Electrospinning of PCL-Based Blends: Processing Optimization for Their Scalable Production

Electrospinning-netting of spider-inspired polycaprolactone/collagen nanofiber-nets incorporated with Propolis extract for enhanced wound healing applications

Nanofibers hold significant promise for wound healing applications, but their potential is limited by their large diameter. To overcome this limitation, the development of nanofibrous systems with refined nanonets (approximately 20 nm in diameter) represents a notable improvement. In this study, a composite of polycaprolactone/collagen (PCLC) nano-fiber/nets (NFNs) was fabricated using benign solvents (acetic acid and formic acid) via the electro-spinning/netting (ESN) technique, harnessing the regenerative potential of collagen as a biological macromolecule. Additionally, to enhance the natural attributes of the NFNs structure, Propolis extract, renowned for its wound healing properties, was incorporated. Five ESN solutions were prepared: PCL, PCLC, PCLC/Pro 5 %, PCLC/Pro 10 %, and PCLC/Pro 15 %. NaCl salt was introduced into all ESN solutions to improve nanonets formation. FE-SEM imaging demonstrated successful nano-net formation in all ESN solutions except for the PCL formulation. The fabricated scaffolds exhibited spider-like nanonets with the addition of collagen and further enhanced nano-net formation with Propolis incorporation. Trunk nanofibers showed filamentous structures without any beads, with an average diameter of 164-728 nm, while the diameter of branched fibers (nanonets) was approximately 20 nm. WVTR values of the NFNs were comparable to commercial dressings such as Tegaderm. The results also demonstrated the potent cytoprotective effects of Propolis-loaded NFNs in a dose-dependent manner. Furthermore, the viability of HFF-2 cells after 72 h of culture on PCLC NFNs significantly increased compared to PCL nanofibers. The highest cell viability was observed in PCLC/Pro 15 % nanofibers after 24, 48, and 72 h of cell culture, indicating the proliferative effect of Propolis extract in nanoformulated form. Additionally, the scaffolds exhibited a hemocompatibility of <3 %, further highlighting their potential in wound healing therapeutics.

Exploring temperature-responsive drug delivery with biocompatible fatty acids as phase change materials in ethyl cellulose nanofibers

This study introduces a novel temperature-responsive drug delivery system using ethyl cellulose (EC) nanofibers encapsulating a eutectic mixture of lauric acid/stearic acid (LA/SA) as phase change materials (PCMs) and Rhodamine B (RhB) as a model drug. Employing blend electrospinning, the nanofibers achieved controlled drug release responsive to temperature changes. The peak shift of the carbonyl group in FTIR analysis confirmed drug-polymer compatibility, while the absence of RhB peaks in the XRD and DSC assessments revealed RhB's amorphous distribution within the fibers. Our findings demonstrate that RhB release is dependent on its loading, with a slow initial release (<2 %) for 1 % and 5 % RhB loadings and a burst release (~12 %) for 10 % loading. Notably, the release rate was tunable at 37 °C by adjusting LA/SA concentration. The optimal LA/SA loading for temperature-responsive release is identified as 10 %. Over 240 h, there is a 32 % increase in RhB release at 37 °C, and an additional 8 % increase at 40 °C, compared to 25 °C. This research illustrates the potential of PCM-integrated nanofibers in smart drug delivery, particularly for chemotherapy, antibiotics, and anti-inflammatory drugs, showcasing an innovative approach to improving therapeutic efficiency while reducing side effects.

Braided biomimetic PCL grafts for anterior cruciate ligament repair and regeneration

Anterior cruciate ligament (ACL) is a knee joint stabilizer with a limited regeneration capacity mainly because of low cellular content. State-of-the-art procedures are unable to restore the functions of the tissue as demonstrated by limited success rates. Regenerative engineering can offer a solution for restoring the functions of torn/ruptured ligaments provided that biomimetic grafts are available as grafts/scaffolds. However, a model construct to test behavior of cells to better understand the healing mechanism of ACL is still missing. This study, firstly, aimed at creating an injured rabbit ACL model. Then, the injured and healthy ACL tissues were characterized in terms of alignment and diameter distributions of collagen fibrils. Next, polycaprolactone (PCL) grafts were prepared from braided electrospun meshes and were characterized in terms of alignment and diameter distributions of fibers. Finally, biomechanical properties of ACL tissue and mechanical properties of PCL grafts were determined and compared. Findings demonstrated that distributions of the fiber diameters of PCL electrospun grafts were similar to diameter distribution of collagens of healthy and injured rabbit ACL. The novelty of this study relies on the determination of the diameter distribution of collagens of healthy and injured rabbit ACL tissues, and fabrication of PCL grafts with diameter distributions similar to that seen in healthy and injured ACLs. This study is significant because it addresses a worldwide clinical problem associated with millions of patients. The fibrous biomimetic graft designed in this study is different from the traditional grafts that exhibit unimodal distribution, and it is expected to have a significant contribution to ACL regeneration efforts.

Electrospun Nanofibers: Shaping the Future of Controlled and Responsive Drug Delivery

Electrospun nanofibers for drug delivery systems (DDS) introduce a revolutionary means of administering pharmaceuticals, holding promise for both improved drug efficacy and reduced side effects. These biopolymer nanofiber membranes, distinguished by their high surface area-to-volume ratio, biocompatibility, and biodegradability, are ideally suited for pharmaceutical and biomedical applications. One of their standout attributes is the capability to offer the controlled release of the active pharmaceutical ingredient (API), allowing custom-tailored release profiles to address specific diseases and administration routes. Moreover, stimuli-responsive electrospun DDS can adapt to conditions at the drug target, enhancing the precision and selectivity of drug delivery. Such localized API delivery paves the way for superior therapeutic efficiency while diminishing the risk of side effects and systemic toxicity. Electrospun nanofibers can foster better patient compliance and enhanced clinical outcomes by amplifying the therapeutic efficiency of routinely prescribed medications. This review delves into the design principles and techniques central to achieving controlled API release using electrospun membranes. The advanced drug release mechanisms of electrospun DDS highlighted in this review illustrate their versatility and potential to improve the efficacy of medical treatments.

An exploratory research on antitumor effect of drug-eluting slow-releasing electrospinning membranes

Objective

To evaluate the long-term inhibition of malignant biliary tumor growth using paclitaxel (PTX)-covered polycaprolactone (PCL) electrospun membranes.

Methods

A mixture of PCL, a material used to fabricate polymer stents, and PTX, a widely used chemotherapeutic agent, was synthesized by electrospinning. After preparing the drug-eluting membrane, drug release and fiber degradation were assessed in vitro under different pH conditions. The QBC939 cholangiocarcinoma cell line was cultured to establish a xenograft nude mouse model. Finally, the drug-eluting membrane was implanted into the mouse model, and the relative tumor inhibition rate was evaluated.

Results

A new PTX-loaded PCL electrospun fiber membrane was developed. The drug release rate was about 20-40% in the 32-day release cycle, and the release quantity was between 20 and 170 mg. As pH decreased, the release rate increased significantly. The degradation rate of the fiber membranes in vitro was approximately 20-48%, and was positively correlated with the drug loading rate. In animal experiments, the growth of tumors in mice was suppressed using drug-eluting membranes.

Conclusion

The PTX-loaded PCL electrospun fiber membrane enhanced the long-term drug release and exhibited excellent antitumor effects in vivo.

Smart Wearable Patches Using Light-Controlled Activation and Delivery of Photoswitchable Antimicrobial Peptides

A novel strategy to treat Staphylococcus aureus (S. aureus) skin infections is presented, where UV light is used to facilitate concomitant light-controlled activation and delivery of an antimicrobial therapeutic agent. Specifically, a new photoswitchable gramicidin S analogue was immobilized onto a polymeric wearable patch via a photocleavable linker that undergoes photolysis at the same wavelength of light required for activation of the peptide. Unlike toxic gramicidin S, the liberated active photoswitchable peptide exhibits antimicrobial activity against S. aureus while being ostensibly non-haemolytic to red blood cells. Moreover, irradiation with visible light switches off the antimicrobial properties of the peptide within seconds, presenting an ideal strategy to regulate antibiotic activity for localized bacterial infections with the potential to mitigate resistance.

Centrifugal Force-Spinning to Obtain Multifunctional Fibers of PLA Reinforced with Functionalized Silver Nanoparticles

The design and development of multifunctional fibers awakened great interest in biomaterials and food packaging materials. One way to achieve these materials is by incorporating functionalized nanoparticles into matrices obtained by spinning techniques. Here, a procedure for obtaining functionalized silver nanoparticles through a green protocol, using chitosan as a reducing agent, was implemented. These nanoparticles were incorporated into PLA solutions to study the production of multifunctional polymeric fibers by centrifugal force-spinning. Multifunctional PLA-based microfibers were obtained with nanoparticle concentrations varying from 0 to 3.5 wt%. The effect of the incorporation of nanoparticles and the method of preparation of the fibers on the morphology, thermomechanical properties, biodisintegration, and antimicrobial behavior, was investigated. The best balance in terms of thermomechanical behavior was obtained for the lowest amount of nanoparticles, that is 1 wt%. Furthermore, functionalized silver nanoparticles confer antibacterial activity to the PLA fibers, with a percentage of killing bacteria between 65 and 90%. All the samples turned out to be disintegrable under composting conditions. Additionally, the suitability of the centrifugal force-spinning technique for producing shape-memory fiber mats was tested. Results demonstrate that with 2 wt% of nanoparticles a good thermally activated shape-memory effect, with high values of fixity and recovery ratios, is obtained. The results obtained show interesting properties of the nanocomposites to be applied as biomaterials.

Biominerals Added Bioresorbable Calcium Phosphate Loaded Biopolymer Composites

Nanocrystalline calcium phosphate (CP) bioceramic coatings and their combination with biopolymers are innovative types of resorbable coatings for load-bearing implants that can promote the integration of metallic implants into human bodies. The nanocrystalline, amorphous CP particles are an advantageous form of the various calcium phosphate phases since they have a faster dissolution rate than that of crystalline hydroxyapatite. Owing to the biomineral additions (Mg, Zn, Sr) in optimized concentrations, the base CP particles became more similar to the mineral phase in human bones (dCP). The effect of biomineral addition into the CaP phases was thoroughly studied. The results showed that the shape, morphology, and amorphous characteristic slightly changed in the case of biomineral addition in low concentrations. The optimized dCP particles were then incorporated into a chosen polycaprolactone (PCL) biopolymer matrix. Very thin, non-continuous, rough layers were formed on the surface of implant substrates via the spin coating method. The SEM elemental mapping proved the perfect incorporation and distribution of dCP particles into the polymer matrix. The bioresorption rate of thin films was followed by corrosion measurements over a long period of time. The corrosion results indicated a faster dissolution rate for the dCP-PCL composite compared to the dCP and CP powder layers.

Aptamer engineering exosomes loaded on biomimetic periosteum to promote angiogenesis and bone regeneration by targeting injured nerves via JNK3 MAPK pathway

Repairing critical bone defects is a complex problem in the clinic. The periosteum rich in nerve plays a vital role in initiating and regulating bone regeneration. However, current studies have paid little attention to repairing nerves in the periosteum to promote bone regeneration. Thus, it is essential to construct bionic periosteum with the targeted injured nerves in the periosteum. We coupled phosphatidylserine (PS) targeted aptamers with repair Schwann cell exosomes to construct exosome@aptamer (EA). Then through PEI, EA was successfully built on the surface of the electrospun fiber, which was PCL@PEI@exosome@aptamer (PPEA). Through SEM, TEM, and other technologies, PPEA was characterized. Experiments prove in vivo and in vitro that it has an excellent repair effect on damaged nerves and regeneration of vascular and bones. In vivo, we confirmed that biomimetic periosteum has an apparent ability to promote nerve and bone regeneration by using Microcomputer tomography, hematoxylin-eosin, Masson, and Immunofluorescence. In vitro, we used Immunofluorescence, Real-Time Quantitative PCR, Alkaline phosphatase staining, and other tests to confirm that it has central nerve, blood vessel, and bone regeneration ability. The PPEA biomimetic periosteum has apparent neurogenic, angiogenic, and osteogenic effects. The PPEA biomimetic periosteum will provide a promising method for treating bone defects.

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To construct a biomimetic periosteum that can target injured axons and bone regeneration.

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PS targeted aptamer is coupled with repair Schwann cell exosomes.

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PEI self-assembly was used for the PCL electrospun biomimetic membrane loading.

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It targeted and repaired the injured axons and promoted the secretion of CGRP and SP.

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Biomimetic periosteum promotes vascular regeneration and bone regeneration.

High fibroin-loaded silk-PCL electrospun fiber with core-shell morphology promotes epithelialization with accelerated wound healing

Silk fibroin (SF) is a widely explored biopolymer for wound-healing applications due to the presence of amino acids in the biodegradable polymer chain with superior mechanical properties. Herein, a high SF-loaded fibrous matrix along with poly(ε-caprolactone) (PCL) was fabricated using electrospinning of emulsion and blend compositions to modulate nanostructure morphology. A comparative study of the physicomechanical properties of electrospun fibers with emulsion (^eS₇P₃) and homogenous blend (^bS₇P₃) was performed as well. In both compositions, SF loading of up to 70% was successfully achieved in the spun fibers while emulsion yielded core-shell morphology, and the blend resulted in monolith fiber architecture as evidenced by TEM microscopy. Further characterization revealed superior mechanical properties in S₇P₃ fiber with core-shell morphology, as compared to those in the monolith in terms of a higher degree of crystallinity with Young's modulus of 60 MPa under tensile test and nanoindentation modulus of 1.59 ± 0.8 GPa. Further, ^eS₇P₃ nanostructure morphology containing silk in the core with a thin outer layer of PCL facilitated relatively faster biodegradation in the lysozyme medium, as compared to that in the monolith. Owing to the presence of a hydrophobic shell, protein adsorption on the fibrous mat presented slow but steady kinetics up to 24 h. When the scaffold was seeded with human placenta-derived mesenchymal stem cells (hPMSCs), in vitro study confirmed that the ^eS₇P₃ structure had marginally higher cell proliferation with superior cell infiltration than the monolith. Further, in vivo study involving a rodent model showed the potential of the ^eS₇P₃ fiber substrate with a core-shell structure for accelerating full-thickness wound healing by inducing hair follicle and wound closure with less scar formation after 15 days.

Ofloxacin Removal from Aqueous Media by Means of Magnetoactive Electrospun Fibrous Adsorbents

Functionalized electrospun polymer microfibrous membranes were fabricated by electrospinning and further surface-functionalized with magnetic iron oxide (Fe_xO_y) nanoparticles to yield magnetoactive nanocomposite fibrous adsorbents. The latter were characterized in respect to their morphology, mechanical properties and magnetic properties while they were further evaluated as substrates for removing Ofloxacin (OFL) from synthetic aqueous media and secondary urban wastewater (UWW) under varying physicochemical parameters, including the concentration of the pharmaceutical pollutant, the solution pH and the membranes' magnetic content. The magnetic-functionalized fibrous adsorbents demonstrated significantly enhanced adsorption efficacy in comparison to their non-functionalized fibrous analogues while their magnetic properties enabled their magnetic recovery and regeneration.

Essential Oil—Loaded Nanofibers for Pharmaceutical and Biomedical Applications: A Systematic Mini-Review

Essential oils (EOs) have been widely exploited for their biological properties (mainly as antimicrobials) in the food industry. Encapsulation of EOs has opened the way to the utilization of EOs in the pharmaceutical and biomedical fields. Electrospinning (ES) has proved a convenient and versatile method for the encapsulation of EOs into multifunctional nanofibers. Within the last five years (2017–2022), many research articles have been published reporting the use of ES for the fabrication of essential oil—loaded nanofibers (EONFs). The objective of the present mini-review article is to elucidate the potential of EONFs in the pharmaceutical and biomedical fields and to highlight their advantages over traditional polymeric films. An overview of the conventional ES and coaxial ES technologies for the preparation of EONFs is also included. Even though EONFs are promising systems for the delivery of EOs, gaps in the literature can be recognized (e.g., stability studies) emphasizing that more research work is needed in this field to fully unravel the potential of EONFs.

Decorin mediated biomimetic PCL-gelatin nano-framework to impede scarring

Scars occur as a result of fibrosis after tissue damage or surgery and reports suggest that excessive Transforming growth factor-β (TGF-β) activity during the process of wound healing leads to progressive fibrosis. Decorin is an extracellular matrix (ECM) protein which regulates collagen fibrillogenesis. However, targeted delivery and effective protein therapy remains a challenge owing to degradation byproteases. Hence, we aimed to deliver Decorin in a sustainable mode for the reduction of TGF-β levels and subsequent scar formation. Herein, we have fabricated PCL-Gelatin bio-mimetic scaffolds to optimize the bio-activity and provide localized delivery of recombinant Decorin. The degradation and drug release patterns reveals that this biomaterial is biodegradable and offers sustained release of the recombinant Decorin. Decorin loaded nanofiber displayed lower adhesion and proliferation rates in in-vitro conditions. Moreover, Decorin loaded scaffolds demonstrated morphological changes in cells, specifically targeting the myofibroblast. The expression of TGF-β was also scrutinized to understand the effect of Decorin loaded nanofibers. Besides, in the in-vitro fibrotic model, Decorin loaded nanofibers efficiently reduced the expression of ECM related proteins. Therefore, we report the sustained delivery of the recombinant Decorin from nanofiber dressing to potentially obstruct scar formation during the process of wound healing.

The Use of Polymer Blends in the Treatment of Ocular Diseases

The eye is an organ with limited drug access due to its anatomical and physiological barriers, and the usual forms of ocular administration are limited in terms of drug penetration, residence time, and bioavailability, as well as low patient compliance. Hence, therapeutic innovations in new drug delivery systems (DDS) have been widely explored since they show numerous advantages over conventional methods, besides delivering the content to the eye without interfering with its normal functioning. Polymers are usually used in DDS and many of them are applicable to ophthalmic use, especially biodegradable ones. Even so, it can be a hard task to find a singular polymer with all the desirable properties to deliver the best performance, and combining two or more polymers in a blend has proven to be more convenient, efficient, and cost-effective. This review was carried out to assess the use of polymer blends as DDS. The search conducted in the databases of Pubmed and Scopus for specific terms revealed that although the physical combination of polymers is largely applied, the term polymer blend still has low compliance.

Compositional Influence on the Morphology and Thermal Properties of Woven Non-Woven Mats of PLA/OLA/MgO Electrospun Fibers

In the present work, a statistical study of the morphology and thermal behavior of poly(lactic acid) (PLA)/oligomer(lactic acid) (OLA)/magnesium oxide nanoparticles (MgO), electrospun fibers (efibers) has been carried out. The addition of both, OLA and MgO, is expected to modify the final properties of the electrospun PLA-based nanocomposites for their potential use in biomedical applications. Looking for the compositional optimization of these materials, a Box−Wilson design of experiment was used, taking as dependent variables the average fiber diameter as the representative of the fiber morphologies, as well as the glass transition temperature (Tg) and the degree of crystallinity (Xc) as their thermal response. The results show <r2> values of 73.76% (diameter), 88.59% (Tg) and 75.61% (Xc) for each polynomial fit, indicating a good correlation between both OLA and MgO, along with the morphological as well as the thermal behavior of the PLA-based efibers in the experimental space scanned.

Microfluidic-assisted electrospinning, an alternative to coaxial, as a controlled dual drug release system to treat inflammatory arthritic diseases

Inflammatory arthritic diseases are characterized by a persistent inflammation of the synovial tissues where tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) pro-inflammatory cytokines are over-expressed, leading to progressive musculoskeletal disability. Methotrexate (MTX), a disease-modifying-anti-rheumatic drug (DMARD) commonly applied in their treatment, can be used in combination with biological-DMARDs as anti-TNFα antibody to improve the treatments efficacy. However, their systemic administration comes with severe side-effects and limited therapeutic efficacy due to their off-target distribution and short half-life. To overcome such limitations, encapsulation of clinically relevant concentrations of MTX and anti-TNFα antibody into polycaprolactone (PCL) or poly(vinyl-alcohol) (PVA) microfluidic-assisted or coaxial electrospun fibrous meshes is proposed as local controlled dual drug release systems. Release studies show that microfluidic-assisted electrospinning meshes encapsulating both drugs achieved higher concentrations than coaxials. Biological assays using human articular chondrocytes (hACs) and monocytic cells (THP-1 cell line) demonstrate that fibrous meshes encapsulating the drugs are non-toxic. The systems' efficacy is proved by a significant decrease of TNFα and IL-6 concentrations in conditioned medium of lipopolysaccharide (LPS)-stimulated THP-1 cells, especially in the presence of microfluidic-assisted electrospun meshes, when compared with THP-1 conditioned medium (59.5% and 83.9% less, respectively). Therefore, microfluidic-assisted electrospinning fibrous meshes with encapsulating drugs represent an alternative to coaxial, as a local therapy for inflammatory arthritis diseases.

Dual-jet electrospun PDLGA/PCU nonwovens and their mechanical and hydrolytic degradation properties

A dual-jet electrospinning was used to mix a different hydrophilicity poly(carbonate urethanes) (PCUs) nanofibers with a biodegradable poly(D,L-lactide-co-glycolide) (PDLGA) copolyester microfibers. As a result, PDLGA/PCU partially degradable nonwovens consisting of an interlaced of both components fibers were obtained. In order to examine the hydrolytic degradation process of polyester fraction, as well as changes that occurred in the mechanical properties of the whole nonwovens, gel permeation chromatography, proton nuclear magnetic resonance spectroscopy, differential scanning calorimetry and scanning electron microscopy as well as static tensile test were performed. Obtained results showed that for the introduction of more hydrophobic PCU nanofibers (ChronoSil), the process of copolyester chain scission slowed down and the erosion mechanism proceeded in bulk. Unexpectedly, even greater deceleration of PDLGA fibers degradation was observed in case of more hydrophilic PCU (HydroThane), and erosion mechanism changed to surface. Enhancement the affinity of the whole nonwoven to the water, manifested by strong water uptake, facilitated the diffusion processes of both: water and acid degradation by-products, which limited autocatalysis reactions of the hydrolysis of ester bonds. On the other hand, strength tests showed the synergy in the mechanical characteristics of both components. Presented method allows influencing the mechanism and rate of polyester degradation without changing its chemical composition and physical properties, affecting only the physical interactions between the nonwoven and the degradation environment, and thus, on diffusion processes. Obtained partially degradable materials possessed also time prolonged functional properties, compared to the copolyester-only nonwoven itself, thus could be considered as promising for biomedical applications e.g. in drug release systems, implants or surgical meshes for supporting soft tissues.

Electrospun PCL/MoS2 Nanofiber Membranes Combined with NIR-Triggered Photothermal Therapy to Accelerate Bone Regeneration

Electrospun nanofiber membranes have been widely used for guided bone regeneration (GBR). For assistance in bone healing, photothermal therapy which renders moderate heat stimulation to defect regions by near-infrared (NIR) light irradiation has attracted much attention in recent years. Combined with photothermal therapy, novel electrospun poly(ε-caprolactone)/molybdenum disulfide (PCL/MoS₂ ) nanofiber membranes are innovatively synthesized as GBR for bone therapy, wherein the exfoliated MoS₂ nanosheets served as osteogenic enhancers and NIR photothermal agents. With the doping of MoS₂ , the mechanical properties of nanofiber membranes got improved with the degradation unaffected. The composite PCL/MoS₂ membranes show enhanced cell growth and osteogenic performance compared with PCL alone. Under NIR-triggered mild photothermal therapy, osteogenesis and bone healing are accelerated by using PCL/MoS₂ nanofiber membranes for growth of bone mesenchymal stem cells in vitro and repair of rat tibia bone defect in vivo. The novel nanofiber membranes may be developed as intelligent GBR in the therapy of bone defects.

PLA Electrospun Fibers Reinforced with Organic and Inorganic Nanoparticles: A Comparative Study

In this work, different poly (lactic acid) (PLA)-based nanocomposite electrospun fibers, reinforced with both organic and inorganic nanoparticles, were obtained. As organic fibers, cellulose nanocrystals, CNC, both neat and functionalized by “grafting from” reaction, chitosan and graphene were used; meanwhile, hydroxyapatite and silver nanoparticles were used as inorganic fibers. All of the nanoparticles were added at 1 wt% with respect to the PLA matrix in order to be able to compare their effect. The main aim of this work was to study the morphological, thermal and mechanical properties of the different systems, looking for differences between the effects of the addition of organic or inorganic nanoparticles. No differences were found in either the glass transition temperature or the melting temperature between the different electrospun systems. However, systems reinforced with both neat and functionalized CNC exhibited an enhanced degree of crystallinity of the electrospun fibers, by up to 12.3%. From a mechanical point of view, both organic and inorganic nanoparticles exhibited a decreased elastic modulus and tensile strength in comparison to neat electrospun PLA fibers, improving their elongation at break. Furthermore, all of the organic and inorganic reinforced systems disintegrated under composting conditions after 35 days.

In Vitro Degradation of Plasticized PLA Electrospun Fiber Mats: Morphological, Thermal and Crystalline Evolution

In the present work, fiber mats of poly(lactic acid), PLA, plasticized by different amounts of oligomer lactic acid, OLA, were obtained by electrospinning in order to investigate their long term hydrolytic degradation. This was performed in a simulated body fluid for up to 352 days, until the complete degradation of the samples is reached. The evolution of the plasticized electrospun mats was followed in terms of morphological, thermal, chemical and crystalline changes. Mass variation and water uptake of PLA-based electrospun mats, together with pH stability of the immersion media, were also studied during the in vitro test. The results showed that the addition of OLA increases the hydrolytic degradation rate of PLA electrospun fiber mats. Moreover, by adding different amounts of OLA, the time of degradation of the electrospun fiber mats can be modulated over the course of a year. Effectively, by increasing the amount of OLA, the diameter of the electrospun fibers decreases more rapidly during degradation. On the other hand, the degree of crystallinity and the dimension of the α crystals of the electrospun fiber mats are highly affected not only by the presence but also by the amount of OLA during the whole process.