Recent advances in multiaxial electrospinning for drug delivery

Recent Progress in Coaxial Electrospinning: New Parameters, Various Structures, and Wide Applications

Electrospinning, a common method for synthesizing 1D nanostructures, has contributed to developments in the electrical, electrochemical, biomedical, and environmental fields. Recently, a coaxial electrospinning process has been used to fabricate new nanostructures with advanced performance, but intricate and delicate process conditions hinder reproducibility and mass production. Herein, recent progress in new emerging parameters for successful coaxial electrospinning, and the various nanostructures and critical application areas resulting from these activities. Relationships between the new parameters and final product characteristics are described, new possibilities for nanostructures achievable via coaxial electrospinning are identified, and new research directions with a view to future applications are suggested.

Electrospun Nanomaterials Implementing Antibacterial Inorganic Nanophases

Electrospinning is a versatile, simple, and low cost process for the controlled production of fibers. In recent years, its application to the development of multifunctional materials has encountered increasing success. In this paper, we briefly overview the general aspects of electrospinning and then we focus on the implementation of inorganic nanoantimicrobials, e.g., nanosized antimicrobial agents in electrospun fibers. The most relevant characteristics sought in nanoantimicrobials supported on (or dispersed into) polymeric materials are concisely discussed as well. The interesting literature issued in the last decade in the field of antimicrobial electrospun nanomaterials is critically described. A classification of the most relevant studies as a function of the different approaches chosen for incorporating nanoantimicrobials in the final material is also provided.

Electrospun amorphous solid dispersions of poorly water-soluble drugs: A review

The development of oral dosage forms for poorly water-soluble active pharmaceutical ingredients (APIs) is a persistent challenge. A range of methods has been explored to address this issue, and amorphous solid dispersions (ASDs) have received increasing attention. ASDs are typically prepared by starting with a liquid precursor (a solution or melt) and applying energy for solidification. Many techniques can be used, with the emergence of electrospinning as a potent option in recent years. This method uses electrical energy to induce changes from liquid to solid. Through the direct applications of electrical energy, electrospinning can generate nanofiber-based ASDs from drug-loaded solutions, melts and melt-solutions. The technique can also be combined with other approaches using the application of mechanical, thermal or other energy sources. Electrospinning has numerous advantages over other approaches to produce ASDs. These advantages include extremely rapid drying speeds, ease of implentation, compatibility with a wide range of active ingredients (including those which are thermally labile), and the generation of products with large surface areas and high porosity. Furthermore, this technique exhibits the potential to create so-called 'fifth-generation' ASDs with nanostructured architectures, such as core/shell or Janus systems and their combinations. These advanced systems can improve dissolution behaviour and provide programmable drug release profiles. Additionally, the fiber components and their spatial distributions can be precisely controlled. Electrospun fiber-based ASDs can maintain an incorporated active ingredient in the amorphous physical form for prolonged periods of time because of their homogeneous drug distribution within the polymer matrix (typically they comprise solid solutions), and ability to inhibit molecular motion. These ASDs can be utilised to generate oral dosage forms for poorly water-soluble drugs, resulting in linear or multiple-phase release of one or more APIs. Electrospun ASDs can also be exploited as templates for manipulating molecular self-assembly, offering a bridge between ASDs and other types of dosage forms. This review addresses the development, advantages and pharmaceutical applications of electrospinning for producing polymeric ASDs. Material preparation and analysis procedures are considered. The mechanisms through which performance has been improved are also discussed.

Recent advances in electrospun for drug delivery purpose

Electrospun, an advanced technology, has been successfully employed for fibre production and offers many merits in novel drug delivery systems (DDSs). In recent years, electrospun has gained significant attention and attraction of the scientists in soaring numbers. This technology is superior to other technologies in fabricating the fibres which range from micrometers to manometers scale. The selection of appropriate polymers, electrospun processes and electrospun parameters play important roles in controlling the drug release while, treating serious illness. Besides, electrospraying process has similar characteristics to the electrospun and is presented briefly here. Further, in vivo and in vitro evaluations of the electrospun nanofibers are comprehensively discussed. In addition, the electrospun nanotechnology has been exploited to design drug release systems, investigate drug's pharmacokinetics and further develop DDS. The electrospun nanofibers improve bioactivity of various types of drugs including water-insoluble, soluble, anticancer and antibacterial drugs and genetic materials. In the end, the prospects and challenges in the process of designing drug-loaded electrospun nanofibers are discussed in detail.

Ultrasensitive label-free electrochemical immunosensor based on PVA-co-PE nanofibrous membrane for the detection of chloramphenicol residues in milk

An ultrasensitive label-free amperometric immunosensor for the detection of chloramphenicol (CAP) residues in milk has been developed by using a screen-printed carbon electrode laminated with a layer of poly (vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membrane that is covalently immobilized with a CAP antibody (anti-CAP). The performance of the PVA-co-PE nanofiber membrane (PVA-co-PE NFM) on the electrode was compared with a PVA-co-PE casted membrane (PVA-co-PE CM), necessary fabrication steps and performance of the sensors were investigated by electrochemical impedance spectroscopy (EIS). The application of the PVA-co-PE NFM decreased the electron-transfer-resistance by about 4 times compared with a conventional PVA-co-PE casted membrane. Under the optimal conditions, the established immunosensor exhibited high sensitivity for determination of CAP in a range 0.01-10 ng mL^-1, with a limit of detection of 0.0047 ng mL^-1. In addition to the good selectivity, reusability and stability over time, the prepared immunosensor was successfully used in the detection of CAP in milk samples without any pretreatment.

Current and Emerging Approaches to Engineer Antibacterial and Antifouling Electrospun Nanofibers

From ship hulls to bandages, biological fouling is a ubiquitous problem that impacts a wide range of industries and requires complex engineered solutions. Eliciting materials to have antibacterial or antifouling properties describes two main approaches to delay biofouling by killing or repelling bacteria, respectively. In this review article, we discuss how electrospun nanofiber mats are blank canvases that can be tailored to have controlled interactions with biologics, which would improve the design of intelligent conformal coatings or freestanding meshes that deliver targeted antimicrobials or cause bacteria to slip off surfaces. Firstly, we will briefly discuss the established and emerging technologies for addressing biofouling through antibacterial and antifouling surface engineering, and then highlight the recent advances in incorporating these strategies into electrospun nanofibers. These strategies highlight the potential for engineering electrospun nanofibers to solicit specific microbial responses for human health and environmental applications.

Electrospun Blank Nanocoating for Improved Sustained Release Profiles from Medicated Gliadin Nanofibers

Nanomaterials providing sustained release profiles are highly desired for efficacious drug delivery. Advanced nanotechnologies are useful tools for creating elaborate nanostructure-based nanomaterials to achieve the designed functional performances. In this research, a modified coaxial electrospinning was explored to fabricate a novel core-sheath nanostructure (nanofibers F2), in which a sheath drug-free gliadin layer was successfully coated on the core ketoprofen (KET)-gliadin nanocomposite. A monolithic nanocomposite (nanofibers F1) that was generated through traditional blending electrospinning of core fluid was utilized as a control. Scanning electron microscopy demonstrated that both nanofibers F1 and F2 were linear. Transmission electron microscopy verified that nanofibers F2 featured a clear core-sheath nanostructure with a thin sheath layer about 25 nm, whereas their cores and nanofibers F1 were homogeneous KET-gliadin nanocomposites. X-ray diffraction patterns verified that, as a result of fine compatibility, KET was dispersed in gliadin in an amorphous state. In vitro dissolution tests demonstrated that the thin blank nanocoating in nanofibers F2 significantly modified drug release kinetics from a traditional exponential equation of nanofibers F1 to a zero-order controlled release model, linearly freeing 95.7 ± 4.7% of the loaded cargoes over a time period of 16 h.

Influence of shell compositions of solution blown PVP/PCL core–shell fibers on drug release and cell growth

Developing a facile means of controlling drug release is of utmost interest in drug delivery systems. In this study, core–shell structured nanofibers containing a water-soluble porogen were fabricated via solution blow spinning, to be used as drug-loaded bioactive tissue scaffolds. Hydrophilic polyvinylpyrrolidone (PVP) and hydrophobic poly(ε-caprolactone) (PCL) were chosen to produce the core and the shell compartments of the fiber, respectively. In the core, a hydrophilic sulforhodamine B (SRB) dye was loaded as a model drug. In the PCL shell, two kinds of PVP with different molecular weights (40 kDa and 1300 kDa) were added, and the influence of PVP leaching on the SRB release and cell growth was investigated. The monolithic PCL-shelled fibers displayed a sustained SRB release with a weak burst effect. The addition of PVP in the shell induced a phase separation, forming microscale PVP domains. The PVP domain, acting as a porogen, was leached out in the medium and, as a result, the burst release of SRB was promoted. This burst effect was more prominent with the lower molecular weight PVP. The biocompatibility of the core–shell fibers was evaluated with human epidermal keratinocytes (HEK) by a cell viability assay and microscopic observation of cell proliferation. The HEK cells on fibers with a PVP/PCL composite shell formed self-assembled spherical clusters, displaying higher cell viability and proliferation than those on the monolithic PCL-shelled fibers that induced HEK cell growth in two-dimensional monolayers. The results demonstrate that the presence of hydrophilic porogens on tissue scaffolds can accelerate drug release and enhance cell proliferation by increasing surface wettability, roughness and porosity. The findings of this study provide a basic insight into the construction of bioactive three-dimensional tissue scaffolds.

The presence of hydrophilic porogens on the surface of core–shell fibers can accelerate drug release and enhance cell proliferation.

Еlectrospun сellulose acetate membranes decorated with curcumin-PVP particles: preparation, antibacterial and antitumor activities

Curcumin (Curc) exhibits anti-inflammatory, antibacterial and antitumor activity. However, its clinical application is limited by its poor bioavailability related to its extremely low water solubility. Novel materials allowing enhanced release of Curc in aqueous medium were obtained. The new materials consisted of electrospun fibers from cellulose acetate (CA) (mean fiber diameter ca. 780 nm ± 110 nm) with electrosprayed Curc/polyvinylpyrrolidone (Curc/PVP) particles. Scanning electron microscopy (SEM) showed that separated and evenly distributed particles of Curc/PVP were deposited on the surface of the mats and on the inner layers of the mat. X-ray diffraction studies showed that Curc was in amorphous state. In vitro studies demonstrated that Curc release was facilitated from Curc/PVP-on-CA mats (ca. 78% for 24 h) compared with the materials in which Curc was incorporated in CA fibers (17% for 24 h). Moreover, the curcumin-containing materials exhibited antibacterial activity against Gram-positive bacteria Staphylococcus aureus (S. aureus) and Gram-negative bacteria Escherichia coli (E. coli). Curc/PVP-on-CA fibrous mats exhibited high in vitro cytotoxicity towards HeLa tumor cells. Therefore, the obtained materials are promising for antibacterial wound dressing applications as well as for application in local treatment of cervical tumors.

Synergistic effect of a drug loaded electrospun patch and systemic chemotherapy in pancreatic cancer xenograft

Pancreatic cancer has a high rate of local recurrence and poor prognosis even with adjuvant chemotherapy after curative resection. The aim of this study was to investigate if local drug delivery combined with low dose systemic chemotherapy can increase the therapeutic effect of chemotherapy while reducing systemic toxicities. Poly-L-lactic acid-based 5-FU releasing patch was fabricated by electrospinning, and its tumour killing effects were first confirmed in vitro. The 5-FU patch directly adhered to the tumour in subcutaneous and orthotopic murine models, and induced a significant decrease in tumour size. Systemic gemcitabine treatment group, 5-FU drug releasing patch group, and systemic gemcitabine plus 5-FU patch group were compared by tumour size measurement, non-invasive bio-imaging, and histology in subcutaneous models. Combination of local drug patch and systemic chemotherapy led to increased tumour suppression effects that lasted longer, as well as increased survival rate. Histology revealed higher degree of apoptosis in the combined group. Systemic toxicity was recovered within 7 days after the treatment in all mice. Conclusively, local drug delivery using biocompatible polymer patch significantly inhibited tumour growth, and combination with systemic chemotherapy was more effective than single systemic chemotherapy.

Recent Advances in Electrospun Nanofiber Interfaces for Biosensing Devices

Electrospinning has emerged as a very powerful method combining efficiency, versatility and low cost to elaborate scalable ordered and complex nanofibrous assemblies from a rich variety of polymers. Electrospun nanofibers have demonstrated high potential for a wide spectrum of applications, including drug delivery, tissue engineering, energy conversion and storage, or physical and chemical sensors. The number of works related to biosensing devices integrating electrospun nanofibers has also increased substantially over the last decade. This review provides an overview of the current research activities and new trends in the field. Retaining the bioreceptor functionality is one of the main challenges associated with the production of nanofiber-based biosensing interfaces. The bioreceptors can be immobilized using various strategies, depending on the physical and chemical characteristics of both bioreceptors and nanofiber scaffolds, and on their interfacial interactions. The production of nanobiocomposites constituted by carbon, metal oxide or polymer electrospun nanofibers integrating bioreceptors and conductive nanomaterials (e.g., carbon nanotubes, metal nanoparticles) has been one of the major trends in the last few years. The use of electrospun nanofibers in ELISA-type bioassays, lab-on-a-chip and paper-based point-of-care devices is also highly promising. After a short and general description of electrospinning process, the different strategies to produce electrospun nanofiber biosensing interfaces are discussed.

Coaxial electrospun PCL/Gelatin-MA fibers as scaffolds for vascular tissue engineering

Coaxial electrospinning is a technique that allows the production of nanofibers with a core-shell structure. Such fibers present several advantages as materials for the preparation of scaffolds, namely due to the possibility of combining a core with the desired mechanical properties with a shell prepared from biocompatible materials that will establish proper interactions with the host. Herein, core-shell fibrous meshes, composed of a polycaprolactone (PCL) core and a functionalized gelatin shell, were prepared by coaxial electrospinning and then photocrosslinked under UV light aiming to be used in vascular tissue regeneration. The suitability of the meshes for the pretended biomedical application was evaluated by assessing their chemical/physical properties as well as their haemo and biocompatibility in vitro. The obtained results revealed that meshes' shell prepared with a higher content of gelatin showed fibers with diameters presenting a unimodal distribution and a mean value of 600nm. Moreover, those fibers with higher content of gelatin also displayed lower water contact angles, and therefore higher hydrophilicities. Such features are crucial for the good biologic performance displayed by these meshes, when in contact with blood and with Normal Human Dermal Fibroblasts cells.

Melt electrospinning vs. solution electrospinning: A comparative study of drug-loaded poly (ε-caprolactone) fibres

Curcumin-loaded poly (ε-caprolactone) (PCL) fibres prepared by melt and solution electrospinning methods were both fabricated to investigate their difference in characterization and drug release behaviour. The increasing curcumin content did not influence the morphologies of melt electrospun fibre, but enhanced the range of diameter distribution of solution electrospun fibre owing to the curcumin aggregates in the spinning solution which disturbed the stability of jet. Moreover, a large amount of curcumin with amorphous state could be loaded in the melt electrospun fibre. Whereas the limited solubility of curcumin in the solvent led to the drug aggregates dispersing within the solution electrospun fibre. In addition, the melt electrospun fibres had low drug release rate without burst release on the profiles due to the high crystallinity in the fibre, but high drug release rate and burst release occurred on the release profiles of the solution electrospun fibres because of their low crystallinity, porous structure and roughness surface.