Virgin olive oil blended polyurethane micro/nanofibers ornamented with copper oxide nanocrystals for biomedical applications

Polymeric biomaterials for wound healing

Skin indicates a person's state of health and is so important that it influences a person's emotional and psychological behavior. In this context, the effective treatment of wounds is a major concern, since several conventional wound healing materials have not been able to provide adequate healing, often leading to scar formation. Hence, the development of innovative biomaterials for wound healing is essential. Natural and synthetic polymers are used extensively for wound dressings and scaffold production. Both natural and synthetic polymers have beneficial properties and limitations, so they are often used in combination to overcome overcome their individual limitations. The use of different polymers in the production of biomaterials has proven to be a promising alternative for the treatment of wounds, as their capacity to accelerate the healing process has been demonstrated in many studies. Thus, this work focuses on describing several currently commercially available solutions used for the management of skin wounds, such as polymeric biomaterials for skin substitutes. New directions, strategies, and innovative technologies for the design of polymeric biomaterials are also addressed, providing solutions for deep burns, personalized care and faster healing.

Effect of composite biodegradable biomaterials on wound healing in diabetes

The repair of diabetic wounds has always been a job that doctors could not tackle quickly in plastic surgery. To solve this problem, it has become an important direction to use biocompatible biodegradable biomaterials as scaffolds or dressing loaded with a variety of active substances or cells, to construct a wound repair system integrating materials, cells, and growth factors. In terms of wound healing, composite biodegradable biomaterials show strong biocompatibility and the ability to promote wound healing. This review describes the multifaceted integration of biomaterials with drugs, stem cells, and active agents. In wounds, stem cells and their secreted exosomes regulate immune responses and inflammation. They promote angiogenesis, accelerate skin cell proliferation and re-epithelialization, and regulate collagen remodeling that inhibits scar hyperplasia. In the process of continuous combination with new materials, a series of materials that can be well matched with active ingredients such as cells or drugs are derived for precise delivery and controlled release of drugs. The ultimate goal of material development is clinical transformation. At present, the types of materials for clinical application are still relatively single, and the bottleneck is that the functions of emerging materials have not yet reached a stable and effective degree. The development of biomaterials that can be further translated into clinical practice will become the focus of research.

Advanced Face Mask Filters Based on PCL Electrospun Meshes Dopped with Antimicrobial MgO and CuO Nanoparticles

The pandemic situation caused by coronavirus clearly demonstrated the need for alternatives able to protect the respiratory tract and inactivate the infectious agents. Based on this, antibacterial face-mask filters of polycaprolactone (PCL) dopped with magnesium oxide (MgO) and copper oxide (CuO) nanoparticles (NPs) were produced using an electrospinning technique. A morphological analysis of electrospun meshes evaluated the success of nanoparticles’ incorporation as well as the average fibers’ diameters (481 ± 272 nm). The performance of electrospun nanofibers was also assessed in terms of tensile strength (0.88 ± 0.25 MPa), water vapor permeability (11,178.66 ± 35.78 g·m⁻²·day⁻¹), stability under wet conditions and antibacterial activity according to the standard guidelines. The filters showed structural stability up to 2 h of washing and improved antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) for optimized concentrations of MgO and CuO NPs. Overall, electrospun meshes with antibacterial activity were successfully developed for advanced filtering applications.

Antibacterial adhesive self-healing hydrogels to promote diabetic wound healing

The development of compressible, stretchable and self-healing hydrogel dressings with good adhesive, antibacterial and angiogenesis properties is needed to promote the regeneration of diabetic wounds in clinical applications. In this work, a series of self-healing, adhesive and antibacterial hydrogels based on gelatin methacrylate (GelMA), adenine acrylate (AA), and CuCl₂ were designed through covalent bonding, coordination complexation of Cu²⁺ and carboxyl groups and hydrogen bonding to promote diabetic wound healing. These hydrogels exhibit efficient self-healing properties, remarkable fatigue resistance, and good adhesive properties due to the hydrogen bond and the metal-ligand coordination provided by the Cu²⁺ and the carboxyl group. The GelMA/AA/Cu1.0 hydrogel (containing 1.0 mg/mL Cu²⁺) with well-balanced biocompatibility and antibacterial properties exhibited efficient hemostatic performance in a mouse liver trauma model and significantly promoted the healing process in a full-thickness skin diabetic wound model. The immunohistochemistry results showed that the GelMA/AA/Cu1.0 hydrogel can promote regular epithelialization and collagen deposition when compared to the Tegaderm^TM Film, GelMA hydrogel, and GelMA/AA/Cu0 hydrogel. The immunofluorescence results confirmed that the GelMA/AA/Cu1.0 hydrogel can reduce the expression of proinflammatory factors and promote angiogenesis. In conclusion, the GelMA/AA/Cu hydrogel is an effective wound dressing to promote the healing process of diabetic skin wounds. STATEMENT OF SIGNIFICANCE: Diabetic wounds exhibit an extremely high risk of bacterial infection and poor angiogenesis in a high-sugar environment, hindering their healing process. Hydrogel wound dressings are a promising wound care material that need to have stable and long-lasting adhesive properties, avoid shedding, provide lasting protection to wounds, antibacterial properties and promote angiogenesis. In this study, a series of self-healing, adhesive, and antibacterial hydrogels based on gelatin methacrylate (GelMA), acrylated adenine (AA), and CuCl₂ were designed and synthesized via free radical polymerization, hydrogen bond, and ionic bond to promote diabetic wound healing. Overall, GelMA/AA/Cu hydrogels are promising materials to promote diabetic wound healing.

Bactericidal and Antiviral Bionic Metalized Nanocoatings

In diverse living organisms, bionanocoatings provide multiple functionalities, to the surfaces they cover. We have, previously, identified the molecular mechanisms of Turing-based self-assembly of insect corneal nanocoatings and developed forward-engineering approaches to construct multifunctional soft bionic nanocoatings, encompassing the Drosophila protein Retinin. Here, we expand the versatility of the bionic nanocoatings, by identifying and using diverse Retinin-like proteins and different methods of their metallization, using nickel, silver, and copper ions. Comparative assessment, of the resulting bactericidal, antiviral, and cytotoxic properties, identifies the best protocols, to construct safe and anti-infective metalized bionic nanocoatings. Upscaled application of these protocols, to various public surfaces, may represent a safe and economic approach to limit hazardous infections.

Development and Characterizations of Engineered Electrospun Bio-Based Polyurethane Containing Essential Oils

We report the fabrication of bio-based thermoplastic polyurethane (TPU) fibrous scaffolds containing essential oils (EO). The main goal of this study was to investigate the effects of essential oil type (St. John’s Wort oil (SJWO), lavender oil (LO), and virgin olive oil (OO))/concentration on the electrospinnability of TPU. The effects of applied voltage, flow rate, and end-tip distance on the diameter, morphology, and wettability of the TPU/EO electrospun fibers were investigated. The electrospun TPU/EO scaffolds were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle (CA), and Fourier transform infrared spectroscopy (FTIR). The addition of oil resulted in an increase in the fiber diameter, reduction in the surface roughness, and, accordingly, a reduction in the contact angle of the composite fibers. TPU fibers containing SJWO and LO have a more flexible structure compared to the fibers containing OO. This comparative study fills the existing information gap and shows the benefits of the fabrication of essential-oil-incorporated electrospun fiber with morphology and size range with respect to the desired applications, which are mostly wound dressing and food packaging.

Evaluation of Nigella sativa oil loaded electrospun polyurethane nanofibrous mat as wound dressing

Electrospun nanofibers have a natural wound healing effect due to their similarity to the extracellular matrix (ECM). Nigella sativa oil, which has therapeutic properties, is used for a wide variety of applications in traditional medicine. The aim of this study was to investigate the release characteristic and wound healing performance of Nigella sativa oil (NSO) loaded polyurethane (PU) electrospun nanofibrous mats in wound dressing applications. In addition, the antibacterial activity and cytotoxicity of the electrospun mats were studied. Analyses using a scanning electron microscope (SEM) showed that PU/NSO nanofibrous mat with an average fiber diameter of 416 ± 66 nm were successfully fabricated. NSO was released at a maximum ratio of 30% from the electrospun mat, and the Korsmeyer-Peppas model was identified as best for determining the release mechanism. Significant antibacterial activity was observed against Staphylococcus aureus (90.26%) and Escherichia coli (95.75%). The developed PU/NSO nanofibrous mat increased the cell viability more than 100% in human umbilical vein endothelial cell line (HUVEC) cell line. The NSO loaded PU nanofibrous mat significantly promoted the wound healing process on a rat wound model, and its wound closure reached approximately 85% compared to the control groups on the 9^th day (p < 0.01). The results indicated PU/NSO nanofibrous mat is a suitable candidate for a wound dressing.

Prospects of Polymeric Nanofibers Loaded with Essential Oils for Biomedical and Food-Packaging Applications

Essential oils prevent superbug formation, which is mainly caused by the continuous use of synthetic drugs. This is a significant threat to health, the environment, and food safety. Plant extracts in the form of essential oils are good enough to destroy pests and fight bacterial infections in animals and humans. In this review article, different essential oils containing polymeric nanofibers fabricated by electrospinning are reviewed. These nanofibers containing essential oils have shown applications in biomedical applications and as food-packaging materials. This approach of delivering essential oils in nanoformulations has attracted considerable attention in the scientific community due to its low price, a considerable ratio of surface area to volume, versatility, and high yield. It is observed that the resulting nanofibers possess antimicrobial, anti-inflammatory, and antioxidant properties. Therefore, they can reduce the use of toxic synthetic drugs that are utilized in the cosmetics, medicine, and food industries. These nanofibers increase barrier properties against light, oxygen, and heat, thereby protecting and preserving the food from oxidative damage. Moreover, the nanofibers discussed are introduced with naturally derived chemical compounds in a controlled manner, which simultaneously prevents their degradation. The nanofibers loaded with different essential oils demonstrate an ability to increase the shelf-life of various food products while using them as active packaging materials.

Surface Engineered Metal-Organic Frameworks (MOFs) Based Novel Hybrid Systems for Effective Wound Healing: A Review of Recent Developments

Wounds present serious medical complications and their healing requires strategies that promote angiogenesis, deposition of collagen as well as re-epithelialization of wounds. Currently used conventional wound healing strategies have become less effective due to various issues associated with them. Thus, novel strategies are needed to be developed for early and effective healing of wounds. Metal-organic frameworks (MOFs), formed by linking of metal ions through organic bridging ligands, are highly tunable hybrid materials and have attracted more considerable scientific attention due to their charming and prominent properties, such as abundant pore structures and multiple functionalities. Surface engineering of MOFs with unique ligands can overcome issues associated with conventional wound healing methods, thus resulting in early and effective wound healing. This review has been undertaken to elaborate wound healing, and the use of surface engineered MOFs for effective and rapid wound healing. The process of wound healing will be discussed followed by a detailed review of recent literature for summarizing applications of surface engineered MOFs for wound healing. MOFs wound healing will be discussed in terms of their use as antibacterial agents, therapeutic delivery vehicles, and dressing systems in wound healing.

Recent advances in tissue engineering scaffolds based on polyurethane and modified polyurethane

Organ repair, regeneration, and transplantation are constantly in demand due to various acute, chronic, congenital, and infectious diseases. Apart from traditional remedies, tissue engineering (TE) is among the most effective methods for the repair of damaged tissues via merging the cells, growth factors, and scaffolds. With regards to TE scaffold fabrication technology, polyurethane (PU), a high-performance medical grade synthetic polymer and bioactive material has gained significant attention. PU possesses exclusive biocompatibility, biodegradability, and modifiable chemical, mechanical and thermal properties, owing to its unique structure-properties relationship. During the past few decades, PU TE scaffold bioactive properties have been incorporated or enhanced with biodegradable, electroactive, surface-functionalised, ayurvedic products, ceramics, glass, growth factors, metals, and natural polymers, resulting in the formation of modified polyurethanes (MPUs). This review focuses on the recent advances of PU/MPU scaffolds, especially on the biomedical applications in soft and hard tissue engineering and regenerative medicine. The scientific issues with regards to the PU/MPU scaffolds, such as biodegradation, electroactivity, surface functionalisation, and incorporation of active moieties are also highlighted along with some suggestions for future work.

Light-Activatable Synergistic Therapy of Drug-Resistant Bacteria-Infected Cutaneous Chronic Wounds and Nonhealing Keratitis by Cupriferous Hollow Nanoshells

Due to the inability to spontaneously heal and vulnerability to bacterial infection, diabetic patients are frustrated by unexpected epithelium injuries in daily life. Notably, a drug-resistant bacterial infection may result in a long-term impact to the natural function of damaged organs. It is imperative to develop strategies that promote injury recovery and eradicate drug-resistant infection simultaneously. Here, we present a composite structured cupriferous hollow nanoshell (AuAgCu₂O NS) that consists of a hollow gold-silver (AuAg) core and Cu₂O shell as a photothermal therapeutic agent for a cutaneous chronic wound and nonhealing keratitis with drug-resistant bacterial infection. The controllable photothermal therapeutic effect and released silver ion from the hollow AuAg core possess a synergistic effect to eradicate multi-drug-resistant bacteria, including extended-spectrum β-lactamase Escherichia coli (ESBL E. coli) and methicillin-resistant Staphylococcus aureus (MRSA). Meanwhile, the released copper ion from the Cu₂O shell could expedite endothelial cell angiogenesis and fibroblast cell migration, thus boosting wound-healing effects. In both infection-complicated disease models, the ophthalmic clinical score, wound closure rates, and histopathology analysis demonstrate that the AuAgCu₂O NSs could facilitate the re-epithelialization at the wound area and eliminate the complicated bacterial infection from diabetic mice. A primary signal path involved in the promoted healing effect was further illustrated by comprehensive assays of immunohistochemical evaluation, Western blot, and quantitative polymerase chain reaction. Taken together, our AuAgCu₂O NSs are shown to be potent candidates for clinical utilization in the treatment of diabetic epithelium injuries.

Elastic net of polyurethane strands for sustained delivery of triamcinolone around silicone implants of various sizes

We propose an elastic net made of a biocompatible polymer to wrap silicone implants of various sizes, which also allows for the sustained release of an anti-inflammatory drug, triamcinolone, to prevent fibrosis. For this, we first prepared a strand composed of a mixture of polyurethane and triamcinolone via electrospinning, which was then assembled to prepare the elastic drug-delivery net (DDN). The DDN was prepared to just fit for wrapping the small silicone implant sample herein, but was also able to wrap a sample 7 times as large at 72% strain due to the elastic property of polyurethane. The DDN exhibited sustained drug release for 4 weeks, the profile of which was not very different between the intact and strained DDNs. When implanted in a subcutaneous pocket in living rats, the DDN-wrapped silicone implant samples showed an obvious antifibrotic effect due to the sustained release of triamcinolone. Importantly, this effect was similar for the small and large silicone samples, both wrapped with the same DDN. Therefore, we conclude that this drug-loaded net made of an elastic, biocompatible polymer has high potential for sustained drug delivery around silicone implants manufactured in various sizes.

Recent advances in biomaterials for 3D scaffolds: A review

Considering the advantages and disadvantages of biomaterials used for the production of 3D scaffolds for tissue engineering, new strategies for designing advanced functional biomimetic structures have been reviewed. We offer a comprehensive summary of recent trends in development of single- (metal, ceramics and polymers), composite-type and cell-laden scaffolds that in addition to mechanical support, promote simultaneous tissue growth, and deliver different molecules (growth factors, cytokines, bioactive ions, genes, drugs, antibiotics, etc.) or cells with therapeutic or facilitating regeneration effect. The paper briefly focuses on divers 3D bioprinting constructs and the challenges they face. Based on their application in hard and soft tissue engineering, in vitro and in vivo effects triggered by the structural and biological functionalized biomaterials are underlined. The authors discuss the future outlook for the development of bioactive scaffolds that could pave the way for their successful imposing in clinical therapy.

Development of Thermally Conductive Polyurethane Composite by Low Filler Loading of Spherical BN/PMMA Composite Powder

The issue of electronic heat dissipation has received much attention in recent times and has become one of the key factors in electronic components such as circuit boards. Therefore, designing of materials with good thermal conductivity is vital. In this work, a thermally conductive SBP/PU composite was prepared wherein the spherical h-BN@PMMA (SBP) composite powders were dispersed in the polyurethane (PU) matrix. The thermal conductivity of SBP was found to be significantly higher than that of the pure h-BN/PU composite at the same h-BN filler loading. The SBP/PU composite can reach a high thermal conductivity of 7.3 Wm^-1 K^-1 which is twice as high as that of pure h-BN/PU composite without surface treatment in the same condition. This enhancement in the property can be attributed to the uniform dispersion of SBP in the PU polymer matrix that leads to a three-dimensional continuous heat conduction thereby improving the heat diffusion of the entire composite. Hence, we provide a valuable method for preparing a 3-dimensional heat flow path in polyurethane composite, leading to a high thermal conductivity with a small amount of filler.

Synergism of cisplatin-oleanolic acid co-loaded calcium carbonate nanoparticles on hepatocellular carcinoma cells for enhanced apoptosis and reduced hepatotoxicity

Background: Cisplatin (CDDP), a widely used chemotherapeutic agent against hepatocellular carcinoma (HCC), faces severe resistance and hepatotoxicity problems which can be alleviated through combination therapy.

Purpose: The objective of this study was to develop a pH-dependent calcium carbonate nano-delivery system for the combination therapy of CDDP with oleanolic acid (OA).

Methods: A microemulsion method was employed to generate lipid coated cisplatin/oleanolic acid calcium carbonate nanoparticles (CDDP/OA-LCC NPs), and the loading concentration of CDDP and OA was measured by atomic absorption spectroscopy and HPLC respectively.Transmission electron microscopy (TEM) was used to examine the nanoparticles morphology while its pH dependent release characteristics were investigated through in vitro release study. Cellular uptake was examined through a fluorescence microscopy. Apoptotic assays and western blot analysis were conducted to explore the synergistic apoptotic effect of OA on CDDP against HCC cells. The hepatoprotective of OA for CDDP was evaluated through H&E staining.

Results: TEM analysis revealed nanoparticles spherical shape with an average particle size of 206±15 nm, and the overall entrapment efficiency was 63.70%±3.9%. In vitro drug release study confirmed the pH-dependent property of the formulation, with the maximum CDDP release of 70%±4.6% at pH 5.5, in contrast to 28%±4.1% CDDP release at pH 7.4. Annexin V-FITC/PI assay and cell cycle analysis confirmed that CDDP and OA synergistically promoted greater HepG2 cells apoptosis for the CDDP/OA-LCC NPs as compared to their individual free drug solutions and NPs-treated groups. Western blot analysis also proved that CDDP/OA-LCC NPs induced the apoptosis by enhancing the proapoptotic protein expressions through downregulating P13K/AKT/mTOR pathway and upregulating p53 proapoptotic pathway. OA helped CDDP to overcome the resistance by downregulating the expression of proteins like XIAP, Bcl-2 via NF-κB pathway. OA also significantly alleviated CDDP-induced hepatotoxicity as evident from the decreased alanine transaminase, aspartate transaminase levels and histochemical evaluation. The possible mechanism may be related to the Nrf-2 induction via its antioxidant mechanism to maintain the redox balance and reduction in CYP2E1 activity which can lead to ROS-mediated oxidative stress.

Conclusion: These results suggest that CDDP/OA-LCC NPs have promising applications for co-delivering CDDP and OA to synergize their anti-tumor activity against HCC and to utilize OA’s protective effect against CDDP-induced hepatotoxicity.

Electrospun Combination of Peppermint Oil and Copper Sulphate with Conducive Physico-Chemical properties for Wound Dressing Applications

The ultimate goal in tissue engineering is to fabricate a scaffold which could mimic the native tissue structure. In this work, the physicochemical and biocompatibility properties of electrospun composites based on polyurethane (PU) with added pepper mint (PM) oil and copper sulphate (CuSO₄) were investigated. Field Emission Electron microscope (FESEM) study depicted the increase in mean fiber diameter for PU/PM and decrease in fiber diameter for PU/PM/CuSO₄ compared to the pristine PU. Fourier transform infrared spectroscopy (FTIR) analysis revealed the formation of a hydrogen bond for the fabricated composites as identified by an alteration in PU peak intensity. Contact angle analysis presented the hydrophobic nature of pristine PU and PU/PM while the PU/PM/CuSO₄ showed hydrophilic behavior. Atomic force microscopy (AFM) analysis revealed the increase in the surface roughness for the PU/PM while PU/PM/CuSO₄ showed a decrease in surface roughness compared to the pristine PU. Blood compatibility studies showed improved blood clotting time and less toxic behavior for the developed composites than the pristine PU. Finally, the cell viability of the fabricated composite was higher than the pristine PU as indicated in the MTS assay. Hence, the fabricated wound dressing composite based on PU with added PM and CuSO₄ rendered a better physicochemical and biocompatible nature, making it suitable for wound healing applications.

Processing polymer nanocomposites with natural additives for medical applications

The aim of this study is to analyze the effect of natural additive incorporation on processing nanocomposites and their effect on the functional characteristics of nanocomposites such as water uptake characteristics, drug adsorption and dissolution behaviors. Chitosan and montmorillonite were processed with olive oil and glycerin natural additives. In order to compare the processing results, the structure and the morphology of the polymer nanocomposites were examined by using infrared spectra, X-ray diffractograms and electron microscope images. Processing with nontoxic and healthful olive oil as a hydrophobizing agent overcame the high water uptake properties of the polymer nanocomposites and eliminated the use of other expensive chemicals. The nanocomposites without additives adsorbed the highest amounts of methylene blue at equilibrium. In vitamin B12 dissolution studies, not only the additives but also the reinforcement affected the results. Obviously, it can be seen that both the natural additive types and the reinforcement modification effects governed the drug adsorption and dissolution behaviors of the new tailored polymer nanocomposites. Moreover, the additives also improved the processing and handling abilities of these polymer nanocomposites. According to the results, these nanocomposites are promising candidates for medical applications like as a carrier for drug delivery and for skin treatment studies.

Single-stage electrospun innovative combination of polyurethane and neem oil: Synthesis, characterization and appraisal of blood compatibility

Wound healing is a complex process and it requires proper scaffolding for regeneration. An ideal scaffold should provide optimal environmental conditions in order to assist cellular attachment, proliferation and differentiation. In this work, a new composite based on polyurethane and neem oil was fabricated using one-step electrospinning technique. Fabricated composite patch along with the pristine polyurethane was characterized through scanning electron microscopy, Fourier transform and infrared spectroscopy, thermogravimetric analysis, contact angle measurement and atomic force microscopy. Moreover, the blood compatibility was evaluated using activated partial thromboplastin time, partial thromboplastin time and haemolysis assay. Scanning electron microscopy studies of composites revealed the existence of fibres with a smaller diameter (635  ± 105 nm) compared to the pristine polyurethane (969 ± 217 nm). Fourier transform and infrared analysis revealed the formation of hydrogen bond and peak shifting characteristics confirming the interaction of the neem oil with the polyurethane. Contact angle analysis showed the decrease in contact angle indicating the hydrophilic nature of the fabricated patch compared to pristine polyurethane. Thermal gravimetric analysis depicted the better thermal stability of the novel composite patch due to the existence of neem oil in the pristine polyurethane. The presence of neem oil in polyurethane matrix also resulted in an increase in the surface roughness as observed in the AFM analysis. The novel composite patch showed an ability to reduce the thrombogenicity and promoting the anticoagulant nature signified by blood compatibility assays like activated partial thromboplastin time and partial thromboplastin time. Finally, the haemolytic percentage of the fabricated composite (1%) was found to be reduced compared to control (2.733%) indicating better blood compatibility and safety with the red blood cells. Following the results, the fabricated patches offered enhanced physicochemical and blood compatible nature making it as a promising candidate for wound healing application.

Electrospun polyurethane nanofibrous composite impregnated with metallic copper for wound-healing application

In this study, a wound dressing based on polyurethane (PU) blended with copper sulphate nanofibers was developed using an electrospinning technique. The prepared PU and PU nanocomposites showed smooth fibers without any bead defects. The prepared nanocomposites showed smaller fiber (663 ± 156.30 nm) and pore (888 ± 70.93 nm) diameter compared to the pristine PU (fiber diameter 1159 ± 147.48 nm and pore diameter 1087 ± 62.51 nm). The interaction of PU with copper sulphate was evident in the infrared spectrum through hydrogen-bond formation. Thermal analysis displayed enhanced weight residue at higher temperature suggesting interaction of PU with copper sulphate. The contact angle measurements revealed the hydrophilic nature of the prepared nanocomposites (71° ± 2.309°) compared with pure PU (100° ± 0.5774°). The addition of copper sulphate into the PU matrix increased the surface roughness, as revealed in the atomic force microscopy (AFM) analysis. Mechanical testing demonstrated the enhanced tensile strength behavior of the fabricated nanocomposites (18.58 MPa) compared with the pristine PU (7.12 MPa). The coagulation assays indicated the enhanced blood compatibility of the developed nanocomposites [activated partial thromboplastin time (APTT)-179 ± 3.606 s and partial thromboplastin time (PT)-105 ± 2.646 s] by showing a prolonged blood clotting time compared with the pristine PU (APTT-147.7 ± 3.512 s and PT-84.67 ± 2.517 s). Furthermore, the hemolysis and cytotoxicity studies suggested a less toxicity nature of prepared nanocomposites by displaying low hemolytic index and enhanced cell viability rates compared with the PU membrane. It was observed that the fabricated novel wound dressing possesses better physicochemical and enhanced blood compatibility properties, and may be utilized for wound-healing applications.

Production and hemocompatibility assessment of novel electrospun polyurethane nanofibers loaded with dietary virgin coconut oil for vascular graft applications

To develop biodegradable polymer scaffolds suitable for vascular tissue engineering applications, the bioengineering community has invested an extensive effort. The most common cause for the failure of vascular graft scaffolds is thrombosis. In this work, the scaffold based on polyurethane and virgin coconut oil was produced by electrospinning process for vascular tissue engineering applications with improved antithrombogenicity. The diameter of this electrospun polyurethane/virgin coconut oil composite was found to be reduced in the range of 886 ± 207 nm compared to pristine polyurethane which was in the range of 969 ± 217 nm. The Fourier transform infrared spectroscopy analysis revealed the interaction between polyurethane and virgin coconut oil as indicated by phase shifting of CH bond along with the formation of hydrogen bond. The contact angle measurement of fabricated composites was found to be increased owing to hydrophobic nature and also exhibited enhanced thermal stability as noted in thermogravimetric analysis. The atomic force microscopy analysis insinuated the increased surface roughness of the composite in comparison with the pure polyurethane. Developed scaffold resulted in delayed blood clotting as revealed by activated partial thromboplastin time and partial thromboplastin time assay. The hemolytic index of fabricated composites was found to be low indicating the enhanced safety of red blood cells. Hence, the newly developed nanofibrous composite scaffold could open the door for a suitable alternative for vascular graft applications.

A Cooperative Copper Metal-Organic Framework-Hydrogel System Improves Wound Healing in Diabetes

Chronic non-healing wounds remain a major clinical challenge that would benefit from the development of advanced, regenerative dressings that promote wound closure within a clinically relevant time frame. The use of copper ions has shown promise in wound healing applications possibly by promoting angiogenesis. However, reported treatments that use copper ions require multiple applications of copper salts or oxides to the wound bed, exposing the patient to potentially toxic levels of copper ions and resulting in variable outcomes. Herein we set out to assess whether copper metal organic framework nanoparticles (HKUST-1 NPs) embedded within an antioxidant thermoresponsive citrate-based hydrogel would decrease copper ion toxicity and accelerate wound healing in diabetic mice. HKUST-1 and poly-(polyethyleneglycol citrate-co-N-isopropylacrylamide) (PPCN) were synthesized and characterized. HKUST-1 NP stability in a protein solution with and without embedding them in PPCN hydrogel was determined. Copper ion release, cytotoxicity, apoptosis, and in vitro migration processes were measured. Wound closure rates and wound blood perfusion were assessed in vivo using the splinted excisional dermal wound diabetic mouse model. HKUST-1 NP disintegrated in protein solution while HKUST-1 NPs embedded in PPCN (H-HKUST-1) were protected from degradation and copper ions were slowly released. Cytotoxicity and apoptosis due to copper ion release were significantly reduced while dermal cell migration in vitro and wound closure rates in vivo were significantly enhanced. In vivo, H-HKUST-1 induced angiogenesis, collagen deposition, and re-epithelialization during wound healing in diabetic mice. These results suggest that a cooperatively stabilized, copper ion-releasing H-HKUST-1 hydrogel is a promising innovative dressing for the treatment of chronic wounds.

Preparation and antitumor evaluation of self-assembling oleanolic acid-loaded Pluronic P105/d-α-tocopheryl polyethylene glycol succinate mixed micelles for non-small-cell lung cancer treatment

Oleanolic acid (OA) is a triterpenoid found in various fruits and vegetables and used in traditional Chinese medicine. OA plays a crucial role in the treatment of several cancers, but poor water solubility, low permeability, and significant efflux have limited its widespread clinical use. Vitamin E-d-α-tocopheryl polyethylene glycol succinate (vitamin E-TPGS) and Pluronic P105 were used to improve the solubility and permeability and to decrease the efflux of OA. OA-loaded mixed micelles were prepared by ethanol thin-film hydration. The physicochemical properties of the micelles, including zeta potential, morphology, particle size, solubility, drug loading, and drug entrapment efficiency were characterized. OA release from micelles was slower than that from the free drug system. OA uptake by A549 non-small-cell lung cancer (NSCLC) cells was enhanced by the micelles. A tumor model was established by injecting A549 cells into nude mice. In vivo imaging showed that OA-micelles could accumulate in the tumors of nude mice. Additionally, smaller tumor size and increased expression of pro-apoptotic proteins were observed in OA-micelle-treated mice, indicating that OA-micelles are more effective than free OA in treating cancer. In vitro experiments were performed using two NSCLC cell lines (A549 and PC-9). Cytotoxicity evaluations showed that the half-maximal inhibitory concentrations of free OA and OA-micelles were 36.8±4.8 and 20.9±3.7 μM, respectively, in A549 cells and 82.7±7.8 and 56.7±4.7 μM, respectively, in PC-9 cells. Apoptosis assays revealed that the apoptotic rate of OA-micelle-treated A549 and PC-9 cells was higher than that of cells treated with the same concentration of free OA. Wound healing and transwell assays showed that migration and invasion were significantly suppressed in OA-micelle-treated cells. Immunofluorescence and Western blot analyses confirmed that the epithelial–mesenchymal transition was reversed in OA-micelle-treated cells. Mixed micelles are a promising nano-drug delivery system for lung cancer treatment.