Electrospun triaxial nanofibers with middle blank cellulose acetate layers for accurate dual-stage drug release

The Incorporated Drug Affects the Properties of Hydrophilic Nanofibers

Hydrophilic nanofibers offer promising potential for the delivery of drugs with diverse characteristics. Yet, the effects of different drugs incorporated into these nanofibers on their properties remain poorly understood. In this study, we systematically explored how model drugs, namely ibuprofen, carvedilol, paracetamol, and metformin (hydrochloride), affect hydrophilic nanofibers composed of polyethylene oxide and poloxamer 188 in a 1:1 weight ratio. Our findings reveal that the drug affects the conductivity and viscosity of the polymer solution for electrospinning, leading to distinct changes in the morphology of electrospun products. Specifically, drugs with low solubility in ethanol, the chosen solvent for polymer solution preparation, led to the formation of continuous nanofibers with uniform diameters. Additionally, the lower solubility of metformin in ethanol resulted in particle appearance on the nanofiber surface. Furthermore, the incorporation of more hydrophilic drugs increased the surface hydrophilicity of nanofiber mats. However, variations in the physicochemical properties of the drugs did not affect the drug loading and drug entrapment efficiency. Our research also shows that drug properties do not notably affect the immediate release of drugs from nanofibers, highlighting the dominant role of the hydrophilic polymers used. This study emphasizes the importance of considering specific drug properties, such as solubility, hydrophilicity, and compatibility with the solvent used for electrospinning, when designing hydrophilic nanofibers for drug delivery. Such considerations are crucial for optimizing the properties of the drug delivery system, which is essential for achieving therapeutic efficacy and safety.

Electrospun multi-chamber core-shell nanofibers and their controlled release behaviors: A review

Core-shell structure is a concentric circle structure found in nature. The rapid development of electrospinning technology provides more approaches for the production of core-shell nanofibers. The nanoscale effects and expansive specific surface area of core-shell nanofibers can facilitate the dissolution of drugs. By employing ingenious structural designs and judicious polymer selection, specialized nanofiber drug delivery systems can be prepared to achieve controlled drug release. The synergistic combination of core-shell structure and materials exhibits a strong strategy for enhancing the drug utilization efficiency and customizing the release profile of drugs. Consequently, multi-chamber core-shell nanofibers hold great promise for highly efficient disease treatment. However, little attention concentration is focused on the effect of multi-chamber core-shell nanofibers on controlled release of drugs. In this review, we introduced different fabrication techniques for multi-chamber core-shell nanostructures, including advanced electrospinning technologies and surface functionalization. Subsequently, we reviewed the different controlled drug release behaviors of multi-chamber core-shell nanofibers and their potential needs for disease treatment. The comprehensive elucidation of controlled release behaviors based on electrospun multi-chamber core-shell nanostructures could inspire the exploration of novel controlled delivery systems. Furthermore, once these fibers with customizable drug release profiles move toward industrial mass production, they will potentially promote the development of pharmacy and the treatment of various diseases. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Co- and Triaxial Electrospinning for Stem Cell-based Bone Regeneration

Bone tissue is composed of organic minerals and cells. It has the capacity to heal for certain minor damages, but when the bone defects surpass the critical threshold, they need fixing. Bone regeneration through natural and synthetic biodegradable materials requires various steps, such as manufacturing methods and materials selection. A successful biodegradable bone graft should have a high surface area/ volume ratio, strength, and a biocompatible, porous structure capable of promoting cell adhesion, proliferation, and differentiation. Considering these requirements, the electrospinning technique is promising for creating functional nano-sized scaffolds. The multi-axial methods, such as coaxial and triaxial electrospinning, are the most popular techniques to produce double or tri-layered scaffolds, respectively. Recently, stem cell culture on scaffolds and the application of osteogenic differentiation protocols on these scaffolds have opened new possibilities in the field of biomaterials research. This review discusses an overview of the progress in coaxial and triaxial technology through biodegradable composite bone materials. The review also carefully elaborates the osteogenic differentiation using stem cells and their performance with nano-sized scaffolds.

Multifunctional Electrospun Nanofibers for Biosensing and Biomedical Engineering Applications

Nanotechnology is experiencing unprecedented developments, leading to the advancement of functional nanomaterials. The properties that stand out include remarkable porosity, high-specific surface area, excellent loading capacity, easy modification, and low cost make electrospun nanofibers. In the biomedical field, especially in biosensors, they exhibit amazing potential. This review introduces the principle of electrospinning, describes several structures and biomaterials of electrospun nanofibers used for biomedicine, and summarizes the applications of this technology in biosensors and other biomedical applications. In addition, the technical challenges and limitations of electrospinning for biomedicine are discussed; however, more research work is needed to elucidate its full potential.

Gout therapeutics and drug delivery

Gout is a common inflammatory arthritis caused by persistently elevated uric acid levels. With the improvement of people's living standards, the consumption of processed food and the widespread use of drugs that induce elevated uric acid, gout rates are increasing, seriously affecting the human quality of life, and becoming a burden to health systems worldwide. Since the pathological mechanism of gout has been elucidated, there are relatively effective drug treatments in clinical practice. However, due to (bio)pharmaceutical shortcomings of these drugs, such as poor chemical stability and limited ability to target the pathophysiological pathways, traditional drug treatment strategies show low efficacy and safety. In this scenario, drug delivery systems (DDS) design that overcome these drawbacks is urgently called for. In this review, we initially describe the pathological features, the therapeutic targets, and the drugs currently in clinical use and under investigation to treat gout. We also comprehensively summarize recent research efforts utilizing lipid, polymeric and inorganic carriers to develop advanced DDS for improved gout management and therapy.

Electrospun Nanofiber Membranes with Various Structures for Wound Dressing

Electrospun nanofiber membranes (NFMs) have high porosity and a large specific surface area, which provide a suitable environment for the complex and dynamic wound healing process and a large number of sites for carrying wound healing factors. Further, the design of the nanofiber structure can imitate the structure of the human dermis, similar to the natural extracellular matrix, which better promotes the hemostasis, anti-inflammatory and healing of wounds. Therefore, it has been widely studied in the field of wound dressing. This review article overviews the development of electrospinning technology and the application of electrospun nanofibers in wound dressings. It begins with an introduction to the history, working principles, and transformation of electrospinning, with a focus on the selection of electrospun nanofiber materials, incorporation of functional therapeutic factors, and structural design of nanofibers and nanofiber membranes. Moreover, the wide application of electrospun NFMs containing therapeutic factors in wound healing is classified based on their special functions, such as hemostasis, antibacterial and cell proliferation promotion. This article also highlights the structural design of electrospun nanofibers in wound dressing, including porous structures, bead structures, core-shell structures, ordered structures, and multilayer nanofiber membrane structures. Finally, their advantages and limitations are discussed, and the challenges faced in their application for wound dressings are analyzed to promote further research in this field.

Multi-material electrospinning: from methods to biomedical applications

Electrospinning as a versatile, simple, and cost-effective method to engineer a variety of micro or nanofibrous materials, has contributed to significant developments in the biomedical field. However, the traditional electrospinning of single material only can produce homogeneous fibrous assemblies with limited functional properties, which oftentimes fails to meet the ever-increasing requirements of biomedical applications. Thus, multi-material electrospinning referring to engineering two or more kinds of materials, has been recently developed to enable the fabrication of diversified complex fibrous structures with advanced performance for greatly promoting biomedical development. This review firstly gives an overview of multi-material electrospinning modalities, with a highlight on their features and accessibility for constructing different complex fibrous structures. A perspective of how multi-material electrospinning opens up new opportunities for specific biomedical applications, i.e., tissue engineering and drug delivery, is also offered.

Preparation and Characterization of Porous Cellulose Acetate Nanofiber Hydrogels

The currently reported methods for preparing cellulose acetate hydrogels use chemical reagents as cross-linking agents, and the prepared ones are non-porous structured cellulose acetate hydrogels. Nonporous cellulose acetate hydrogels limit the range of applications, such as limiting cell attachment and nutrient delivery in tissue engineering. This research creatively proposed a facile method to prepare cellulose acetate hydrogels with porous structures. Water was added to the cellulose acetate-acetone solution as an anti-solvent to induce the phase separation of the cellulose acetate-acetone solution to obtain a physical gel with a network structure, where the cellulose acetate molecules undergo re-arrangement during the replacement of acetone by water to obtain hydrogels. The SEM and BET test results showed that the hydrogels are relatively porous. The maximum pore size of the cellulose acetate hydrogel is 380 nm, and the specific surface area reaches 62 m²/g. The porosity of the hydrogel is significantly higher than that of the cellulose acetate hydrogel reported in the previous literature. The XRD results show that the nanofibrous morphology of cellulose acetate hydrogels is caused by the deacetylation reaction of cellulose acetate.

Biphasic drug release from electrospun structures

INTRODUCTION

Biphasic release, as a special drug-modified release profile that combines immediate and sustained release, allows fast therapeutic action and retains blood drug concentration for long periods. Electrospun nanofibers, particularly those with complex nanostructures produced by multi-fluid electrospinning processes, are potential novel biphasic drug delivery systems (DDSs).

AREAS COVERED

This review summarizes the most recent developments in electrospinning and related structures. In this review, the role of electrospun nanostructures in biphasic drug release was comprehensively explored. These electrospun nanostructures include monolithic nanofibers obtained through single-fluid blending electrospinning, core-shell and Janus nanostructures prepared via bifluid electrospinning, three-compartment nanostructures obtained via trifluid electrospinning, nanofibrous assemblies obtained through the layer-by-layer deposition of nanofibers, and the combined structure of electrospun nanofiber mats with casting films. The strategies and mechanisms through which complex structures facilitate biphasic release were analyzed.

EXPERT OPINION

Electrospun structures can provide many strategies for the development of biphasic drug release DDSs. However, many issues such as the scale-up productions of complex nanostructures, the in vivo verification of the biphasic release effects, keeping pace with the developments of multi-fluid electrospinning, drawing support from the state-of-the-art pharmaceutical excipients, and the combination with traditional pharmaceutical methods need to be addressed for real applications.

Electrospun fibers as carriers for topical drug delivery and release in skin bandages and patches for atopic dermatitis treatment

The skin is a complex layer system and the most important barrier between the environment and the organism. In this review, we describe some widespread skin problems, with a focus on eczema, which are affecting more and more people all over the world. Most of treatment methods for atopic dermatitis (AD) are focused on increasing skin moisture and protecting from bacterial infection and external irritation. Topical and transdermal treatments have specific requirements for drug delivery. Breathability, flexibility, good mechanical properties, biocompatibility, and efficacy are important for the patches used for skin. Up to today, electrospun fibers are mostly used for wound dressing. Their properties, however, meet the requirements for skin patches for the treatment of AD. Active agents can be incorporated into fibers by blending, coaxial or side-by-side electrospinning, and also by physical absorption post-processing. Drug release from the electrospun membranes is affected by drug and polymer properties and the technique used to combine them into the patch. We describe in detail the in vitro release mechanisms, parameters affecting the drug transport, and their kinetics, including theoretical approaches. In addition, we present the current research on skin patch design. This review summarizes the current extensive know-how on electrospun fibers as skin drug delivery systems, while underlining the advantages in their prospective use as patches for atopic dermatitis. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Tuning the Drug Release from Antibacterial Polycaprolactone/Rifampicin-Based Core-Shell Electrospun Membranes: A Proof of Concept

The employment of coaxial fibers for guided tissue regeneration can be extremely advantageous since they allow the functionalization with bioactive compounds to be preserved and released with a long-term efficacy. Antibacterial coaxial membranes based on poly-ε-caprolactone (PCL) and rifampicin (Rif) were synthesized here, by analyzing the effects of loading the drug within the core or on the shell layer with respect to non-coaxial matrices. The membranes were, therefore, characterized for their surface properties in addition to analyzing drug release, antibacterial efficacy, and biocompatibility. The results showed that the lower drug surface density in coaxial fibers hinders the interaction with serum proteins, resulting in a hydrophobic behavior compared to non-coaxial mats. The air-plasma treatment increased their hydrophilicity, although it induced rifampicin degradation. Moreover, the substantially lower release of coaxial fibers influenced the antibacterial efficacy, tested against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Indeed, the coaxial matrices were inhibitory and bactericidal only against S. aureus, while the higher release from non-coaxial mats rendered them active even against E. coli. The biocompatibility of the released rifampicin was assessed too on murine fibroblasts, revealing no cytotoxic effects. Hence, the presented coaxial system should be further optimized to tune the drug release according to the antibacterial effectiveness.

Drug Delivery Systems for Photodynamic Therapy: The Potentiality and Versatility of Electrospun Nanofibers

Recently, photodynamic therapy (PDT) has become a promising approach for the treatment of a broad range of diseases, including oncological and infectious diseases. This minimally invasive and localized therapy is based on the production of reactive oxygen species (ROS) able to destroy cancer cells and inactivate pathogens by combining the use of photosensitizers (PSs), light and molecular oxygen. To overcome the drawbacks of drug systemic administration, drug delivery systems (DDS) can be used to carrier the PSs, allowing higher therapeutic efficacy and minimal toxicological effects. Polymeric nanofibers produced by electrospinning emerged as powerful platforms for drug delivery applications. Electrospun nanofibers exhibit outstanding characteristics, such as large surface area to volume ratio associated with high drug loading, high porosity, flexibility, ability to incorporate and release a wide variety of therapeutic agents, biocompatibility and biodegradability. Due to the versatility of this technique, fibers with different morphologies and functionalities, including drug release profile can be produced. The possibility of scalability makes electrospinning even more attractive for the development of DDS. This review aims to explore and show an up to date of the huge potential of electrospun nanofibers as DDS for different PDT applications and discuss the opportunities and challenges in this field. This article is protected by copyright. All rights reserved.

Surface Reconstruction on Electro-Spun PVA/PVP Nanofibers by Water Evaporation

Tailoring the secondary surface morphology of electro-spun nanofibers has been highly desired, as such delicate structures equip nanofibers with distinct functions. Here, we report a simple strategy to directly reconstruct the surface of polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) nanofibers by water evaporation. The roughness and diameter of the nanofibers depend on the temperature during vacuum drying. Surface changes of the nanofibers from smooth to rough were observed at 55 °C, with a significant drop in nanofiber diameter. We attribute the formation of the secondary surface morphology to the intermolecular forces in the water vapor, including capillary and the compression forces, on the basis of the results from the Fourier-transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopy. The strategy is universally effective for various electro-spun polymer nanofibers, thus opening up avenues toward more detailed and sophisticated structure design and implementation for nanofibers.

Adsorption, and controlled release of doxorubicin from cellulose acetate/polyurethane/multi-walled carbon nanotubes composite nanofibers

The cellulose acetate (CA)/poly (ε-caprolactone diol)/poly (tetramethylene ether) glycol-polyurethane (PCL-Diol/PTMG-PU)/multi-walled carbon nanotubes (MWCNTs) composite nanofibers were prepared via two-nozzle electrospinning on both counter sides of the collector. The performance of synthesized composite nanofibers was investigated as an environmental application and anticancer delivery system for the adsorption/release of doxorubicin (DOX). The synergic effect of MWCNTs and DOX incorporated into the nanofibers was investigated against LNCaP prostate cancer cells. The status of MWCNTs and DOX in composite nanofibers was demonstrated by SEM, FTIR and UV-vis determinations. The adsorption tests using nanofibrous adsorbent toward DOX sorption was evaluated under various DOX initial concentrations (100-2000 mg l^-1), adsorption times (5-120 min), and pH values (pH:2-9). Due to the fitting of isotherm and kinetic data with Redlich-Peterson and pseudo-second order models, both chemisorption and surface adsorption of DOX molecules mechanisms have been predicted. The drug release from both nanofibers and MWCNTs-loaded nanofibers was compared. The better drug sustained release profiles verified in the presence of composite nanofibers. LNCaP prostate cancer and L929 normal cells were treated to investigate the cytotoxicity and compatibility of synthesized composite nanofibers. The apoptosis/necrosis of hybrid nanofibers and MWCNTs loaded-nanofibers was investigated. The obtained results demonstrated the synergic effects of MWCNTs and DOX loaded-nanofibers on the LNCaP prostate cancer cells death.

Cellulose-Based Nanofibers Processing Techniques and Methods Based on Bottom-Up Approach-A Review

In the past decades, cellulose (one of the most important natural polymers), in the form of nanofibers, has received special attention. The nanofibrous morphology may provide exceptional properties to materials due to the high aspect ratio and dimensions in the nanometer range of the nanofibers. The first feature may lead to important consequences in mechanical behavior if there exists a particular orientation of fibers. On the other hand, nano-sizes provide a high surface-to-volume ratio, which can have important consequences on many properties, such as the wettability. There are two basic approaches for cellulose nanofibers preparation. The top-down approach implies the isolation/extraction of cellulose nanofibrils (CNFs) and nanocrystals (CNCs) from a variety of natural resources, whereby dimensions of isolates are limited by the source of cellulose and extraction procedures. The bottom-up approach can be considered in this context as the production of nanofibers using various spinning techniques, resulting in nonwoven mats or filaments. During the spinning, depending on the method and processing conditions, good control of the resulting nanofibers dimensions and, consequently, the properties of the produced materials, is possible. Pulp, cotton, and already isolated CNFs/CNCs may be used as precursors for spinning, alongside cellulose derivatives, namely esters and ethers. This review focuses on various spinning techniques to produce submicrometric fibers comprised of cellulose and cellulose derivatives. The spinning of cellulose requires the preparation of spinning solutions; therefore, an overview of various solvents is presented showing their influence on spinnability and resulting properties of nanofibers. In addition, it is shown how bottom-up spinning techniques can be used for recycling cellulose waste into new materials with added value. The application of produced cellulose fibers in various fields is also highlighted, ranging from drug delivery systems, high-strength nonwovens and filaments, filtration membranes, to biomedical scaffolds.

Tunable Spun Fiber Constructs in Biomedicine: Influence of Processing Parameters in the Fibers' Architecture

Electrospinning and wet-spinning have been recognized as two of the most efficient and promising techniques for producing polymeric fibrous constructs for a wide range of applications, including optics, electronics, food industry and biomedical applications. They have gained considerable attention in the past few decades because of their unique features and tunable architectures that can mimic desirable biological features, responding more effectively to local demands. In this review, various fiber architectures and configurations, varying from monolayer and core-shell fibers to tri-axial, porous, multilayer, side-by-side and helical fibers, are discussed, highlighting the influence of processing parameters in the final constructs. Additionally, the envisaged biomedical purposes for the examined fiber architectures, mainly focused on drug delivery and tissue engineering applications, are explored at great length.

Strategies for sustained drug release from electrospun multi-layer nanostructures

Among different kinds of modified release profiles, sustained drug release (SDR) has received the most attention due to its capability to provide a "safe, efficacious, and convenient" drug delivery effect. Electrospun nanofibers have shown their popularity in this interdisciplinary field, as demonstrated by the first reports about SDRs on drug delivery applications of blended nanofibers and core-shell nanofibers. Along with the evolution of electrospinning from a single-fluid blending process to coaxial, tri-axial, side-by-side, and other multi-fluid processes, more multi-chamber nanostructures can be created through a single-step straight forward manner. These multi-chamber nanostructures can act as a powerful platform to support a wide variety of new strategies for the development of novel SDR nanomaterials. Thus, this review describes a combination history of electrospinning and SDR and its further development trend. After a summary of the presently popular multi-chamber core-shell nanostructures, 15 strategies for furnishing SDR profiles are categorized and exemplified. The perspectives of electrospun multi-chamber nanostructures for further promoting SDR are narrated. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Recent Progress in Electrospun Nanofiber-Based Degenerated Intervertebral Disc Repair

Annulus fibrosus fissure and fibrosis of nucleus pulposus are severe morphological characteristics of intervertebral disc degeneration. Currently, surgery or drugs are used to relieve pain in such cases. Tissue engineering is a new multidisciplinary strategy with great potential for use in joint replacement and organ regeneration. Based on the natural anatomy of intervertebral discs, intervertebral disc scaffolds are fabricated by exploiting the special arrangement of extracellular matrix fibers. Electrospun nanofibers possess clear advantages in repairing degenerated intervertebral discs. This article reviews and summarizes recently developed methods for improving and fabricating electrospun nanofiber annulus fibrosus scaffolds in terms of nanofiber alignment, material selection, loading additives, and the progress made in combining other advanced technologies with electrospun nanofibers. In addition, the improvement in mechanical properties and biocompatibility of nucleus pulposus scaffolds by electrospun nanofiber-reinforced hydrogels is discussed. Finally, complete intervertebral disc scaffolds can be fabricated using the disc-like angle-ply structure and other emerging fabrication methods. Taken together, electrospun nanofiber intervertebral disc scaffolds are promising for clinical applications.

Electrospun PVP-Core/PHBV-Shell Fibers to Eliminate Tailing Off for an Improved Sustained Release of Curcumin

Tailing off release in the sustained release of water-insoluble curcumin (Cur) is a significant challenge in the drug delivery system. As a novel solution, core-shell nanodrug containers have aroused many interests due to their potential improvement in drug-sustained release. In this work, a biodegradable polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and hydrophilic polyvinylpyrrolidone (PVP) were exploited as drug delivery carriers by coaxial electrospinning, and the core-shell drug-loaded fibers exhibited improved sustained release of Cur. A cylindrical morphology and a clear core-shell structure were observed by scanning and transmission electron microscopies. The X-ray diffraction pattern and infrared spectroscopy revealed that Cur existed in amorphous form due to its good compatibility with PHBV and PVP. The in vitro drug release curves confirmed that the core-shell container manipulated Cur in a faster drug release process than that in the traditional PHBV monolithic container. The combination of the material and structure forms a novel nanodrug container with a better sustained release of water-insoluble Cur. This strategy is beneficial for exploiting more functional biomedical materials to improve the drug release behavior.

Mercaptopurine-Loaded Sandwiched Tri-Layered Composed of Electrospun Polycaprolactone/Poly(Methyl Methacrylate) Nanofibrous Scaffolds as Anticancer Carrier with Antimicrobial and Antibiotic Features: Sandwich Configuration Nanofibers, Release Study and in vitro Bioevaluation Tests

BACKGROUND

6-Mercaptopurine (6-MP) is a potential anti-cancer agent which its therapeutic and limitation applicability due to its high toxicity.

OBJECTIVE

Herein, 6-MP was loaded into tri-layered sandwich nanofibrous scaffold (the top layer composed of poly methyl methacrylate/polycaprolactone (PMMA/PCL), the middle layer was PCL/PMMA/6-MP, and the bottom layer was PCL/PMMA to improve its bioactivity, adjusting the release-sustainability and reduce its toxicity.

METHODS

Electrospun tri-layered nanofibers composed of PCL/PMMA were utilized as nano-mats for controlling sustained drug release. Four groups of sandwich scaffold configurations were investigated with alteration of (PMMA: PCL) composition.

RESULTS

The sandwich scaffold composed of 2%PCL/4%PMMA/1%6-MP showed the best miscibility, good homogeneity and produced the smoothest nanofibers and low crystallinity. All fabricated 6-MP-loaded-PCL/PMMA scaffolds exhibited antimicrobial properties on the bacterial and fungal organisms, where the cytotoxicity evaluation proved the safety of scaffolds on normal cells, even at high concentration. Scaffolds provided a sustained-drug release profile that was strongly dependent on (PCL: PMMA). As (PCL: PMMA) decreased, the sustained 6-MP release from PCL/PMMA scaffolds increased. Results established that ~18% and 20% of 6-MP were released after 23h from (4%PCL/4%PMMA/1%6-MP) and (2%PCL/4%PMMA/1%6-MP), respectively, where this release was maintained for more than 20 days. The anti-cancer activity of all fabricated scaffolds was also investigated using different cancerous cell lines (e.g., Caco-2, MDA, and HepG-2) results showed that 6-MP-loaded-nanofibrous mats have an anti-cancer effect, with a high selective index for breast cancer. We observed that viability of a cancer cell was dropped to about 10%, using nanofibers containing 2%PCL/4%PMMA/1%6-MP.

CONCLUSION

Overall, the PCL: PMMA ratio and sandwich configuration imparts a tight control on long-term release profile and initial burst of 6-MP for anticancer treatment purposes.

Recent applications of electrical, centrifugal, and pressurised emerging technologies for fibrous structure engineering in drug delivery, regenerative medicine and theranostics

Advancements in technology and material development in recent years has led to significant breakthroughs in the remit of fiber engineering. Conventional methods such as wet spinning, melt spinning, phase separation and template synthesis have been reported to develop fibrous structures for an array of applications. However, these methods have limitations with respect to processing conditions (e.g. high processing temperatures, shear stresses) and production (e.g. non-continuous fibers). The materials that can be processed using these methods are also limited, deterring their use in practical applications. Producing fibrous structures on a nanometer scale, in sync with the advancements in nanotechnology is another challenge met by these conventional methods. In this review we aim to present a brief overview of conventional methods of fiber fabrication and focus on the emerging fiber engineering techniques namely electrospinning, centrifugal spinning and pressurised gyration. This review will discuss the fundamental principles and factors governing each fabrication method and converge on the applications of the resulting spun fibers; specifically, in the drug delivery remit and in regenerative medicine.

A Diels-Alder polymer platform for thermally enhanced drug release toward efficient local cancer chemotherapy

We reports a novel thermally enhanced drug release system synthesized via a dynamic Diels-Alder (DA) reaction to develop chemotherapy for pancreatic cancer. The anticancer prodrug was designed by tethering gemcitabine (GEM) to poly(furfuryl methacrylate) (PFMA) via N-(3-maleimidopropionyloxy)succinimide as a linker by DA reaction (PFMA-L-GEM). The conversion rate of the DA reaction was found to be approximately 60% at room temperature for 120 h. The reversible deconstruction of the DA covalent bond in retro Diels-Alder (rDA) reaction was confirmed by proton nuclear magnetic resonance, and the reaction was significantly accelerated at 90 °C. A PFMA-LGEM film containing magnetic nanoparticles (MNPs) was prepared for thermally enhanced release of the drug via the rDA reaction. Drug release was initiated by heating MNPs by alternating magnetic field. This enables local heating within the film above the rDA reaction temperature while maintaining a constant surrounding medium temperature. The MNPs/PFMA-L-GEM film decreased the viability of pancreatic cancer cells by 49% over 24 h. Our results suggest that DA/rDA-based thermally enhanced drug release systems can serve as a local drug release platform and deliver the target drug within locally heated tissue, thereby improving the therapeutic efficiency and overcoming the side effects of conventional drugs used to treat pancreatic cancer.

Electrospun hydrogels for dynamic culture systems: advantages, progress, and opportunities

The extracellular matrix (ECM) is a water-swollen, tissue-specific material environment in which biophysiochemical signals are organized and influence cell behaviors. Electrospun nanofibrous substrates have been pursued as platforms for tissue engineering and cell studies that recapitulate features of the native ECM, in particular its fibrous nature. In recent years, progress in the design of electrospun hydrogel systems has demonstrated that molecular design also enables unique studies of cellular behaviors. In comparison to the use of hydrophobic polymeric materials, electrospinning hydrophilic materials that crosslink to form hydrogels offer the potential to achieve the water-swollen, nanofibrous characteristics of endogenous ECM. Although electrospun hydrogels require an additional crosslinking step to stabilize the fibers (allowing fibers to swell with water instead of dissolving) in comparison to their hydrophobic counterparts, researchers have made significant advances in leveraging hydrogel chemistries to incorporate biochemical and dynamic functionalities within the fibers. Consequently, dynamic biophysical and biochemical properties can be engineered into hydrophilic nanofibers that would be difficult to engineer in hydrophobic systems without strategic and sometimes intensive post-processing techniques. This Review describes common methodologies to control biophysical and biochemical properties of both electrospun hydrophobic and hydrogel nanofibers, with an emphasis on highlighting recent progress using hydrogel nanofibers with engineered dynamic complexities to develop culture systems for the study of biological function, dysfunction, development, and regeneration.

Ethyl cellulose coated sustained release aspirin spherules for treating COVID-19: DOE led rapid optimization using arbitrary interface; applicable for emergency situations

This work attempts to resolve one of the key issues related to the design and development of sustained-release spherule of aspirin for oral formulations, tailored to treat COVID-19. For that, in the Design of Experiments (DOE) an arbitrary interface, "coating efficiency" (CE) is introduced and scaled the cumulative percentage coating (CPC) to get predictable control over drug release (DR). Subsequently, the granules containing ASP are converted to spherules and then to Ethyl cellulose (EC) Coated spherules (CS) by a novel bed coating during the rolling (BCDR) process. Among spherules, one with 0.35 mm than 0.71 mm shows required properties. The CS has a low 120⁰ angle by Optical Microscopy (OM), smooth surface without cracks by scanning electron microscopy (SEM), and better flow properties (Angle of repose 29.69 ± 0.78⁰, Carr's index 6.73 ± 2.24%, Hausner's Ratio 1.07 ± 0.03) than granules and spherules. Once certain structure-dependent control over release is attained (EC coated spherules shows 10% reduction in burst release (BR) than uncoated spherules showing a release of 80-91%) the predictability is achieved and Design of space (DOS) by DOE (CE-70.14%and CPC-200% and DR-61.54%) is established. The results of DOE to experimentally validated results were within 20% deviation. The aspirin is changing its crystal structure by powder X-ray diffraction (PXRD) and differential scanning calorimetry (DSC) from Form-I to Form-II showing polymorphism inside the drug reservoir with respect to the process. This CE and CPC approach in DOE can be used for delivery system design of other labile drugs similar to aspirin in emergency situations.

Synthesis of rifaximin loaded chitosan-alginate core-shell nanoparticles (Rif@CS/Alg-NPs) for antibacterial applications

The present work aims to synthesize the rifaximin loaded chitosan-alginate core-shell nanoparticles (Rif@CS/Alg-NPs) for antibacterial applications. The core-shell nanoparticles (Rif@CS/Alg-NPs) were characterized by Fourier Transform Infrared (FT-IR) spectroscopy, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-rays diffraction (XRD) and zeta analyzer. The antibacterial activities of Rif@CS/Alg-NPs were investigated against three species of bacteria namely Escherichia coli (E. coli), Pseudomonas aeruginosa (PA) and Bacillus haynesii (BH). Rif@CS/Alg-NPs exhibited outstanding antibacterial activities against E. coli, P. aeroginosa and Bacillus haynesii (BH) with 24 mm, 30 mm and 34 mm zone of inhibitions, respectively. Cytotoxicity of Rif@CS/Alg-NPs was also evaluated against human lung adenocarcinoma cell line A549 and found to be nontoxic. The drug release behavior of Rif@CS/Alg-NPs was investigated at different pH levels and maximum drug release (80%) was achieved at pH (7.2). The drug release kinetic data followed the Higuchi (R² = 0.9963) kinetic model, indicating the drug release from Rif@CS/Alg-NPs as a square root of time-dependent process and diffusion controlled. Current research provides a cost-effective and green approach toward the synthesis of Rif@CS/Alg-NPs for its antibacterial applications.

The Dynamic Inflammatory Tissue Microenvironment: Signality and Disease Therapy by Biomaterials

Tissue regeneration is an active multiplex process involving the dynamic inflammatory microenvironment. Under a normal physiological framework, inflammation is necessary for the systematic immunity including tissue repair and regeneration as well as returning to homeostasis. Inflammatory cellular response and metabolic mechanisms play key roles in the well-orchestrated tissue regeneration. If this response is dysregulated, it becomes chronic, which in turn causes progressive fibrosis, improper repair, and autoimmune disorders, ultimately leading to organ failure and death. Therefore, understanding of the complex inflammatory multiple player responses and their cellular metabolisms facilitates the latest insights and brings novel therapeutic methods for early diseases and modern health challenges. This review discusses the recent advances in molecular interactions of immune cells, controlled shift of pro- to anti-inflammation, reparative inflammatory metabolisms in tissue regeneration, controlling of an unfavorable microenvironment, dysregulated inflammatory diseases, and emerging therapeutic strategies including the use of biomaterials, which expand therapeutic views and briefly denote important gaps that are still prevailing.

Fast Dissolution Electrospun Medicated Nanofibers for Effective Delivery of Poorly Water-Soluble Drugs

BACKGROUND

Electrospinning is developing rapidly from an earlier laboratory method into an industrial process. The clinical applications are approached in various ways through electrospun medicated nanofibers. The fast-dissolving oral drug delivery system (DDS) among them is one of the most promising routes in the near future for commercial applications.

METHODS

Related papers are investigated, including the latest research results, on electrospun nanofiber-based fast-dissolution DDSs.

RESULTS

Several relative topics have been concluded: 1) the development of electrospinning, ranging from 1-fluid blending to multi-fluid process and potential applications in the formation of medicated nanofibers involving poorly water-soluble drugs; 2) Selection of appropriate polymer matrices and drug carriers for filament formation; 3) Types of poorly water-soluble drugs ideal for fast oral delivery; 4) The methods for evaluating fast-dissolving nanofibers; 5) The mechanisms that promote the fast dissolution of poorly water-soluble drugs by electrospun nanofibers; 6) the important issues for further development of electrospun medicated nanofibers as oral fast-dissolving drug delivery systems. Conclusions & Perspectives: The unique properties of electrospun-medicated nanofibers can be used as oral fast dissolving DDSs of poorly water-soluble drugs. However, some significant issues need to be investigated, such as scalable productions and solid dosage form conversions.

Electrospun collagen core/poly-l-lactic acid shell nanofibers for prolonged release of hydrophilic drug

The development of sustained control drug release for delivering hydrophilic drugs has been challenging due to a burst release. Nanofibers are used as materials that enable efficient drug delivery systems. In this study, we designed drug-encapsulated core-shell nanofibers comprising a hydrophilic core of collagen (Col) incorporated with berberine chloride (BC), an anti-inflammatory and anti-cancer agent used as a model drug, and a hydrophobic shell of poly-l-lactic acid (PLLA). Long-term drug release profiles under both the physiological and hydrolysis-accelerated conditions were measured and analyzed using a Korsmeyer-Peppas kinetics model. We found that the Col/PLLA core-shell fiber achieved a controllable long-term release of the hydrophilic drug incorporated inside the core by the slow degradation of the PLLA shell to prevent the burst release while PLLA monolithic fibers showed early release due to the dissolution of drug and the following rapid hydrolysis of fibers. As shown by the results of Col/PLLA core-shell fiber under a hydrolysis-accelerated condition to promote the release of drugs test, it would provide sustained release over 16 days under physiological conditions. Here, the development of the nanomaterial for the long-term drug release of hydrophilic drugs was achieved, leading to its potential medical application including cancer treatment.

Electrospun Functional Nanofiber Membrane for Antibiotic Removal in Water: Review

As a new kind of water pollutant, antibiotics have encouraged researchers to develop new treatment technologies. Electrospun fiber membrane shows excellent benefits in antibiotic removal in water due to its advantages of large specific surface area, high porosity, good connectivity, easy surface modification and new functions. This review introduces the four aspects of electrospinning technology, namely, initial development history, working principle, influencing factors and process types. The preparation technologies of electrospun functional fiber membranes are then summarized. Finally, recent studies about antibiotic removal by electrospun functional fiber membrane are reviewed from three aspects, namely, adsorption, photocatalysis and biodegradation. Future research demand is also recommended.

Efficient Synthesis of Folate-Conjugated Hollow Polymeric Capsules for Accurate Drug Delivery to Cancer Cells

This study presents an efficient and systematic approach to synthesize bioapplicable porous hollow polymeric capsules (HPCs). The hydroxyl-functionalized nanoporous polymers with hollow capsular shapes could be generated via the moderate Friedel-Crafts reaction without using any hard or soft template. The numerous primitive hydroxyl groups on these HPCs were further converted to carboxyl groups. Owing to the abundance of highly branched carboxyl groups on the surface of the HPCs, biomolecules [such as folic acid (FA)] could be covalently decorated on these organic capsules (FA-HPCs) for drug delivery applications. The intrinsic hollow porosities and specific targeting agent offered a maximum drug encapsulation efficiency of up to 86% and drug release of up to 50% in 30 h in an acidic environment. The in vitro studies against cancer cells demonstrated that FA-HPCs exhibited a more efficient cellular uptake and intracellular doxorubicin release than bare HPCs. This efficient approach to fabricate carbonyl-functionalized hollow organic capsules may open avenues for a new type of morphological-controlled nanoporous polymers for various potential bioengineering applications.

Electrospinning of PVA-carboxymethyl cellulose nanofibers for flufenamic acid drug delivery

A prominent medical application of nanotechnology is represented in drug delivery. In this work, carboxymethyl cellulose (CMC) and poly(vinyl alcohol) (PVA) were used for producing CMC/PVA aqueous-based nanofibers loaded with flufenamic acid (FFA) as a drug containing amine groups. The CMC/PVA solutions with 90/10, 80/20, 70/30, 60/40 and 50/50 ratios were considered for electrospinning. Two integration methods were studied for loading FFA on the nanofibers during the electrospinning process. The characterization techniques of SEM, AFM, fluorescence microscopy and FT-IR spectroscopy were used to study the produced nanofibers, indicating a uniform distribution of FFA throughout the samples. The resulting nanofibers were formed in a diameter range of 176-285 nm and exhibited a 5 h degradation time in the PBS buffer solution. A standard diagram of drug loading was obtained for the samples. The drug release pattern was examined using a dialysis tube method. UV-visible spectroscopy revealed a time-dependent drug release behavior in CMC/PVA/FFA nanofibers where a sharp release occurred over the first 20 min. However, a prolonged release time of 10 h was achieved using a cross-linker (EDC).

Method for production of aligned nanofibers and fiber elasticity measurement

A novel method for collection of electrospun polymer nanofibers is proposed. This method can be applied to extrusion of various polymers and deposition on various types of substrates or without use of a substrate at all. The fiber is forced to alternate in its deposit in between two different segments of a collector electrode by a pair of square electric potential functions in anti-phase applied to these two electrode segments. As the fiber oscillation frequency is equal to the potential function frequency, the fiber deposition rate in between these two collector segments can be controlled. If an electrically non-conductive material is placed in between the two segments of the collector electrode, aligned fibers are simply deposited on the surface of this material. The method is used to perform stiffness measurements of the fibers demonstrating Young's modulus of 200.1 MPa with a standard deviation of 30.7 MPa. The stiffness measurement does not require any specialized equipment and requires minimal sample preparation. A sample consists of known amount of aligned fibers collected between a pair of thin coaxial rods leading to a cylindrical bundle with known number of fibers. A tensile test is then performed to obtain stress-strain curve and to find the Young's modulus of the fiber material.

Bioactive Sambong oil-loaded electrospun cellulose acetate nanofibers: Preparation, characterization, and in-vitro biocompatibility

Blumea balsamifera oil loaded cellulose acetate nanofiber mats were prepared by electrospinning. The inclusion of blumea oil increased the nanofiber diameter. FTIR spectra confirm the addition of blumea oil in the nanofiber mats. The XRD pattern suggests that the inclusion of blumea oil has caused a misalignment in the polymer chains of the cellulose acetate. Thus, a decrease in the tensile strength was observed for the blumea oil loaded nanofibers. The increase in fiber diameter causes a reduction in the porosity of the nanofiber mats. The blumea oil loaded nanofiber mats showed antibacterial efficacy against Escherichia coli and Staphylococcus aureus. The blumea oil showed antioxidant abilities against the DPPH solution. MVTR of the neat and blumea oil loaded nanofiber mats was in the range of 2450-1750 g/m²/day, which is adequate for the transport of air and moisture from the wound surface. Blumea oil loaded mats showed good cell viability ~92% for NIH 3T3 cells in more extended periods of incubation. A biphasic release profile was obtained, and the release followed the first-order kinetics depending upon the highest value of the coefficient of correlation R 2 (88.6%).

Fabrication of tri-layered electrospun polycaprolactone mats with improved sustained drug release profile

Modulation of initial burst and long term release from electrospun fibrous mats can be achieved by sandwiching the drug loaded mats between hydrophobic layers of fibrous polycaprolactone (PCL). Ibuprofen (IBU) loaded PCL fibrous mats (12% PCL-IBU) were sandwiched between fibrous polycaprolactone layers during the process of electrospinning, by varying the polymer concentrations (10% (w/v), 12% (w/v)) and volume of coat (1 ml, 2 ml) in flanking layers. Consequently, 12% PCL-IBU (without sandwich layer) showed burst release of 66.43% on day 1 and cumulative release (%) of 86.08% at the end of 62 days. Whereas, sandwich groups, especially 12% PCLSW-1 & 2 (sandwich layers-1 ml and 2 ml of 12% PCL) showed controlled initial burst and cumulative (%) release compared to 12% PCL-IBU. Moreover, crystallinity (%) and hydrophobicity of the sandwich models imparted control on ibuprofen release from fibrous mats. Further, assay for cytotoxicity and scanning electron microscopic images of cell seeded mats after 5 days showed the mats were not cytotoxic. Nuclear Magnetic Resonance spectroscopic analysis revealed weak interaction between ibuprofen and PCL in nanofibers which favors the release of ibuprofen. These data imply that concentration and volume of coat in flanking layer imparts tighter control on initial burst and long term release of ibuprofen.

Electrospun Multiple-Chamber Nanostructure and Its Potential Self-Healing Applications

To address the life span of materials in the process of daily use, new types of structural nanofibers, fabricated by multifluid electrospinning to encapsulate both epoxy resin and amine curing agent, were embedded into an epoxy matrix to provide it with self-healing ability. The nanofibers, which have a polyacrylonitrile sheath holding two separate cores, had an average diameter of 300 ± 140 nm with a uniform size distribution. The prepared fibers had a linear morphology with a clear three-chamber inner structure, as verified by scanning electron microscope and transmission electron microscope images. The two core sections were composed of epoxy and amine curing agents, respectively, as demonstrated under the synergistic characterization of Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry. The TGA results disclosed that the core-shell nanofibers contained 9.06% triethylenetetramine and 20.71% cured epoxy. In the electrochemical corrosion experiment, self-healing coatings exhibited an effective anti-corrosion effect, unlike the composite without nanofibers. This complex nanostructure was proven to be an effective nanoreactor, which is useful to encapsulate reactive fluids. This engineering process by multiple-fluid electrospinning is the first time to prove that this special multiple-chamber structure has great potential in the field of self-healing.

Williams G. Energy-Saving Electrospinning with a Concentric Teflon-Core Rod Spinneret to Create Medicated Nanofibers

Although electrospun nanofibers are expanding their potential commercial applications in various fields, the issue of energy savings, which are important for cost reduction and technological feasibility, has received little attention to date. In this study, a concentric spinneret with a solid Teflon-core rod was developed to implement an energy-saving electrospinning process. Ketoprofen and polyvinylpyrrolidone (PVP) were used as a model of a poorly water-soluble drug and a filament-forming matrix, respectively, to obtain nanofibrous films via traditional tube-based electrospinning and the proposed solid rod-based electrospinning method. The functional performances of the films were compared through in vitro drug dissolution experiments and ex vivo sublingual drug permeation tests. Results demonstrated that both types of nanofibrous films do not significantly differ in terms of medical applications. However, the new process required only 53.9% of the energy consumed by the traditional method. This achievement was realized by the introduction of several engineering improvements based on applied surface modifications, such as a less energy dispersive air-epoxy resin surface of the spinneret, a free liquid guiding without backward capillary force of the Teflon-core rod, and a smaller fluid-Teflon adhesive force. Other non-conductive materials could be explored to develop new spinnerets offering good engineering control and energy savings to obtain low-cost electrospun polymeric nanofibers.

On-line dissolution analysis of multiple drugs encapsulated in electrospun nanofibers

Electrospun nanofiber is a very attractive material which can be used as the support to form multiple-drug dosage. Understanding the dissolution process of different active drug ingredients released from electrospun fibers is of great importance to control and evaluate the quality of medicated nanofibers. Here we present the first study of on-line automatic analysis of dissolution of multiple drugs in electrospun fiber mats. Single-needle electrospinning technology is utilized to combine polymers, hydrophilic polyvinylpyrrolidone (PVP) and hydrophobic polycaprolactone (PCL) as carrier to load three poorly water-soluble non-steroidal anti-inflammatory drugs (paracetamol, nimesulide, and ibuprofen). The loading of the drugs in PVP/PCL electrospun fibers are characterized by various techniques, including scanning electron microscopy, X-ray diffraction, Fourier infrared spectroscopy and differential scanning calorimetry. The in vitro dissolution is investigated by our home-made portable analyzer, which can simultaneously on-line determine multiple drugs released from the nanofibers by a single step. The analysis shows a wide linear detection range of the drugs with limit-of-detection (LOD) down to μg/mL-level. The dissolution profiles of three ingredients in nanofibers can be monitored every thirty seconds from the beginning to the end in the entire dissolution process from only one HSCE run. The kinetic information of the dissolution, including the dissolution curve, characteristic dissolution time and dissolution efficiency, is obtained and evaluated for different dissolution media, drug loading content and the ratio of PVP/PCL. Our study provides a promising method for rapid and accurate dissolution testing of nanofiber-based drugs, and would extend the applications of separation techniques in pharmaceutical analysis.

Hydrodynamic Compatibility of Hyaluronic Acid and Tamarind Seed Polysaccharide as Ocular Mucin Supplements

Hyaluronic acid (HA) has been commonly used in eyedrop formulations due to its viscous lubricating properties even at low concentration, acting as a supplement for ocular mucin (principally MUC5AC) which diminishes with aging in a condition known as Keratoconjunctivitis sicca or “dry eye”. A difficulty has been its short residence time on ocular surfaces due to ocular clearance mechanisms which remove the polysaccharide almost immediately. To prolong its retention time, tamarind seed gum polysaccharide (TSP) is mixed as a helper biopolymer with HA. Here we look at the hydrodynamic characteristics of HA and TSP (weight average molar mass M_w and viscosity η) and then explore the compatibility of these polymers, including the possibility of potentially harmful aggregation effects. The research is based on a novel combination of three methods: sedimentation velocity in the analytical ultracentrifuge (SV-AUC), size-exclusion chromatography coupled to multiangle light scattering (SEC-MALS) and capillary viscometry. HA and TSP were found to have Mw=(680±30) kg/mol and (830±30) kg/mol respectively, and η=1475±30 ml/g and 675±20 ml/g, respectively. The structure of HA ranges from a rodlike molecule at lower molar masses changing to a random coil for M_w > 800 kg/mol, based on the Mark–Houwink–Kuhn–Sakurada (MHKS) coefficient. TSP, by contrast, is a random coil across the range of molar masses. For the mixed HA-TSP systems, SEC-MALS indicates a weak interaction. However, sedimentation coefficient (s) distributions obtained from SV-AUC measurements together with intrinsic viscosity demonstrated no evidence of any significant aggregation phenomenon, reassuring in terms of eye-drop formulation technology involving these substances.

Serine Protease-Mediated Cutaneous Inflammation: Characterization of an Ex Vivo Skin Model for the Assessment of Dexamethasone-Loaded Core Multishell-Nanocarriers

Standard experimental set-ups for the assessment of skin penetration are typically performed on skin explants with an intact skin barrier or after a partial mechanical or chemical perturbation of the stratum corneum, but they do not take into account biochemical changes. Among the various pathological alterations in inflamed skin, aberrant serine protease (SP) activity directly affects the biochemical environment in the superficial compartments, which interact with topically applied formulations. It further impacts the skin barrier structure and is a key regulator of inflammatory mediators. Herein, we used short-term cultures of ex vivo human skin treated with trypsin and plasmin as inflammatory stimuli to assess the penetration and biological effects of the anti-inflammatory drug dexamethasone (DXM), encapsulated in core multishell-nanocarriers (CMS-NC), when compared to a standard cream formulation. Despite a high interindividual variability, the combined pretreatment of the skin resulted in an average 2.5-fold increase of the transepidermal water loss and swelling of the epidermis, as assessed by optical coherence tomography, as well as in a moderate increase of a broad spectrum of proinflammatory mediators of clinical relevance. The topical application of DXM-loaded CMS-NC or DXM standard cream revealed an increased penetration into SP-treated skin when compared to untreated control skin with an intact barrier. Both formulations, however, delivered sufficient amounts of DXM to effectively suppress the production of interleukin-6 (IL-6), interleukin-8 (IL-8) and Thymic Stromal Lymphopoietin (TSLP). In conclusion, we suggest that the herein presented ex vivo inflammatory skin model is functional and could improve the selection of promising drug delivery strategies for anti-inflammatory compounds at early stages of development.

Core-Shell Eudragit S100 Nanofibers Prepared via Triaxial Electrospinning to Provide a Colon-Targeted Extended Drug Release

In this study, a new modified triaxial electrospinning is implemented to generate an Eudragit S100 (ES100)-based core-shell structural nanofiber (CSF), which is loaded with aspirin. The CSFs have a straight line morphology with a smooth surface, an estimated average diameter of 740 ± 110 nm, and a clear core-shell structure with a shell thickness of 65 nm, as disclosed by the scanning electron microscopy and transmission electron microscopy results. Compared to the monolithic composite nanofibers (MCFs) produced using traditional blended single-fluid electrospinning, aspirin presented in both of them amorously owing to their good compatibility. The CSFs showed considerable advantages over the MCFs in providing the desired drug-controlled-release profiles, although both of them released the drug in an erosion mechanism. The former furnished a longer time period of time-delayed-release and a smaller portion released during the first two-hour acid condition for protecting the stomach membranes, and also showed a longer time period of aspirin-extended-release for avoiding possible drug overdose. The present protocols provide a polymer-based process-nanostructure-performance relationship to optimize the reasonable delivery of aspirin.

Electrosprayed Ultra-Thin Coating of Ethyl Cellulose on Drug Nanoparticles for Improved Sustained Release

In nanopharmaceutics, polymeric coating is a popular strategy for modifying the drug release kinetics and, thus, new methods for implementing the nanocoating processes are highly desired. In the present study, a modified coaxial electrospraying process was developed to formulate an ultra-thin layer of ethyl cellulose (EC) on a medicated composite core consisting of tamoxifen citrate (TAM) and EC. A traditional single-fluid blending electrospraying and its monolithic EC-TAM nanoparticles (NPs) were exploited to compare. The modified coaxial processes were demonstrated to be more continuous and robust. The created NPs with EC coating had a higher quality than the monolithic ones in terms of the shape, surface smoothness, and the uniform size distribution, as verified by the SEM and TEM results. XRD patterns suggested that TAM presented in all the NPs in an amorphous state thanks to the fine compatibility between EC and TAM, as indicated by the attenuated total reflection (ATR)-FTIR spectra. In vitro dissolution tests demonstrated that the NPs with EC coating required a time period of 7.58 h, 12.79 h, and 28.74 h for an accumulative release of 30%, 50%, and 90% of the loaded drug, respectively. The protocols reported here open a new way for developing novel medicated nanoparticles with functional coating.

Dual-function membranes based on alginate/methyl cellulose composite for control drug release and proliferation enhancement of fibroblast cells

Membranes based on natural polymers are highly promising therapies for skin damaged sites as they can mimic its biological microstructure to support the fibroblasts cells survival and proliferation. In addition, these membranes could be loaded with active molecules that help in skin regeneration and eliminate the potential bacterial infection. This research aims to formulate novel medicated membranes for controlled release and cytocompatibility elevation of fibroblast cells for engineering of soft tissue. Pre-formulation researches have been conducted for membranes of sodium alginate (Alg)/methyl cellulose (MC) that used loaded with undoped, Bi doped and Bi, Cu co-doped SrTiO₃ using solvent casting technique. In addition, another group of these membranes were loaded with DOXycycline antibiotic (DOX) as model drug as well as for eliminating the potential bacterial infections. The prepared membranes were evaluated by XRD, SEM-EDX, FTIR, Zetasizer, and swelling behaviour was also tested. Profiles of the released drug were determined using phosphate-buffered saline (PBS) (pH 7.4) at 37 °C for 30 days. The investigation of the cytocompatibility and proliferation of fibroblast cells with the prepared membranes were conducted. The XRD, FTIR and SEM data recognised the possible interaction that takes place among Alg and MC, through presence of hydrogen bonds. Existence of the nano-particles within the membrane polymer matrix enhanced the membrane stability and enhanced the drug release rate (from 20 to 45%). Medication release mechanism elucidated that DOX was released from all the fabricated membranes through the relaxation of polymer matrix that takes place after swelling. The filler type and/or dopant type possess no remarkable influence on the cytotoxicity of the membranes against the investigated cells when compared to their individual influence on the same cells. Cells attachments results have revealed an impressive effect for DOX-loaded membranes on the cells affinity and growth. These membranes are recommended for treatments of skin infections.