective in inhibiting tumor recurrence and accelerating wound closure when applied to the postoperative tumor wounds. This study provided a simple and reliable strategy for postoperative tumor wound care using antimicrobial and anti-inflammatory injectable dressings, confirming their great potential in the field of postoperative wound dressings.

Hair Follicle Development of Rex Rabbits Is Regulated Seasonally by Wnt10b/ß-Catenin, TGFß-BMP, IGF1, and EGF Signaling Pathways.

This experiment was conducted to study the effects of different skinning seasons on the fur quality and hair follicle development of Rex rabbits. A total of 80,150-day-old Rex rabbits were slaughtered on 15 July 2022 (summer), 15 October 2022 (autumn), 15 January 2023 (winter), and 15 April 2023 (spring) in Shandong Province (10 males and 10 females in each season). The results show that the skin weight, skin area, skin thickness, and hair follicle density of the Rex rabbits (at 150 days of age) were lower in summer than in winter (p < 0.05). Moreover, the coat length was shorter in summer than in spring, autumn, and winter (p < 0.05). The shoulder fat weight, perirenal fat weight, and perigastric fat weight of the Rex rabbits in winter were higher than those in summer (p < 0.05). Furthermore, the leptin levels in serum were higher in winter than in summer in the Rex rabbits (p < 0.05). In terms of serum biochemistry, the glucose levels were higher in autumn and winter than in spring and summer (p < 0.05). The cholesterol, high-density lipoprotein cholesterol (HDL), and low-density lipoprotein cholesterol (LDL) in summer had higher values than in winter in the Rex rabbits (p < 0.05). In winter, the expression of the Wnt10b, catenin beta 1 (CTNNB1), glycogen synthase kinase 3 beta (GSK3ß), insulin like growth factor I (IGF-I), Type I insulin-like growth factor receptor (IGF-IR), and epidermal growth factor (EGF) genes was higher (p < 0.05), and the expression of the dickkopf-1 (DDK1), transforming growth factor beta 1 (TGFß-1), bone morphogenetic protein 2 (BMP2), and bone morphogenetic protein 4 (BMP4) genes was lower than in summer (p < 0.05). In summer, the heat shock 70 kDa protein (HSP70) expression and CTNNB1 protein phosphorylation levels in skin tissue were higher than in spring, autumn, and winter (p < 0.05). In winter, Wnt10b protein expression was higher (p < 0.05), and GSK-3ß protein phosphorylation levels were lower than in spring, autumn, and winter (p < 0.05). These results show that the skinning season can affect the production performance and hair follicle development of Rex rabbits. Compared with other seasons, the quality of skin from rabbits slaughtered in winter is better. Seasons may regulate hair follicle development via the Wnt10b/ß-catenin, TGFß-BMP, IGF1, and EGF signaling pathways in Rex rabbits.

Zwitterionic silver nanoparticle based antibacterial eye drops for efficient therapy of bacterial keratitis.

Inefficient biofilm clearance and the risk of drug resistance pose significant challenges for antibiotic eye drops in the treatment of bacterial keratitis (BK). Recently, silver nanoparticles (AgNPs) have emerged as promising alternatives to antibiotics due to their potent antibacterial activity and minimal drug resistance. However, concerns regarding the potential biotoxicity of aggregated AgNPs in tissues have limited their practical application. In this study, polyzwitterion-functionalized AgNPs with excellent dispersion stability in the ocular physiological environment were chosen to prepare antibacterial eye drops. Zwitterionic AgNPs were synthesized using a copolymer, poly(sulfobetaine methacrylate-co-dopamine methacrylamide) (PSBDA), as a stabilizer and a reducing agent. The resulting antibacterial eye drops, named ZP@Ag-drops, demonstrated outstanding biocompatibility in in vitro cytotoxicity tests and in vivo rabbit eye instillation experiments, attributed to the zwitterionic PSBDA surface. Furthermore, the ZP@Ag-drops exhibited strong antibacterial activity against multiple pathogenic bacteria, particularly in penetrating and eradicating biofilms, due to the synergistic bactericidal effect of the released Ag+ and reactive oxygen species (ROS). Importantly, in vivo BK rabbit models showed that the ZP@Ag-drops effectively inhibited corneal infection and prevented ocular tissue damage, surpassing the therapeutic effect of commercial levofloxacin eye drops (LEV-drops). Overall, this study presents a promising alternative option for the effective treatment of BK using antibacterial eye drops.

Metallic-Polyphenolic Nanoparticles Reinforced Cationic Guar Gum Hydrogel for Effectively Treating Burn Wound.

The development of injectable hydrogel dressings which are long-term moisturizing, easy-to-apply, and effectively inhibiting infection and inflammatory is essential to promote burn wound repairing. Herein, an injectable hydrogel with moisturizing, antibacterial, and anti-inflammation abilities via multiple reversible interactions between cation guar gum (CG) and metallic-polyphenolic nanoparticles (PA-ZnII NPs) is developed. Specifically, PA-ZnII NPs is formed by synergistic complexation of protocatechualdehyde (PA) and zinc ion (Zn2+ ), provides CGPZ hydrogel with plentiful reversible interactions to inhibit the loss of moist. By interacting with PA-ZnII NPs, the CGPZ hydrogel can provide enhanced moisturization for more than 3 days. Moreover, the CGPZ hydrogel can maintain good adhesion for a period of time with injection and self-healing capabilities due to reversible interactions between CG and PA-ZnII NPs. In addition, CGPZ hydrogel exhibits outstanding broad spectrum antibacterial performance, as its killing efficiency against Escherichia coli and Staphylococcus aureus is all greater than 99.99%. Importantly, compared with commercial dressing, the CGPZ hydrogel can promote wound healing faster by inhibiting tissue damage from dysregulated inflammation and accelerating neovascularization. It is believed that the moisturizing CGPZ hydrogel with antibacterial and anti-inflammation performance can serve as a promising dressing for the effective treatment of burn wound.

Gelatin Sponges with a Uniform Interoperable Pore Structure and Biodegradability for Liver Injury Hemostasis and Tissue Regeneration.

Developing a hemostatic sponge that can effectively control bleeding from visceral injuries while guiding in situ tissue regeneration in incompressible wounds remains a challenge. Most of the existing hemostatic sponges degrade slowly, are relatively single-functioning, and cannot cope with complex environments. Herein, a biodegradable rapidly hemostatic sponge (GPZ) was created by dual-dynamic-bond cross-linking among Zn2+, protocatechualdehyde (PA)-containing catechol and aldehyde groups, and gelatin. GPZ had a uniformly distributed interconnected pore structure with excellent fluid absorption. It could effectively absorb the oozing blood and increase the blood concentration while stimulating platelet activation and accelerating blood coagulation. Compared to commercial hemostats, GPZ treatment significantly accelerated hemostasis in the rat liver defect model (∼0.33 min, ≥50% reduction in the hemostatic time) and in the rabbit liver defect model (∼1.02 min, ≥60% reduction in the hemostatic time). Additionally, GPZ had excellent antibacterial and antioxidant properties that effectively protected the wound from infection and excessive inflammation. In the liver regeneration model, GPZ significantly increased the rate of hepatic tissue repair and promoted rapid functional recovery without complications and adverse reactions. Overall, we designed a simple and effective biodegradable rapid hemostatic sponge with good clinical translational potential for treating lethal incompressible bleeding and promoting wound healing.

A robust mixed-charge zwitterionic polyurethane coating integrated with antibacterial and anticoagulant functions for interventional blood-contacting devices.

Antifouling coatings based on zwitterionic polymers have been widely applied for surface modification of interventional blood-contacting devices to combat thrombosis and infection. However, the weak adhesion stability of the zwitterionic coating to the device surface is still the key challenge. In this work, biocompatible mixed-charge zwitterionic polyurethane (MPU) polymers, that bear equal amounts of cationic quaternary amine groups and anionic carboxyl groups, were developed and further uniformly dip-coated onto a thermoplastic polyurethane (TPU) substrate with a commercial aliphatic isocyanate cross-linker (AIC). During the curing process, AIC not only crosslinks MPU chains into a polymer network but also reacts with hydroxyl groups of TPU to interlink the polymer network to the substrate, resulting in a cross-linking reinforced MPU coating (CMPU) with excellent mechanical robustness and adhesion strength. Taking advantage of the mixed-charge feature, the final zwitterionic CMPU coating exhibits both excellent antifouling and antibacterial activities against protein adsorption and bacterial growth, respectively, which is beneficial for effectively inhibiting the occurrence of in vivo infection. Moreover, anticoagulation studies show that CMPU-coated TPU catheters can also prevent the formation of blood clots in ex vivo rabbit blood circuits without anticoagulants. Hence, the designed CMPU coating has immense potential to address thrombosis and infection for interventional blood-contacting devices.

Surface Engineering of Central Venous Catheters via Combination of Antibacterial Endothelium-Mimicking Function and Fibrinolytic Activity for Combating Blood Stream Infection and Thrombosis.

Long-term blood-contacting devices (e.g., central venous catheters, CVCs) still face the highest incidence of blood stream infection and thrombosis in clinical application. To effectively address these complications, this work reports a dual-functional surface engineering strategy for CVCs by organic integration of endothelium-mimicking and fibrinolytic functions. In this proposal, a lysine (Lys)/Cu2+ -incorporated zwitterionic polymer coating (defined as PDA/Lys/Cu-SB) is designed and robustly fabricated onto commercial CVCs using a facile two-step process. Initially, adhesive ene-functionalized dopamine is covalently reacted with Lys and simultaneously coordinated with bactericidal Cu2+ ions, leading to the deposition of a PDA/Lys/Cu coating on CVCs through mussel foot protein inspired surface chemistry. Next, zwitterionic poly(sulfobetaine methacrylate) (pSB) brushes are grafted onto the PDA/Lys/Cu coating to endow lubricant and antifouling properties. In the final PDA/Lys/Cu-SB coating, endothelium-mimicking function is achieved by combining the catalytic generation of nitric oxide from the chelated Cu2+ with antifouling pSB brushes, which led to significant prevention of thrombosis, and bacterial infection in vivo. Furthermore, the immobilized Lys with fibrinolytic activity show remarkably enhanced long-term anti-thrombogenic properties as evidenced in vivo by demonstrating the capability to lyse nascent clots. Therefore, this developed strategy provides a promising solution for long-term blood-contacting devices to combat thrombosis and infection.

Antibacterial, antiviral, and biodegradable collagen network mask for effective particulate removal and wireless breath monitoring.

Functional face masks that can effectively remove particulate matter and pathogens are critical to addressing the urgent health needs arising from industrial air pollution and the COVID-19 pandemic. However, most commercial masks are manufactured by tedious and complicated network-forming procedures (e.g., meltblowing and electrospinning). In addition, the materials used (e.g., polypropylene) have significant limitations such as a lack of pathogen inactivation and degradability, which can cause secondary infection and serious environmental concerns if discarded. Here, we present a facile and straightforward method for creating biodegradable and self-disinfecting masks based on collagen fiber networks. These masks not only provide superior protection against a wide range of hazardous substances in polluted air, but also address environmental concerns associated with waste disposal. Importantly, collagen fiber networks with naturally existing hierarchical microporous structures can be easily modified by tannic acid to improve its mechanical characteristics and enable the in situ production of silver nanoparticles. The resulting masks exhibit excellent antibacterial (>99.99%, 15 min) and antiviral (>99.999%, 15 min) capabilities, as well as high PM2.5 removal efficiency (>99.9%, 30 s). We further demonstrate the integration of the mask into a wireless platform for respiratory monitoring. Therefore, the smart mask has enormous promise for combating air pollution and contagious viruses, managing personal health, and alleviating waste issues caused by commercial masks.

Impact of different dietary fibre sources on production performance, bacterial composition and metabolites in the caecal contents of rabbits.

This study was conducted to investigate the effects of different dietary fibre sources on growth performance, gastrointestinal tract development, caecal fermentation and bacterial composition in the caecal contents of rabbits. A total of 120 35-day-old weaned Minxinan black rabbits were divided into three groups and fed a diet composed of peanut straw powder (Group A), alfalfa powder (Group B) and soybean straw powder (Group C) as the main fibre source. The final body weight and average daily gain in Group B were higher than those in Group C, and the average daily feed intake and feed conversion ratio in Group A were lower than those in Group C (p < 0.05). The relative weights of the stomach, small intestine and caecum of rabbits in Group C were higher than those in Groups of B and A, and the relative weights of the caecal contents in Group C were lower than those in Groups A or B (p < 0.05). The pH value and propionic acid, butyric acid and valeric acid concentrations in the caecum of Group C were lower than those in the caecum of Groups A or B, and the concentration of acetic acid in the caecum was lower (p < 0.05). The dominant microbes in the caecal contents of Minxinan black rabbits were Firmicutes, Bacteroidetes and Proteobacteria at the phylum level, and the number of species, Chao1 index and ACE index measured was different between the B-C and A-C groups (p < 0.05). Different dietary fibre sources could affect the growth performance, gastrointestinal tract development and intestinal microbiota of rabbits, and the nutritional value of alfalfa powder was better than that of peanut straw and soybean straw.

Multifunctional and Tunable Coacervate Powders to Enable Rapid Hemostasis and Promote Infected Wound Healing.

Hemostatic powders provide an important treatment approach for time-sensitive hemorrhage control. Conventional hemostatic powders are challenged by the lack of tissue adhesiveness, insufficient hemostatic efficacy, limited infection control, and so forth. This study develops a hemostatic powder from tricomponent GTP coacervates consisting of gelatin, tannic acid (TA), and poly(vinyl alcohol) (PVA). The physical cross-linking by TA results in facile preparation, good storage stability, ease of application to wounds, and removal, which provide good potential for clinical translation. When rehydrated, the coacervate powders rapidly form a cohesive layer with interconnected microporous structure, competent flexibility, switchable wet adhesiveness, and antibacterial properties, which facilitate the hemostatic efficacy for treating irregular, noncompressible, or bacteria-infected wounds. Compared to commercial hemostats, GTP treatment results in significantly accelerated hemostasis in a liver puncture model (∼19 s, >30% reduction in the hemostatic time) and in a tail amputation model (∼38 s, >60% reduction in the hemostatic time). In the GTP coacervates, gelatin functioned as the biodegradable scaffold, while PVA introduced the flexible segments to enable shape-adaptability and interfacial interactions. Furthermore, TA contributed to the physical cross-linking, adhesiveness, and antibacterial performance of the coacervates. The study explores the tunability of GTP coacervate powders to enhance their hemostatic and wound healing performances.

Fungal aerosols in rabbit breeding environment: Metagenetic insight into PM2.5 based on third-generation sequencing technology.

Fungal aerosols are a vital environmental hazard factor impeding the development of the rabbit breeding industry and threatening public health. This study aimed to determine fungal abundance, diversity, composition, diffusion, and variability in aerosols in rabbit breeding environments. Twenty PM2.5 filter samples were collected from five sampling sites (i.e. En5, In, Ex5, Ex15, and Ex45) in a modern rabbit farm in Linyi City, China. Fungal component diversity at the species level was analyzed in all samples using third-generation sequencing technology. Results revealed that fungal diversity and community composition in PM2.5 significantly differed across different sampling sites, and different pollution levels. The highest concentrations of PM2.5 and fungal aerosols (i.e., 102.5 µg/m3 and 18.8 × 103 CFU/m3, respectively) were found at Ex5, and these concentrations were found to decrease as the distance from the exit increased. However, no significant correlation was observed between the internal transcribed spacer (ITS) gene abundance and overall PM2.5 levels, except for Aspergillus ruber and Alternaria eichhorniae. Although most fungi are not pathogenic to humans, zoonotic pathogenic microorganisms that cause pulmonary aspergillosis (e.g., Aspergillus ruber) and invasive fusariosis (e.g., Fusarium pseudensiforme) were observed. The relative abundance of A. ruber was higher at Ex5 than that at In, Ex15, and Ex45 (p < 0.01), and the relative abundance of the fungal species decreased with an increase in distance from the rabbit houses. Moreover, four potential novel strains of Aspergillus ruber were discovered, with 82.9%-90.3% of the nucleotide and amino acid sequences similar to those of reference strains. This study highlights the importance of rabbit environments as a source in shaping fungal aerosol microbial communities. To the best of our knowledge, this is the first study to uncover the initial characteristics of fungal biodiversity and dispersion of PM2.5 in rabbit breeding environments, contributing to infectious disease control and prevention in rabbits.

Surface modification of commercial intraocular lens by zwitterionic and antibiotic-loaded coating for preventing postoperative endophthalmitis.

After cataract surgery, to prevent possible postoperative endophthalmitis (POE) caused by attached pathogenic bacteria onto the surface of implanted intraocular lens (IOL), various antibiotic-loaded IOLs have been proposed and widely studied to inhibit bacterial infection. However, most of these developed antibiotic-loaded IOLs still suffer from shortcomings such as insufficient drug loading, short release time, poor biocompatibility, and risk of secondary infection. Herein, we propose a zwitterionic and high-drug loading coating for surface modification of commercial hydrophobic IOL with both antifouling and antibacterial properties to effectively prevent POE. In this strategy, zwitterionic poly(carboxylbetaine-co-dopamine methacrylamide) copolymers (pCBDA) and dopamine (DA) were first robustly co-deposited onto IOL surface via facile mussel-inspired chemistry, resulting in a hydrophilic coating (defined as PCB) without sacrificing the high light transmittance of the native IOL. Subsequently, amikacin (AMK), an amine-rich antibiotic was reversibly conjugated onto the coating through the acid-sensitive Schiff base bonds formed by the reaction between amino and catechol groups, with high-drug payload over ∼35.5 µg per IOL and 30 days of sustained drug release under weak acid environment. Benefiting from the antifouling property of zwitterionic pCBDA copolymers, the intraocularly implanted PCB/AMK-coated IOL could effectively resist the adhesion and proliferation of residual LECs to inhibit the development of posterior capsule opacification (PCO) without affecting the normal ocular tissues, demonstrating excellent in vivo biocompatibility. Moreover, the synergy of zwitterionic pCBDA and conjugated AMK with acidic-dependent release behavior endowed this PCB/AMK-coated IOL strong antibacterial activity against both in vitro biofilm formation and in vivo postoperative Staphylococcus aureus infection, suggesting its promising application in preventing POE.

Hemocompatibility Multi-in-One Hydrogel Coating with ROS-Triggered Inflammation Suppression and Anti-Infection Properties for Blood-Contacting Device.

In traditional blood-contacting medical devices, infection and thrombosis are easily formed on the surface of the materials. In addition, inflammation is also a clinical complication that cannot be ignored. More importantly, there is a mutually promoting relationship between the inflammatory response and the infection as well as thrombosis. In this work, we propose a self-adaptive anti-inflammatory coating strategy combined with anti-infection and anticoagulant capacity, which was accomplished based on nano-Ag particles and dexamethasone (Dex)-loaded hydrogel coating. The coating loaded with nano-Ag endows it with good bactericidal performance, including Gram-positive and Gram-negative bacteria. As an anti-inflammatory drug, Dex was grafted onto hydrogel coating by a reactive oxygen species (ROS)-cleavable thioketal (TK) bond and released upon the trigger of an inflammatory environment, blocking further inflammatory cascade, providing self-adaptive anti-inflammatory properties, and avoiding side effects of the drug. It was demonstrated that the coating worked as a precise strategy to resist coagulation, infection, and inflammation, provided a new perspective for designing clinical complication-conformable coatings, and had great application prospects on blood-contacting medical devices.

A zwitterionic silver nanoparticle-incorporating injectable hydrogel with a durable and efficient antibacterial effect for accelerated wound healing.

Antibacterial wound dressing is essential for inflammation control and accelerated wound healing. This study investigates polyzwitterion-functionalized silver nanoparticles (AgNPs) with enhanced antibacterial performance in an injectable wound dressing hydrogel. A mussel-inspired poly(sulfobetaine methacrylate-co-dopamine methacrylamide) (PSBDA) copolymer consisting of sulfobetaine and catechol moieties is developed and used in the stabilizing strategy for a facile one-step synthesis of AgNPs. The catechol moieties in PSBDA reduce AgNO3 in an alkaline solution and anchor PSBDA onto the surface of AgNPs. The zwitterionic AgNPs exhibit a uniform size profile and significantly improved stability, which are critical for maintaining antibacterial efficiency in a physiological environment. An injectable wound dressing hydrogel is developed by incorporating zwitterionic AgNPs into the mixed precursors of gelatin methacryloyl (GelMA) and poly(vinyl alcohol) (PVA). The hydrogel precursors exhibit good injectability and rapidly respond to UV-induced in situ gelation. The zwitterionic AgNP-incorporating hydrogel demonstrates significantly improved antibacterial efficiency compared to the non-zwitterionic counterpart both in vitro and in vivo. The zwitterionic modification also provides enhanced hemocompatibility and biocompatibility. The as-developed hydrogel dressing facilitates the resolution of inflammation and results in a rapid re-epithelization for the accelerated wound healing process in a rat full-thickness wound model.

Methionine can subside hair follicle development prejudice of heat-stressed rex rabbits.

In the present experiment, we study the function of methionine on hair follicle development in heat-stressed Rex Rabbits and its potential molecular mechanism. Rex rabbits were randomly divided into 5 groups (30 replicates per group): control group (20-25°C, fed basic diet), heat stress group (30-34°C, fed basic diet), heat stress + methionine group (30-34°C, fed 0.15% methionine in addition to the basic diet). fed basic diet (control), heat stress + methionine group (30-34°C, fed 0.3% methionine in addition to the basic diet), heat stress + methionine group (30-34°C, fed 0.45% methionine in addition to the basic diet). The results show that heat stress decreases the hair follicle density of Rex rabbits, and the diet methionine addition significantly increases the hair follicle density of heat-stressed Rabbits (p < .05). Heat stress increased serum HSP70 concentration and skin HSP70 gene expression, 0.15%-0.3% methionine but not 0.45% addition alleviated the effect of heat stress. Dietary 0.15% methionine addition significantly increases the gene expression of Wnt10b, ß-catenin, LEF, FZD4, LRP6, Shh, HGF, EGF, and Noggin in heat-stressed Rex rabbits and observably decreases the gene expression of BMP2/4 and TGFb. There was no significant effect of methionine on the expression of IGF1 and FGF5/7 gene expression. In conclusion, methionine maybe promotes hair follicle development via TGFß-BMP/Shh-Noggin, Wnt10b/ß-catenin, EGF, and HGF signaling pathways in heat-stressed rabbits.

Polyphenol modified natural collagen fibrous network towards sustainable and antibacterial microfiltration membrane for efficient water disinfection.

Because of their low-cost and high bacterial interception efficiency, large-scale membrane separation technologies like microfiltration (MF) have been widely implemented for water disinfection. However, lack of antibacterial ability and low sustainability are two major drawbacks of most petroleum-based MF membranes, which are normally associated with hazardous issues including biofouling and nonbiodegradable waste. In this work, abundant animal hides, which are by-products of the meat processing industry, were proposed as raw materials to fabricate a sustainable MF membrane due to their natural, hierarchical, and renewable collagen fibrous network (CFN) with inherent biodegradability. After the removal of non-collagen compositions from animal hides, such as hair and fat, through a facile pretreating process base on green chemistry principles, a thin CFN based membrane (CFN-M) with a similar micropore size to that of commercial MF membranes could be produced. Furthermore, inspired by conventional leather tanning technology, tannic acids (TA) were selected as plant polyphenol tanning agent to modify collagen fibers based on tanning chemistry to improve the thermal stability of CFN-M. Moreover, the TA cross-linked CFN-M (TA@CFN-M) exhibited excellent antibacterial properties due to the production of reactive oxygen species (ROS) by the catechol functional group. The resulting TA@CFN-M achieved >99.9% water disinfection efficiency with a flux of ∼150 L m-2 h-1 via gravity-driven operation, while simultaneously showing admirable anti-biofouling ability. Different from the commercial MF membrane, based on the green chemistry principle, this work may shed light on designing new sustainable and antibacterial membranes for anti-biofouling water disinfection.

Breathable, Antibacterial, and Biocompatible Collagen Fiber Network Decorated with Zwitterionic Silver Nanoparticles for Plantar Pressure Monitoring.

Foot plantar pressure monitoring and gait analysis are of great significant in footwear design, sport biomechanics, injury prevention, and early warning of disease. Flexible and wearable smart insoles pave a feasible way for these application scenarios. However, the majority of the currently developed smart insoles are composed of synthetic polymers (e.g., plastics, rubbers, etc.), leading to inevitable problems associated with air permeability, hygiene condition, biocompatibility, and wearing comfort. Here, a new paradigm of a natural collagen fiber network (CFN) with soft and breathable features, which can be obtained by facilely treating animal hides via conventional leather pretreatment process, is selected as substrate material for constructing smart insoles due to its high permeability and porosity. Further, biocompatible zwitterionic silver nanoparticles (AgNPs) with both carboxybetaine and catechol groups on the interface were designed for firmly and uniformly immobilization onto the hierarchical micro-/nanoscale fibers of CFN through mussel-inspired catechol/amino chemistry, giving rise to both good antibacterial property and pressure sensing capability of the resultant material. The finally developed smart insole by using the AgNPs decorated CFN exhibits good capability for plantar pressure mapping and gait feature analysis. Especially, the smart insole will be very suitable for pressure monitoring and gait analysis of a diabetic foot with sensitive skin that requires a high biocompatible and antibacterial environment.

Hierarchical collagen fibers complexed with tannic acid and Fe3+ as a heterogeneous catalyst for enhancing sulfate radical-based advanced oxidation process.

Efficient sulfate radical-based advanced oxidation processes (SR-AOPs) are important for treating organic contaminants of industrial wastewater. To achieve this goal, tannic acid (TA)-modified skin collagen fibers (CFs) were prepared for the enhanced immobilization of Fe3+ based on multiple complexation interactions, resulting in a heterogeneous catalyst with more catalytic sites (defined as TA-Fe-CFs) for activating peroxymonosulfate (PMS). During the removal of an organic dye (rhodamine B, RhB) from water, the hierarchical TA-Fe-CFs exhibited excellent adsorption capacity at the early stage before the introduction of PMS, which can be ascribed to the π-π interaction between TA and aromatic RhB. Such improved mass transfer of target contaminants into the catalytic support was proved to be beneficial for improving the utilization efficiency of sulfate radicals in subsequent SR-AOPs. After introducing PMS, the reductive TA moieties of the heterogeneous catalyst were able to accelerate the redox cycle of Fe3+/Fe2+ in Fenton reactions, facilitating the activation of PMS to generate sulfate radicals for the degradation of organic RhB.

Modular penetration and controlled release (MP-CR): improving the internal modification of natural hierarchical materials with smart nanoparticles.

The internal modification of natural hierarchical materials can largely improve their inherent properties and afford them new functions. However, conventional methods using small-molecule agents often encounter poor uniformity and low efficiency. By comparing the penetration of small molecules and nanoparticles into hierarchical collagen fibers, we propose a general strategy, namely modular penetration and controlled release (MP-CR), for the internal modification of 3D biomass materials. We demonstrate that nano-sized aluminum-loaded particles can penetrate into collagen networks more effectively and evenly than small-molecule crosslinkers. After the on-demand pH-triggered release of interactive aluminum ions, enhanced internal crosslinking is achieved. Importantly, we elucidate the mechanism in depth and show that the MP-CR strategy can comprehensively improve the overall performance of natural hierarchical materials. The MP-CR strategy represents a significant step forward for the internal modification of hierarchical materials, which will find broad applications in biomedicine, catalysis, water treatment, soft electronics, and energy storage.