A comparative study on cross-linking of fibrillar gel prepared by tilapia collagen and hyaluronic acid with EDC/NHS and genipin

Investigations into the topical hemostatic and wound healing efficacy of binary Hyaluronic acid/Collagen membranes coated with tranexamic acid and vitamin K; InVitro

A hemostatic dressing refers to a specific category of medical dressings that have been developed for managing and controlling bleeding. A synthesized hyaluronic acid/collagen (HA/COL) membrane integrated with tranexamic acid (TRAX) and/or vitamin K (Vit K) using the lyophilization technique is fabricated, followed by physical, chemical, and biological assessment. The clotting time and coagulation variables, as prothrombin (PT), partial thromboplastin time (PPT), and international normalized ratio (INR), were also assessed. The antimicrobial properties were tested against Gram-positive & Gram-negative bacteria, yeast, and fungi. The obtained membranes exhibited porous and swellable characteristics, demonstrating their ability to encapsulate vitamin K and/or tranexamic acid effectively. The cell studies demonstrated that the samples containing vitamin K exhibited less toxicity, in contrast to the TRAX compounds. The assessment of cytotoxicity is substantiated by conducting research on wound healing and determining the IC50 values. Additionally, the samples of vitamin K exhibited rapid clotting, which was corroborated by assessing the coagulation blood factors such as PT, PTT, and INR. The antibacterial activity seen in all samples can be attributed to the presence of HA among the membrane constituents. It is advisable to integrate vitamin K into the HA/COL membrane rather than within TRAX or a combination of TRAX.

Antibacterial and flame-retardant TEMPO-oxidized cellulose nanofibrils/chitosan-based sponge for efficient PM2.5 capture

PM2.5, which can carry many bacteria, poses a serious threat to health when inhaled. Therefore, developing porous materials with efficient filtration and antibacterial properties is essential for preventing the invasion of PM2.5 on respiratory health. In this study, we designed a multifunctional sponge filter through the synergistic integration of TEMPO-oxidized cellulose nanofibrils (TCNF), chitosan (CS), graphene oxide (GO), and lignin hybrid particles. A robust three-dimensional network was constructed via amide cross-linking between TCNF and CS, endowing the sponge with exceptional mechanical stability. GO enhances the PM2.5 interception efficiency through electrostatic adsorption. Additionally, we introduce lignin nanoparticles (LNP) as carriers for growing zinc oxide (ZnO), forming organic-inorganic hybrid particles (LNP@ZnO). This approach minimizes the negative impact of ZnO on the mechanical properties of the sponge while enhancing antibacterial performance. The resulting sponge filter demonstrates high PM2.5 filtration efficiency (99.14 %) with low pressure drop (38 Pa), excellent antibacterial properties against E. coli (92.63 %) and S. aureus (89.05 %), and outstanding flame-retardant properties (LOI value of 27.1 %). This study addresses the limitations of existing systems by minimizing the trade-off between antibacterial performance and mechanical strength, offering a novel approach for the design of advanced air filtration materials.

A silk nanofiber and hyaluronic acid composite hemostatic sponge for compressible hemostasis

Uncontrolled traumatic blood loss is a leading cause of hemorrhagic shock and death, highlighting the critical need for compressible and rapid hemostatic first-aid materials. In this study, silk nanofibers (MA-SNFs) were prepared through maleic acid (MA) hydrolysis decorated with enriched carboxyl groups. The MA-SNFs were then combined with hyaluronic acid (HA) through EDC/NHS crosslinking to form a porous sponge (i.e., MA-SNF/HA) through freeze-drying. The fabricated MA-SNF/HA sponges demonstrated excellent blood compatibility (hemolysis ratio < 5 %), outstanding hemocompatibility (blood clotting index (BCI) < 35 % within 60 s), and good cytocompatibility (cell viability >85 %). Among the different sponges prepared, M4-H6 (MA-SNFs: HA = 4:6) exhibited the best liquid reabsorption capacity after 80 % compression, outperforming M6-H4 and M5-H5 sponges. Furthermore, M4-H6 sponge absorbed liquid rapidly (~30 s) while matching the liquid absorption capacity of commercial gelatin sponge (GS), which require over 5 min for similar absorption (2232.84 ± 141.69 %). These findings suggest that M4-H6 sponge is highly suitable for compressible hemostasis applications and provide further insights into its potential hemostatic mechanism.

Nanocoating of quinoa protein and hyaluronic acid enhances viability and stability of Limosilactobacillus fermentum RC4 microcapsules

Nanocoating represents an effective strategy for creating a protective barrier on probiotic surfaces, preventing them from damage. Here, we developed HAQ microcapsules comprising Limosilactobacillus fermentum RC4, which were nanocoated with hyaluronic acid and quinoa protein. We characterized the stability and safety, and investigated the intermolecular forces and transcriptome to elucidate the mechanisms underlying the nanocoating. The encapsulation efficiency, survival rates following freeze drying, simulated oro-gastrointestinal conditions, and storage at 4 °C for 56 d were 10.32 %, 12.74 %, 7.56 %, and 14.56 % higher, respectively, than those of LF RC4 alone. The HAQ microcapsules demonstrated adhesion to Caco-2 cells and safely promoted proliferation in RAW 264.7 cells. Electrostatic and hydrophobic interactions emerged as the primary forces within the HAQ microcapsules, facilitating structural rearrangements of wall materials, promoting the ordered aggregation of quinoa protein, and enhancing the stability of microcapsules. Transcriptome analysis revealed that HAQ upregulated argF and carB involved in lysine and glutamic acid biosynthesis, while downregulating mraY and murG associated with carbohydrate biosynthesis. It is postulated that these regulatory effects may enhance bacterial metabolism and proliferation, thereby facilitating the exertion of functional properties such as adhesion. Our findings offer valuable insights into the development of highly active and stable probiotic freeze-dried powders.

High-strength, solvent-resistant carboxymethyl chitosan composite rubber based on dual covalent crosslinking network and hydrogen bond network for multi-functional sensing

In order to prepare natural polymer composite rubber with excellent mechanical properties, solvent resistance and electrical conductivity, and to apply it to multifunctional sensing. In this study, an environmentally friendly and effective strategy was employed to solve these problems. Carboxymethyl chitosan composite rubber was prepared by introducing the dual covalent crosslinking network into carboxy nitrile butadiene rubber via amide and radical reactions, followed by blending with carboxymethyl chitosan to introduce a hydrogen bonding network. The tensile strength of the prepared composite rubber was increased by 45 times, the crosslink density was increased by 405 times, the mechanical properties and solvent resistance were significantly improved, and the electrical conductivity was also obtained. Based on these excellent properties, carboxymethyl chitosan composite rubber can be used in strain sensors to detect human movement, and realize information encryption; it can also be used in humidity sensors to detect human respiration, environmental humidity and industrial pipeline safety. The nature polymer composite rubber prepared in this work will have great potential for application in flexible electronic devices.

Comprehensive Review on Application Progress of Marine Collagen Cross-Linking Modification in Bone Repairs

Bone tissue injuries are a significant health risk, and their repair is challenging. While various materials have potential for bone repair, issues like sourcing and immune rejection limit their use. Marine-derived collagen, abundant and free from religious and disease transmission concerns, is a promising biomaterial in bone tissue engineering. Cross-linking modification can enhance its mechanical properties and degradation rate, making it more suitable for bone repair. However, detailed analysis of cross-linking methods, property changes post-cross-linking, and their impact on bone repair is needed. This review examines marine collagen's modification methods, improved characteristics, and potential in bone tissue repair, providing a foundation for its effective use in bone tissue engineering.

Collagen (peptide) extracted from sturgeon swim bladder: Physicochemical characterization and protective effects on cyclophosphamide-induced premature ovarian failure in mice

Premature ovarian failure (POF) is a common female reproductive disorder, with oxidative damage playing a significant role in its development. Studies had demonstrated the beneficial antioxidant, anti-aging, and other biological properties of swim bladder collagen (peptide). In this study, acid extraction, water extraction, and enzymatic hydrolysis methods were used to extract collagen (peptide) from sturgeon (Acipenser sinensis) swim bladder, all of which exhibited significant antioxidant activity. Moreover, the effects observed in POF mice were enhanced, including an increasing in the number of growing ovarian follicles, regulation of serum hormone levels, and alterations in signaling pathways, as evidenced by the up-regulation of Phosphatidylinositol 3-kinase/Protein Kinase B (PI3K/Akt) and B cell lymphoma-2/ Bcl-associated x protein (Bcl-2/Bax) pathways, alongside the down-regulation of the mitogen-activated protein kinases (MAPK) signaling pathway. Sturgeon swim bladder collagen (peptide) could protect against cyclophosphamide-induced POF in mice, which could be very beneficial in the future advancement of health products.

Amidated and Aminated PMSSO-Hydrogels as a Promising Enzyme-Sensitive Vehicle for Antianemic Drugs

In this study, we report the synthesis and characterization of aminated poly(methyl silsesquioxane)-based hydrogels ((AP/MS)SO-hydrogels) as potential enzyme-sensitive vehicles for antianemic drugs. The hydrogels were synthesized via sol-gel polymerization and functionalized with amine groups. Characterization techniques included Congo red assay, Brunauer-Emmett-Teller (BET) surface area analysis, scanning electron microscopy, elemental analysis, 13C NMR, 29Si NMR, and ATR-FTIR spectroscopy and microscopy of hydrogels. The sorption of ferric chloride and ferrous D-gluconate, as well as complexes of ferrous D-gluconate with HPCD, was evaluated. Crosslinking of the gel with bifunctional agents was performed to create a new amide enzyme-sensitive bond, followed by infrared characterization of the crosslinked product. Trypsin-mediated degradation studies demonstrated the sensitivity of the hydrogel to enzymatic cleavage under model conditions. Iron release experiments in gastric and intestine-simulating media confirmed prolonged release. Overall, our findings suggest that aminated PMSSO-hydrogels hold promise as versatile and biocompatible carriers for targeted delivery of antianemic agents, warranting further exploration in preclinical and clinical applications.

Biomimetic Mineralized Collagen Scaffolds for Bone Tissue Engineering: Strategies on Elaborate Fabrication for Bioactivity Improvement

Biomimetic mineralized collagen (BMC) scaffolds represent an innovative class of bone-repair biomaterials inspired by the natural biomineralization process in bone tissue. Owing to their favorable biocompatibility and mechanical properties, BMC scaffolds have garnered significant attention in bone tissue engineering. However, most studies have overlooked the importance of bioactivity, resulting in collagen scaffolds with suboptimal osteogenic potential. In this review, the composition of the mineralized extracellular matrix (ECM) in bone tissue is discussed to provide guidance for biomimetic collagen mineralization. Subsequently, according to the detailed fabrication procedure of BMC scaffolds, the substances that can regulate both the fabrication process and biological activities is summarized. Furthermore, a potential strategy for developing BMC scaffolds with superior mechanical properties and biological activities for bone tissue engineering is proposed.

A novel method to enhance the efficiency of aldehyde tanning agents via collagen amination

The utilization of chromium free tanning agents generates lots of pollutants such as chromium containing wastewater and sludge. Besides, trivalent chromium may be converted into carcinogenic hexavalent chromium under certain conditions, causing permanent harm to the human body. Therefore, the promotion of chromium free tanning technology is extremely significant. In this study, it reports a green strategy to build a novel tanning system via the amination of collagen fibers. Leather collagen was aminated by diethanolamine to improve the positive charge and number of amino groups. This allowed the regulation of functional groups in collagen fibers and enabled the high employment of aldehyde tanning agents. On this matter, experimental work combined with molecular dynamics simulation was used to investigate the enhancement mechanism of amination. Collagen fibers aminated by diethanolamine achieved better aldehyde tanning effect than untreated collagen fibers, such as a higher shrinkage temperature (87.5 °C), dyeing absorption (74.6 %), and lower free formaldehyde content (160.8 mg/kg). This work provided a novel strategy for the establishment of a green and efficient chromium free tanning system.

Preparation of fibre-reinforced PLA-collagen@PLA-PCL@PCL-gelatin three-layer vascular graft by EDC/NHS cross-linking and its performance study

In this study, a three-layer small diameter artificial vascular graft with a structure similar to that of natural blood vessels was first constructed by triple-step electrospinning technology, in which polylactic acid (PLA) and collagen (COL) were used for the inner layer, polylactic acid and polycaprolactone (PCL) was used for the middle layer and polycaprolactone and gelatin was used for the outer layer. The properties of the artificial vascular graft were adjusted by the EDC/NHS cross-linking agent through the reaction between the collagen or gelatine and EDC/NHS. The mechanical and hydrophilic properties of the cross-linked artificial vessels were substantially enhanced, with a maximum stress of 9.56 MPa in the axial direction and 9.31 MPa in the radial direction for the P/C (4:1) vascular graft, which exceeded that of many textile-based and natural vascular grafts. The increased hydrophilicity of the inner layer of the vessel before crosslinking was due to the addition of COL, and the inner layer of the artificial vessel after crosslinking had a substantial increase in hydrophilicity due to the production of a more hydrophilic urea derivative. The increased hydrophilicity led to easier cell adhesion to the inner layer of the artificial vessel, especially for the P/C (2:1) vascular graft, where the cell proliferation rate and adhesion were high due to COL incorporation and cross-linking. The three-layer vascular grafts studied did not lead to haemolysis. Therefore, the EDC/NHS cross-linked three-layer vascular graft had good mechanical properties, hydrophilicity, anticoagulation and could enhance cell adhesion and proliferation.

Mechanistic study of the stabilization of dentin-bonded restorative interfaces via collagen reinforcement by multi-acrylamides

Hydrolytically and enzymatically-stable multi-acrylamides have been proposed to increase the long-term durability of dental adhesive interfaces as alternatives to methacrylates. The aim of this study was to investigate the mechanical and biochemical properties of experimental adhesives containing multi-functional acrylamides concerning collagen reinforcement and metalloproteinases (MMP) activity. Multi-functional acrylamides, TMAAEA (Tris[(2-methylaminoacryl) ethylamine) and DEBAAP (N,N-Diethyl-1,3-bis(acrylamido) propane), along with the commercially available DMAM (N,N-dimethylacrylamide) (monofunctional acrylamide) and HEMA (2-Hydroxyethyl methacrylate) (monofunctional methacrylate - control) were tested for stability against enzymatic hydrolysis by cholesterol esterase/pseudocholinesterase (PC/PCE) solutions for up to 30 days. Collagen-derived substrate and gelatin zymography were performed to examine the effect of the compounds on the biological activity of human recombinant and dentin-extracted gelatinases MMP-2 and MMP-9. In situ zymography was carried out by fluorescent collagen degradation combined with confocal microscopy analysis. Hydroxyproline content was measured in collagen derived from dentin extracts though reaction with Ehrlich's reagent p-dimethylaminobenzaldehyde (DMAB), generating a stable chromophore measured at 550 nm. Storage shear modulus of demineralized dentin discs treated with the tested compounds was measured by oscillatory rheometry, in order to investigate potential collagen reinforcement. FT-IR was performed to determine qualitative differences in collagen based on observed changes in amide bands. The results were analyzed by ANOVA/Tukey's test (α = 0.05). Multi-acrylamides survived 30 days of incubation in cholinesterase/pseudo-cholinesterase (PC/PCE) solutions, while HEMA showed approximately 70 % overall degradation. Incubation with multi-acrylamides reduced collagen degradation as evidenced by the reduced hydroxyproline levels and by the 30 % increase inshear storage modulus. Biochemical and zymography assays showed no noticeable inhibition of recombinant and extracted MMPs enzymatic activity. The infra-red spectroscopy results for multi-functional acrylamides treated samples demonstrated shifts of the amide II bonds and marked increase in intensity of the bands 1200 cm-1, which may indicate partial collagen denaturation and some degree of cross-linking of the compounds with collagen, respectively. The multi-acrylamides exhibited not only comparable mechanical properties but also demonstrated significantly enhanced biochemical stability when compared to the widely used methacrylate control. Clinical relevance: These findings highlight the potential of multi-acrylamides to increase the bonding stability to tissues and, ultimately, contribute to the longevity of dental restorations.

Engineering a durable BDDE cross-linked collagen filler for skin rejuvenation

Skin aging, characterized by reduced regeneration, chronic inflammation, and heightened skin cancer risk, poses a significant challenge. Collagen fillers have emerged as a potential solution for skin rejuvenation by stimulating collagen regeneration. However, their clinical efficacy is limited by inherent instability and vulnerability toin vivodegradation by collagenase. Chemical cross-linking presents a promising approach to enhance stability, but it carries risks such as cytotoxicity, calcification, and discoloration. Here, we introduce a highly durable 1,4-butanediol diglycidyl ether (BDDE) cross-linked collagen filler for skin rejuvenation. BDDE effectively cross-links collagen, resulting in fillers with exceptional mechanical strength and injectability. These fillers demonstrate favorable stability and durability, promoting proliferation, adhesion, and spreading of human foreskin fibroblast-1 cellsin vitro. In vivostudies confirm enhanced collagen regeneration without inducing calcification. BDDE cross-linked collagen fillers offer promising prospects for medical cosmetology and tissue regeneration.

Human Cell-Derived Matrix Composite Hydrogels with Diverse Composition for Use in Vasculature-on-chip Models

Microphysiological and organ-on-chip platforms seek to address critical gaps in human disease models and drug development that underlie poor rates of clinical success for novel interventions. While the fabrication technology and model cells used to synthesize organs-on-chip have advanced considerably, most platforms rely on animal-derived or synthetic extracellular matrix as a cell substrate, limiting mimicry of human physiology and precluding use in modeling diseases in which matrix dynamics play a role in pathogenesis. Here, the development of human cell-derived matrix (hCDM) composite hydrogels for use in 3D microphysiologic models of the vasculature is reported. hCDM composite hydrogels are derived from human donor fibroblasts and maintain a complex milieu of basement membrane, proteoglycans, and nonfibrillar matrix components. The use of hCDM composite hydrogels as 2D and 3D cell culture substrates is demonstrated, and hCDM composite hydrogels are patterned to form engineered human microvessels. Interestingly, hCDM composite hydrogels are enriched in proteins associated with vascular morphogenesis as determined by mass spectrometry, and functional analysis demonstrates proangiogenic signatures in human endothelial cells cultured in these hydrogels. In conclusion, this study suggests that human donor-derived hCDM composite hydrogels could address technical gaps in human organs-on-chip development and serve as substrates to promote vascularization.

Crosslinked Collagen-Hyaluronic Acid Scaffold Enhances Interleukin-10 Under Co-Culture of Macrophages And Adipose-Derived Stem Cells

The skin, the human body's largest organ, possesses a protective barrier that renders it susceptible to various injuries, including burns. Following burn trauma, the inflammatory process triggers both innate and adaptive immune responses, leading to the polarization of macrophages into two distinct phenotypes: the pro-inflammatory M1 and the anti-inflammatory M2. This dual response sets the stage for wound healing and subsequent tissue regeneration. Contributing to this transition from M1 to M2 polarization are human adipose-derived stem cells (ASCs), which employ paracrine signaling and inflammation suppression to enhance the remodeling phase. ASCs, when combined with biocompatible polymers, can be integrated into functional scaffolds. This study introduces an 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-crosslinked (EDC-crosslinked) collagen-hyaluronic acid (Col-HA) scaffold assembled with ASCs, designed as a natural biomaterial device to modulate macrophage behavior in vitro under co-culture conditions. This innovation aims to improve wound healing processes. The EDC-crosslinked Col-HA scaffold favored the release of anti-inflammatory cytokines by ASCs, which indicated the M2 prevalence. In tissue engineering, a critical objective lies in the development of functional biomaterials capable of guiding specific tissue responses, notably the control of inflammatory processes. Thus, this research not only presents original findings but also points toward a promising avenue within regenerative medicine.

Visualized adsorption and enhanced photocatalytic removal of Cr6+ by carbon dots-incorporated fluorescent nanocellulose aerogels

In this study, carbon dots (CDs) and titanate nanofibers (TNs) were mixed with TEMPO-oxidized nanocellulose (TOCNC) to prepare fluorescent nanocellulose aerogels (FNAs) by a Schiff base reaction. The resulting FNA can detect the adsorption of Cr6+ through the fluorescence quenching in CDs and promote the removal of Cr6+ through the synergistic effect of CDs in photocatalysis. The optimized FNA has a maximum adsorption capacity of 543.38 mg/g, higher than most reported Cr6+ adsorbents. This excellent performance is due to the porous structure of the aerogel, which gives it a high specific surface area of 20.53 m2/g and provides abundant adsorption sites. Simultaneously, CDs can enhance the amino-induced Cr6+ adsorption, improve the photocatalytic performance of TNs, and expose more adsorption sites through electrostatic adsorption of amino-induced reduction products (Cr3+). This study explores the preparation of visualized nanosorbents with enhanced photocatalytic removal of Cr6+ and provides a new direction for nanoscale photocatalysts.

Effects of Phenolics on the Physicochemical and Structural Properties of Collagen Hydrogel

In the current era, the treatment of collagen hydrogels with natural phenolics for the improvement in physicochemical properties has been the subject of considerable attention. The present research aimed to fabricate collagen hydrogels cross-linked with gallic acid (GA) and ellagic acid (EA) at different concentrations depending on the collagen dry weight. The structural, enzymatic, thermal, morphological, and physical properties of the native collagen hydrogels were compared with those of the GA/EA cross-linked hydrogels. XRD and FTIR spectroscopic analyses confirmed the structural stability and reliability of the collagen after treatment with either GA or EA. The cross-linking also significantly contributed to the improvement in the storage modulus, of 435 Pa for 100% GA cross-linked hydrogels. The thermal stability was improved, as the highest residual weight of 43.8% was obtained for the hydrogels cross-linked with 50% GA in comparison with all the other hydrogels. The hydrogels immersed in 30%, 50%, and 100% concentrations of GA also showed improved swelling behavior and porosity, and the highest resistance to type 1 collagenase (76.56%), was obtained for 50% GA cross-linked collagen hydrogels. Moreover, GA 100% and EA 100% obtained the highest denaturation temperatures (Td) of 74.96 °C and 75.78 °C, respectively. In addition, SEM analysis was also carried out to check the surface morphology of the pristine collagen hydrogels and the cross-linked collagen hydrogels. The result showed that the hydrogels cross-linked with GA/EA were denser and more compact. However, the improved physicochemical properties were probably due to the formation of hydrogen bonds between the phenolic hydroxyl groups of GA and EA and the nitrogen atoms of the collagen backbone. The presence of inter- and intramolecular cross-links between collagen and GA or EA components and an increased density of intermolecular bonds suggest potential hydrogen bonding or hydrophobic interactions. Overall, the present study paves the way for further investigations in the field by providing valuable insights into the GA/EA interaction with collagen molecules.

An antibacterial and healing-promoting collagen fibril constructed by the simultaneous strategy of fibril reconstitution and ε-polylysine anchoring for infected wound repair

The development of antibacterial dressings has attracted much attention to address the disordered wound healing caused by bacterial infection. Constructing dressings that have desirable antibacterial activity and could promote wound healing is important for infected wound repair. Inspired by the role of the key regulator collagen fibrils with D-periodic functional domains in the physiological wound healing process, we developed an antibacterial and wound healing-promoting collagen fibril with a structure highly similar to natural collagen in ECM and inherent antibacterial activity by the simultaneous strategy of fibril reconstitution and the antibacterial agent ε-polylysine (ε-PL) anchoring. Accompanied by the fibrillogenesis of collagen molecules, the anchorage of ε-PL into collagen fibrils was actualized through the formation of the covalent bond catalyzed by transglutaminase (TGase) between ε-PL and collagen. The collagen fibril possessed natural D-periodicity and achieved 20% ε-PL graft yield by co-assembling collagen/ε-PL mediated by 25 U g-1 TGase, which showed a satisfactory proliferation of L929 fibroblasts and sustained inhibition rates above 90% against E. coli and S. aureus. The rat S. aureus-infected dermal wound model further demonstrated that the reconstituted antibacterial collagen fibril visibly promoted re-epithelialization, new collagen deposition, and angiogenesis by down-regulating the inflammatory-relative gene IL-6 and up-regulating the relative activity factor expression of CD31, achieving accelerated infected wound healing with 61.89% ± 3.96% wound closure on postoperative day 7 and full closure on day 14.

Rechargeable Multifunctional Anti-Bacterial AEMs for Electrodialysis: Improving Anti-Biological Performance via Synergistic Antibacterial Mechanism

Constructing a functional layer on the surface of commercial membrane (as a substrate) to inhibit the formation of biofilms is an efficient strategy to prepare an antibacterial anion exchange membrane (AEM). Herein, a rechargeable multifunctional anti-biological system is reported by utilizing the mussel-inspired L-dopa connection function on commercial AEMs. Cobalt nanoparticles (Co NPs) and N-chloramine compounds are deposited on the AEM surface by a two-step modification procedure. The anti-biofouling abilities of the membranes are qualitatively and quantitatively analyzed by adopting common Gram-negative (E. coli) and Gram-positive (S. aureus & Bacillus) bacteria as model biofouling organisms. The optimized membrane exhibits a high stability concerning the NaCl solution separation performance within 240 min. Meantime, the mechanism of the anti-adhesion is un-veiled at an atomic level and molecular dynamics (MD) simulation are conducted to measure the interaction, adsorption energy and average loading by using lipopolysaccharide (LPS) of E. coli. In view of the superior performance of antibacterial surfaces, it is believed that this work could provide a valuable guideline for the design of membrane materials with resistance to biological contamination.

Effects of ultrasound treatment on the morphological characteristics, structures and emulsifying properties of genipin cross-linked myofibrillar protein

Genipin is a natural crosslinker that improves the functional properties of proteins by modifying its structures. This study aimed to investigate the effects of sonication on the emulsifying properties of different genipin concentration-induced myofibrillar protein (MP) cross-linking. The structural characteristics, solubility, emulsifying properties, and rheological properties of genipin-induced MP crosslinking without sonication (Native), sonication before crosslinking (UMP), and sonication after crosslinking (MPU) treatments were determined, and the interaction between genipin and MP were estimated by molecular docking. The results demonstrated that hydrogen bond might be the main forces for genipin binding to the MP, and 0.5 μM/mg genipin was a desirable concentration for protein cross-linking to improve MP emulsion stability. Ultrasound treatment before and after crosslinking were better than Native treatment to improve the emulsifying stability index (ESI) of MP. Among the three treatment groups at the 0.5 μM/mg genipin treatment, the MPU treatment group showed the smallest size, most uniform protein particle distribution, and the highest ESI (59.89%). Additionally, the highest α-helix (41.96%) in the MPU + G5 group may be conducive to the formation of a stable and multilayer oil-water interface. Furthermore, the free groups, solubility, and protein exposure extent of the MPU groups were higher than those of UMP and Native groups. Therefore, this work suggests that the treatment of cross-linking followed by ultrasound (MPU) could be a desirable approach for improving the emulsifying stability of MP.

Biodegradable wound dressing-based collagen/hyaluronic acid loaded antibacterial agents for wound healing application

Three biodegradable wound dressing based on binary Collagen (COL), Hyaluronic acid (HA) crosslinked loaded with silver nanoparticles (AgNPs), Gentamicin (GENT) and AgNPs/GENT successfully prepared using freeze drying technique. Chemical evaluations for synthesized membranes were carried out using FTIR- ATR. While physical properties were evaluated through swelling and degradation percent. Antibacterial activity was evaluated against G+, G-, yeast and fungi. Finally, cytotoxicity and wound healing evaluations were carried out against skin fibroblast normal cell line, while anti-inflammatory evaluated using RAW 264.7 macrophage cell line. The three produced membrane showed physically interaction between polymer network and the loaded antibiotic. Swelling properties showed superior results for three membranes. Degradability of prepared sheets was rapidly no more than three days. Toxicity evaluations and anti-inflammatory showed superior results for all examined samples except mixed with AgNPs and Gentamicin (GENT). Antibacterial activity showed resistance to G+, G- and yeast. All prepared sheet showed safe towards cell except COL/HA/AgNPs/GENT. Wound healing studied showed efficient of both COL/HA/AgNPs and COL/HA/GENT compared to blank and mixed membrane COL/HA/AgNPs/GENT. The obtained results recommended COL/HA loaded individually either AgNPs or Gentamicin (GENT) as antibacterial and wound healing sheet rather than mixed prepared membrane.

Adipose-Derived Stem Cells in Reinforced Collagen Gel: A Comparison between Two Approaches to Differentiation towards Smooth Muscle Cells

Scaffolds made of degradable polymers, such as collagen, polyesters or polysaccharides, are promising matrices for fabrication of bioartificial vascular grafts or patches. In this study, collagen isolated from porcine skin was processed into a gel, reinforced with collagen particles and with incorporated adipose tissue-derived stem cells (ASCs). The cell-material constructs were then incubated in a DMEM medium with 2% of FS (DMEM_part), with added polyvinylalcohol nanofibers (PVA_part sample), and for ASCs differentiation towards smooth muscle cells (SMCs), the medium was supplemented either with human platelet lysate released from PVA nanofibers (PVA_PL_part) or with TGF-β1 + BMP-4 (TGF + BMP_part). The constructs were further endothelialised with human umbilical vein endothelial cells (ECs). The immunofluorescence staining of alpha-actin and calponin, and von Willebrand factor, was performed. The proteins involved in cell differentiation, the extracellular matrix (ECM) proteins, and ECM remodelling proteins were evaluated by mass spectrometry on day 12 of culture. Mechanical properties of the gels with ASCs were measured via an unconfined compression test on day 5. Gels evinced limited planar shrinkage, but it was higher in endothelialised TGF + BMP_part gel. Both PVA_PL_part samples and TGF + BMP_part samples supported ASC growth and differentiation towards SMCs, but only PVA_PL_part supported homogeneous endothelialisation. Young modulus of elasticity increased in all samples compared to day 0, and PVA_PL_part gel evinced a slightly higher ratio of elastic energy. The results suggest that PVA_PL_part collagen construct has the highest potential to remodel into a functional vascular wall.

Computer chip-inspired design of nanocellulose/carbon dots hydrogel as superior intensifier of nano-sized photocatalyst for effective Cr(VI) removal

Hydrogel, a common carrier of photocatalyst that suffers from compromised catalytic efficiency, is still far from practical application. Herein, based on "computer chip-inspired design", a novel nanocellulose/carbon dots hydrogel (NCH) was fabricated as superior intensifier instead of common carrier of sodium titanate nanofibre (STN), where carbon dots (CDs) enhanced amino group-induced adsorption for Cr(VI), promoted photocatalytic properties of STN via transferring the photogenerated electron-hole pairs and improved amino group-induced desorption for reduced product (Cr(III)) via electrostatic repulsion, showing an efficiency of 1 + 1 > 2. Adsorption and photocatalysis experiments demonstrated superior removal performance of the NCH incorporating STN, as shown by theoretical maximum adsorption capacity of 425.74 mg/g and kinetic constant of 0.0374 min^-1 in the photocatalytic process, which was nearly 6.6 and 7.3 times of STN. A series of experiments was conducted to confirm the novel mechanism of CDs-enhanced adsorption-photocatalysis-desorption synergy. This work not only provides new insights into the fabrication of a superior intensifier for nanosized photocatalyst, but also proposes one new mechanism of CDs-enhanced adsorption-photocatalysis-desorption synergy, which is helpful for designing and optimizing nanosized photocatalyst.