Decrease In Fiber Diameter Research Articles

Polyglycerol Sebacate/polycaprolactone/reduced graphene oxide composite scaffold for myocardial tissue engineering

The aim of this research was to fabricate and evaluate polyglycerol sebacate/polycaprolactone/reduced graphene oxide (PGS-PCL-RGO) composite scaffolds for myocardial tissue engineering. Polyglycerol sebacate polymer was synthesized using glycerol and sebacic acid prepolymers, confirmed by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). Six PGS-PCL-RGO composite scaffolds (S1-S6) with various weight ratios were prepared in chloroform (CF) and acetone (Ace) solvents at 8 CF:2Ace and 9 CF:1Ace volume ratios, using the electrospinning method at a rate of 1 ml/h and a voltage of 18 kV. The scaffolds' chemical composition and microstructure were characterized by FTIR, XRD, and scanning electron microscopy (SEM). Further investigations included tensile testing, contact angle testing, four-point probe testing for electrical conductivity, degradation testing, and cytotoxicity testing (MTT). The results showed that adding 2%wt RGO to the composite scaffold decreased fiber diameter and degradation rate, while increasing electrical conductivity and ductility. The 33%PGS-65%PCL-2%RGO (S3) composite scaffold exhibited the lowest degradation rate (23.87 % over 60 days) and the highest electrical conductivity (51E-3 S/m). Mechanical evaluations revealed an elastic modulus of 2.46 MPa and elongation of 62.43 %, aligning closely with the heart muscle's elastomeric properties. The contact angle test indicated that the scaffold was hydrophilic, with a water contact angle of 61 ± 2°. Additionally, the cell toxicity test confirmed that scaffolds containing RGO were non-toxic and supported good cell viability. In conclusion, the 33%PGS-65%PCL-2%RGO composite scaffold exhibits mechanical and structural properties similar to heart tissue, making it an ideal candidate for myocardial tissue engineering.

Novel Honeycomb Nanoclay Frameworks With Hemostatic and Antibacterial Properties.

Our laboratory recently developed a new class of high surface area, honeycomb Nanoclay Microsphere Framework absorbents (NMFs) that prompt rapid hemostasis. In the present work, we propose a novel approach to develop antibacterial Topical Hemostatic Agents (THAs) by anchoring silver nanoparticles (AgNPs) onto NMFs. This combination was obtained by a chemical co-reduction approach, followed by freeze-processing, and was shown to ensure stability and on-site delivery of AgNPs, without altering the hemostatic properties of NMFs. Silver-loaded NMFs showed no change in their unique architecture and led to a 55% increase in clot strength, compared to standard control plasma or commercially available THA, and a significant decrease in mean fibrin fiber diameter. Silver nanoparticles were successfully released when solubilized and prevented the growth of both Pseudomonas aeruginosa and Staphylococcus aureus at concentrations of 22 and 30 ppm of silver released, respectively. Overall, cell mortality was between 9.1 ± 5.1% and 6.3 ± 3.2%, depending on AgNP concentration, confirming a low cytotoxicity. Silver-loaded nanoclay microsphere frameworks appear to constitute promising candidates as topical hemostatic agents for secondary management of hemostasis when infection control is needed.

Preparation and characterization of poly (lactic acid)-chitosan blend fibrous electrospun membrane loaded with bioactive glass nanoparticles for guided bone/tissue regeneration

In this study, bioactive fibrous membranes composed of poly (lactic) acid (PLA), chitosan (CHS), and strontium-doped bioactive glass nanoparticles (BG) were produced via electrospinning technique using a triple solvent system and characterized via thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), static contact angle (CA), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX).All fiber samples exhibited consistent one-step thermal degradation profiles, regardless of BG content, and the intended BG contents in the membranes ware confirmed. The addition of 3% w/w CHS to form PLA-CHS blend lowered the glass transition temperature (Tg) by 1.62 °C. FTIR analysis validated the presence of CHS in the PLA-CHS blend fibers through the appearance of a low-intensity broad peak around 1658–1566 cm⁻1, indicating primary amide functional groups. Incorporating 3% w/w CHS reduced water contact angle by 7% and decreased fiber diameter by 57%. Wettability improved with increasing BG content, as confirmed by SEM images showing well-dispersed BG nanoparticles within the fibers.After 35 days of immersion in simulated body fluid (SBF), a substantial layer of hydroxyapatite (HA) with a Ca/P ratio resembling that of natural human bones coated the BG particles and fibers. The membranes demonstrated excellent cell adhesion capabilities, especially in the PLA_3%CHS and PLA_3% CHS_5% BG configurations, with minimal cellular toxicity compared to a well-known cell-killing agent, highlighting their biocompatibility.Incorporating chitosan and strontium-doped bioactive glass nanoparticles into PLA blends positively influenced cell viability and proliferation, emphasizing the enhanced cellular response resulting from surface modifications. These properties make these fibrous membranes promising for guided bone and tissue regeneration applications.

Rice straw-based cellulose nanofiber reinforcing polyvinyl alcohol antibacterial film through electrospinning

TEMPO-cellulose nanofibers (T-CNF) were prepared from rice straw through 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation method. Subsequently, T-CNF reinforced polyvinyl alcohol fiber films (T-CNF/PVA) were fabricated by electrospinning. SEM images revealed that the introduction of T-CNF into PVA resulted in a slight decrease in fiber diameter within the T-CNF/PVA films. The tensile strength and elastic modulus of the T-CNF/PVA-2 fiber film were 44.59 MPa and 20.75 MPa, respectively, with T-CNF content of 1.64 wt%. The tensile strength of T-CNF/PVA-2 being approximately 9 times greater than that of pure PVA fiber film. Molecular dynamics (MD) simulation showed that the intermolecular forces between T-CNF and PVA were stronger than those within pure PVA. Additionally, the T-CNF/PVA-2 fiber film exhibited excellent antibacterial properties, achieving an inhibition rate of 99.99 % against S. aureus.

Submicron PAN and nanofiber CTA air filters: Fabrication, optimization, and performance

This study investigates the fabrication, optimization, and performance of submicron polyacrylonitrile (PAN) and nanofiber cellulose triacetate (CTA) air filters produced through electrospinning. PAN fibers with diameters ranging from 379 to 804 nm were generated from PAN/DMF solutions, while genuine CTA nanofibers (65–102 nm) were successfully produced using a recycled CTA polymer and a binary solvent system (DMSO/TCM). The effects of electrospinning parameters, including solution concentration (10–12 wt% for PAN, 8 wt% for CTA), applied voltage (10–16 kV), tip-to-collector distance (16–24 cm), solution supply rate (0.08–0.10 mL/hr), and binary solvent ratio (7:1 to 20:1 DMSO/TCM), on fiber morphology and diameter were systematically examined. Reducing PAN solution concentration and increasing applied voltage effectively decreased fiber diameter, enhancing filtration efficiency. Filtration performance tests revealed that CTA nanofibers outperformed PAN submicron fibers, exhibiting higher quality factors (0.043–0.046 Pa−1) due to their smaller fiber diameters and increased fiber packing density. Decreasing CTA solution supply rate and increasing DMSO/TCM ratio reduced fiber diameter and increased packing density. Longer spinning collection times improved filtration efficiency but increased thickness and pressure drop. The optimization of electrospinning parameters proved crucial for controlling fiber diameter and achieving enhanced filtration efficiency, particularly at the most penetrating particle size (MPPS), which usually covers the ultrafine particle size range. This study provides valuable insights into the development of high-performance air filtration media through the optimization of electrospinning parameters and the utilization of recycled materials.

Aging Larynx: Molecular and Cellular Aspect

In South Korea, the elderly population is rapidly growing, projected to reach 20.6% by 2025. With increased social engagement among older individuals, the demand for voice-related interventions rises. Age-related changes in these structures impact vocal function and quality. Understanding the mechanisms underlying these changes is crucial for developing effective therapeutic approaches. The aging of the larynx occurs in each part of the cartilage, muscles, and vocal folds. The change in cartilage is most prominently characterized by ossification, which begins in the twenties and accelerates significantly after the age of 60. This ossification is particularly evident in the thyroid and cricoid cartilages. Muscle aging is characterized by a decrease in muscle fiber diameter, a reduction in gender differences, an increase in the proportion of type I muscle fibers, along with a decrease in myocyte function and the deposition of extracellular matrix and adipocytes. In the vocal folds, collagen increases, while type III collagen, which is involved in healing, decreases. Additionally, collagen production and breakdown decrease, as well as hyaluronic acid levels and factors involved in mucosal vibration, such as surface elastic fibers.

Impact of fiber diameter on mechanical and water absorption properties of short bamboo fiber-reinforced polyester composites

Abstract This study aims to investigate the effect of fiber diameter on the mechanical and water absorption characteristics of short bamboo fiber-reinforced polyester composites. Three different fiber sizes (180–250 µm, 250–500 µm, and 700–1000 µm) were used to prepare composites with varying fiber loadings of 10 wt.%, 20 wt.%, and 30 wt.%. The fabricated composites were cut to standard dimensions, and tension tests, impact tests, and water absorption tests were performed. Reproducible results were obtained, revealing that using fibers of smaller diameter (180–250 µm) increased the tensile strength of the composite by 20 % compared to composites with larger diameter fibers (700–1000 µm), while the tensile modulus showed a 22 % enhancement with decreasing fiber diameter. Composites with larger diameter fibers exhibited more defects (voids and matrix detachment), as revealed by SEM analysis of fractured surfaces. The impact strength of composites with a diameter size of 700–1000 µm increased by 33 % compared to composites reinforced with the smallest fiber diameter. Water absorption of the composites was also studied by long-term immersion in water, showing that water intake was high initially, reaching a saturation point after a certain time interval. The absorbed water values indicated that composites with the smallest diameter (180–250 µm) showed maximum water intake due to the creation of more water intake sites (increased interfacial area), while composites with the largest diameter fibers (700–1000 µm) exhibited the least water absorption as the interaction region between fibers and matrix was reduced.

A facile fabrication of PU/rGO/MoS2 self-cleaning fibrous membrane for oil-water separation

Electrospun membranes have unique properties to treat water containing various pollutants such as oils, dyes, bacteria, heavy metal ions, etc. The present work comprises the facile fabrication of the functionalized polyurethane (PU) fibrous membrane by doping reduced graphene oxide (rGO) and molybdenum sulfide (MoS2). Complete optimization of the fabricated PU/rGO/MoS2 fibrous membrane was performed to evaluate its ability in oil sorption, dye adsorption, and heavy metal ion removal. The increment in hydrophobicity of PU with functionalization paved the way for oil sorption studies. The improved porous nature and pronounced decrease in average fiber diameter on adding the fillers make the PU membrane potentially viable for adsorption applications. The self-cleaning ability, oil sorption capacity, and UV resistance nature of the functionalized membranes are experimented. Excellent self-cleaning nature, durability and good adsorption of water in oil emulsion were observed. The PU/rGO/MoS2 fibrous membrane showed a high-water permeation flux (˷1800 L/m2/hr) and 20 times recyclability in a continuous separation process. Tuning the wettability by decreasing the polymer concentration and increasing the filler quantity resulted in an improved hydrophilic nature. Additionally, these membranes showed excellent methylene blue removal ability and metal ion adsorption which proved its ability to act as a multi-functional membrane.

Влияние полипропиленового волокна на цементный закладочный композит на основе хвостов обогащения

Introduction. The advantages of technology with backfill in minerals extraction predetermined their widespread use despite the high cost of production. One of the ways to reduce the backfilling cost is the use of tailings. However, earlier studies did not consider the inhomogeneity of shapes, sizes and internal mutual arrangement of particles, as well as the inhomogeneity of phases and density, which is characterized by the presence of pores. Materials and methods. Comparative analysis of samples with different recipes was used to investigate the bending strength of polypropylene fiber-reinforced backfill. A high-frequency automatic laboratory setup with strength transducers (load cells) was used to measure the bending characteristics. Optical moving digital image correlation (3D-DIC) method was used to track and automatically store the obtained results. Microstructure of the prepared and cured backfill was studied to correlate the obtained values. Results. 1. Maximum bending strength was demonstrated by unreinforced samples with 1:4 cement/tailings combination compared to the rest of samples regardless of the presence or absence of reinforcing fiber in the composition; 2. Directly proportional dependence between the increase in bending strength of samples and increase in the cement/ tailings ratio in backfill was established; 3. Increase in bending strength of the samples is maximum at low cement/tailings ratio in backfill composite; 4. There is a linear increase in peak strength and deflection values as the cement/tailings ratio in reinforced backfill increases. Discussion. Compaction of the internal structure is observed when reinforcing the composite with polypropylene fiber. It is noticeable that the compaction occurs due to fiber bonding, which allows improving the bending characteristics of samples. Such compaction is observed in all the investigated reinforced composites with ratios of 1:4, 1:6, 1:8. In some cases a decrease in fiber diameter is observed, which can be explained by the factor of occurrence of yanking or torsional forces at the moment of fracture. All the changes in reinforcing fibers confirm the fact that they are prone to deformations. Conclusion. The following conclusions can be drawn from the research conducted: 1. Unreinforced samples with a cement/tailings combination of 1:4 have the maximum bending strength in comparison with other samples, regardless of the presence or absence of reinforcing fiber in the composition; 2. Reinforcement of backfill with polypropylene fiber changes the fracture behavior of samples and passes from brittle to ductile at maximum strain rate; 3. Reinforcing fibers in the cement backfill have an overlapping effect, which significantly slows the development of cracks and increases the ductility of the material. Resume. The results of the research can be useful in the creation of high-strength and resistant to increased bending stresses artificial mass where tailings are used as an aggregate. In the future there is a need to study the cement backfill with different types of reinforcing fibers.

Multivitamin complex-loaded electrospun polyvinyl alcohol core/shell structure fibers for transdermal delivery system: In-silico and experimental studies

Transdermal delivery systems offer a controlled and targeted environment for releasing drugs compared to other delivery systems. This study presents the fabrication of polyvinyl alcohol (PVA) fibers with a multivitamin complex (MV) using the electrospinning technique (ES). The research focuses on understanding how various fiber structures, such as core/shell, simple fibers, and ES parameters, affect the MC release mechanism and cell viability behavior.The vitamin complexes were uniformly encapsulated within the polymeric chains in all structure fibers. PVA simple fibers with and without the vitamin complex don't significantly differ in diameter size. However, the core/Shell fiber has a notable decrease in fiber diameter of 45 %.The fiber with a core/shell structure resulted in a slower release rate of the vitamin complex than simple fiber. According to the Korsmeyer-Peppas model, the release mechanism observed in our study for the simple fibers is classical Fickian diffusion. Instead, core/shell fibers indicate a more anomalous or non-Fickian behavior.The structural configurations of the fibers do not result in statistically significant differences in cell viability. This could be attributed to the identical nature of materials used, including the polymer and MV, across all cases.Finally, a computational chemistry study was used to examine the interaction between polyvinyl alcohol (PVA) and vitamins K3 and B3, like a model of MV. The analysis showed four strong hydrogen bonds between PVA and vitamin B3, whereas the interaction between PVA and vitamin K3 only had one hydrogen bond. Furthermore, the PVA and vitamin B3 interaction had higher energy and was more exothermic and spontaneous than the PVA-vitamin K3 interaction. On the other hand, the PVA-vitamin K4 interaction displayed higher reactivity due to its lower separation energy. In contrast, the PVA-vitamin B3 interaction was more stable.

PLLA-COI multilayer nanofiber membrane for anti-adhesion of the Achilles tendon

Peritendinous Adhesion is a complication after surgery for Achilles tendon injury. This complication can be treated with surgical stents. Anti-adhesion membrane is an effective scaffold material to prevent adhesion. However, currently available PLA anti-adhesion membranes have the problems of poor anti-adhesion performance and low healing effect on the Achilles tendon. In this study, combined the advantages of L-polylactic acid (PLLA) hydrophobicity and Collagen type I (COI) hydrophilicity, a PLLA-COI multilayer nanofiber membrane composed of a multilayer structure was prepared by solution electrospinning and characterized its morphology, physical, mechanical, and in vitro properties. The membrane has a structure characteristic of gradually decreasing fiber diameter, increasing porosity and increasing hydrophilicity from the outer to the inner layer. The cell experiment results show that the PLLA-COI multilayer nanofiber membrane has good cell compatibility. We also carried out in vivo research with the rabbit Achilles tendon adhesion model. The results indicate that the membrane has an excellent anti-adhesion effect and strong hydrophilicity, effectively promoting Achilles tendon injury recovery and preventing adhesion. In addition, this membrane does not require sutures for surgery, effectively reducing the complexity of use, with great potential in preventing peritendinous adhesion.

Structural and pathophysiological muscle changes up to one year after post-stroke hemiplegia: a systematic review.

Muscle changes after stroke cannot be explained solely on the basis of corticospinal bundle damage. Muscle-specific changes contribute to limited functional recovery but have been poorly characterized. We conducted a systematic review of muscular changes occurring at the histological, neuromuscular and functional levels during the first year after the onset of post-stroke hemiplegia. A literature search was performed on PubMed, Embase and CINHAL databases up to November 2022 using a keyword combination comprising cerebral stroke, hemiplegic, atrophy, muscle structure, paresis, skeletal muscle fiber type, motor unit, oxidative stress, strength, motor control. Twenty-seven trial reports were included in the review, out of 12,798 articles screened. Structural modifications described on the paretic side include atrophy, transformation of type II fibers into type I fibers, decrease in fiber diameter and apparent myofilament disorganization from the first week post-stroke up to the fourth month. Reported biochemical changes comprise the abnormal presence of lipid droplets and glycogen granules in the subsarcolemmal region during the first month post-stroke. At the neurophysiological level, studies indicate an early decrease in the number and activity of motor units, correlated with the degree of motor impairment. All these modifications were present to a lesser degree on the non-paretic side. Although only sparse data concerning the subacute stage are available, these changes seem to appear during the first two weeks post-stroke and continue up to the third or fourth month. Considering these early pathophysiological changes on both the paretic and non-paretic sides, it seems crucial to promptly stimulate central and also peripheral muscular activation after stroke through specific rehabilitation programs focused on the maintenance of muscle capacities associated with neurological recovery or plasticity.

Nanocrystals AuNi9 fibers: Ultra-high strength and synergetic strengthening mechanism

The enhancement of mechanical properties of the material leads to an increase in its resistance. In this study, the AuNi9 fibers with different diameters were prepared through continuous multi-die cold-drawing. With the decrease of the fiber diameter, there was a significant reduction in grain size, resulting in an increase in mechanical properties, while resistivity showed a slight decrease as well. When the fiber diameter decreases from 70 μm to 30 μm, the grain size reduces from 130 nm to 95 nm. Consequently, the hardness and tensile strength of the fiber are enhanced from 3.29 GPa and 1238 MPa to 4.09 GPa and 1351 MPa, respectively, while resistivity drops from 0.191 mΩ·mm to 0.182 mΩ·mm. A synergetic strengthening model has been proposed for the AuNi9 fibers, where both fine-grain and dislocation strengthening are the primary mechanisms. Additionally, twin boundaries contribute significantly to low resistivity.

Design and manufacture of an additive manufacturing printer based on 3D melt electrospinning writing of polymer

Abstract Objectives Electrospinning is one of the most well-known approaches to producing polymer nanofibers from a polymer solution by applying a potential difference (voltage) between the spinner and the collector, which is used in various industries such as medicine and military. This method has some significant restrictions, like low process efficiency due to the evaporation of the solvent, remaining solvent on the fibers, which are sometimes toxic, and inability to control the geometry of the produced fibers. On the other hand, preparing some solvents used in the electrospinning of polymer solutions is costly. Polymer melt electrospinning writing is a replacement for this type of electrospinning, which can be mentioned in terms of economy, efficiency, and production of solvent-free fibers. Therefore, in this research, a melt polymer electrospinning device was designed and manufactured according to existing extrusion-based additive manufacturing (AM) devices (3D printer). Methods Changes in an extrusion-based 3D printer to convert it into a writing electrospinning device experimentally. Results PLA and PCL fibers with diameters ranging from 8 to 84 μm were produced. The effect of process variables on the produced fibers’ diameter was investigated: Applied potential difference between the nozzle and the substrate: As its increases, the fiber diameter decreases. Increasing temperature: As its increases, the fiber diameter decreases. Distance between the nozzle and the substrate: As its increases, the fiber diameter increases. Flow rate: As its increases, the fiber diameter increases. Conclusions By presenting a 3D printer-electrospinning device, it is possible to control the fiber’s diameter and the 3D geometry in the 3D printing-electrospinning process.

Fabrication of drug-eluting polycaprolactone and chitosan blend microfibers for topical drug delivery applications

Chronic and non-healing wounds show delayed and incomplete healing process, which expose the patients to a high risk of infection. These types of wounds require frequent change of dressing, which is a burden on the patients. In addition, ideal dressing needs to meet the requirements in minimizing microbial infiltration and growth while balancing moisture and exchanging oxygen with outside environment. To overcome the challenge in frequent change of dressing and meet the design requirements, current researches have focused on the development of electrospun fibers with incorporation of small molecule drugs for sustained release purpose. In this study, electrospinning was performed to fabricate blend fibers consisting of 15 wt% of polycaprolactone (PCL) and 4 wt% of chitosan (CS) at various blend ratios with the incorporation of a model small molecule drug, acetylsalicylic acid (ASA). Results showed that fibers became more hydrophilic when increasing CS concentration from 0% to 60% in PCL/CS blank fibers. Increasing CS concentration decreased fiber diameter resulting in the decrease of fiber mechanical properties. Furthermore, the addition of 10% w/w ASA also made the fibers more hydrophilic and further decreased the fiber diameter. There were no linear relationships between CS concentrations and fiber mechanical properties in the drug-loaded samples, which indicated some level of drug-polymer interactions. Fiber mechanical properties and drug release rates were two major aspects indicative of strong and/or weak drug-polymer interactions. In vitro drug release in PBS buffer solution showed a burst profile of ASA (30%) up to 2 h followed by a zero-order release rate up to 2 days.

High yield production of nanocrystalline cellulose from corn cob through a chemical-mechanical treatment under mild conditions

Agricultural biomass waste such as corn cob is available in large quantities and can be used as renewable materials for various applications. Corn cob was converted into nanocrystalline cellulose by using mild sulfuric acid concentrations (30 % w/v) at low temperature (50 °C) and a relatively shorter time extraction (30 min) combined with mechanical treatment using a conventional high-speed blender. NCC from cellulose and α-cellulose from corn cobs have been successfully isolated with relatively high yields and crystallinities of 50.07–65.33 % and 65.5–69.9 %, respectively. Scanning electron microscopy (SEM) evaluated the morphological variation and dimension from corn cob fiber (CF), delignification fiber (DF), cellulose, and α-cellulose, which shows that each pretreatment stage causes a decrease in fiber diameter from 16.56 to 5.48 μm. Transmission electron microscopy (TEM) images confirmed the nano-scale dimension with fiber diameters ranging between 9.35 nm and 6.51 nm. Thermogravimetric analysis shows that NCC has relatively high thermal stability ranging from 429 to 437 °C. Thus, this characteristic of NCC has the potential to be applied as a reinforcing agent in various fields of polymer composites. Finally, this study presents a method for isolating NCC from corncob waste using a conventional high-speed blender in a mild condition process with a relatively low cost, environmentally friendly pathway, and high yield that was still preserved.

Direct Fabrication of Functional Shapes on 3D Surfaces Using Electrospinning.

In this work, we demonstrate the ability to simultaneously pattern fibers and fabricate functional 2D and 3D shapes (e.g., letters, mask-like structures with nose bridges and ear loops, aprons, hoods) using a single step electrospinning process. Using 2D and 3D mesh templates, electrospun fibers were preferentially attracted to the metal protrusions relative to the voids so that the pattern of the electrospun mat mimicked the woven mesh macroscopically. On a microscopic scale, the electrostatic lensing effect decreased fiber diameter and narrowed the fiber size distribution, e.g., the coefficient of variation of the fiber diameter for sample collected on a 0.6 mm mesh was 14% compared to 55% for the sample collected on foil). Functionally, the mesh did not affect the wettability of the fiber mats. Notably, the fiber patterning increased the rigidity of the fiber mat. There was a 2-fold increase in flexural rigidity using the 0.6 mm mesh compared to the sample collected on foil. Overall, we anticipate this approach will be a versatile tool for design and fabrication of 2D and 3D patterns with potential applications in personalized wound care and surgical meshes.

Electrospinning of peanut protein isolate/poly-L-lactic acid nanofibers containing tetracycline hydrochloride for wound healing

In the present study, we explored the feasibility of using electrospinning technology to prepare tetracycline-hydrochloride (TCH)-containing peanut protein isolate/poly-L-lactic acid (TCH/PPI/PLLA) nanofiber membranes as a new type of wound dressing. PPI was prepared using the alkali-dissolved acid precipitation method, and PPI/PLLA nanofibers containing TCH at mass loadings of 5%, 10%, and 15% were prepared by electrospinning. The resultant nanofibers were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and comprehensive thermal analysis. Furthermore, the wettability, mechanical properties, and drug release efficacy of the TCH/PPI/PLLA nanofibers were evaluated, and their effect on Staphylococcus aureus and mouse skin fibroblasts were investigated. A mouse-skin wound model was established to assess the healing effect of TCH/PPI/PLLA nanofibers. The results revealed that TCH exists in the nanofibers in an amorphous state, and that the addition of TCH has no observable effect on the morphology of the nanofiber membrane. As the TCH content increases, the fiber diameter decreases, while the mechanical strength and wettability of the membranes increase. TCH/PPI/PLLA composite nanofibers provide a significant initial release of TCH, and the release mechanism of TCH appears to be Fick's diffusion. The hemolysis rates of the electrospun PLLA nanofibers, PPI/PLLA composite nanofibers, and drug-loaded PPI/PLLA nanofibers are all below 5%. TCH retains its anticoagulant effect when composited with the PPI/PLLA composite nanofibers and exhibits low toxicity to cells. The PPI/PLLA nanofiber membrane loaded with TCH has an inhibitory effect on S. aureus and E. coli，and promotes skin-wound healing in mice. Therefore, TCH/PPI/PLLA nanofiber membranes prepared by electrospinning technology show promise as a next-generation wound dressing material.

Fabrication and Characterization of Piezoelectric Polymer Composites and Cytocompatibility with Mesenchymal Stem Cells.

Piezoelectric materials are promising for biomedical applications because they can provide mechanical or electrical stimulations via converse or direct piezoelectric effects. The stimulations have been proven to be beneficial for cell proliferation and tissue regeneration. Recent reports showed that doping different contents of reduced graphene oxide (rGO) or polyaniline (PANi) into biodegradable polyhydroxybutyrate (PHB) enhanced their piezoelectric response, showing potential for biomedical applications. In this study, we aim to determine the correlation between physiochemical properties and the in vitro cell response to the PHB-based composite scaffolds with rGO or PANi. Specifically, we characterized the surface morphology, wetting behavior, electrochemical impedance, and piezoelectric properties of the composites and controls. The addition of rGO and PANi resulted in decreased fiber diameters and hydrophobicity of PHB. The increased surface energy of PHB after doping nanofillers led to a reduced water contact angle (WCA) from 101.84 ± 2.18° (for PHB) to 88.43 ± 0.83° after the addition of 3 wt % PANi, whereas doping 1 wt % rGO decreased the WCA value to 92.56 ± 2.43°. Meanwhile, doping 0.2 wt % rGO into PHB improved the piezoelectric properties compared to the PHB control and other composites. Adding up to 1 wt % rGO or 3 wt % PANi nanofillers in PHB did not affect the adhesion densities of bone marrow-derived mesenchymal stem cells (BMSCs) on the scaffolds. The aspect ratios of attached BMSCs on the composite scaffolds increased compared to the PHB control. The study indicated that the PHB-based composites are promising for potential applications such as regenerative medicine, tissue stimulation, and bio-sensing, which should be further studied.

The Effect of Alkaline Treatment On the Schizostachyum Grande Fibre for Textile Applications

Among commercial Malaysian bamboo species, Schizostachyum Grandespecies are characterised by their longest internode and thinner culm wall, which allow more attainable fibres during the extraction process. However, the chemical composition of bamboo fibres is higher than any other natural fibre, resulting in coarse and stiff fibres that require alkaline treatment to develop fine fibres. This paper presents the effect of alkaline treatment concentration and soaking time on the physical properties and tensile properties of bamboo fibres. The bamboo fibre was treated with an alkaline solution at 4 and 8 wt.% concentration for 6, 12, 18, and 24 hours. The diameter and fineness of bamboo fibre wereevaluated to determine if alkaline concentration and soaking time affected the fibres. Results showed that the treated fibre diameter decreased by 23.2% to 66.51μm at 8 wt.% alkaline concentrationsfor 12 hours of soaking timecompared to the untreated bamboo fibre of 86.56μm.The fibre fineness of 11.96 tex was produced at 24 hours of soaking time and8 wt.% alkaline concentrations. Alkaline treatment was effective in causing a decrease in fibre diameter and produced the finest fibre. Thinner and finer fibre was produced as alkaline concentration and soaking time increased.The highest tensile strength of treated bamboo fibre was 1.42 GPa at a 4 wt% alkaline concentration and6 hours of soaking time. Elongation at break and tenacity improved remarkably when the alkaline concentration and soaking time were increased, which were 3.11% and 45 cN/Tex, respectively, at 8 wt% alkaline concentrationsfor 12 hours of soaking time. Moreover, the 8 wt% alkaline concentration was the best for bamboo fibre because the treatment was effective in causing a decrease in fibre diameter and produced the finest fibre. The elongation at break and tenacity of fibres were also improved at 12 hours of soaking time. The tensile strength and modulus of fibre were reduced at longer soaking times at high alkaline concentrations of more than 18 hours.