Enhanced blood coagulation and antibacterial activities of carboxymethyl-kappa-carrageenan-containing nanofibers

Surface coating nanoarchitectonics for optimizing cytocompatibility and antimicrobial activity: The impact of hyaluronic acid positioning as the outermost layer

Polyelectrolyte multilayers (PEMs) based on hyaluronic acid (HA) and poly (diallyldimethylammonium chloride) (PDDA) were deposited on oxidized polystyrene (PSox) via the layer-by-layer (LbL) method. The X-ray photoelectron spectroscopy (XPS) confirmed the PEM deposition on PSox, and atomic force microscopy (AFM) indicated that the surface roughness of PS also increased after PEM deposition. The PEMs significantly enhanced PS wettability, reducing the contact angle from 73° on PS to 24° on PDDA-terminated (PDDA/HA)2.5 PEM (2.5 bilayers, 5 layers) and 36° on HA-terminated (PDDA/HA)3 PEM (3 bilayers, 6 layers). The HA-terminated (PDDA/HA)₃ PEM demonstrated antimicrobial activity. Compared to uncoated PS surfaces, this PEM reduced the surface coverage of viable P. aeruginosa cells from 36.5 % to 3.7 % and S. aureus cells from 13.3 % to 2.5 % on uncoated PS surfaces. The antimicrobial assay following the JIS Z 2801-2010 standard demonstrated that the PDDA-terminated (PDDA/HA)2.5 PEM inhibited S. aureus growth by 48 %, compared to 32 % inhibition by the HA-terminated (PDDA/HA)3 PEM relative to the uncoated and non-oxidized polystyrene (PS) surface (control). HA-terminated PEM demonstrated lesser antimicrobial activity than PDDA-terminated PEM. However, both PEMs were cytocompatible against erythrocytes and human adipose-derived stem cells (ADSCs), indicating their potential for biomedical applications, particularly prosthetic coatings.

Ultrathin Nanofibers Ameliorate Commercial Gauze for Rapid Hemorrhage Control Via Improved Clotting Kinetics and Rbc Modulation

Timely control of bleeding is crucial to reduce mortality in traumatic injuries, highlighting the urgent need for biomaterials with anti-hemorrhagic properties. Polycaprolactone (PCL) is commonly used for producing nanofibers in the range of 100-200 nm. However, creating ultrafine PCL nanofibers with diameters below 100 nm remains a challenge, limiting its potential as a hemostatic bandage. In this study, various ratios of low molecular weight PCL are blended with reduced keratin to modulate the solution shear-thinning behavior. The optimized blend enables the production of ultrafine nanofibers with a mean diameter of ≈50 nm, providing a high surface area. The surfaces of these nanofibers demonstrate excellent platelet adhesion, aggregation, and activation. Additionally, they are cytocompatible with fibroblasts. The ultrathin nanofibers are electrospun on gauze to create a hemostatic product that shows favorable plasma and blood clotting kinetics. An in vivo study demonstrates reduced clotting times for nanofiber-based products compared to plain gauze. Mechanistically, the RBCs on the nanofiber composites attain a polyhedral shape reducing the space between them and creating a compact seal to prevent fresh blood from oozing out. The intrinsic hemostatic properties of keratin, combined with reduced fiber diameter and the hydrophilic nature of gauge make this a promising hemostatic bandage.

Tanfloc-Modified Titanium Surfaces: Optimizing Blood Coagulant Activity and Stem Cell Compatibility

This study explores the synergistic effects of combining titania nanotubes (TiNTs) with the biopolymer Tanfloc (TAN) to enhance the surface properties of TiNTs for biomedical applications. We investigated the interactions of blood components and human adipose-derived stem cells (ADSCs) with TiNT surfaces covalently functionalized with Tanfloc (TAN), an aminolyzed polyphenolic tannin derivative. The functionalized surfaces (TiNT-TAN) have great potential to control protein adsorption and platelet adhesion and activation. Fluorescence and scanning electron microscopy (SEM) were used to analyze platelet adherence and activation. The amphoteric nature and multiple functional groups on TAN can control blood protein adsorption, platelet adhesion, and activation. Further, the modified surface supports adipose-derived stem cell (ADSC) viability, attachment, and growth without any cytotoxic effect. The TAN conjugation significantly (****p < 0.0001) increased the proliferation rate of ADSCs compared to the TiNT surfaces.

Anti-Bacterial Properties and Hemocompatibility of Alkali Treated Nano-Structured Micro-Porous Titanium Surfaces

Titanium and its alloys have been the material of choice for orthopedic implants due to their excellent physical properties as well as biocompatibility. However, titanium is not able to integrate with bone due to the mismatch of mechanical properties. Additionally, bone has a micro-nano hierarchy, which is absent on titanium's surface. A potential solution to the former is to make the surfaces porous to bring the mechanical properties closer to that of the bone, and a solution for the latter is to fabricate nanostructures. In this study, micro-porous titanium surfaces were hydrothermally treated using an alkali medium to fabricate nanostructures on the existing micro-porosity of the surface. The surface properties were evaluated using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and nanoindentation. The anti-bacterial properties of the surfaces were evaluated against Gram-positive and Gram-negative bacteria using fluorescence microscopy and scanning electron microscopy. Blood clotting is shown to improve the surface-to-bone integration; hence, whole blood clotting and platelet adhesion and activation were evaluated using a whole blood clotting assay, fluorescence microscopy, and scanning electron microscopy. The results indicate that nanostructured micro-porous titanium surfaces display significantly enhanced anti-bacterial properties as well as equivalent blood clotting characteristics compared to non-porous titanium surfaces.

Multifunctional nanofibrous scaffolds for enhancing full-thickness wound healing loaded with Bletilla striata polysaccharides

The considerable challenge of wound healing remains. In this study, we fabricated a novel multifunctional core-shell nanofibrous scaffold named EGF@BSP-CeO2/PLGA (EBCP), which is composed of Bletilla striata polysaccharide (BSP), Ceria nanozyme (CeO2) and epidermal growth factor (EGF) as the core and poly(lactic-co-glycolic acid) (PLGA) as the shell via an emulsion electrospinning technique. An increase in the BSP content within the scaffolds corresponded to improved wound healing performance. These scaffolds exhibited increased hydrophilicity and porosity and improved mechanical properties and anti-UV properties. EBCP exhibited sustained release, and the degradation rate was <4 % in PBS for 30 days. The superior biocompatibility was confirmed by the MTT assay, hemolysis, and H&E staining. In addition, the in vitro results revealed that, compared with the other groups, the EBCP group presented excellent antioxidant and antibacterial effects. More importantly, the in vivo results indicated that the wound closure rate of the EBCP group reached 94.0 % on day 10 in the presence of H2O2. The results demonstrated that EBCP could comprehensively regulate the wound microenvironment, possess hemostatic abilities, and significantly promote wound healing. In conclusion, the EBCP is promising for facilitating the treatment of infected wounds and represents a potential material for clinical applications.

Tranexamic acid loaded in a physically crosslinked trilaminate dressing for local hemorrhage control: Preparation, characterization, and in-vivo assessment using two different animal models

This work aimed at formulating a trilaminate dressing loaded with tranexamic acid. It consisted of a layer of 3 % sodium hyaluronate to initiate hemostasis. It was followed by a mixed porous layer of 5 % polyvinyl alcohol and 2 % kappa-carrageenan. This layer acted as a drug reservoir that controlled its release. The third layer was 5 % ethyl cellulose backing layer for unidirectional release of tranexamic acid towards the wound. The 3 layers were physically crosslinked by hydrogen bonding as confirmed by Infrared spectroscopy. Swelling and release studies were performed, and results proposed that increasing number of layers decreased swelling properties and sustained release of tranexamic acid for 8 h. In vitro blood coagulation study was performed using human blood and showed that the dressing significantly decreased coagulation time by 70.5 % compared to the negative control. In vivo hemostatic activity was evaluated using tail amputation model in Wistar rats. Statistical analysis showed the dressing could stop bleeding in a punctured artery of the rat tail faster than the negative control by 59 %. Cranial bone defect model in New Zealand rabbits was performed to check for bone hemostasis and showed significant decrease in the hemostatic time by 80 % compared to the control.

Fabrication and characterization of new levan@CBD biocomposite sponges as potential materials in natural, non-toxic wound dressing applications

Wound healing is a complex process; therefore, new dressings are frequently required to facilitate it. In this study, porous bacterial levan-based sponges containing cannabis oil (Lev@CBDs) were prepared and fully characterized. The sponges exhibited a suitable swelling ratio, proper water vapor transmission rate, sufficient thermal stability, desired mechanical properties, and good antioxidant and anti-inflammatory properties. The obtained Lev@CBD materials were evaluated in terms of their interaction with proteins, human serum albumin and fibrinogen, of which fibrinogen revealed the highest binding effect. Moreover, the obtained biomaterials exhibited antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa, as well as being non-hemolytic material as indicated by hemolysis tests. Furthermore, the sponges were non-toxic and compatible with L929 mouse fibroblasts and HDF cells. Most significantly, the levan sponge with the highest content of cannabis oil, in comparison to others, retained its non-hemolytic, anti-inflammatory, and antimicrobial properties after prolonged storage in a climate chamber at a constant temperature and relative humidity. The designed sponges have conclusively proven their beneficial physicochemical properties and, at the preliminary stage, biocompatibility as well, and therefore can be considered a promising material for wound dressings in future in vivo applications.

Biomimetic alginate-based electroconductive nanofibrous scaffolds for bone tissue engineering application

Novel electrically conductive nanofibrous scaffolds were designed and fabricated through the grafting of aniline monomer onto a phenylamine-functionalized alginate (Alg-NH2) followed by electrospinning with poly(vinyl alcohol) (PVA). Performance of the prepared scaffolds in bone tissue engineering (TE) were studied in terms of physicochemical (e.g., conductivity, electroactivity, morphology, hydrophilicity, water uptake, and mechanical) and biological (cytocompatibility, in vitro biodegradability, cells attachment and proliferation, hemolysis, and protein adsorption) properties. The contact angles of the scaffolds with water drop were obtained about 50 to 60° that confirmed their excellent hydrophilicities for TE applications. Three dimensional (3D), inter-connected and uniform porous structures of the scaffolds without any bead formation was confirmed by scanning electron microscopy (SEM). Electrical conductivities of the fabricated scaffolds were obtained as 1.5 × 10-3 and 2.7 × 10-3 Scm-1. MTT assay results revealed that the scaffolds have acceptable cytocompatibilities and can enhance the cells adhesion as well as proliferation, which approved their potential for TE applications. Hemolysis rate of the developed scaffolds were quantified <2 % even at high concentration (200 μgmL-1) of samples that approved their hemocompatibilities. The scaffolds were also exhibited acceptable protein adsorption capacities (65 and 68 μgmg-1). As numerous experimental results, the developed scaffolds have acceptable potential for bone TE.

Multifunctional xyloglucan-containing electrospun nanofibrous dressings for accelerating infected wound healing

Preventing wound infection is a major challenge in biomedicine. Conventional wound dressings often have poor moisturizing and antimicrobial properties unfavorable for wound healing. In this study, we prepared a multifunctional electrospun nanofiber dressing (PCQX-M) containing xyloglucan, quaternized chitosan, Polyvinyl alcohol, and collagen. By applying the concept of wet healing, xyloglucan and quaternized chitosan polysaccharides with excellent water solubility were employed to improve the absorption and moisturizing properties and maintain a moist microenvironment for the wound healing process. PCQX-M demonstrated high mechanical, thermodynamic, and biocompatible properties, providing suitable healing conditions for wounds. In addition, PCQX-M showed exceptional antibacterial properties and a potential inhibitory effect on the growth of microorganisms in infected wounds. More intriguingly, the restorative healing effect was investigated on a mouse model of whole skin injury infected with Staphylococcus aureus. Wound healing, collagen deposition, and immunofluorescence results showed that PCQX-M significantly promoted cell proliferation and angiogenesis at the injury site and facilitated the healing of the infected wound. Our study suggests that PCQX-M has excellent potential for clinical application in infected wound healing.

Polysaccharide-based (kappa carrageenan/carboxymethyl chitosan) nanofibrous membrane loaded with antifibrinolytic drug for rapid hemostasis- in vitro and in vivo evaluation

This work aimed to establish a novel membrane consisting of hemostatic polysaccharides, kappa-carrageenan (KC), and carboxymethyl chitosan (CMC) in tandem with polyvinyl alcohol that spun together as a matrix and loaded with tranexamic acid (TXA) as antifibrinolytic agent for further coagulation effect during and after oral surgeries. The electrospinning of KC was done for the first time and in comparison of CMC has better hemostatic efficacy. The effect of the hemostat was investigated by its surface morphology (SEM), FTIR/ATR analysis, swelling behavior in both PBS and blood, hydrophilicity, porosity, mechanical properties, and cumulative release rate. The effect of materials and the drug concentration ratio were considered. The effect of acetic acid percent in aqueous solutions of CMC/PVA and KC/PVA on morphology was investigated. The cell culture assay showed that all membranes interacted well (98 %) with fibroblast cells attached and grown on the fabricated substrate. Furthermore, the membranes are evaluated by clotting time, whole blood clotting, hemocompatibility, and platelet and RBC adhesion tests. Also, the hemostatic performance of the membrane was analyzed in vivo, using the tail and liver bleeding model in rats. Therefore, TXA loading into CMC and KC dressing could be an attractive hemostatic system for various clinical applications.

Decellularized Liver Nanofibers Enhance and Stabilize the Long-Term Functions of Primary Human Hepatocytes In Vitro

Owing to significant differences across species in liver functions, in vitro human liver models are used for screening the metabolism and toxicity of compounds, modeling diseases, and cell-based therapies. However, the extracellular matrix (ECM) scaffold used for such models often does not mimic either the complex composition or the nanofibrous topography of native liver ECM. Thus, here novel methods are developed to electrospin decellularized porcine liver ECM (PLECM) and collagen I into nano- and microfibers (≈200-1000 nm) without synthetic polymer blends. Primary human hepatocytes (PHHs) on nanofibers in monoculture or in coculture with nonparenchymal cells (3T3-J2 embryonic fibroblasts or primary human liver endothelial cells) display higher albumin secretion, urea synthesis, and cytochrome-P450 1A2, 2A6, 2C9, and 3A4 enzyme activities than on conventionally adsorbed ECM controls. PHH functions are highest on the collagen/PLECM blended nanofibers (up to 34-fold higher CYP3A4 activity relative to adsorbed ECM) for nearly 7 weeks in the presence of the fibroblasts. In conclusion, it is shown for the first time that ECM composition and topography synergize to enhance and stabilize PHH functions for several weeks in vitro. The nanofiber platform can prove useful for the above applications and to elucidate cell-ECM interactions in the human liver.

Biodegradable Block Poly(ester amine)s with Pendant Hydroxyl Groups for Biomedical Applications

The article presents the results of the synthesis and characteristics of the amphiphilic block terpolymers, built of a hydrophilic polyesteramine block, and hydrophobic blocks made of lactidyl and glycolidyl units. These terpolymers were obtained during the copolymerization of L-lactide with glycolide carried out in the presence of previously produced macroinitiators with protected amine and hydroxyl groups. The terpolymers were prepared to produce a biodegradable and biocompatible material containing active hydroxyl and/or amino groups, with strong antibacterial properties and high surface wettability by water. The control of the reaction course, the process of deprotection of functional groups, and the properties of the obtained terpolymers were made based on 1H NMR, FTIR, GPC, and DSC tests. Terpolymers differed in the content of amino and hydroxyl groups. The values of average molecular mass oscillated from about 5000 g/mol to less than 15,000 g/mol. Depending on the length of the hydrophilic block and its composition, the value of the contact angle ranged from 50° to 20°. The terpolymers containing amino groups, capable of forming strong intra- and intermolecular bonds, show a high degree of crystallinity. The endotherm responsible for the melting of L-lactidyl semicrystalline regions appeared in the range from about 90 °C to close to 170 °C, with a heat of fusion from about 15 J/mol to over 60 J/mol.

Recent advances in exploiting carrageenans as a versatile functional material for promising biomedical applications

Carrageenans are a group of biopolymers widely found in red seaweeds. Commercial carrageenans have been traditionally used as emulsifiers, stabilizers, and thickening and gelling agents in food products. Carrageenans are regarded as bioactive polysaccharides with disease-modifying and microbiota-modulating activities. Novel biomedical applications of carrageenans as biocompatible functional materials for fabricating hydrogels and nanostructures, including carbon dots, nanoparticles, and nanofibers, have been increasingly exploited. In this review, we describe the unique structural characteristics of carrageenans and their functional relevance. We summarize salient physicochemical features, including thixotropic and shear-thinning properties, of carrageenans. Recent results from clinical trials in which carrageenans were applied as both antiviral and antitumor agents and functional materials are discussed. We also highlight the most recent advances in the development of carrageenan-based targeted drug delivery systems with various pharmaceutical formulations. Promising applications of carrageenans as a bioink material for 3D printing in tissue engineering and regenerative medicine are systematically evaluated. We envisage some key hurdles and challenges in the commercialization of carrageenans as a versatile material for clinical practice. This comprehensive review of the intimate relationships among the structural features, unique rheological properties, and biofunctionality of carrageenans will provide novel insights into their biomedicine application potential.

Implantable biomedical materials for treatment of bone infection

The treatment of bone infections has always been difficult. The emergence of drug-resistant bacteria has led to a steady decline in the effectiveness of antibiotics. It is also especially important to fight bacterial infections while repairing bone defects and cleaning up dead bacteria to prevent biofilm formation. The development of biomedical materials has provided us with a research direction to address this issue. We aimed to review the current literature, and have summarized multifunctional antimicrobial materials that have long-lasting antimicrobial capabilities that promote angiogenesis, bone production, or "killing and releasing." This review provides a comprehensive summary of the use of biomedical materials in the treatment of bone infections and a reference thereof, as well as encouragement to perform further research in this field.

Proactive Hemocompatibility Platform Initiated by PAMAM Dendrimer Adapting to Key Components in Coagulation System

Surface modification manipulates the application performance of materials, and thrombosis caused by material contact is a key risk factor of biomaterials failure in blood-contacting/implanting devices. Therefore, building a safe and effective hemocompatibility platform is still urgent. Owing to the unique properties of polyamidoamine (PAMAM) dendrimers, in this study, modified surfaces with varying dendrimer densities were interacted with elements maintaining blood homeostasis. These included the plasma proteins bovine serum albumin and fibrinogen, cells in blood (platelets and erythrocyte), as well as endothelial cells (ECs), and the objective was to evaluate the blood compatibility of the chosen materials. Whole blood test and dynamic blood circulation experiment by the arteriovenous shunt mode of rabbit were also conducted, based on the complexity and fluidity of blood. The PAMAM-modified substrates, particularly that with a high density of PAMAM (N1.0), adsorbed proteins with lessened fibrinogen adsorption, reduced platelet activation and aggregation, and suppressed clotting in whole blood and dynamic blood testing. Furthermore, the designed PAMAM dendrimer densities were safe and showed negligible erythrocyte lysis. Concurrently, PAMAM modification could maintain EC growth and did not trigger the release of procoagulant factors. These results suggest that the PAMAM-modified materials are compatible for maintaining blood homeostasis. Thus, PAMAM dendrimers can work as excellent surface modifiers for constructing a hemocompatibility platform and even a primer layer for desired functional design, promoting the service performance of blood-contacting devices.

Iota-carrageenan/xyloglucan/serine powders loaded with tranexamic acid for simultaneously hemostatic, antibacterial, and antioxidant performance

This study sought to prepare powder hemostats based on iota-carrageenan (ιC), xyloglucan (XYL), l-serine (SER), and tranexamic acid (TA). The powder form was chosen because it enables the hemostat to be used in wounds of any shape and depth. The powder hemostats showed irregular shapes and specific surface areas ranging from 34 to 46 m²/g. Increasing TA amount decreases the specific surface area, bulk density, water and blood absorption, and the antibacterial activities of the powder hemostats, but not the water retention ability. Conversely, in vitro biodegradation was positively impacted by increasing the TA content in the powder hemostats. In both the in vitro and in vivo tests, powder hemostats showed reduced bleeding time, significant adhesion of red blood cells, great hemocompatibility, moderate antioxidant activity, and high biocompatibility. These findings shed new light on designing powder hemostats with intrinsic antibacterial and antioxidant activity and excellent hemostatic performance.

Marine Biopolymers as Bioactive Functional Ingredients of Electrospun Nanofibrous Scaffolds for Biomedical Applications

Marine biopolymers, abundantly present in seaweeds and marine animals, feature diverse structures and functionalities, and possess a wide range of beneficial biological activities. Characterized by high biocompatibility and biodegradability, as well as unique physicochemical properties, marine biopolymers are attracting a constantly increasing interest for the development of advanced systems for applications in the biomedical field. The development of electrospinning offers an innovative technological platform for the production of nonwoven nanofibrous scaffolds with increased surface area, high encapsulation efficacy, intrinsic interconnectivity, and structural analogy to the natural extracellular matrix. Marine biopolymer-based electrospun nanofibrous scaffolds with multifunctional characteristics and tunable mechanical properties now attract significant attention for biomedical applications, such as tissue engineering, drug delivery, and wound healing. The present review, covering the literature up to the end of 2021, highlights the advancements in the development of marine biopolymer-based electrospun nanofibers for their utilization as cell proliferation scaffolds, bioadhesives, release modifiers, and wound dressings.

Expanding the Repertoire of Electrospinning: New and Emerging Biopolymers, Techniques, and Applications

Electrospinning has emerged as a versatile and accessible technology for fabricating polymer fibers, particularly for biological applications. Natural polymers or biopolymers (including synthetically derivatized natural polymers) represent a promising alternative to synthetic polymers, as materials for electrospinning. Many biopolymers are obtained from abundant renewable sources, are biodegradable, and possess inherent biological functions. This review surveys recent literature reporting new fibers produced from emerging biopolymers, highlighting recent developments in the use of sulfated polymers (including carrageenans and glycosaminoglycans), tannin derivatives (condensed and hydrolyzed tannins, tannic acid), modified collagen, and extracellular matrix extracts. The proposed advantages of these biopolymer-based fibers, focusing on their biomedical applications, are also discussed to highlight the use of new and emerging biopolymers (or new modifications to well-established ones) to enhance or achieve new properties for electrospun fiber materials.

Antithrombogenic properties of Tulbaghia violacea aqueous leaf extracts: assessment of platelet activation and whole blood clotting kinetics

Tulbaghia violacea plant extracts have been investigated for their potential therapeutic effects in the management of various ailments, among which are cardiovascular diseases, due to the wide range of phytocompounds that the plant possesses. One of the major challenges in clinical practice is the inability to control platelet activation and clotting caused by cardiovascular disease interventions. Current treatment methods to inhibit platelet aggregation and thromboxane formation have been associated with major undesirable side effects. This has led to increased research studies on the development of newer and more effective antiplatelet agents. In particular, there has been a growing interest on the potential antiplatelet activity of plant-derived extracts. Hence this study methodically evaluates the anticlotting and antiplatelet properties of T. violacea aqueous leaf extracts. The platelet activity of the plant extracts was assessed using total platelet adhesion, platelet morphology and whole blood clotting kinetics. The 0.1 mg ml-1 T. violacea extract mixed with blood plasma demonstrated the lowest platelet adhesion and activation and also reduced whole blood clotting kinetics. There was a reduction of about 70% in platelet adhesion for the 0.1 mg ml-1 treatment compared to the control in the first 15 min which was supported by morphological characterization under SEM. These observations suggest that T. violacea may be a potential antiplatelet therapeutic agent to inhibit the initial step of platelet adhesion and ultimately reduce the incidence of cardiovascular events.