Amoxicillin-loaded multilayer pullulan-based nanofibers maintain long-term antibacterial properties with tunable release profile for topical skin delivery applications

A new strategy for the treatment of middle ear infection using ciprofloxacin/amoxicillin-loaded ethyl cellulose/polyhydroxybutyrate nanofibers

A middle ear infection occurs due to the presence of several microorganisms behind the eardrum (tympanic membrane) and is very challenging to treat due to its unique location and requires a well-designed treatment. If not treated properly, the infection can result in severe symptoms and unavoidable side effects. In this study, excellent biocompatible ethyl cellulose (EC) and biodegradable polyhydroxybutyrate (PHB) biopolymer were used to fabricate drug-loaded nanofiber scaffolds using an electrospinning technique to overcome antibiotic overdose and insufficient efficacy of drug release during treatment. PHB polymer was produced from Halomonas sp., and the purity of PHB was found to around be 90 %. Additionally, ciprofloxacin (CIP) and amoxicillin (AMX) are highly preferable since both drugs are highly effective against gram-negative and gram-positive bacteria to treat several infections. Obtained smooth nanofibers were between 116.24 and 171.82 nm in diameter and the addition of PHB polymer and antibiotics improved the morphology of the nanofiber scaffolds. Thermal properties of the nanofiber scaffolds were tested and the highest Tg temperature resulted at 229 °C. The mechanical properties of the scaffolds were tested, and the highest tensile strength resulted in 4.65 ± 6.33 MPa. Also, drug-loaded scaffolds were treated against the most common microorganisms that cause the infection, such as S.aureus, E.coli, and P.aeruginosa, and resulted in inhibition zones between 10 and 21 mm. MTT assay was performed by culturing human adipose-derived mesenchymal stem cells (hAD MSCs) on the scaffolds. The morphology of the hAD MSCs' attachment was tested with SEM analysis and hAD MSCs were able to attach, spread, and live on each scaffold even on the day of 7. The cumulative drug release kinetics of CIP and AMX from drug-loaded scaffolds were analysed in phosphate-buffered saline (pH: 7.4) within different time intervals of up to 14 days using a UV spectrophotometer. Furthermore, the drug release showed that the First-Order and Korsmeyer-Peppas models were the most suitable kinetic models. Animal testing was performed on SD rats, matrix and collagen deposition occurred on days 5 and 10, which were observed using Hematoxylin-eosin and Masson's trichrome staining. At the highest drug concentration, a better repair effect was observed. Results were promising and showed potential for novel treatment.

High-yield fabrication of monodisperse multilayer nanofibrous microparticles for advanced oral drug delivery applications

Recent advances in the use of nano- and microparticles in drug delivery, cell therapy, and tissue engineering have led to increasing attention towards nanostructured microparticulate formulations for maximum benefit from both nano- and micron sized features. Scalable manufacturing of monodisperse nanostructured microparticles with tunable size, shape, content, and release rate remains a big challenge. Current technology, mainly comprises complex multi-step chemical procedures with limited control over these aspects. Here, we demonstrate a novel technique for high-yield fabrication of monodisperse monolayer and multilayer nanofibrous microparticles (MoNami and MuNaMi respectively). The fabrication procedure includes sequential electrospinning followed by micro-cutting at room temperature and transfer of particles for collection. The big advantage of the introduced technique is the potential to apply several polymer-drug combinations forming multilayer microparticles enjoying extracellular matrix (ECM)-mimicking architecture with tunable release profile. We demonstrate the fabrication and study the factors affecting the final three-dimensional structure. A model drug is encapsulated into a three-layer sheet (PLGA-pullulan-PLGA), and we demonstrate how the release profile changes from burst to sustain by simply cutting particles out of the electrospun sheet. We believe our fabrication method offers a unique and facile platform for realizing advanced microparticles for oral drug delivery applications.

Multilayer PVA/gelatin nanofibrous scaffolds incorporated with Tanacetum polycephalum essential oil and amoxicillin for skin tissue engineering application

Wound infection is still an important challenge in healing of different types of skin injuries. This highlights the need for new and improved antibacterial agents with novel and different mechanisms of action. In this study, by electrospinning process Tanacetum polycephalum essential oil (EO), as a natural antibacterial and anti-inflammatory agent, along with Amoxicillin (AMX) as an antibiotic are incorporated into PVA/gelatin-based nanofiber mats individually and in combination to fabricate a novel wound dressing. Briefly, we fabricated PVA/gelatin loaded by Amoxicillin as first layer for direct contact with wound surface to protects the wound from exogenous bacteria, and then built a PVA/gelatin/Tanacetum polycephalum essential oil layer on the first layer to help cleanses the wound from infection and accelerates wound closure. Finally, PVA/gelatin layer as third layer fabricated on middle layer to guarantee desirable mechanical properties. For each layer, the electrospinning parameters were adjusted to form bead-free fibers. The morphology of fabricated nanofiber scaffolds was characterized by Fourier-transform infrared (FTIR) and scanning electron microscopy (SEM). Microscopic images demonstrated the smooth bead-free microstructures fabrication of every layer of nanofiber with a uniform fiber size of 126.888 to 136.833 nm. While, EO and AMX increased the diameter of nanofibers but there was no change in physical structure of nanofiber. The water contact angle test demonstrated hydrophilicity of nanofibers with 47.35°. Although EO and AMX had little effect on reducing hydrophilicity but nanofibers with contact angle between 51.4° until 65.4° are still hydrophilic. Multilayer nanofibers loaded by EO and AMX killed 99.99 % of both gram-negative and gram-positive bacteria in comparison with control and PVA/gelatin nanofiber. Also, in addition to confirming the non-toxicity of nanofibers, MTT results also showed the acceleration of cell proliferation. In vivo wound evaluation in mouse models showed that designed nanofibrous scaffolds could be an appropriate option for wound treatment due to their positive effect on angiogenesis, collagen deposition, granulation tissue formation, epithelialization, and wound closure.

Airbrushed nanofibers with bioactive core and antibacterial shell for wound healing application

Acute and chronic wounds are vulnerable to infection and delayed healing and require critical care and advanced wound protection. To overcome the challenges, dual therapy of antibacterial and growth factors will be a novel wound care strategy. The present study explores airbrushed core-shell nanofiber for dual delivery of epidermal growth factor (EGF) and amoxicillin (AMOX) in a sustained manner. A blend of polycaprolactone (PCL)-polyethylene oxide (PEO) was used to prepare the shell compartment for amoxicillin loading and poly-DL-lactide (PDLLA) core for EGF loading by using a customized airbrush setup. Characterization result shows a uniform distribution of nanofibers ranging between 200 and 500 nm in diameter. Amoxicillin loading in the shell compartment offers an initial burst release followed by a sustained release for up to 14 days. Whereas EGF in the core part shows a continuous sustained release throughout the release study.In-vitrostudy indicates the biocompatibility of EGF-AMOX loaded core-shell nanofibers with human dermal fibroblast cell (HDF) cells and a higher cellular proliferation compared to control samples. Gene expression data show an increase in fold change of collagen I and tropoelastin expression, indicating the regenerative properties of EGF-AMOX encapsulated nanofiber. The combination of bioactive core (EGF) and antibiotic shell (amoxicillin) in an airbrushed nanofibrous scaffold is a novel approach, which is the first time explored to deliver sustainable therapy to treat skin wounds. Our results demonstrate that PCL-PEO-Amoxicillin/PDLLA-EGF-loaded core-shell nanofibers are promising dual therapy scaffolds to deliver effective skin wound care, with the possibility of direct deposition on the wound.

Electrospinning/3D printing drug-loaded antibacterial polycaprolactone nanofiber/sodium alginate-gelatin hydrogel bilayer scaffold for skin wound repair

Skin injuries and defects, as a common clinical issue, still cannot be perfectly repaired at present, particularly large-scale and infected skin defects. Therefore, in this work, a drug-loaded bilayer skin scaffold was developed for repairing full-thickness skin defects. Briefly, amoxicillin (AMX) was loaded on polycaprolactone (PCL) nanofiber via electrospinning to form the antibacterial nanofiber membrane (PCL-AMX) as the outer layer of scaffold to mimic epidermis. To maintain wound wettability and promote wound healing, external human epidermal growth factor (rhEGF) was loaded in sodium alginate-gelatin to form the hydrogel structure (SG-rhEGF) via 3D printing as inner layer of scaffold to mimic dermis. AMX and rhEGF were successfully loaded into the scaffold. The scaffold exhibited excellent physicochemical properties, with elongation at break and tensile modulus were 102.09 ± 6.74% and 206.83 ± 32.10 kPa, respectively; the outer layer was hydrophobic (WCA was 112.09 ± 4.67°), while the inner layer was hydrophilic (WCA was 48.87 ± 5.52°). Meanwhile, the scaffold showed excellent drug release and antibacterial characteristics. In vitro and in vivo studies indicated that the fabricated scaffold could enhance cell adhesion and proliferation, and promote skin wound healing, with favorable biocompatibility and great potential for skin regeneration and clinical application.

State-of-the-Art Review of Advanced Electrospun Nanofiber Composites for Enhanced Wound Healing

Wound healing is a complex biological process with four main phases: hemostasis, inflammation, proliferation, and remodeling. Current treatments such as cotton and gauze may delay the wound healing process which gives a demand for more innovative treatments. Nanofibers are nanoparticles that resemble the extracellular matrix of the skin and have a large specific surface area, high porosity, good mechanical properties, controllable morphology, and size. Nanofibers are generated by electrospinning method that utilizes high electric force. Electrospinning device composed of high voltage power source, syringe that contains polymer solution, needle, and collector to collect nanofibers. Many polymers can be used in nanofiber that can be from natural or from synthetic origin. As such, electrospun nanofibers are potential scaffolds for wound healing applications. This review discusses the advanced electrospun nanofiber morphologies used in wound healing that is prepared by modified electrospinning techniques.

Electrospun Nanofibers for Biomedical, Sensing, and Energy Harvesting Functions

The process of electrospinning is over a century old, yet novel material and method achievements, and later the addition of nanomaterials in polymeric solutions, have spurred a significant increase in research innovations with several unique applications. Significant improvements have been achieved in the development of electrospun nanofibrous matrices, which include tailoring compositions of polymers with active agents, surface functionalization with nanoparticles, and encapsulation of functional materials within the nanofibers. Recently, sequentially combining fabrication of nanofibers with 3D printing was reported by our group and the synergistic process offers fiber membrane functionalities having the mechanical strength offered by 3D printed scaffolds. Recent developments in electrospun nanofibers are enumerated here with special emphasis on biomedical technologies, chemical and biological sensing, and energy harvesting aspects in the context of e-textile and tactile sensing. Energy harvesting offers significant advantages in many applications, such as biomedical technologies and critical infrastructure protection by using the concept of finite state machines and edge computing. Many other uses of devices using electrospun nanofibers, either as standalone or conjoined with 3D printed materials, are envisaged. The focus of this review is to highlight selected novel applications in biomedical technologies, chem.-bio sensing, and broadly in energy harvesting for use in internet of things (IoT) devices. The article concludes with a brief projection of the future direction of electrospun nanofibers, limitations, and how synergetic combination of the two processes will open pathways for future discoveries.

The preparation, resources, applications, and future trends of nanofibers in active food packaging: a review

Active packaging is a novel strategy for maintaining the shelf life of products and ensuring their safety, freshness, and integrity that has emerged with the consumer demand for safer, healthier, and higher quality food. Nanofibers have received a lot of attention for the application in active food packaging due to their high specific surface area, high porosity, and high loading capacity of active substances. Three common methods (electrospinning, solution blow spinning, and centrifugal spinning) for the preparation of nanofibers in active food packaging and their influencing parameters are presented, and advantages and disadvantages between these methods are compared. The main natural and synthetic polymeric substrate materials for the nanofiber preparation are discussed; and the application of nanofibers in active packaging is elaborated. The current limitations and future trends are also discussed. There have been many studies on the preparation of nanofibers using substrate materials from different sources for active food packaging. However, most of these studies are still in the laboratory research stage. Solving the issues of preparation efficiency and cost of nanofibers is the key to their application in commercial food packaging.

Topically Applied Biopolymer-Based Tri-Layered Hierarchically Structured Nanofibrous Scaffold with a Self-Pumping Effect for Accelerated Full-Thickness Wound Healing in a Rat Model

Wound healing has grown to be a significant problem at a global scale. The lack of multifunctionality in most wound dressing-based biopolymers prevents them from meeting all clinical requirements. Therefore, a multifunctional biopolymer-based tri-layered hierarchically nanofibrous scaffold in wound dressing can contribute to skin regeneration. In this study, a multifunctional antibacterial biopolymer-based tri-layered hierarchically nanofibrous scaffold comprising three layers was constructed. The bottom and the top layers contain hydrophilic silk fibroin (SF) and fish skin collagen (COL), respectively, for accelerated healing, interspersed with a middle layer of hydrophobic poly-3-hydroxybutyrate (PHB) containing amoxicillin (AMX) as an antibacterial drug. The advantageous physicochemical properties of the nanofibrous scaffold were estimated by SEM, FTIR, fluid uptake, contact angle, porosity, and mechanical properties. Moreover, the in vitro cytotoxicity and cell healing were assessed by MTT assay and the cell scratching method, respectively, and revealed excellent biocompatibility. The nanofibrous scaffold exhibited significant antimicrobial activity against multiple pathogenic bacteria. Furthermore, the in vivo wound healing and histological studies demonstrated complete wound healing in wounded rats on day 14, along with an increase in the expression level of the transforming growth factor-β1 (TGF-β1) and a decrease in the expression level of interleukin-6 (IL-6). The results revealed that the fabricated nanofibrous scaffold is a potent wound dressing scaffold, and significantly accelerates full-thickness wound healing in a rat model.

Development of Sustainable Hydrophilic Azadirachta indica Loaded PVA Nanomembranes for Cosmetic Facemask Applications

Nanofiber-based facial masks have attracted the attention of modern cosmetic applications due to their controlled drug release, biocompatibility, and better efficiency. In this work, Azadirachta indica extract (AI) incorporated electrospun polyvinyl alcohol (PVA) nanofiber membrane was prepared to obtain a sustainable and hydrophilic facial mask. The electrospun AI incorporated PVA nanofiber membranes were characterized by scanning electron microscope, Ultraviolet-visible spectroscopy (UV-Vis) drug release, water absorption analysis, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, and antibacterial activity (qualitative and quantitative) at different PVA and AI concentrations. The optimized nanofiber of 376 ± 75 nm diameter was obtained at 8 wt/wt% PVA concentration and 100% AI extract. The AI nanoparticles of size range 50~250 nm in the extract were examined through a zeta sizer. The water absorption rate of ~660% and 17.24° water contact angle shows good hydrophilic nature and water absorbency of the nanofiber membrane. The UV-Vis also analyzed fast drug release of >70% in 5 min. The prepared membrane also exhibits 99.9% antibacterial activity against Staphylococcus aureus and has 79% antioxidant activity. Moreover, the membrane also had good mechanical properties (tensile strength 1.67 N, elongation 48%) and breathability (air permeability 15.24 mm/s). AI-incorporated nanofiber membrane can effectively be used for facial mask application.

Delivery of streptomycin to the rat colon by use of electrospun nanofibers

Drug-loaded electrospun nanofibers are potential drug carrier systems that may optimize disease treatment while reducing the impact on commensal microbes. The feasibility of streptomycin-loaded pullulan nanofibers fabricated from a green electrospinning procedure using water as the solvent was assessed. We conducted a rat study including a group treated with streptomycin-loaded nanofibers (STR-F, n = 5), a group treated with similar concentrations of streptomycin in the drinking water (STR-W, n = 5), and a non-treated control group (CTR, n = 5). Streptomycin was successfully loaded into nanofibers and delivered by this vehicle, which minimized the quantity of the drug released in the ileal compartment of the gut. Ingested streptomycin-resistant E. coli colonized of up to 10⁶ CFU/g feces, revealing a selective effect of streptomycin even when given in the low amounts allowed by the nanofiber-based delivery. 16S amplicon sequencing of the indigenous microbiota revealed differential effects in the three groups. An increase of Peptostreptococcaceae in the cecum of STR-F animals may indicate that the fermentation of nanofibers directly or indirectly promoted growth of bacteria within this family. Our results elucidate relevant properties of electrospun nanofibers as a novel vehicle for delivery of antimicrobials to the large intestine.