Fabrication of electrospun poly(vinyl alcohol)/dextran nanofibers via emulsion process as drug delivery system: Kinetics and in vitro release study

A structure-functionality insight into the bioactivity of microbial polysaccharides toward biomedical applications: A review

Microbial polysaccharides (MPs) are biopolymers secreted by microorganisms such as bacteria and fungi during their metabolic processes. Compared to polysaccharides derived from plants and animals, MPs have advantages such as wide sources, high production efficiency, and less susceptibility to natural environmental influences. The most attractive feature of MPs lies in their diverse biological activities, such as antioxidative, anti-tumor, antibacterial, and immunomodulatory activities, which have demonstrated immense potential for applications in functional foods, cosmetics, and biomedicine. These bioactivities are precisely regulated by their sophisticated molecular structure. However, the mechanisms underlying this precise regulation are not yet fully understood and continue to evolve. This article presents a comprehensive review of the most representative species of MPs, including their fermentation and purification processes and their biomedical applications in recent years. In particular, this work presents an in-depth analysis into the structure-activity relationships of MPs across multiple molecular levels. Additionally, this review discusses the challenges and prospects of investigating the structure-activity relationships, providing valuable insights into the broad and high-value utilization of MPs.

Development of antifungal fibrous ocular insert using freeze-drying technique

Candida species is one of the pathogenic fungi of the eye responsible for keratitis that frequently causes vision impairment and blindness. Effective treatment requires long-term use of antifungal drugs, which is opposed by the defensive mechanisms of the eye and inadequate corneal penetration. The objective of this study was to develop a carrier for prolonged ocular application of fluconazole (FLZ) to treat keratitis. FLZ was encapsulated into chitosan fibrous matrices (F1-F4) using different chitosan concentrations (0.02, 0.1, 0.5, and 1%w/v, respectively) by freeze-drying as a single-step technique. Studying the morphology and surface properties of the inserts revealed a porous matrix with fibrous features with a large surface area. Thermal stability and chemical compatibility were confirmed by DSC/TGA/DTA and FT-IR, respectively. Loading capacity (LC) and entrapment efficiency (EE) were determined. According to the in vitro release study, F4 (0.11 mg mg-1 LC and 87.53% EE) was selected as the optimum insert because it had the most sustained release, with 15.85% burst release followed by 75.62% release within 12 h. Ex vivo corneal permeation study revealed a 1.2-fold increase in FLZ permeation from F4 compared to FLZ aqueous solution. Also, in the in vivo pharmacokinetic study in rabbits, F4 increased the AUC0-8 of FLZ by 9.3-fold and its concentration in aqueous humor was maintained above the MIC through the experimentation time. Studies on cytotoxicity (MTT assay) provide evidence for the safety and biocompatibility of F4. Therefore, the freeze-dried FLZ-loaded chitosan fibrous insert could be a promising candidate for treating ocular keratitis.

Computational quality-by-design strategy to validate high-performance liquid chromatography method for the estimation of meloxicam in bulk dosage forms and milk samples

Bovine clinical mastitis has significant repercussions for farmers across the globe. Meloxicam, a COX-2 inhibitor, attenuates mastitis symptoms and is also approved for veterinary use. An RP-HPLC (Reverse Phase-High Performance Liquid Chromatography) method development and validation is essential in the pharmaceutical industry to assess API (Active Pharmaceutical Ingredient) quantity present in the pharmaceutical dosage forms. RP-HPLC method of meloxicam was developed and optimized with the aid of QbD (Quality by Design) using Box-Behnken design (BBD). The pH of the aqueous mobile phase, acetonitrile (ACN) percentage, and column temperature were chosen as influence variables, and retention time (RT) and tailing factor (Tf) were selected as response variables. The optimum experimental conditions were selected as pH ~ 3 of the aqueous mobile phase, 65% v/v ACN, and 30˚C as column temperature. The drug was eluted at 6.02 min RT with 1.18 as Tf. The method was subjected to validation for accuracy, linearity, precision, range, sensitivity, and robustness and was found to comply with ICH Q2 (R1) guidelines. The in vitro bioequivalent studies were performed in hydrochloric acid, pH ~ 1.2; acetate buffer, pH ~ 4.5; and phosphate buffer, pH ~ 6.8 for two veterinary brands of meloxicam tablets, and their release profiles were compared by mathematical models. Both the brands, brand 1 and 2 exhibited significant (Unpaired t-test, P < 0.05) differences in dissolution efficiency (DE) and mean dissolution time (MDT) except DE at pH 1.2. However, brands 1 and 2 showed similarity (f2 > 50) in terms of release of meloxicam except at pH 6.8 (f2 = 47.01). The in vitro release of meloxicam followed Peppas kinetics except for brand 2 at pH 6.8, where it followed the Higuchi model. Moreover, the recovery of meloxicam extracted with ACN in the milk sample was estimated to be 99.67 ± 0.58% significantly (Unpaired t-test, P < 0.05) higher than 90.34 ± 6.77% extracted with methanol. In conclusion, the optimized and validated RP-HPLC method of meloxicam may further be used for the analysis of drug content in pharmaceutical dosage forms in addition to biological fluids.

Herbal active ingredient-loaded poly(ω-pentadecalactone-co-δ-valerolactone)/gelatin nanofibrous membranes

Recently, there has been an accelerating interest in novel biocompatible wound dressings made of nano-sized materials, especially nanofibers. Electrospun nanofibers provide high surface area and mimic the extracellular matrix which enhances biocompatibility. Besides, nanofibrous structures have high active ingredient loading capacity as a result of their high surface-to-volume ratio and porosity. In the present study, curcumin-loaded poly(ω-pentadecalactone-co-δ-valerolactone)/gelatin (PDL-VL/Gel) nanofibrous membranes were fabricated to be used for healing skin wounds. Poly(ω-pentadecalactone-co-δ-valerolactone) copolymer has been enzymatically synthesized in previous studies, thus it improves the originality of the membrane. It was aimed to obtain a synergetic effect and increase the novelty of the work by blending synthetic and natural polymers. Moreover, it was preferred to provide antibacterial activity by the incorporation of a herbal ingredient (curcumin) as a natural alternative to commercial antibiotics. Varied amounts of curcumin (5-25 %, w:v) were electrospun together with PDL-VL/Gel (equal volume ratio) polymer blend (fiber diameters ranged between 554 and 1074 nm) and several characterizations (morphological and molecular structure, wettability characteristics, and thermal behavior) were applied to examine the curcumin incorporation. Afterwards, in vitro curcumin release studies were carried out and mathematical modeling was applied to release data to clarify the transport mechanism. Curcumin release profiles comprised of an initial burst release in the first hour followed by a sustained release through 24 h. Based on the antibacterial activity test results, 15 % curcumin loading ratio was found to be sufficient for the treatment of skin wounds infected by Gram-negative (E. coli) and Gram-positive (S. aureus and B. subtilis) bacteria. Additionally, nanofibrous membranes did not lead to cytotoxicity, and curcumin content further enhanced the viability of fibroblasts. Thus, the presented antibacterial nanofibrous membrane is suggested to be applied for the treatment of wound infections and accelerating the healing process.

Fabrication and characterization of chlorhexidine gluconate loaded poly(vinyl alcohol)/45S5 nano-bioactive glass nanofibrous membrane for guided tissue regeneration applications

Polymeric barrier membranes are used in periodontal applications to prevent fibroblastic cell migration into the cavities of bone tissue and to properly guide the proliferation of tissues. In this study, the fabrication, characterization, bioactivity, and in vitro biological properties of polyvinyl alcohol-based nanofibrous membranes containing nano-sized 45S5 bioactive glass (BG) loaded with chlorhexidine (CH) gluconate with biocompatible, bioactive, and antibacterial properties for using as dental barrier membranes were investigated. Nanofibrous membranes with an average fiber diameter, pore size, and porosity of 210 nm, 24.73 μm, and 12.42%, respectively, were loaded with 1% and 2% CH, and the release profile was investigated. The presence of BG in the membranes promoted fibroblastic proliferation and the presence of CH provided antibacterial properties. Nanofibrous membranes exhibit a high ability to restrict bacterial growth while fulfilling the necessary conditions for use as a dental barrier thanks to their low swelling rates, significant surface bioactivities, and appropriate degradation levels.

Nedaplatin/Peganum harmala Alkaloids Co-Loaded Electrospun, Implantable Nanofibers: A Chemopreventive Nano-Delivery System for Treating and Preventing Breast Cancer Recurrence after Tumorectomy

Currently, the main pillars in treating breast cancer involve tumorectomy pursued by hormonal, radio, or chemotherapies. Nonetheless, these approaches exhibit severe adverse effects and might suffer from tumor recurrence. Therefore, there is a considerable demand to fabricate an innovative controlled-release nano-delivery system to be implanted after tumor surgical removal to guard against cancer recurrence. In addition, combining platinum-based drugs with phytochemicals is a promising approach to improving the anticancer activity of the chemotherapeutics against tumor cells while minimizing their systemic effects. This study designed polycaprolactone (PCL)-based electrospun nanofiber mats encapsulating nedaplatin (N) and Peganum harmala alkaloid-rich fraction (L). In addition to physicochemical characterization, including average diameters, morphological features, degradation study, thermal stability, and release kinetics study, the formulated nanofibers were assessed in terms of cytotoxicity, where they demonstrated potentiated effects and higher selectivity towards breast cancer cells. The dual-loaded nanofiber mats (N + L@PCL) demonstrated the highest antiproliferative effects against MCF-7 cells with a recorded IC50 of 3.21 µg/mL, as well as the topmost achieved selectivity index (20.45) towards cancer cells amongst all the tested agents (N, L, N@PCL, and L@PCL). This indicates that the dual-loaded nanofiber excelled at conserving the normal breast epithelial cells (MCF-10A). The combined therapy, N + L@PCL treatment, resulted in a significantly higher percent cell population in the late apoptosis and necrosis quartiles as compared to all other treatment groups (p-value of ≤0.001). Moreover, this study of cell cycle kinetics revealed potentiated effects of the dual-loaded nanofiber (N + L@PCL) at trapping more than 90% of cells in the sub-G1 phase and reducing the number of cells undergoing DNA synthesis in the S-phase by 15-fold as compared to nontreated cells; hence, causing cessation of the cell cycle and confirming the apoptosis assay results. As such, our findings suggest the potential use of the designed nanofiber mats as perfect implants to prevent tumor recurrence after tumorectomy.

Curcumin-Loaded Bamboo Shoot Cellulose Nanofibers: Characterization and In Vitro Studies

Given its high biological and pharmacological activities, curcumin (CUR) offers promising applications in functional foods. However, its low stability and bioavailability have greatly hindered its application in the food industry. The present study prepared cellulose nanofiber (CNF) from bamboo shoot processing byproducts and investigated its potential as a low-cost carrier. Our results showed that CUR was immobilized on CNF surfaces mainly through hydrogen bonding and eventually encapsulated in CNF matrices, forming a CNF-CUR complex with an encapsulation efficiency of 88.34% and a loading capacity of 67.95%. The CUR encapsulated in the complex showed improved stability after thermal and UV light treatments. Moreover, a slow and extended release pattern of CUR in a simulated gastrointestinal tract was observed, which could be appropriately described using the Korsmeyer-Peppas model. These results revealed that CNF is a promising protective carrier for the slow release of CUR, making it a better candidate for functional foods.

Fabrication of carboxymethyl starch/xanthan gum combinations Pickering emulsion for protection and sustained release of pterostilbene

Carboxymethyl starch (CMS)/xanthan gum (XG) combinations with different ratios (CMS/XG: 1/1, 3/1, 5/1, 7/1, 9/1, w/w) were used as Pickering emulsion delivery systems to encapsulate pterostilbene (PTS) to improve its stability. The results showed that the Pickering emulsion prepared using CMS/XG combinations could effectively encapsulate PTS. When the mass ratio of CMS to XG was 1:1, the encapsulation efficiency reached 91.20 %. The spherical particles in the PTS emulsion were dissociated and homogenous. The results of backscattered light experiments and storage stability studies showed that the PTS emulsion system prepared using CMS/XG was uniform and stable, with no obvious phase separation or emulsion droplet coalescence. With an increase in the mass ratio of XG, the water distribution in the emulsion became more evenly distributed, and the aggregation of droplets was reduced. The PTS emulsion prepared using CMS/XG improved the storage retention percentage of PTS. The cumulative release of PTS in the simulated gastric fluid was significantly lower than that in simulated intestinal fluid. The Pickering emulsion prepared using CMS/XG combinations can be used as a delivery system for functional foods and help to develop an efficient and reliable release system for hydrophobic bioactive substances.

Engineered biomimetic micro/nano-materials for tissue regeneration

The incidence of tissue and organ damage caused by various diseases is increasing worldwide. Tissue engineering is a promising strategy of tackling this problem because of its potential to regenerate or replace damaged tissues and organs. The biochemical and biophysical cues of biomaterials can stimulate and induce biological activities such as cell adhesion, proliferation and differentiation, and ultimately achieve tissue repair and regeneration. Micro/nano materials are a special type of biomaterial that can mimic the microstructure of tissues on a microscopic scale due to its precise construction, further providing scaffolds with specific three-dimensional structures to guide the activities of cells. The study and application of biomimetic micro/nano-materials have greatly promoted the development of tissue engineering. This review aims to provide an overview of the different types of micro/nanomaterials, their preparation methods and their application in tissue regeneration.

Perspectives of nanofibrous wound dressings based on glucans and galactans - A review

Wound healing is a complex and dynamic process that needs an appropriate environment to overcome infection and inflammation to progress well. Wounds lead to morbidity, mortality, and a significant economic burden, often due to the non-availability of suitable treatments. Hence, this field has lured the attention of researchers and pharmaceutical industries for decades. As a result, the global wound care market is expected to be 27.8 billion USD by 2026 from 19.3 billion USD in 2021, at a compound annual growth rate (CAGR) of 7.6 %. Wound dressings have emerged as an effective treatment to maintain moisture, protect from pathogens, and impede wound healing. However, synthetic polymer-based dressings fail to comprehensively address optimal and quick regeneration requirements. Natural polymers like glucan and galactan-based carbohydrate dressings have received much attention due to their inherent biocompatibility, biodegradability, inexpensiveness, and natural abundance. Also, nanofibrous mesh supports better proliferation and migration of fibroblasts because of their large surface area and similarity to the extracellular matrix (ECM). Thus, nanostructured dressings derived from glucans and galactans (i.e., chitosan, agar/agarose, pullulan, curdlan, carrageenan, etc.) can overcome the limitations associated with traditional wound dressings. However, they require further development pertaining to the wireless determination of wound bed status and its clinical assessment. The present review intends to provide insight into such carbohydrate-based nanofibrous dressings and their prospects, along with some clinical case studies.

Development of Mucoadhesive Electrospun Scaffolds for Intravaginal Delivery of Lactobacilli spp., a Tenside, and Metronidazole for the Management of Bacterial Vaginosis

Bacterial vaginosis (BV) is an infection of the vagina associated with thriving anaerobes, such as Gardnerella vaginitis and other associated pathogens. These pathogens form a biofilm responsible for the recurrence of infection after antibiotic therapy. The aim of this study was to develop a novel mucoadhesive polyvinyl alcohol and polycaprolactone electrospun nanofibrous scaffolds for vaginal delivery, incorporating metronidazole, a tenside, and Lactobacilli. This approach to drug delivery sought to combine an antibiotic for bacterial clearance, a tenside biofilm disruptor, and a lactic acid producer to restore healthy vaginal flora and prevent the recurrence of bacterial vaginosis. F7 and F8 had the least ductility at 29.25% and 28.39%, respectively, and this could be attributed to the clustering of particles that prevented the mobility of the crazes. F2 had the highest at 93.83% due to the addition of a surfactant that increased the affinity of the components. The scaffolds exhibited mucoadhesion between 31.54 ± 0.83% and 57.86 ± 0.95%, where an increased sodium cocoamphoacetate concentration led to increased mucoadhesion. F6 showed the highest mucoadhesion at 57.86 ± 0.95%, as compared to 42.67 ± 1.22% and 50.89 ± 1.01% for the F8 and F7 scaffolds, respectively. The release of metronidazole via a non-Fickian diffusion-release mechanism indicated both swelling and diffusion. The anomalous transport within the drug-release profile pointed to a drug-discharge mechanism that combined both diffusion and erosion. The viability studies showed a growth of Lactobacilli fermentum in both the polymer blend and the nanofiber formulation that was retained post-storage at 25 °C for 30 days. The developed electrospun scaffolds for the intravaginal delivery of Lactobacilli spp., along with a tenside and metronidazole for the management of bacterial vaginosis, provide a novel tool for the treatment and management of recurrent vaginal infection.

Poly (l-lactic acid)-based modified nanofibrous membrane with dual drug release capability for GBR application

Electrospun multilayer nanofibers guided bone regeneration (GBR) with a new design were developed in this study. The synthesized multilayer GBR was composed of two distinct layers. Poly l-lactic acid (PLA) incorporated with simvastatin (SIM) was designed as PLA/SIM layer to contact with a bone defect. In addition, the hydrophilic gelatin (GT) containing thymol (THY) was fabricated as GT/THY layer to contact connective tissue, potentially for bacterial gathering. Due to the different chemical nature and weak cohesion of the hydrophilic and hydrophobic layers, hybrid fibers made of PLA/SIM and GT/THY were electrospun as cohesion promoters between these layers. The microstructure and characteristics of the synthesized multilayer substrate, named GT/PLA, were evaluated, and different fibrous monolayers were fabricated to determine the optimal concentrations of drugs. Scanning electron microscopy (SEM) images showed continuous, smooth, randomly aligned, and bead-free fibers. In addition, there were no drug particles on the fiber surfaces which displayed the good placement of those inside the fibers. The mats exhibited satisfactory tensile strength (4.60 ± 0.14 MPa) and favorable physicochemical properties, including proper porosity percentage (<50 %) and appropriate pore size. Suitable swelling behavior (293 ± 0.05 %) and adequate degradation rates were also approved by characterizing swelling and degradability in vitro. The GT/PLA membrane exhibited a prolonged and sustained SIM release and controlled THY release with high antibacterial efficiency. Cell viability, cell attachment assay, and nuclear staining using 4',6-diamidino-2-phenylindole (DAPI) showed that the designed GT/PLA substrate had good biocompatibility and cell attachment. Cell infiltration testing also showed that the cells were finely prevented by the outer layer (GT/THY). Overall, the obtained results in this study indicated the great potential of the prepared GT/PLA for use as a GBR which can develop osteogenic and antibacterial biomimetic periosteum optimizing the clinical application of GBR strategies.

Dextran Formulations as Effective Delivery Systems of Therapeutic Agents

Dextran is by far one of the most interesting non-toxic, bio-compatible macromolecules, an exopolysaccharide biosynthesized by lactic acid bacteria. It has been extensively used as a major component in many types of drug-delivery systems (DDS), which can be submitted to the next in-vivo testing stages, and may be proposed for clinical trials or pharmaceutical use approval. An important aspect to consider in order to maintain high DDS' biocompatibility is the use of dextran obtained by fermentation processes and with a minimum chemical modification degree. By performing chemical modifications, artefacts can appear in the dextran spatial structure that can lead to decreased biocompatibility or even cytotoxicity. The present review aims to systematize DDS depending on the dextran type used and the biologically active compounds transported, in order to obtain desired therapeutic effects. So far, pure dextran and modified dextran such as acetalated, oxidised, carboxymethyl, diethylaminoethyl-dextran and dextran sulphate sodium, were used to develop several DDSs: microspheres, microparticles, nanoparticles, nanodroplets, liposomes, micelles and nanomicelles, hydrogels, films, nanowires, bio-conjugates, medical adhesives and others. The DDS are critically presented by structures, biocompatibility, drugs loaded and therapeutic points of view in order to highlight future therapeutic perspectives.

Bioinspired Electropun Fibrous Materials Based on Poly-3-Hydroxybutyrate and Hemin: Preparation, Physicochemical Properties, and Weathering

The development of innovative fibrous materials with valuable multifunctional properties based on biodegradable polymers and modifying additives presents a challenging direction for modern materials science and environmental safety. In this work, high-performance composite fibrous materials based on semicrystalline biodegradable poly-3-hydroxybutyrate (PHB) and natural iron-containing porphyrin, hemin (Hmi) were prepared by electrospinning. The addition of Hmi to the feed PHB mixture (at concentrations above 3 wt.%) is shown to facilitate the electrospinning process and improve the quality of the electrospun PHB/Hmi materials: the fibers become uniform, their average diameter decreases down to 1.77 µm, and porosity increases to 94%. Structural morphology, phase composition, and physicochemical properties of the Hmi/PHB fibrous materials were studied by diverse physicochemical methods, including electronic paramagnetic resonance, optical microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, elemental analysis, differential scanning calorimetry, Fourier-transformed infrared spectroscopy, mechanical analysis, etc. The proposed nonwoven Hmi/PHB composites with high porosity, good mechanical properties, and retarded biodegradation due to high antibacterial potential can be used as high-performance and robust materials for biomedical applications, including breathable materials for wound disinfection and accelerated healing, scaffolds for regenerative medicine and tissue engineering.

Polysaccharide-based nanofibers for pharmaceutical and biomedical applications: A review

Nanofibers are fibrous nanocarriers that can be synthesized from natural polymers, synthetic polymers, semiconducting materials, composite materials, and carbon-based materials. Recently, natural polysaccharides-based nanofibers are gaining attention in the field of pharmaceuticals and biomedical as these are biocompatible, biodegradable, non-toxic, and economic. Nanofibers can deliver a significant amount of drug to the targeted site and provide effective interaction of therapeutic agent at the site of action due to a larger surface area. Other important advantages of nanofibers are low density, high porosity, small pore size, high mechanical strength, and low cost. In this review, natural polysaccharides such as alginate, pullulan, hyaluronic acid, dextran, cellulose, chondroitin sulfate, chitosan, xanthan gum, and gellan gum are discussed for their characteristics, pharmaceutical utility, and biomedical applications. The authors have given particular emphasis to the several fabrication processes that utilize these polysaccharides to form nanofibers, and their recent updates in pharmaceutical applications such as drug delivery, tissue engineering, skin disorders, wound-healing dressings, cancer therapy, bioactive molecules delivery, anti-infectives, and solubility enhancement. Despite these many advantages, nanofibers have been explored less for their scale-up and applications in advanced therapeutic delivery.

Microorganism-derived biological macromolecules for tissue engineering

According to literature, certain microorganism productions mediate biological effects. However, their beneficial characteristics remain unclear. Nowadays, scientists concentrate on obtaining natural materials from live creatures as new sources to produce innovative smart biomaterials for increasing tissue reconstruction in tissue engineering and regenerative medicine. The present review aims to introduce microorganism-derived biological macromolecules, such as pullulan, alginate, dextran, curdlan, and hyaluronic acid, and their available sources for tissue engineering. Growing evidence indicates that these materials can be used as biological material in scaffolds to enhance regeneration in damaged tissues and contribute to cosmetic and dermatological applications. These natural-based materials are attractive in pharmaceutical, regenerative medicine, and biomedical applications. This study provides a detailed overview of natural-based biomaterials, their chemical and physical properties, and new directions for future research and therapeutic applications.

A novel combination therapy for multidrug resistant pathogens using chitosan nanoparticles loaded with β-lactam antibiotics and β-lactamase inhibitors

Antimicrobial resistance is one of the greatest global threats. Particularly, multidrug resistant extended-spectrum β-lactamase (ESBL)-producing pathogens confer resistance to many commonly used medically important antibiotics, especially beta-lactam antibiotics. Here, we developed an innovative combination approach to therapy for multidrug resistant pathogens by encapsulating cephalosporin antibiotics and β-lactamase inhibitors with chitosan nanoparticles (CNAIs). The four combinations of CNAIs including two cephalosporin antibiotics (cefotaxime and ceftiofur) with two β-lactamase inhibitors (tazobactam and clavulanate) were engineered as water-oil-water emulsions. Four combinations of CNAIs showed efficient antimicrobial activity against multidrug resistant ESBL-producing Enterobacteriaceae. The CNAIs showed enhanced antimicrobial activity compared to naïve chitosan nanoparticles and to the combination of cephalosporin antibiotics and β-lactamase inhibitors. Furthermore, CNAIs attached on the bacterial surface changed the permeability to the outer membrane, resulting in cell damage that leads to cell death. Taken together, CNAIs have provided promising potential for treatment of diseases caused by critically important ESBL-producing multidrug resistant pathogens.

Electrospun poly(ω-pentadecalactone-co-ε-caprolactone)/gelatin/chitosan ternary nanofibers with antibacterial activity for treatment of skin infections

In recent years, there is an increasing attention on biocompatible electrospun nanofibers for drug delivery applications since they provide high surface area, controlled and sustained drug release, and they mimic the extracellular matrix. In the present study, tetracycline hydrochloride (TCH) antibiotic loaded poly(ω-pentadecalactone-co-ε-caprolactone)/gelatin/chitosan nanofibrous membranes were fabricated as a controlled drug delivery system. Poly(ω-pentadecalactone-co-ε-caprolactone) copolymer has been enzymatically synthesized in previous studies, thus it provides an originality to the membrane. Combination of a synthetic polymer, a protein, and a polysaccharide in order to obtain a synergetic effect is another novelty of this work and there exists limited examples for such electrospun membrane. Varied amounts of TCH was electrospun together with poly(ω-pentadecalactone-co-ε-caprolactone)/gelatin/chitosan (50/40/10 vol ratio) polymer blend (fiber diameters ranged between 85.7-225.2 nm) and several characterizations (morphological and molecular structure, wettability characteristics, and thermal behavior) were applied to examine the drug incorporation. Subsequently, in vitro drug release studies were conducted and mathematical modeling was applied for the detection of transport mechanism of drug. TCH release proceeded 14 days through an initial burst release in first hour and followed by a sustained release. 1% TCH-loaded sample was shown as optimal preparation with 96.5% total drug release and 11.8% initial burst release. TCH-loaded preparations demonstrated a good antibacterial activity against Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacteria and a limited effect (no inhibition zone observed below 3% TCH concentration) against Gram-negative (Escherichia coli) bacterium. Thus, TCH concentrations of ≥ 3% could be preferred to obtain a wide-spectrum effectiveness. The presented drug delivery system is suggested to be applied for treatment of skin infections as a wound dressing device.

Fabrication and characterization of dextran/zein hybrid electrospun fibers with tailored properties for controlled release of curcumin

BACKGROUND

In recent years, there has been considerable interest in the use of biopolymer electrospun nanofibers for various food applications due to the biocompatibility, biodegradability, and high loading capacity. Herein, we fabricated and characterized novel hybrid electrospun fibers from dextran (50%, w/v) and zein (0-30%, w/v) solutions, and the effects of various zein concentrations on the properties of the hybrid electrospun fibers were investigated.

RESULTS

When zein was added at low concentrations (5% and 10%), dextran and zein showed poor miscibility, as reflected by significantly decreased viscosity of the solutions, and the poor mechanical properties of the derived fiber membranes. When zein was added at medium concentrations (15-25%), hydrogen bonds were formed between dextran and zein molecules, as indicated by the red shift of Fourier-transform infrared bands and β-sheet to α-helix structural transformations. The fiber membranes electrospun from a solution with 25% zein showed the most hydrophobic surface, with a water contact angle of 116.9°. The homogenous dispersion of dextran and zein resulted in improved mechanical properties for fibers electrospun from a solution with 30% zein. Curcumin encapsulating dextran/zein electrospun fibers exhibited effective radical scavenging activity and ferric reducing power, along with the desired controlled release behavior for curcumin delivery.

CONCLUSION

Food grade dextran/zein hybrid electrospun fibers demonstrated tunable properties, and appear to be promising as delivery systems for bioactive and edible antimicrobial food packaging. © 2021 Society of Chemical Industry.

Fabrication and Characterization of Electrospun Folic Acid/Hybrid Fibers: In Vitro Controlled Release Study and Cytocompatibility Assays

The fabrication of skin-care products with therapeutic properties has been significant for human health trends. In this study, we developed efficient hydrophilic composite nanofibers (NFs) loaded with the folic acid (FA) by electrospinning and electrospraying processes for tissue engineering or wound healing cosmetic applications. The morphological, chemical and thermal characteristics, in vitro release properties, and cytocompatibility of the resulting composite fibers with the same amount of folic acid were analyzed. The SEM micrographs indicate that the obtained nanofibers were in the nanometer range, with an average fiber diameter of 75-270 nm and a good porosity ratio (34-55%). The TGA curves show that FA inhibits the degradation of the polymer and acts as an antioxidant at high temperatures. More physical interaction between FA and matrices has been shown to occur in the electrospray process than in the electrospinning process. A UV-Vis in vitro study of FA-loaded electrospun fibers for 8 h in artificial acidic (pH 5.44) and alkaline (pH 8.04) sweat solutions exhibited a rapid release of FA-loaded electrospun fibers, showing the effect of polymer matrix-FA interactions and fabrication processes on their release from the nanofibers. PVA-CHi/FA webs have the highest release value, with 95.2% in alkaline media. In acidic media, the highest release (92%) occurred on the PVA-Gel-CHi/sFA sample, and this followed first-order and Korsmeyer-Peppas kinetic models. Further, the L929 cytocompatibility assay results pointed out that all NFs (with/without FA) generated had no cell toxicity; on the contrary, the FA in the fibers facilitates cell growth. Therefore, the nanofibers are a potential candidate material in skin-care and tissue engineering applications.

Controlled Release of Chlorogenic Acid from Polyvinyl Alcohol/Poly(γ-Glutamic Acid) Blended Electrospun Nanofiber Mats with Potential Applications in Diabetic Foot Treatment

This work biosynthesized poly(γ-glutamic acid) (γ-PGA) produced by Bacillus licheniformis ATCC-9945a. This material was utilized to prepare electrospun nanofibers with solutions of 10% polyvinyl alcohol (PVA) (w/v) mixed with γ-PGA at 5 and 10% w/v, intended as a wound dressing for diabetic foot treatment. These solutions were loaded with chlorogenic acid (CGA), an active hypoglycemic agent. Morphological analysis showed a decrease in size of the fibers with the combination of PVA/γ-PGA compared to pure PVA nanofibers, which was attributed to the hydrogen bonding interactions between the glutaraldehyde vapors, γ-PGA, and PVA that permitted nanofiber cross-linking and allowed CGA release. The in vitro release analysis showed that the PVA membranes reached 28% delivery after the first 24 h. Notably, the nanofiber mat with PVA blended with 5% γ-PGA reached 57% delivery, and the PVA nanofiber with 10% γ-PGA reached 66% release after the same amount of time. The rate constant for the release kinetics showed that PVA with 5% γ-PGA had a higher value than that of the other samples, reaching saturation first.

Nanofiber as a novel vehicle for transdermal delivery of therapeutic agents: challenges and opportunities

Background

Transdermal delivery of drugs is a quite challenging task for pharmaceutical scientists. The transdermal route is preferred over the oral route due to various advantages like avoidance of the first-pass effect, non-invasiveness, and high patient compliance. Therefore, it is necessary to develop an effective carrier system that enables the effective passage of the drug through the dermal barrier.

Main body of abstract

Various novel drug delivery systems are used to enhance the permeation of a variety of drugs through the skin barrier. Researchers around the globe have explored nanofibers for the transdermal delivery of various therapeutic agents. Nanofibers are designed to have a high concentration of therapeutic agents in them promoting their flux through various skin layers. Polymeric nanofibers can be explored for the loading of both hydrophilic and lipophilic drugs. Biopolymer-based nanofibers have been also explored for transdermal delivery. They are capable of controlling the release of therapeutic agents for a prolonged time.

Short conclusion

The literature presented in this review paper provides significant proof that nanofibers will have an intense impact on the transdermal delivery of different bioactive molecules in the future.

Graphic abstract

Electrospun Nanofibers of Polycaprolactone/Collagen as a Sustained-Release Drug Delivery System for Artemisinin

The application of artemisinin (ART) in the treatment of malaria has been restricted to a certain degree due to its inherent limitations, such as short half-life, poor solubility, limited bioavailability, and re-crystallization. Electrospun nanofibers loaded with ART provide an excellent solution to these limitations and yield sustained drug release as well as inhibition of drug re-crystallization. In this study, ART-loaded polycaprolactone (PCL)/collagen (Col) nanofibers with different proportions of polymers were prepared. ART-loaded PCL/Col nanofibers were characterized, and further ART anti-crystallization and release behaviors were studied. SEM was used to observe the morphology of PCL/Col nanofibers. X-ray diffraction (XRD) was used to characterize the physical state of ART in ART-loaded PCL/Col nanofibers. Fourier transform infrared spectroscopy (FTIR), water contact angle measurement, weight loss, degree of swelling, and drug release experiments can verify the differences in performance of ART-loaded PCL/Col nanofibers due to different polymer ratios. The release curve was analyzed by kinetics, showing sustained release for up to 48 h, and followed the Fickian release mechanism, which was shown by the diffusion index value obtained from the Korsmeyer-Peppas equation.

Recent advances in PVA-polysaccharide based hydrogels and electrospun nanofibers in biomedical applications: A review

Among several types of carbohydrate polymers blend PVA hydrogel membranes used for biomedical applications in particular wound dressings; electrospun nanofibrous membranes have gained increased interest because of their extraordinary features e.g. huge surface area to volume ratio, high porosity, adequate permeability, excellent wound-exudates absorption capacity, architecture similarity with skin ECM and sustained release-profile over long time. In this study, modern perspectives of synthesized/developed electrospun nanofibrous hydrogel membranes based popular carbohydrate polymers blend PVA which recently have been employed for versatile biomedical applications particularly wound dressings, were discussed intensively and compared in detail with traditional fabricated membranes based films, as well. Clinically relevant and advantages of electrospun nanofibrous membranes were discussed in terms of their biocompatibility and easily fabrication and functionalization in different biomedical applications.

Polysaccharides as wall material for the encapsulation of essential oils by electrospun technique

Electrospinning is a versatile, inexpensive and reliable technique for the synthesis of nanometric fibers or particles from polymeric solutions, under a high voltage electric field. The use of natural polysaccharides such as starch, chitosan, pectin, alginate, pullulan, cellulose and dextran as polymeric materials allows the formation of biodegradable fibers and capsules. Bioactive compounds extracted from natural sources, such as essential oils, have been widely studied due to their antioxidant, antimicrobial and antifungal properties. The combination of natural polymers and the electrospinning technique allows the production of structures capable of incorporating these bioactive compounds, which are highly sensitive to degradation reactions. This review describes several approaches to the development of nanofibers and nanocapsules from polysaccharides and the possibility of incorporating hydrophobic compounds, such as essential oils. The review also discusses the use of electrosprayed products incorporated with essential oils for direct application in food or for use as active food packaging.

Fabrication of multifunctional mucoadhesive buccal patch for drug delivery applications

Mucoadhesive buccal patch is a promising dosage form for a successful oral drug delivery, which provides unique advantages for various applications such as treatment of periodontal disease and postdental surgery disorders. The aim of this study is to synthesize a novel multifunctional mucoadhesive buccal patch in a multilayer reservoir design for therapeutic applications. The patches were fabricated through simultaneous electrospinning of chitosan/poly(vinylalcohol) (PVA)/ibuprofen and electrospraying of phenylalanine amino acid nanotubes (PhNTs) containing metronidazole into the electrospun mats through a layer-by-layer process. An electrospun poly(caprolactone) (PCL) was used as an impermeable backing layer to protect the mucoadhesive component from tongue movement and drug loss. Buccal patches were characterized using scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM) and also evaluated in terms of physicomechanical parameters such as pH, weight, thickness, tensile strength, folding endurance, and mucoadhesive properties. The swelling index of the patches was examined with respect to the PVA/chitosan ratio. The effect of genipin addition to the electrospinning solution was also studied on mucoadhesive and swelling properties. The cell viability of buccal patches was assessed by methylthiazolydiphenyl-tetrazolium bromide test on L929 fibroblast cell line. The patch with an optimal amount of mucoadhesive polymers (PVA/chitosan 80:20) and crosslinking agent (0.05 g) indicated an ideal hemostatic activity along with antibacterial properties against Streptococcus mutans bacteria. The synthesized multifunctional mucoadhesive patch with a novel composition and design has a great potential for oral therapeutic applications.

Dual-drug delivery of Ag-chitosan nanoparticles and phenytoin via core-shell PVA/PCL electrospun nanofibers

Dual-drug delivery systems were constructed through coaxial techniques, which were convenient for the model drugs used the present work. This study aimed to fabricate core-shell electrospun nanofibrous membranes displaying simultaneous cell proliferation and antibacterial activity. For that purpose, phenytoin (Ph), a well-known proliferative agent, was loaded into a polycaprolactone (PCL) shell membrane, and as-prepared silver-chitosan nanoparticles (Ag-CS NPs), as biocidal agents, were embedded in a polyvinyl alcohol (PVA) core layer. The morphology, chemical composition, mechanical and thermal properties of the nanofibrous membranes were characterized by FESEM/STEM, FTIR and DSC. The coaxial PVA-Ag CS NPs/PCL-Ph nanofibers (NFs) showed more controlled Ph release than PVA/PCL-Ph NFs. There was notable improvement in the morphology, thermal, mechanical, antibacterial properties and cytobiocompatibility of the fibers upon incorporation of Ph and Ag-CS NPs. The proposed core-shell PVA/PCL NFs represent promising scaffolds for tissue regeneration and wound healing by the effective dual delivery of phenytoin and Ag-CS NPs.

Applications of bacteria and their derived biomaterials for repair and tissue regeneration

Microorganisms such as bacteria and their derived biopolymers can be used in biomaterials and tissue regeneration. Various methods have been applied to regenerate damaged tissues, but using probiotics and biomaterials derived from bacteria with improved economic-production efficiency and highly applicable properties can be a new solution in tissue regeneration. Bacteria can synthesize numerous types of biopolymers. These biopolymers possess many desirable properties such as biocompatibility and biodegradability, making them good candidates for tissue regeneration. Here, we reviewed different types of bacterial-derived biopolymers and highlight their applications for tissue regeneration.

Recent advances in the production of biomedical systems based on polyhydroxyalkanoates and exopolysaccharides

In recent years, growing attention has been devoted to naturally occurring biological macromolecules and their ensuing application in agriculture, cosmetics, food and pharmaceutical industries. They inherently have antigenicity, low immunogenicity, excellent biocompatibility and cytocompatibility, which are ideal properties for the design of biomedical devices, especially for the controlled delivery of active ingredients in the most diverse contexts. Furthermore, these properties can be modulated by chemical modification via the incorporation of other (macro)molecules in a random or controlled way, aiming at improving their functionality for each specific application. Among the wide variety of natural polymers, microbial polyhydroxyalkanoates (PHAs) and exopolysaccharides (EPS) are often considered for the development of original biomaterials due to their unique physicochemical and biological features. Here, we aim to fullfil a gap on the present associated literature, bringing an up-to-date overview of ongoing research strategies that make use of PHAs (poly (3-hydroxybutyrate), poly (3-hydroxybutyrate-co-3-hydroxyvalerate), poly (3-hydroxyoctanoate), poly(3-hydroxypropionate), poly (3-hydroxyhexanoate-co-3-hydroxyoctanoate), and poly (3-hydroxybutyrate-co-3-hydroxyhexanoate)) and EPS (bacterial cellulose, alginates, curdlan, pullulan, xanthan gum, dextran, hyaluronan, and schizophyllan) as sources of interesting and versatile biomaterials. For the first time, a monograph addressing the properties, pros and cons, status, challenges, and recent progresses regarding the application of these two important classes of biopolymers in biomedicine is presented.

Constructing slow-release formulations of herbicide metribuzin using its co-extrusion with biodegradable polyester poly-ε-caprolactone

Different technologies to prepare long term pesticide forms include polymer coating, preparing composites and encapsulating pesticides in nanoparticles. A simple and low-cost method was proposed to obtain slow-release formulations by co-extrusion of a pesticide with a biodegradable polymer at a temperature above the melting points of both components. A herbicide metribuzin and low-melting polyester poly-ε-caprolactone were chosen for this work. Formulations containing 10%, 20%, and 40% herbicide were prepared. During 7 days of their exposition in water, it was released from 81% to 96% of initially loaded metribuzin; the highest release was detected for 40%-loaded forms. Biodegradation of the constructs and pesticide release were further studied in the model soil. Degradation rates of the specimens increased with an increase in pesticide content, from 9% to 20% over 14 weeks for the 10%/20%-loaded and the 40%-loaded specimens, respectively. The release of metribuzin reached, respectively, 37-38% and 55%. The herbicide content in soil was lower due to its partial degradation in soil; it reached 23-25% and 33%, respectively, from initially loaded into the polymer matrix. Release kinetics of metribuzin in water as in soil best fitted the First-order model. The used approach is promising for obtaining long-term release formulations for soil applications.

A comprehensive review summarizing the recent biomedical applications of functionalized carbon nanofibers

Since the discovery and fabrication of carbon nanofibers (CNFs) over a decade ago, scientists foster to discover novel myriad potential applications for this material in both biomedicine and industry. The unique economic viability, mechanical, electrical, optical, thermal, and structural properties of CNFs led to their rapid emergence. CNFs become an artificial intelligence platform for different uses, including a wide range of biomedical applications. Furthermore, CNFs have exceptionally large surface areas that make them flexible for tailoring and functionalization on demand. This review highlights the recent progress and achievements of CNFs in a wide range of biomedical fields, including cancer therapy, biosensing, tissue engineering, and wound dressing. Besides the synthetic techniques of CNFs, their potential toxicity and limitations, as biomaterials in real clinical settings, will be presented. This review discusses CNF's future investigations in other biomedical fields, including gene delivery and bioimaging and CNFs risk assessment.

Controlled release of tetracycline hydrochloride from poly(ω-pentadecalactone-co-ε-caprolactone)/gelatin nanofibers

Development of drug delivery systems is an extensively researched area in biomedical field. In recent years, there is an increasing interest on fabrication of biocompatible nanofibrous drug delivery systems. In the present study, poly(ω-pentadecalactone-co-ε-caprolactone)/gelatin nanofibrous membranes were fabricated for the controlled delivery and release of tetracycline hydrochloride (TCH) antibiotic. Poly(ω-pentadecalactone-co-ε-caprolactone) content provides an originality to the membrane, since it has been synthesized enzymatically previously. Varied amounts of tetracycline hydrochloride including poly(ω-pentadecalactone-co-ε-caprolactone)/gelatin (1:1, v:v) binary polymer blend was electrospun and characterizations (morphological and molecular structure, wettability characteristics, and thermal behavior) were applied to investigate the incorporation of drug molecule. Afterwards, in vitro drug release studies were carried out and mathematical modelling was applied to drug release data in order to clarify the transport mechanism of drug. TCH release profile comprised of an initial burst release in first hour and followed by a sustained release through 14 days which allowed sufficient antibacterial activity against both Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus and Bacillus subtilis) bacteria. The presented drug delivery system may be applied as an antibacterial wound dressing device for skin infections.

Dual drug delivery of vancomycin and imipenem/cilastatin by coaxial nanofibers for treatment of diabetic foot ulcer infections

Diabetic foot ulcer infections are the main causes of hospitalization in diabetics. The present study aimed to develop vancomycin and imipenem/cilastatin loaded core-shell nanofibers to facilitate the treatment of diabetic foot ulcers. Therefore, novel core-shell nanofibers composed of polyethylene oxide, chitosan, and vancomycin in shell and polyvinylpyrrolidone, gelatin, and imipenem/cilastatin in core compartments were prepared using the electrospinning technique. The nanofibers were characterized using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, tensile test, and drug release. The antibacterial activity of drug-loaded nanofibers in different drugs concentrations was evaluated against Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Pseudomonas aeruginosa by disk diffusion method. Furthermore, the cytotoxicity of fibers was investigated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide assay. The obtained results showed that the prepared nanofibers were smooth having a core-shell structure with almost no cytotoxicity. The nanofibrous mats exhibited significant antibacterial activity against S. aureus and MRSA with the inhibition zones of 2.9 and 2.5 cm and gram-negative bacteria species of E. coli and P. aeruginosa with the inhibition zones of 1.9 and 2.8 cm, respectively. With respect to the significant antibacterial activities of these nanofibrous mats, they might be used as suitable drug delivery devices not only for diabetic foot ulcer infections but also for other chronic wounds.

Biosurfactant electrospun nanofibers exhibit minimal side effects on the structure and function of the liver tissue in male rat model

Oil spills can result in significant damage to marine estuaries, rivers, lakes, wetlands, and shorelines. Electrospun nanofibers containing biosurfactant (ENFs) can be used to clean oil spills up and protect the environmental biology. Present work aimed to study the side-effects of prepared nanofibers on animal models. Screening of the prepared ECNFs on animals showed that three of them (PVA-5, PEO-1, and PEO-5) are safe to hepatic tissues and liver functions. Furthermore, oxidative stress did not change after using these nanofibers. The PVA-1 nanofibers, however, were found to cause major pathological changes in the liver tissue. In addition, PVA-1 nanofibers were proved to alter the total white blood count and the neutrophil percentages significantly in comparison to the control. In conclusion, PVA-5, PEO-1, and PEO-5 are safe to hepatic tissues and liver functions.

An Overview of Biopolymeric Electrospun Nanofibers Based on Polysaccharides for Wound Healing Management

Currently, despite the thoroughgoing scientific research carried out in the area of wound healing management, the treatment of skin injuries, regardless of etiology remains a big provocation for health care professionals. An optimal wound dressing should be nontoxic, non-adherent, non-allergenic, should also maintain a humid medium at the wound interfacing, and be easily removed without trauma. For the development of functional and bioactive dressings, they must meet different conditions such as: The ability to remove excess exudates, to allow gaseous interchange, to behave as a barrier to microbes and to external physical or chemical aggressions, and at the same time to have the capacity of promoting the process of healing by stimulating other intricate processes such as differentiation, cell adhesion, and proliferation. Over the past several years, various types of wound dressings including hydrogels, hydrocolloids, films, foams, sponges, and micro/nanofibers have been formulated, and among them, the electrospun nanofibrous mats received an increased interest from researchers due to the numerous advantages and their intrinsic properties. The drug-embedded nanofibers are the potential candidates for wound dressing application by virtue of: Superior surface area-to volume ratio, enormous porosity (can allow oxy-permeability) or reticular nano-porosity (can inhibit the microorganisms'adhesion), structural similitude to the skin extracellular matrix, and progressive electrospinning methodology, which promotes a prolonged drug release. The reason that we chose to review the formulation of electrospun nanofibers based on polysaccharides as dressings useful in wound healing was based on the ever-growing research in this field, research that highlighted many advantages of the nanofibrillary network, but also a marked versatility in terms of numerous active substances that can be incorporated for rapid and infection-free tissue regeneration. In this review, we have extensively discussed the recent advancements performed on electrospun nanofibers (eNFs) formulation methodology as wound dressings, and we focused as well on the entrapment of different active biomolecules that have been incorporated on polysaccharides-based nanofibers, highlighting those bioagents capable of improving the healing process. In addition, in vivo tests performed to support their increased efficacy were also listed, and the advantages of the polysaccharide nanofiber-based wound dressings compared to the traditional ones were emphasized.