Acid Fibrous Membranes Research Articles

Biobased Triesters as Plasticizers for Improved Mechanical and Biodegradable Performance of Polylactic Acid Fibrous Membranes as Facemask Materials

Biobased Triesters as Plasticizers for Improved Mechanical and Biodegradable Performance of Polylactic Acid Fibrous Membranes as Facemask Materials

Scalable fabrication of multifunctional polylactic acid fibrous membranes with enhanced superhydrophobicity and radiative cooling performance

The disadvantages of traditional bio-based materials melt centrifugal spinning, such as low efficiency, long cycle and poor performance, limit its industrialization process. Herein, a scalable strategy was proposed for the fast and scale fabrication of bio-based melt centrifugal spinning fiber. The polymer melt was continuously transported to the high-speed rotating centrifugal disk, where it was rapidly conveyed and separated. The separated melt was then drawn and cooled by the synergistic supergravity and high-pressure cyclone field, resulting in formatting a nonwoven fabric by self-bonding alone with a diameter of ∼3 μm. Compared to conventional white CVC fabrics, the fabricated polylactic acid fibrous membranes demonstrated exceptional biocompatibility (cell viability of 98.7%), radiative cooling properties and favorable emissivity (94.1%), which can reduce the covered object temperature by 4.6 °C during hot summer. Furthermore, the water vapor transmission rate, moisture regain, water absorption, and boiling water shrinkage rate of PP20/8-F are 39.98 g m−2 h−1, 2.31%, 2.09%, and 8.11%, respectively, meeting the comfort requirements of wearable fabrics. The robust superhydrophobicity with a water contact angle of 153 ± 1° provides excellent antifouling and self-cleaning properties. This novel bio-based material melt centrifugal spinning method provides a viable strategy for the industrial preparation of high-performance and functionalized fibrous.

Monitoring and kinetic study of alkaline hydrolysis of polylactic acid fibrous membrane via aggregation-induced emission (AIE) technique

Hydrolysis mechanism of polylactic acid (PLA) materials has been the focus of PLA material research. Herein, we report a novel method for monitoring the hydrolysis of PLA. Tetraphenylene aldehyde (TPEA) with aggregation induced emission (AIE) property was synthesized as a fluorescence probe for being introduced into PLA-base fibrous membrane via electrospinning. Then, the obtained TPEA/PLA composite fibrous membrane was hydrolyzed in an aqueous environment with controllable temperature and pH. The detection of PLA hydrolysis was achieved by examining the fluorescence intensity changes caused by the release of TPEA during the hydrolysis. On the basis of the structure study of the prepared fibrous membranes, this study investigated the changes in fluorescence intensity of the degradation environment during the hydrolysis process. The correlation between fluorescence and PLA hydrolysis was investigated with the kinetic research to prove the feasibility of monitoring PLA hydrolysis via AIE technique.

Anticancer and bone-enhanced nano-hydroxyapatite/gelatin/polylactic acid fibrous membrane with dual drug delivery and sequential release for osteosarcoma

Surgical resection of osteosarcoma is always accompanied by residual metastasis of tumor cells and bone tissue defects. In this work, a novel kind of gelatin/polylactic acid (PLA) coaxial fiber membrane with a shell layer containing doxorubicin-loaded hydroxyapatite (DOX@nHAp) nanoparticles and a core layer containing Icariin (ICA) was developed for antitumor and bone enhancement at the defect site. Physical evaluation displayed that the composite membrane provided moderate hydrophilicity, enhanced tensile strength (Dry: 2–3 MPa, wet: 1–2 MPa) and elasticity (70–100 %), as well as increased specific surface area and pore volume (19.39 m2/g and 0.16 cm3/g). In SBF, DOX@nHAp in the fibers promoted biomineralization on the fiber surface. In in vitro evaluation, approximately 80 % of DOX had a short-term release during the first 8 days, followed by long-term release behavior of ICA for up to 40 days. CCK-8 results confirmed that the membrane could actively support MC3T3-E1 cells proliferation and was conductive to high alkaline phosphatase expression, while the viability of MG-63 cells was effectively inhibited to 50 %. Thus, the dual-loaded fibrous membrane with a coaxial structure and nHAp is a promising system for anticancer and defects reconstruction after osteosarcoma surgery.

PLGA/Gelatin/Hyaluronic Acid Fibrous Membrane Scaffold for Therapeutic Delivery of Adipose-Derived Stem Cells to Promote Wound Healing.

Hyaluronic acid (HA) has been suggested to be a preferential material for the delivery of adipose-derived stem cells (ASCs) in wound healing. By incorporating HA in electrospun poly (lactide-co-glycolide) (PLGA)/gelatin (PG) fibrous membrane scaffolds (FMS), we aim to fabricate PLGA/gelatin/HA (PGH) FMS to provide a milieu for 3D culture and delivery of ASCs. The prepared FMS shows adequate cytocompatibility and is suitable for attachment and growth of ASCs. Compared with PG, the PGH offers an enhanced proliferation rate of ASCs, shows higher cell viability, and better maintains an ASC-like phenotype during in vitro cell culture. The ASCs in PGH also show upregulated expression of genes associated with angiogenesis and wound healing. From a rat full-thickness wound healing model, a wound treated with PGH/ASCs can accelerate the wound closure rate compared with wounds treated with PGH, alginate wound dressing, and gauze. From H&E and Masson's trichrome staining, the PGH/ASC treatment can promote wound healing by increasing the epithelialization rate and forming well-organized dermis. This is supported by immunohistochemical staining of macrophages and α-smooth muscle actin, where early recruitment of macrophages, macrophage polarization, and angiogenesis was found due to the delivered ASCs. The content of type III collagen is also higher than type I collagen within the newly formed skin tissue, implying scarless wound healing. Taken together, using PGH FMS as a topical wound dressing material for the therapeutic delivery of ASCs, a wound treated with PGH/ASCs was shown to accelerate wound healing significantly in rats, through modulating immunoreaction, promoting angiogenesis, and reducing scar formation at the wound sites.

Enhanced moisture permeability and heat dissipation effect of solvent-free boron nitride fluids based polylactic acid fibrous membranes

Exceptional moisture permeability and heat dissipation performance are vital for wearable polymer fabrics. In this study, solvent-free boron nitride fluids (BNfs) with liquid-like behavior were prepared via an ion exchange reaction. The BNfs were then incorporated into polylactic acid (PLA) fibrous membranes to endow the membranes with multifunctionality. The results showed that the surface wetting behavior of the membranes containing 15 wt% and 20 wt% BNfs changed the hydrophobicity of pure PLA to superhydrophilicity, showing excellent moisture permeability. PLA/BNfs fibrous membranes with 20 wt% loading had 2.9-fold increased thermal conductivity when compared with pure PLA, leading to an enhanced heat dissipation effect. Additionally, the PLA/BNfs fibrous membrane had better mechanical properties than the pure PLA. The resultant multifunctional PLA/BNfs fibrous membranes have great application prospects in flexible wearable fabrics.

Preparation and characterization of solvent-free fluids reinforced and plasticized polylactic acid fibrous membrane

In this paper, the electronspun Polylactic acid (PLA)/TiO2 nanofluids (nfs) fibrous membrane with good toughness, hydrophilicity and antibacterial activities are fabricated by taking full advantages of solvent-free TiO2 nfs with amphiphilicity and ionic conductivity. The resulting PLA/TiO2 nfs fibrous membrane exhibits excellent mechanical performance with a tensile strength and elongation at break of 3.68 MPa and 97.32 MPa at 5 wt% loading, respectively, which is 4 and 8 times higher than that of pure PLA, respectively. Additionally, TiO2 nfs can migrate onto the surface of PLA fibers during electrospun process, which significantly enhanced hydrophilicity, antistatic property, moisture sorption capacity and wicking properties of PLA fabrics. Meanwhile, the membrane also showed ultrafast water filtration of 3500 L m−2 h−1 driven by gravity force, which is 10–12 times higher than that of commercial ultrafiltration membrane. After ion-exchange reaction with salt solution, excellent antibacterial activity (against E. coli and S. aureus was 95% and 99.9%, respectively) and separation efficiency (above 90% on E. coli) of the obtained fabrics are also achieved. Overall, organic nfs are an idea candidate for fabricating hydrophilic PLA based biodegradable fabric that can be applied in contaminated water treatment, antibacterial textiles and biodegradable absorption materials.

Tantalum-coated polylactic acid fibrous membranes for guided bone regeneration.

Guided bone regeneration (GBR) membrane is necessary to reconstruct the defect bone tissue by defending penetration of soft tissues. Polylactic acid (PLA) attracts much attention to utilize as a GBR membrane because it has relatively high mechanical strength and biodegradability. However, the poor osteoconductivity of PLA is a major concern. The aim of this study is to improve the osteoconductivity of fibrous, electrospun, PLA guided bone regeneration membranes by coating the fiber surface with highly biocompatible tantalum (Ta). Ta coating of electrospun PLA membrane was created through sputtered Ta ions surrounding the PLA fibers. The Ta-coated PLA (Ta-PLA) membranes remain a randomly aligned fibrous structure with no defects caused by sputtering. The chemical composition of Ta-PLA membrane indicates Ta coating was well deposited on PLA fibers. Although the mechanical strength of Ta-PLA was reduced compared with bare PLA membrane, the Ta coating layer does not readily delaminate from the single PLA fiber surface due to its cladded structure which indicates that the Ta coating has high mechanical stability on PLA fibers. In vitro cell tests demonstrate that the attachment, proliferation, and differentiation of preosteoblasts are significantly promoted on the Ta-PLA membranes compared to bare PLA. In an in vivo animal test, most calvarial defects in the Ta-PLA group are covered with newly formed bone within six weeks, while the defects in the bare PLA group are rarely covered. Furthermore, the degree of bone healing in the Ta-PLA group is comparable to healing observed on collagen membranes, which are highly bioactive materials. These results indicate the superior osteoconductivity of Ta-PLA will make it particularly useful as a guided bone regeneration membrane.

Solar-driven interfacial evaporation based on double-layer polylactic acid fibrous membranes loading Chinese ink nanoparticles

Freshwater is a crucial resource for human life existence, diminishing freshwater resources and ever-increasing water demand had sprouted interest in desalination and water recycling. Solar energy has been utilized as an alternative to fossil fuels for energy requirements in water recycling. Efficient photo-thermal conversion materials and evaporation module are indispensable for such systems. In the current study, an innovative double-layer interfacial evaporation module of polylactic acid (PLA) fibrous membrane loaded with Chinese ink nanoparticles is synthesized. Electrospun layer of micro-scale diameter with enhanced hydrophilic properties is employed as water transport layer, while solution of electrospun layer of nano-scale diameter fiber loaded with Chinese ink nanoparticles functioned as evaporation interface. Ideal dispersion of Chinese ink nanoparticles in the PLA nanofiber is ensured with Field Emission Scanning Electron Microscopy (FE-SEM). Experiments with designed evaporation module indicates that double-layer membrane with 2 wt% Chinese ink nanoparticles has achieved an evaporation rate of at 1.29 kg cm−2 h−1 at 81.0% efficiency under simulated sunlight with a illumination intensity of 1 sun (1 sun = 1 kW/m2), which is significantly higher than the pure water and conventional membranes without Chinese ink nanoparticles. The developed fibrous membrane is able to retain its enhanced characteristics even after 20 cycles under same operating conditions during the durability test. The designed evaporation module is a promising candidate for conversion of waste water to clean water.

Hydrogen Sulfide-Releasing Fibrous Membranes: Potential Patches for Stimulating Human Stem Cells Proliferation and Viability under Oxidative Stress.

The design of biomaterial platforms able to release bioactive molecules is mandatory in tissue repair and regenerative medicine. In this context, electrospinning is a user-friendly, versatile and low-cost technique, able to process different kinds of materials in micro- and nano-fibers with a large surface area-to-volume ratio for an optimal release of gaseous signaling molecules. Recently, the antioxidant and anti-inflammatory properties of the endogenous gasotramsmitter hydrogen sulfide (H2S), as well as its ability to stimulate relevant biochemical processes on the growth of mesenchymal stem cells (MSC), have been investigated. Therefore, in this work, new poly(lactic) acid fibrous membranes (PFM), doped and functionalized with H2S slow-releasing donors extracted from garlic, were synthetized. These innovative H2S-releasing mats were characterized for their morphological, thermal, mechanical, and biological properties. Their antimicrobial activity and effects on the in vitro human cardiac MSC growth, either in the presence or in the absence of oxidative stress, were here assessed. On the basis of the results here presented, these new H2S-releasing PFM could represent promising and low-cost scaffolds or patches for biomedical applications in tissue repair.

Advanced Functional Materials Solutions to Engineering the Neural Interface

Advanced Functional Materials Solutions to Engineering the Neural Interface

Neural Electrodes Based on 3D Organic Electroactive Microfibers

AbstractNeural electrodes used for in vivo biomedical applications (e.g., prostheses, bionic implants) result in glial invasion, leading to the formation of a nonexcitable scar that increases the distance between neurons and electrode and increases the resistance to current flow. The result is progressive deterioration in the performance of stimulation or recording of neural activity and inevitable device failure. Also, electrodes with a 2D surface have a limited proximity to neurons. In the present study, a macroporous and fibrous 3D neural electrode is developed using poly‐L‐lactic acid fibrous membranes imbued with electroactive properties via a coating of the conductive polymer poly(3,4‐ethylenedioxythiophene) (PEDOT), using vapor phase polymerization. The electrical properties of the PEDOT‐coated substrates are studied using sheet resistance and impedance. PEDOT electrode biocompatibility is assessed through in vitro assays using patch‐clamp electrophysiology and calcium imaging of isolated and cultured rat hippocampal neurons. PEDOT fibers support robust normal functional development of neurons, including synaptic networking and communication. Stimulation and recording of activity in brain slices and from the surface of the brain using 3D‐PEDOT fibrous electrodes are indistinguishable from recordings using conventional glass or platinum electrodes. In vivo studies reveal minimal reactive gliosis in response to electrode implantation.

Repair of urethral defects with polylactid acid fibrous membrane seeded with adipose-derived stem cells in a rabbit model

Aim: The aim of this study is to evaluate the capacity of polylactid acid (PLA) fibrous membrane seeded with allogeneic rabbit adipose tissue-derived stem cells (ADSCs) to repair urethral defects in a rabbit model.Materials and methods: Rabbit ADSCs were harvested and phenotypically characterized. Twenty-four New Zealand male rabbits with 5-mm urethral mucosal defects were randomly divided into two groups. They underwent urethroplasty either with PLA fibrous membrane seeded with ADSCs (group A) or blank PLA fibrous membrane (group B). At 4 and 6 weeks after urethroplasty, the urethral grafts were collected and analyzed grossly and histologically. The incidence rate of urethrostenosis was measured.Results: The adipose tissue-derived cells in monolayer culture showed a typical morphology of mesenchymal stem cells (MSCs). They were positive for the MSC marker CD44 but negative for lineage markers CD45 and CD105. Six weeks after surgery, the incidence rate of urethrostenosis in group A was significantly lower than that in group B (p < 0.05). In group A, the ADSC-seeded grafts showed a normal urethral architecture with a thickened muscle layer. In contrast, the newly developed urethra in group B demonstrated a fewer number of urothelial layers and scarce or no smooth muscle cells.Conclusion: The PLA scaffold seeded with ADSCs is effective in urethral regeneration in a rabbit model. ADSCs may represent a promising source of seed cells for urethral tissue engineering.

Urethral replacement using polylactid acid fibrous membrane seeded with adipose derived stem cells in rabbits with injured urethra

Objective To investigate whether polylactid acid (PLA) fibrous membrane seeded with rabbit adipose derived stem cells (ASCs) could be a potential substitute of urothelium.Methods ASCs were harvested,and their phenotype was identified.The ASCs were cultured onto the PLA fibrous membrane.Twenty-four New Zealand male rabbits were randomly divided into two groups.In male rabbits,a urethral mucosal defect was created,and urethroplasty performed only using a PLA fibrous membrane (12 rabbits; control group) or using a PLA fibrous membrane seeded with ASCs (12 rabbits; experimental group).The animals were euthanized at 4th and 6th week after urethroplasty,and their urethral grafts were harvested and analyzed grossly and histologically.The bladder of rabbit was observed during the operation.Results Twenty-one rabbits were involved in the result analysis.The phenotype of the isolated cells was CD44 positive,CD105 and CD45 negative,which were in accordance with the characteristics of ASCs.After 6 weeks,there was evidence of stratified epithelial cells and some smooth muscle fibers in the experimental group,and single layer of epithelium cells with disorganized muscle fibre was observed in the control group.Gross view of the bladder revealed the rate of stricture in the experimental group was lower than in the control group (27.3％ vs.60.0％,P ＞ 0.05).Conclusion Urethral reconstruction with a PLA fibrous membrane seeded with ASCs could form the tissues similar to corpus cavernous urethra. Key words: Adipose derived stem cells; Polylactid acid fibrous membrane; Tissue engineering

Fabrication of zein/hyaluronic acid fibrous membranes by electrospinning

Electrospinning of biopolymers, such as proteins and polysaccharides, has recently attracted much attention for the fabrication of scaffolds for tissue engineering. In this report, zein/hyaluronic acid (HA) blend fibrous membranes were electrospun and characterized. To facilitate the compatibility of zein and HA, poly(vinyl pyrrolidone) (PVP) was introduced into aqueous ethanol solutions of the blend. A series of zein/HA/PVP blend fibrous membranes with different volume ratios were successfully electrospun. The effect of blend composition on the morphology of electrospun fibrous membranes was investigated by scanning electron microscopy. The average diameter of blend fibers increased with increasing the content of zein component. The electrospun zein/HA/PVP fibrous membranes were then cross-linked by methylene diphenyl diisocyanate (MDI). The morphology of the cross-linked zein/HA/PVP fibrous membranes changed slightly compared with un-cross-linked membranes. Tensile tests demonstrated that the mechanical properties of the zein/HA/PVP fibrous membranes were improved by cross-linking.