Electrospun Polycaprolactone Research Articles

Tailored release of fluorescence quenched drug from the electrospun nanofiber mat for the treatment of oral submucosal fibrosis (OSMF)

The aim of the presented work involves the preparation and characterization of polycaprolactone (PCL) electrospun nanofibers mats (ESNF) loaded with the drug losartan potassium (LP) as a potential localized treatment strategy for treating OSMF.ESNF mats were fabricated using PCL as the biodegradable polymer matrix within which the drug of choice – LP and super disintegrant (SD) – PVP were mixed. The formed ESNF mats were subjected to thorough physico-chemical characterization.The electrospinning technique resulted in the fabrication of controlled diameter PCL nanofibers with no beading and uniform thickness. The presence of LP or PVP was dispersed uniformly within the polymer matrix and did not result in clump formation. The average diameter of blank PCL was 170 nm and that of LP and PVP loaded was 610 nm.The drug loading and encapsulation efficiency were calculated based on theoretical loading and quantification of the drug after destroying the mats and were found to be 89–92 %. The ex-vivo release profile of LP from PCL ESNF was designed to be tailored to release the drug in a few hours to a few days by the addition of super disintegrants in the polymer matrix. The addition of PVP was able to tune the release of LP from the PCL ESNF mat from 6 days to 17 days when compared to 21 days for samples without PVP. This was further studied using DOE® software that used mathematical software techniques to give the optimized formulation of the LP and PVP-loaded PCL ESNF mat. This optimized formulation was then incorporated in a buccal patch to design an effective system for localized drug delivery application. The optimized buccal patch design was later validated through a mucoadhesive strength study using pig mucosa. The mucoadhesive strength of the buccal patch in pig mucosa showed a force of detachment of 153.30 N/m2 and a force of adhesion of 0.27 N.Hence, a novel PCL-ESNF mat containing LP along with PVP was designed with a tailorable release profile as a possible localized therapeutic platform to alter the overproduction of collagen to provide a cure for OSMF.

Biomimetic thymoquinone incorporated nanofibrous matrix as periosteum substitute to promote bone healing

The resemblance of nanofibers to the extracellular matrix (ECM) makes it suitable for various tissue engineering application. In this study, electro-spun polycaprolactone (PCL)-gelatin nanofibers had been fabricated with the incorporation thymoquinone (TQ) biomolecule as a periosteum substitute to promote regeneration of bone. The fabricated nanofibrous matrix possess osteo-conductive and osteo-inductive property. It is biocompatible and also acts as an excellent drug delivery vehicle. The significant expression of the bone matrix proteins, alkaline phosphatase secretion and calcium deposition studied in the MG-63 osteoblast like cells seeded on the nanofibrous matrix proves that it makes a suitable periosteum-substitute by enhancing bone mineralization.

PCL/Fe3O4 magnetic electrospun yarn composites as a novel nanomaterial for biomedical applications

Magnetic composite structures were fabricated by embedding iron oxide nanoparticles (Fe3O4) into polycaprolactone (PCL) nanofibers through an electrospinning process. The PCL nanofibers incorporating 0.5 and 1 wt. % Fe3O4 were electrospun with various yarn and membrane architectures. SEM images of the fabricated fibers revealed diameter increment by raising the Fe3O4 proportion. Additionally, elongation at break, in tandem with the ultimate strength of the electrospun PCL yarn was improved by 63 and 67% through embedding 0.5 and 1 wt. % Fe3O4, respectively. The saturation magnetization results depended on the number of magnetic nanoparticles loaded in the electrospun fibers, as well as the architectural design of the electrospun fibers. The magnetic response of the fibrous yarns was enhanced by increasing the Fe3O4 mass fraction from 0.5 to 1 wt. %. The highest saturation magnetization of 5.38 emu/g was obtained for the electrospun yarn containing 1 wt. % Fe3O4, corroborating 13.6 times greater features than that of the fibrous membrane with a similar chemical composition. The obtained results implied that the as-spun fibrous yarn could be a great candidate as a surgical suture with the release capability of bioactive agents under a magnetic field.

Chitosan oligomer/silver nanoparticles/PCL composite electrospun membrane for severe burn wound healing

In the management of burn wounds, antimicrobial and wound healing properties are crucial. In this study, we prepared a three-layer electrospun poly(ε-caprolactone) (PCL) membrane for burn wound dressing. The hydrophobic electrospun PCL layer, embedded with silver nanoparticles (SNPs) (PCL-Ag), was coated with another layer of electrospun plasma-treated PCL-Ag to enhance the wettability of the membrane. This enhancement was to facilitate the absorption of the hydrophilic chitosan oligomer (COS) - the third layer of the dressing. The resultant membranes were characterised and tested for different properties to demonstrate their applicability as wound dressing materials. The combination of COS and SNPs of the fabricated membrane supports the healing process and reduces burn severity due to the healing capacity of COS and the antibacterial activity of SNPs, without compromising mechanical strength. We conducted several in vitro and in vivo experiments to evaluate its applicability for burn wound healing. The PCL-Ag/COS sample demonstrated outstanding in vitro biocompatibility and excellent antibacterial activity against Staphylococcus aureus strains. We used the membrane to treat burns on rabbits in the laboratory over 30 days, and consistently observed positive outcomes. This research offers insights into the development of bioactive dressings for wound healing and opens up opportunities for practical applications of COS-incorporated materials.

Biocompatibility, anti-hemolytic, and antibacterial assessments of electrospun PCL/collagen composite nanofibers loaded with Acanthophora spicifera extracts mediated copper oxide nanoparticles

Research in the advancement of wound dressings strives to address specific issues related to infections, speed up the healing process, and enhance patient wellness, all of which will lead to improved wound care procedures. This study investigates the synthesis and characterization of electrospun Polycaprolactone (PCL)/Collagen (Col) nanofibers incorporated with Acanthophora spicifera extracts mediated copper oxide nanoparticles (CuO NPs) and to evaluate their biocompatibility, anti-hemolytic properties, and antibacterial efficacy. The synthesized copper oxide nanoparticles were spherical and 58 ± 17 nm in size as evidenced by the field emission scanning electron microscopy. The fiber diameter of PCL, PCL/Col, PCL/Col/CuO 1%, PCL/Col/CuO 2%, and PCL/Col/CuO 5% was found to be 373 ± 141 nm, 281 ± 46 nm, 221 ± 57 nm, 173 ± 40 and 162 ± 47 nm respectively. Contact angle measurements revealed that the addition of copper oxide nanoparticles into Polycaprolactone/Collagen nanofibers resulted in a decrease in water contact angle from 86.9° to 50.8°. The biocompatibility of the composite nanofibers was evaluated in vitro using mouse fibroblast cells. The results established that copper oxide-imbued nanofibers were non-toxic and biocompatible. The hemolytic index for PCL/Col, PCL/Col/CuO 1%, PCL/Col/CuO 2%, and PCL/Col/CuO 5% scaffolds was 0.91 ± 0.14, 0.76 ± 0.14, 1.21 ± 0.19, and 1.52 ± 0.08 % respectively which was below the permissible value. Furthermore, the PCL/Col/CuO 5% nanofibers exhibited bactericidal properties against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. These findings suggest the potential applications of copper oxide-infused nanofibers in various biomedical fields, including tissue engineering, antimicrobial coatings, and wound healing.

Bioreactor Design for Culturing Vascularized Engineered Tissue in Flow Conditions.

Background: Current treatments for congenital heart defects often require surgery and implantation of a synthetic patch or baffle that becomes a fibrous scar and leads to a high number of reoperations. Previous studies in rats have shown that a prevascularized scaffold can integrate into the heart and result in regions of vascularized and muscularized tissue. However, increasing the thickness of this scaffold for use in human hearts requires a method to populate the thick scaffold and mature it under physiologic flow and electrical conditions. Experiment: We developed a bioreactor system that can perfuse up to six 7 mm porous scaffolds with tunable gravity-mediated flow and chronic electrical stimulation. Three polymers, which have been reported to be biocompatible, were evaluated for effects on the viability of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CM). Bioreactor flow and electrical stimulation functions were tested, and the bioreactor was operated for up to 7 days to ensure reliability and lack of leaks in a 37°C, humidified incubator. Height and flow relationships were measured for perfusion through an electrospun polycaprolactone and gelatin scaffold, previously reported by our laboratory. Culture with cells was evaluated by plating human umbilical vein endothelial cells and human dermal fibroblasts on top of the scaffolds in both static and flow conditions for 2, 5, and 7 days. As a proof-of concept, scaffolds were cryosectioned and cell infiltration was quantified using immunofluorescence staining. Results: Neither MED610 (Stratasys), Vero (Stratasys), nor FORMLAB materials affected the viability of iPSC-CM, and MED610 was chosen for manufacture due to familiarity of 3D printing from this material. The generation of electrical field stimulation from 0 to 5 V and physiological ranges of pump capacities were verified. The relationship between height and flow was calculated for scaffolds with and without cells. Finally, we demonstrated evaluation of cell depth and structure in scaffolds cultured for 2, 5, and 7 days. Conclusion: The gravity-mediated flow bioreactor system we developed can be used as a platform for 3D cell culture particularly designed for perfusing vascularized tissue constructs with electrical stimulation for cardiac maturation.

Controlled drug release from policaprolactone-piperine electrospun scaffold for bone tissue engineering

Polymeric drug scaffolds have been intensively studied in orthopedic surgery due to their capacity for the regimented and site-specific liberation of the therapeutic agent at the intended locus. In this context, electrospinning is a promising technique for producing scaffolds using biodegradable and biocompatible polymers. In the present study, scaffolds of Polycaprolactone (PCL) with Piperine (PIP) incorporated at different concentrations (1, 3, and 5 %) were obtained by electrospinning. The electrospun PCL, PCL/PIP 1 %, PCL/PIP 3 %, and PCL/PIP 5 % groups were analyzed by FTIR spectroscopy to identify the incorporated drug and through UV-VIS spectroscopy to evaluate its controlled release. In addition, the bone repair was verified by Raman spectroscopy using ᶹ1PO43- vibration data obtained by in vivo analysis. The morphology and diameter of the nanofibers were obtained by scanning electron microscopy (SEM). The PCL, PCL/PIP 1 %, PCL/PIP 3 %, PCL/PIP 5 % scaffolds had diameters of 0.0015 ± 0.002 μm, 1.08 ± 0.007 μm, 1.09 ± 0.02 μm, 0.59 ± 0.016 μm, respectively. Piperine release was pronounced after 15 days. Therefore, at 30 days, the PCL/PIP 1 % scaffold released 64 % ± 0.00062, while the PCL/PIP 3 % and PCL/PIP 5 % scaffolds released only 16.06 ± 0.00012 and 9.08 % ± 0.00031, respectively. This study provided evidence that PCL/Piperine can be used to significantly increase bone regeneration. Results from Raman spectroscopy and histological analysis demonstrated that the PCL/PIP 1 %, 3 %, and 5 % groups had better bone regeneration than the negative control group after 15 days and 30 days of treatment. The prolonged release of piperine promoted by PCL, a hydrophobic drug carrier, caused the neoformation of the bones to be restricted to the inner part of the bone defect, creating an immature bone with evident cellular differentiation.

A Study of the Relationship between Polymer Solution Entanglement and Electrospun PCL Fiber Mechanics.

Electrospun fibers range in size from nanometers to micrometers and have a multitude of potential applications that depend upon their morphology and mechanics. In this paper, we investigate the effect of polymer solution entanglement on the mechanical properties of individual electrospun polycaprolactone (PCL) fibers. Multiple concentrations of PCL, a biocompatible polymer, were dissolved in a minimum toxicity solvent composed of acetic acid and formic acid. The number of entanglements per polymer (ne) in solution was calculated using the polymer volume fraction, and the resultant electrospun fiber morphology and mechanics were measured. Consistent electrospinning of smooth fibers was achieved for solutions with ne ranging from 3.8 to 4.9, and the corresponding concentration of 13 g/dL to 17 g/dL PCL. The initial modulus of the resultant fibers did not depend upon polymer entanglement. However, the examination of fiber mechanics at higher strains, performed via lateral force atomic force microscopy (AFM), revealed differences among the fibers formed at various concentrations. Average fiber extensibility increased by 35% as the polymer entanglement number increased from a 3.8 ne solution to a 4.9 ne solution. All PCL fibers displayed strain-hardening behavior. On average, the stress increased with strain to the second power. Therefore, the larger extensibilities at higher ne also led to a more than double increase in fiber strength. Our results support the role of polymer entanglement in the mechanical properties of electrospun fiber at large strains.

Diaphragmatic hernia repair porcine model to compare the performance of biodegradable membranes against Gore-Tex®

BackgroundPatch repair of congenital diaphragmatic hernia (CDH) using Gore-Tex® is associated with infection, adhesions, hernia recurrence, long-term musculoskeletal sequels and poor tissue regeneration. To overcome these limitations, the performance of two novel biodegradable membranes was tested to repair CDH in a growing pig model.MethodsTwelve male pigs were randomly assigned to 3 different groups of 4 animals each, determined by the type of patch used during thoracoscopic diaphragmatic hernia repair (Gore-Tex®, polycaprolactone electrospun membrane-PCLem, and decellularized human chorion membrane-dHCM). After 7 weeks, all animals were euthanized, followed by necropsy for diaphragmatic evaluation and histological analysis.ResultsThoracoscopic defect creation and diaphragmatic repair were performed without any technical difficulty in all groups. However, hernia recurrence rate was 0% in Gore-Tex®, 50% in PCLem and 100% in dHCM groups. At euthanasia, Gore-Tex® patches appeared virtually unchanged and covered with a fibrotic capsule, while PCLem and dHCM patches were replaced by either floppy connective tissue or vascularized and floppy regenerated membranous tissue, respectively.ConclusionGore-Tex® was associated with a higher survival rate and lower recurrence. Nevertheless, the proposed biodegradable membranes were associated with better tissue integration when compared with Gore-Tex®.

An in vitro characterization of a PCL-fibrin scaffold for myocardial repair

Each year in the United States approximately 10,000 babies are born with a complex congenital heart defect (CHD) requiring surgery in the first year of after birth. Several of these operations require the implantation of a full-thickness heart patch; however, the current patch materials available to pediatric heart surgeons are exclusively non-living and non-degradable, which do not grow with the patient and are prone to fail due to an inability to integrate with the heart. In this work, the goal was to develop a full-thickness, tissue engineered myocardial patch (TEMP) that is made from biodegradable components, strong enough to withstand the mechanical forces of the heart wall, and able to integrate with the heart and drive neotissue formation. Here, a thick and porous electrospun PCL scaffold filled with high-salt PEGylated fibrin was developed. The scaffold was found to be mechanically sufficient for heart wall repair. Vascular cells were able to infiltrate more than halfway through the scaffold in static culture within three weeks. The scaffold maintained pluripotent stem cells for at least four days, supports viable iPSC-derived cardiomyocytes, and fostered tissue thickening in vitro. The TEMP developed here and tested in vitro is promising for the repair of structural CHD and will next be assessed in situ.

Electrospun PCL Wires Loaded with Vancomycin on Zirconium Substrate.

The current study presents research about electrodeposition in relation to electrospinning PCL wires on a Zr substrate and loading the coating with vancomycin. The structural composition of the coatings was investigated via FT-IR analysis. The morphology evaluated using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, for the composition (SEM-EDS), evidenced the presence of the polymer wires, with and without drug vancomycin loading. The wettability of the coatings was evaluated from the hydrophobic-hydrophilic point of view, and the characterization was completed with mechanical and electrochemical tests. All the electrochemical tests performed in simulated body fluid highlighted that PCL represents a barrier against corrosion processes. The quantitative method to evaluate the loading efficiency shows that almost 80% of the total loaded vancomycin is released within 144 h; after the initial burst at 24 h, a steady release of vancomycin is observed over 7 days. A kinetic model of the drug release was also constructed.

Biosensing of arsenic by whole-cell bacterial bioreporter immobilized on polycaprolactone (PCL) electrospun fiber

ABSTRACT In recent years, heavy metals derived from several anthropogenic sources have both direct and indirect detrimental effects on the health of the environment and living organisms. Whole-cell bioreporters (WCBs) that can be used to monitor the levels of heavy metals in drinking and natural spring waters are important. In this study, whole-cell arsenic bacterial bioreporters were immobilized using polycaprolactone (PCL) electrospun fibers as the support material. The aim is to determine the properties of this immobilized bioreporter system by evaluating its performance in arsenic detection. Within the scope of the study, different growth media and fiber immobilization times were tested to determine the parameters affecting the fluorescent signals emitted by the immobilized bioreporter system in the presence of two dominant forms of arsenic, namely arsenite (As(III)) and arsenate (As(V)). In addition, the sensitivity, selectivity, response time, and shelf-life of the developed bioreporter system were evaluated. As far as the literature is concerned, this is the first study to investigate the potential of using PCL-electrospun fiber-immobilized fluorescent bacterial bioreporter for arsenic detection. This study will open new avenues in environmental arsenic monitoring.

Eradication of Pseudomonas aeruginosa biofilm using quercetin-mediated copper oxide nanoparticles incorporated electrospun polycaprolactone nanofibrous scaffold

Pseudomonas aeruginosa is an opportunistic bacterial pathogen that form biofilms in chronic wounds and is difficult to treat with standard treatment methods. In the present study, flavonoid quercetin-mediated CuONPs (Que-CuONPs) were successfully synthesized and incorporated in the electrospun polycaprolactone (Que-CuONPs-PCL) nanofibrous membrane to eradicate the burn wound infection causing P. aeruginosa biofilm. The fabricated scaffold Que-CuONPs-PCL was characterized using HR-SEM, EDX, XRD, and FTIR. The synthesized Que-CuONPs appeared as spherical in shape with the average size of 36 nm. The crystallite size of the synthesized CuONPs was calculated as 23 nm. Antibacterial activity shows that the ZOI and MIC of Que-CuONPs against P. aeruginosa was found to be 20 mm and 5 μg/mL, respectively. Antibiofilm assay indicates the pre-formed P. aeruginosa biofilm was completely eradicated by Que-CuONPs at 8-MIC. The Que-CuONPs-PCL nanofibrous scaffolds exhibits less cytotoxic effects on mouse fibroblast (L929) cells. Finally, this study highlights the fabricated Que-CuONPs-PCL nanofibrous scaffolds exhibits excellent antibiofilm effect against P. aeruginosa biofilm with a great biocompatibility.

Electrospun PCL Nerve Conduit Filled with GelMA Gel for CNTF and IGF-1 Delivery in Promoting Sciatic Nerve Regeneration in Rat.

Neural tissue engineering is an essential strategy to repair long-segment peripheral nerve defects. Modification of the nerve conduit is an effective way to improve the local microenvironment of the injury site and facilitate nerve regeneration. However, the concurrent release of multiple growth cues that regulate the activity of Schwann cells and neurons remains a challenge. The present study involved the fabrication of a composite hydrogel, specifically methacrylate-anhydride gelatin-ciliary neurotrophic factor/insulin-like growth factor-1 (GelMA-CNTF/IGF-1), with the aim of providing a sustained release of CNTF and IGF-1. The GelMA-CNTF/IGF-1 hydrogels exhibited a swelling rate of 10.2% following a 24 h incubation in vitro. In vitro, GelMA hydrogels demonstrated a high degree of efficiency in the sustained release of CNTF and IGF-1 proteins, with a release rate of 85.9% for CNTF and 90.9% for IGF-1 shown at day 28. In addition, the GelMA-CNTF/IGF-1 composite hydrogel promoted the proliferation of Schwann cells and the production of nerve growth factor (NGF), connective tissue growth factor (CTGF), fibronectin, and laminin and also considerably promoted the axonal growth of neurons. Furthermore, GelMA-CNTF/IGF-1 hydrogels were loaded into PCL electrospun nerve conduits to repair 15 mm sciatic nerve defects in rats. In vivo studies indicated that PCL-GelMA-CNTF/IGF-1 could efficiently accelerate the regeneration of the rat sciatic nerve, promote the formation of the myelin sheath of new axons, promote the electrophysiological function of regenerated nerves, and eventually improve the recovery of motor function in rats. Overall, the PCL-GelMA-CNTF/IGF-1 scaffold presents an attractive new approach for generating an optimal therapeutic alternative for peripheral nerve restoration.

Towards tailored surface topography on electrospun wound dressings for exudate absorption

Since electrospinning can generate micro- to nanometre-scale fibres, it is widely used for fabricating wound dressings. Electrospun scaffolds with defined three-dimensional patterns at the mat surface can be efficiently fabricated using textured collectors that transfer the topography during the manufacturing process. However, the efficacy of surface pattern transfer from the collector to the mat, the correlation between the topography and the absorption capability and the effect of sterilisation on absorption have not yet been analysed. In this study, textured patterns were imprinted over polycaprolactone electrospun mats using textured collectors. The successful transferability of the patterns was quantified through height, hybrid and functional surface topography parameters. Additionally, ethylene oxide, hydrogen peroxide (H2O2) and ultraviolet (UV) sterilisation methods were tested, of which only UV preserved the morphological and functional integrity of the mat. Finally, fibroblasts were used to analyse the cytotoxicity and cellular response of the dressings, verifying their biocompatible nature. This study demonstrates that absorption capacity can be modulated by the surface texture of the wound dressing. The S dq and S dr parameters were identified as key surface characteristics for enhancing absorption capacity and yielded an increase of up to 176.76% compared with the non-textured control, thus revealing the potential of surface functionalisation for increasing exudate absorption.

Electrospun aligned tacrolimus-loaded polycaprolactone biomaterials for peripheral nerve repair.

Background: Efficacious repair of peripheral nerve injury is an unmet clinical need. The implantation of biomaterials containing neurotrophic drugs at the injury site could promote nerve regeneration and improve outcomes for patients. Materials & methods: Random and aligned electrospun poly-ε-caprolactone scaffolds containing encapsulated tacrolimus were fabricated, and the gene expression profile of Schwann cells (SCs) cultured on the surface was elucidated. On aligned fibers, the morphology of SCs and primary rat neurons was investigated. Results: Both scaffold types exhibited sustained release of drug, and the gene expression of SCs was modulated by both nanofibrous topography and thepresence of tacrolimus. Aligned fibers promoted the alignment of SCs and orientated outgrowth from neurons. Conclusion: Electrospun PCL scaffolds with tacrolimus hold promise for the repair of peripheral nerve injury.

Engineering subarachnoid trabeculae with electrospun poly(caprolactone) (PCL) scaffolds to study leptomeningeal metastasis in medulloblastoma

Leptomeningeal metastasis (LM) occurs when cancer cells infiltrate the subarachnoid space (SAS) and metastasize to the fibrous structures that surround the brain and spinal cord. These structures include the leptomeninges (i.e., the pia mater and arachnoid mater), as well as subarachnoid trabeculae, which are collagen-rich fibers that provide mechanical structure for the SAS, support resident cells, and mediate flow of cerebrospinal fluid (CSF). Although there is a strong expectation that the presence of fibers within the SAS influences LM to be a major driver of tumor progression and lethality, exactly how trabecular architecture relates to the process of metastasis in cancer is poorly understood. This lack of understanding is likely due in part to the difficulty of accessing and manipulating this tissue compartment in vivo. Here, we utilized electrospun polycaprolactone (PCL) to produce structures bearing remarkable morphological similarity to native SAS fiber architecture. First, we profiled the native architecture of leptomeningeal and trabecular fibers collected from rhesus macaque monkeys, evaluating both qualitative and quantitative differences in fiber ultrastructure for various regions of the CNS. We then varied electrospinning parameters to produce a small library of PCL scaffolds possessing distinct architectures mimicking the range of fiber properties observed in vivo. For proof of concept, we studied the metastasis-related behaviors of human pediatric medulloblastoma cells cultured in different fiber microenvironments. These studies demonstrated that a more open, porous fiber structure facilitates DAOY cell spread across and infiltration into the meningeal mimic. Our results present a new tissue engineered model of the subarachnoid space and affirm the expectation that fiber architecture plays an important role in mediating metastasis-related behaviors in an in vitro model of pediatric medulloblastoma.

Highly active nisin coated polycaprolactone electrospun fibers against both Staphylococcus aureus and Pseudomonas aeruginosa

In this study, a wound dressing of electrospun polycaprolactone (PCL) fibers incorporating the antimicrobial peptide (AMP) nisin was fabricated. Nisin was physically adsorbed to the PCL fibers and tested for antibacterial activity against both Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa). The PCL fibers had an average diameter of 1.16 μm ± 0.42 μm and no significant change in diameter occurred after nisin adsorption. X-ray photoelectron spectroscopy (XPS) analysis of the fibers detected nitrogen indicative of adsorbed nisin and the signal was used to quantify the levels of coverage on the fiber surfaces. In vitro nisin release studies showed a burst release profile with 80 % of the nisin being released from the fibers within 30 min. Air plasma pre-treatment of the PCL fibers to render them hydrophilic improved nisin loading and release. Antibacterial testing was performed using minimum inhibitory concentration (MIC) and surface attachment assays. The released nisin remained active against both Gram positive S. aureus and Gram negative P. aeruginosa, which has previously been difficult to achieve with single polymer fiber systems. Mammalian cell culture of the nisin coated fibers with L-929 mouse fibroblasts and human epidermal keratinocytes (HEKa) showed that the nisin did not have a significant effect on the biocompatibility of the PCL fibers. The results presented here demonstrate that the physical adsorption, which is a post-treatment, overcomes the potential limitations of harsh chemicals and fabrication conditions of electrospinning from organic solvents and provides a drug loading system having effective antibacterial properties in wound dressings.

Enhanced Antibacterial Ability of Electrospun PCL Scaffolds Incorporating ZnO Nanowires.

The infection of implanted biomaterial scaffolds presents a major challenge. Existing therapeutic solutions, such as antibiotic treatment and silver nanoparticle-containing scaffolds are becoming increasingly impractical because of the growth of antibiotic resistance and the toxicity of silver nanoparticles. We present here a novel concept to overcome these limitations, an electrospun polycaprolactone (PCL) scaffold functionalised with zinc oxide nanowires (ZnO NWs). This study assessed the antibacterial capabilities and biocompatibility of PCL/ZnO scaffolds. The fabricated scaffolds were characterised by SEM and EDX, which showed that the ZnO NWs were successfully incorporated and distributed in the electrospun PCL scaffolds. The antibacterial properties were investigated by co-culturing PCL/ZnO scaffolds with Staphylococcus aureus. Bacterial colonisation was reduced to 51.3% compared to a PCL-only scaffold. The biocompatibility of the PCL/ZnO scaffolds was assessed by culturing them with HaCaT cells. The PCL scaffolds exhibited no changes in cell metabolic activity with the addition of the ZnO nanowires. The antibacterial and biocompatibility properties make PCL/ZnO a good choice for implanted scaffolds, and this work lays a foundation for ZnO NWs-infused PCL scaffolds in the potential clinical application of tissue engineering.

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

ObjectiveTo evaluate the long-term inhibition of malignant biliary tumor growth using paclitaxel (PTX)-covered polycaprolactone (PCL) electrospun membranes. MethodsA 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. ResultsA 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. ConclusionThe PTX-loaded PCL electrospun fiber membrane enhanced the long-term drug release and exhibited excellent antitumor effects in vivo.