Study on the Preparation and Lipophilic Properties of Polyvinyl Alcohol (PVA) Nanofiber Membranes via Green Electrospinning

Preparation and performance study of in situ mineralized bone tissue engineering scaffolds

Traditional bone tissue engineering techniques require the extraction and proliferation of seed cells, followed by prolonged in vitro culture to form bone tissue constructs. In contrast, in situ mineralization bone tissue engineering utilizes alkaline phosphatase within the body's microenvironment to induce scaffold mineralization. This approach promotes further proliferation and differentiation of osteoblasts and the formation of bone tissue constructs, thereby simplifying the traditional bone tissue engineering process. This study uses electrospinning technology to prepare a novel biologically active scaffold for bone tissue engineering using poly(lactic-co-glycolic acid) (PLGA) and calcium glycerophosphate. The morphology and composition of the scaffolds were characterized using SEM, EDS, and XRD, revealing well-defined fibrous structures and the successful incorporation of calcium glycerophosphate into the PLGA fibers. In vitro simulation of the bone microenvironment using alkaline phosphatase effectively catalyzed the in situ mineralization of calcium glycerophosphate within the scaffold. SEM observations showed substantial mineral aggregation on the surface of the fibrous membranes, and XRD characterization confirmed that the diffraction peaks of the minerals correspond to hydroxyapatite. The cytotoxicity, cell proliferation, and osteogenic differentiation assessments on MC3T3-E1 pre-osteoblasts cultured on the prepared scaffolds indicate that the scaffolds are non-toxic to cells and possess good osteogenic differentiation ability, enabling in situ mineralization. This suggests that the scaffolds have broad prospects for application in bone defect repair.

Preparation of poly(vinyl alcohol) nanofibers containing disulfiram-copper complex by electrospinning: a potential delivery system against melanoma

BACKGROUND

Melanoma poses a significant threat to human health, making the development of a safe and effective treatment a crucial challenge. Disulfiram (DS) is a proven anticancer drug that has shown effectiveness when used in combination with copper (DS-Cu complex).

OBJECTIVES

This study focuses on encapsulation of DS-copper complex into nanofiber scaffold from polyvinyl alcohol (PVA) (DS-Cu@PVA). In order to increase bioavailability towards melanoma cell lines and decrease its toxicity.

METHODS

The scaffold was fabricated through an electrospinning process using an aqueous solution, and subsequently analyzed using ART-Fourier transform infrared spectroscopy (ART-FTIR), scanning electron microscopy (SEM), and energy dispersive X-ray analysis (EDX). Additionally, cellular cytotoxicity, flow cytometry analysis, and determination of caspase 3 activity were conducted to further characterize the scaffold.

RESULTS

The results confirmed that encapsulation of DS-Cu complex into PVA was successful via different characterization. The scanning electron microscopy (SEM) analysis revealed that the diameter of the nanofibers remained consistent despite the addition of DS-Cu. Additionally, ATR-FTIR confirmed that the incorporation of DS-Cu into PVA did not significantly alter the characteristic peaks of PVA. Furthermore, the cytotoxicity assessment of the DS-Cu@PVA nanofibrous scaffold using human normal skin cells (HFB4) demonstrated its superior biocompatibility compared to DS-Cu-free counterparts. Notably, the presence of DS-Cu maintained its effectiveness in promoting apoptosis by increasing cellular reactive oxygen species, proapoptotic gene expression, and caspase 3 activity, while simultaneously reducing glutathione levels and oncogene expression in human and mouse melanoma cell lines (A375 and B16F10, respectively). Overall, these findings suggest that the addition of DS-Cu to PVA nanofibers enhances their biocompatibility and cytotoxic effects on melanoma cells, making them a promising candidate for biomedical applications.

CONCLUSION

The findings indicate that the targeted delivery of DS-Cu onto a PVA nanofiber scaffold holds potential approach to enhance the efficacy of DS-Cu in combating melanoma.

Advances in Polyvinyl Alcohol-Based Membranes for Fuel Cells: A Comprehensive Review on Types, Synthesis, Modifications, and Performance Optimization

Fuel cell technology is at the forefront of sustainable energy solutions, and polyvinyl alcohol (PVA) membranes play an important role in improving performance. This article thoroughly investigates the various varieties of PVA membranes, their production processes, and the numerous modification tactics used to solve inherent problems. Various methods were investigated, including chemical changes, composite blending, and the introduction of nanocomposites. The factors impacting PVA membranes, such as proton conductivity, thermal stability, and selectivity, were investigated to provide comprehensive knowledge. By combining various research threads, this review aims to completely investigate the current state of PVA membranes in fuel cell applications, providing significant insights for both academic researchers and industry practitioners interested in efficient and sustainable energy conversion technologies. The transition from traditional materials such as Nafion to PVA membranes has been prompted by limitations associated with the former, such as complex synthesis procedures, reduced ionic conductivity at elevated temperatures, and prohibitively high costs, which have hampered their widespread adoption. As a result, modern research efforts are increasingly focused on the creation of alternative membranes that can compete with conventional technical efficacy and economic viability in the context of fuel cell technologies.

Synthesis of Polyvinyl Alcohol/Coal Fly Ash Hybrid Nano-Fiber Membranes for Adsorption of Heavy Metals in Diesel Fuel

Some studies have shown that the heavy metal emissions (HMEs) emitted from diesel engines can seriously threaten human health. HMEs are mainly related to the content of heavy metal ions in diesel fuel. Therefore, in order to reduce HMEs from diesel engines, a nano-fiber membrane filtration technology for diesel fuel was investigated. Herein, coal fly ash (CFA) from coal-fired power plants combined with polyvinyl alcohol (PVA) was successfully fabricated into nano-fibrous membranes using green electrospinning technology. In order to evaluate the adsorption properties, various hybrid membranes with different mixing ratios (PVA/CFA = 10/0, 10/1, 10/3, 10/5, and 10/7 by weight) were fabricated. The results show that eight metal ions with different concentrations are found in the diesel fuel, including Pb, Cu, Zn, Al, Fe, Cr, Ba, and Ni. All PVA/FA membranes have different adsorption capacities for metal ions, following the order: Cu > Fe > Pb > Al > Zn > Cr > Ba > Ni. In addition, the adsorption capacity of CFA3 (PVA/CFA = 10/3) is the largest. The super lipophilicity of the PVA/FA membranes also provide more adsorption sites for the contact of HMs with the membranes. The above research results provide guidance for development of ultra-fine filters in the future.

Core-Sheath Pt-CeO2/Mesoporous SiO2 Electrospun Nanofibers as Catalysts for the Reverse Water Gas Shift Reaction

One-dimensional (1D) core-sheath nanofibers, platinum (Pt)-loaded ceria (CeO₂) sheath on mesoporous silica (SiO₂) core were fabricated, characterized, and used as catalysts for the reverse water gas shift reaction (RWGS). CeO₂ nanofibers (NFs) were first prepared by electrospinning (ES), and then Pt nanoparticles were loaded on the CeO₂ NFs using two different deposition methods: wet impregnation and solvothermal. A mesoporous SiO₂ sheath layer was then deposited by sol-gel process. The phase composition, structural, and morphological properties of synthesized materials were investigated by scanning electron microscope (SEM), scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), nitrogen adsorption/desorption method, X-ray photoelectron spectroscopy (XPS), inductively coupled plasma-optical emission spectrometry (ICP-OES) analysis, and CO₂ temperature programmed desorption (CO₂-TPD). The results of these characterization techniques revealed that the core-sheath NFs with a core diameter between 100 and 300 nm and a sheath thickness of about 40-100 nm with a Pt loading of around 0.5 wt.% were successfully obtained. The impregnated catalyst, Pt-CeO₂ NF@mesoporous SiO₂, showed the best catalytic performance with a CO₂ conversion of 8.9% at 350 °C, as compared to the sample prepared by the Solvothermal method. More than 99% selectivity of CO was achieved for all core-sheath NF-catalysts.

Fabrication of High-Performance Colorimetric Membrane by Incorporation of Polydiacetylene into Polyarylene Ether Nitriles Electrospinning Nanofibrous Membranes

Polyarylene ether nitrile (PEN) is a novel high-performance engineering plastic with various applications, particularly in thermoresistance-required fields. In this study, a well-known stimuli-response polydiacetylene monomer, 10, 12-pentacosadiynoic acid (PCDA), was encapsulated within electrospun PEN nanofibers to fabricate a colorimetric membrane with satisfactory thermal and corrosion resistance. To optimize the compatibility with PCDA, two PENswith distinct molecular chains were utilized: PEN−PPL and PEN−BPA. The chemical structure and elemental mapping analysis revealed that the PCDA component was successfully incorporated into the PEN fibrous. The PCDA bound significantly better to the PEN−PPL than to the PEN−BPA; due to the carboxyl groups present on the side chains of PEN−PPL, the surface was smooth and the color changed uniformly as the temperature rose. However, owing to its poor compatibility with PEN−BPA, the PCDA formed agglomerations on the fibers. The thermal analysis demonstrated that the membranes obtained after PCDA compounding maintained their excellent heat resistance. The 5% weight loss temperatures of composite nanofibrous membranes manufactured by PEN−PPL and PEN−BPA were 402 °C and 506 °C, respectively, and their glass transition temperatures were 219 °C and 169 °C, respectively, indicating that the blended membranes can withstand high temperatures. The evaluation of application performance revealed that the composite membranes exhibited good dimensional stability upon high thermal and corrosive situations. Specifically, the PEN−P−PCDA did not shrink at 170 °C. Both composite membranes were dimensionally stable when exposed to the alkali aqueous solution. However, PEN−P−PCDA is more sensitive to OH−, exhibiting color transition at pH > 8, whereas PEN−B−PCDA exhibited color transition at high OH− concentrations (pH ≥ 13), with enhanced alkali resistance stability owing to its nanofibrous architecture. This exploratory study reveals the feasibility of PEN nanofibers functionalized using PCDA as a desirable stimulus-response sensor even in high-temperature and corrosive harsh environments.

Preparation and Characterization of an Electrospun Whey Protein/Polycaprolactone Nanofiber Membrane for Chromium Removal from Water

Chromium pollution represents a worldwide concern due to its high toxicity and bioaccumulation in organisms and ecosystems. An interesting material to remove metal ions from water is a whey-protein-based material elaborated by electrospinning, which is an emerging method to produce adsorbent membranes with diverse applications. The aim of this study was to prepare an adsorbent membrane of whey protein isolate (WPI) and polycaprolactone (PCL) by electrospinning to remove chromium ions from water. The adsorbent membrane was synthesized by a central composed design denaturing WPI using 2-Mercaptoethanol and mixing it with PCL to produce electrospun nanofibers. The adsorbent membrane was characterized by denaturation, Scanning Electron Microscope, Fourier-Transform Infrared Spectroscopy, Contact Angle, Thermogravimetric Analysis, and X-ray Photoelectron Spectrometry. The adsorption properties of this membrane were assessed in the removal of chromium. The removal performance of the membrane was enhanced by an increase in temperature showing an endothermic adsorption process. The adsorption process of chromium ions onto the nanofiber membrane followed the Sips adsorption isotherm, while the adsorption kinetics followed a pseudo-second kinetics where the maximum adsorption capacity was 31.0 mg/g at 30 °C and pH 2. This work provides a novel method to fabricate a hybrid membrane with amyloid-type fibrils of WPI and PCL, which is a promising adsorbent to remove heavy metal ions from water.

Impact of Electrospinning Parameters and Post-Treatment Method on Antibacterial and Antibiofilm Activity of Chitosan Nanofibers

Chitosan, a natural biopolymer, is an ideal candidate to prepare biomaterials capable of preventing microbial infections due to its antibacterial properties. Electrospinning is a versatile method ideally suited to process biopolymers with minimal impact on their physicochemical properties. However, fabrication parameters and post-processing routine can affect biological activity and, therefore, must be well adjusted. In this study, nanofibrous membranes were prepared using trifluoroacetic acid and dichloromethane and evaluated for physiochemical and antimicrobial properties. The use of such biomaterials as potential antibacterial agents was extensively studied in vitro using Staphylococcus aureus and Escherichia coli as test organisms. The antibacterial assay showed inhibition of bacterial growth and eradication of the planktonic cells of both E. coli and S. aureus in the liquid medium for up to 6 hrs. The quantitative assay showed a significant reduction in bacteria cell viability by nanofibers depending on the method of fabrication. The antibacterial properties of these biomaterials can be attributed to the structural modifications provided by co-solvent formulation and application of post-treatment procedure. Consequently, the proposed antimicrobial surface modification method is a promising technique to prepare biomaterials designed to induce antimicrobial resistance via antiadhesive capability and the biocide-releasing mechanism.

Adsorption Free Energy of Cellulose Nanocrystal on Water–Oil Interface

To investigate the amphiphilicity of cellulose, a series of molecular dynamics simulations were performed with a cellulose nanocrystal and a water–octane interfacial system. Assuming that the axis of cellulose is parallel to the water–octane interface, the freedoms of motion of the nanocrystal were restricted to two, the distance from the interface and the orientation around the axis. The mean force and the mean torque on the nanocrystal were evaluated with sufficiently long simulation at each crystal configuration, and their numerical integration gave a smooth free energy surface as the potential of mean force. The cellulose sample used here was found to be much more hydrophilic than oleophilic with the free energy difference ΔFw→o=318 kcal/mol. Three adsorption states with local minimum of adsorption free energy are distinguished in the free energy surface—the direct contact type which is similar to previously reported one, the hydrophilic-surface/water/octane type where a thin water layer is sandwiched between the surface and the octane phase, and the oleophilic/water/octane type where a thin water layer also exists. Water molecules in these water layers contribute to stabilize the adsorption states by taking a special orientational order and slow self-diffusion.