Electrospun Nanofibers for Tissue Engineering with Drug Loading and Release

Layer-by-Layer Construction of Antibacterial and Anticoagulant Blood Contacting Materials

Vascular transplantation is a common treatment for Cardiovascular disease (CVD). However, the mismatch of mechanical, structural, or microenvironmental properties of materials limits the clinical application. Therefore, the functional construction of artificial vessels or other blood contact materials remains an urgent challenge. In this paper, the composite nanofibers of polycaprolactone (PCL) with dopamine and polyethylenimine (PEI) coating are first prepared, which are further self-assembled by anticoagulant hirudin (rH) and antimicrobial peptide (AMP) of HHC36 through layer-by-layer (LBL) method. The results of FTIR and XPS analysis show that hirudin and AMP are successfully loaded on PEI-PDA/PCL nanofibers and the hydrophilicity is improved. They also show good mechanical properties that the ultimate tensile strength and elongation at break are better than natural blood vessels. The antibacterial results show that the antibacterial effect is still 93% against E. coli on the fifth day because of the stable and continuous release of HHC36 and rH. The performance of anticoagulant activity also exhibited the same results, which APTT is even 9.7s longer in the experimental group than the control group on the fifth day. The novel materials would be effectively solve the formation of thrombosis around artificial blood vessel grafts and the treatment of inflammation.

Research advancements on nerve guide conduits for nerve injury repair

Peripheral nerve injury (PNI) is one of the most serious causes of disability and loss of work capacity of younger individuals. Although PNS has a certain degree of regeneration, there are still challenges like disordered growth, neuroma formation, and incomplete regeneration. Regarding the management of PNI, conventional methods such as surgery, pharmacotherapy, and rehabilitative therapy. Treatment strategies vary depending on the severity of the injury. While for the long nerve defect, autologous nerve grafting is commonly recognized as the preferred surgical approach. Nevertheless, due to lack of donor sources, neurological deficits and the low regeneration efficiency of grafted nerves, nerve guide conduits (NGCs) are recognized as a future promising technology in recent years. This review provides a comprehensive overview of current treatments for PNI, and discusses NGCs from different perspectives, such as material, design, fabrication process, and composite function.

Innovative Electrospun Nanofiber Mats Based on Polylactic Acid Composited with Silver Nanoparticles for Medical Applications

Nanofibers are some of the most attractive materials that can modify functionalities for developing new kinds of specific applications and are mainly used as a biomedical material. Herein, we designed and prepared antibacterial nonwoven fiber mats of PLA and PLA composited with Ag nanoparticles by electrospinning. The effects of varying filler contents on their chemical, surface morphology, thermal, water absorbency, and antibacterial properties were investigated using FTIR, SEM/EDS, DSC, swelling ratio, and qualitative and quantitative antibacterial tests. FTIR and EDS spectra indicated that Ag nanoparticles were incorporated in the PLA without chemical bonding. SEM revealed that the average diameter of the PLA nanofibers containing the Ag nanoparticles was more significant than those without those particles. In addition, fiber diameters are proportional to the amount of Ag nanoparticle contents. DSC indicated that the Ag nanoparticles can be incorporated within the PLA matrix without strongly affecting their thermal properties. Moreover, the crystallinity of the composite nonwoven fiber mats was higher than those of fiber mats in the neat PLA. However, TGA revealed that the loaded Ag can improve the thermal stability of the PLA electrospun fiber mats. Accordingly, the antibacterial activities revealed that all the composite nanofiber mats exhibited excellent resistance against S. aureus and E. coli bacterial strains. In addition, in the cell toxicity study, all produced hybrids of nonwoven fiber mats induced a reduction in cell viability for the L929 fibroblast cells. Our results suggest that the designed and prepared nonwoven fiber mats may have good potential for use in the biomedical field, particularly in wound dressing applications.

Micro- and Nanostructured Fibrous Composites via Electro-Fluid Dynamics: Design and Applications for Brain

The brain consists of an interconnected network of neurons tightly packed in the extracellular matrix (ECM) to form complex and heterogeneous composite tissue. According to recent biomimicry approaches that consider biological features as active components of biomaterials, designing a highly reproducible microenvironment for brain cells can represent a key tool for tissue repair and regeneration. Indeed, this is crucial to support cell growth, mitigate inflammation phenomena and provide adequate structural properties needed to support the damaged tissue, corroborating the activity of the vascular network and ultimately the functionality of neurons. In this context, electro-fluid dynamic techniques (EFDTs), i.e., electrospinning, electrospraying and related techniques, offer the opportunity to engineer a wide variety of composite substrates by integrating fibers, particles, and hydrogels at different scales-from several hundred microns down to tens of nanometers-for the generation of countless patterns of physical and biochemical cues suitable for influencing the in vitro response of coexistent brain cell populations mediated by the surrounding microenvironment. In this review, an overview of the different technological approaches-based on EFDTs-for engineering fibrous and/or particle-loaded composite substrates will be proposed. The second section of this review will primarily focus on describing current and future approaches to the use of composites for brain applications, ranging from therapeutic to diagnostic/theranostic use and from repair to regeneration, with the ultimate goal of providing insightful information to guide future research efforts toward the development of more efficient and reliable solutions.

Electrospun PCL/gelatin/arbutin nanofiber membranes as potent reactive oxygen species scavengers to accelerate cutaneous wound healing

The presence of excessive reactive oxygen species (ROS) at a skin wound site is an important factor affecting wound healing. ROS scavenging, which regulates the ROS microenvironment, is essential for wound healing. In this study, we used novel electrospun PCL/gelatin/arbutin (PCL/G/A) nanofibrous membranes as wound dressings, with PCL/gelatin (PCL/G) as the backbone, and plant-derived arbutin (hydroquinone-β-d-glucopyranoside, ARB) as an effective antioxidant that scavenges ROS and inhibits bacterial infection in wounds. The loading of ARB increased the mechanical strength of the nanofibres, with a water vapour transmission rate of more than 2500 g/(m2 × 24 h), and the water contact angle decreased, indicating that hydrophilicity and air permeability were significantly improved. Drug release and degradation experiments showed that the nanofibre membrane controlled the drug release and exhibited favourable degradability. Haemolysis experiments showed that the PCL/G/A nanofibre membranes were biocompatible, and DPPH and ABTS+ radical scavenging experiments indicated that PCL/G/A could effectively scavenge ROS to reflect the antioxidant activity. In addition, haemostasis experiments showed that PCL/G/A had good haemostatic effects in vitro and in vivo. In vivo animal wound closure and histological staining experiments demonstrated that PCL/G/A increased collagen deposition and remodelled epithelial tissue regeneration while showing good in vivo biocompatibility and non-toxicity. In conclusion, we successfully prepared a multifunctional wound dressing, PCL/G/A, for skin wound healing and investigated its potential role in wound healing, which is beneficial for the clinical translational application of phytomedicines.

A focused review on hyaluronic acid contained nanofiber formulations for diabetic wound healing

The significant clinical challenge presented by diabetic wounds is due to their impaired healing process and increased risk of complications. It is estimated that a foot ulcer will develop at some point in the lives of 15-25 % of diabetic patients. Serious complications, including infection and amputation, are often led to by these wounds. In the field of tissue engineering and regenerative medicine, nanofiber-based wound dressings have emerged in recent years as promising therapeutic strategies for diabetic wound healing. Hyaluronic acid (HA), among various nanofiber materials, has gained considerable attention due to its unique properties, including biocompatibility, biodegradability, and excellent moisture retention capacity. By promoting skin hydration and controlling inflammation, a crucial role in wound healing is played by HA. Wounds are also helped to heal faster by HA through the regulation of inflammation levels and signaling the body to build more blood vessels in the damaged area. Great potential in various applications, including wound healing, has been shown by the development and use of nanofiber formulations in medicine. However, challenges and limitations associated with nanofibers in medicine exist, such as reproducibility, proper characterization, and biological evaluation. By providing a biomimetic environment that enhances re-epithelialization and facilitates the delivery of active substances, nanofibers promote wound healing. In accelerating wound healing, promising results have been shown by HA-contained nanofiber formulations in diabetic wounds. Key strategies employed by these formulations include revascularization, modulation of the inflammation microenvironment, delivery of active substances, photothermal nanofibers, and nanoparticle-loaded fabrics. Particularly crucial is revascularization as it restores blood flow to the wound area, promoting healing. Wound healing can also be enhanced by modulating the inflammation microenvironment through controlling inflammation levels. Future perspectives in this field involve addressing the current challenges and limitations of nanofiber technology and further optimizing HA-contained nanofiber formulations for improved efficacy in diabetic wound healing. This includes exploring new fabrication techniques, enhancing the biocompatibility and biodegradability of nanofibers, and developing multifunctional nanofibers for targeted drug delivery. Not only does writing a review in the field of nanofiber-based wound dressings, particularly those containing hyaluronic acid, allow us to consolidate our current knowledge and understanding but also broadens our horizons. An opportunity is provided to delve deeper into the intricacies of this innovative therapeutic strategy, explore its potential and limitations, and envision future directions. By doing so, a contribution can be made to the ongoing advancements in tissue engineering and regenerative medicine, ultimately improving the quality of life for patients with diabetic wounds.

Electrospun Nanofiber Scaffolds Loaded with Metal-Based Nanoparticles for Wound Healing

Failures of wound healing have been a focus of research worldwide. With the continuous development of materials science, electrospun nanofiber scaffolds loaded with metal-based nanoparticles provide new ideas and methods for research into new tissue engineering materials due to their excellent antibacterial, anti-inflammatory, and wound healing abilities. In this review, the stages of extracellular matrix and wound healing, electrospun nanofiber scaffolds, metal-based nanoparticles, and metal-based nanoparticles supported by electrospun nanofiber scaffolds are reviewed, and their characteristics and applications are introduced. We discuss in detail the current research on wound healing of metal-based nanoparticles and electrospun nanofiber scaffolds loaded with metal-based nanoparticles, and we highlight the potential mechanisms and promising applications of these scaffolds for promoting wound healing.

Electrospun Polymeric Fibers Decorated with Silk Microcapsules via Encapsulation and Surface Immobilization for Drug Delivery

Hollow polymer microcapsules as drug carriers have the advantages of drug protection, storage, and controlled release. Microcapsules combined with tissue engineering scaffolds such as electrospun microfibers can enhance long-term local drug retention. However, the combination methods of microcapsules and fibers still need to be further explored. Here, different technical approaches to functionalize electrospun polycaprolactone (PCL) microfibers with silk fibroin (SF) microcapsules through encapsulation and surface immobilization are developed, including direct blending and emulsion electrospinning for encapsulation, as well as covalent and cleavable disulfide-linkage for surface immobilization. The results of "blending" approach show that silk microcapsules with different sizes could be uniformly encapsulated inside electrospun fibers without aggregation. To further reduce the use of organic solvents, the microcapsules in the aqueous phase can be uniformly distributed in the PCL organic phase and successfully electrospun into fibers using surfactant span-80. For surface immobilization, silk microcapsules are efficiently covalent binding to the surface of electrospun PCL fibers via click chemistry and exhibited noncytotoxic. Based on this method, with the incorporation of a disulfide bond, the linkages between microcapsule and fiber could be cleaved under reducing conditions. These microcapsule-electrospun fiber combination methods provide sufficient options for different drug delivery requirements.

Development of ibuprofen-loaded electrospun materials suitable for surgical implantation in peripheral nerve injury

The development of nerve wraps for use in the repair of peripheral nerves has shown promise over recent years. A pharmacological effect to improve regeneration may be achieved by loading such materials with therapeutic agents, for example ibuprofen, a non-steroidal anti-inflammatory drug with neuroregenerative properties. In this study, four commercially available polymers (polylactic acid (PLA), polycaprolactone (PCL) and two co-polymers containing different ratios of PLA to PCL) were used to fabricate ibuprofen-loaded nerve wraps using blend electrospinning. In vitro surgical handling experiments identified a formulation containing a PLA/PCL 70/30 molar ratio co-polymer as the most suitable for in vivo implantation. In a rat model, ibuprofen released from electrospun materials significantly improved the rate of axonal growth and sensory recovery over a 21-day recovery period following a sciatic nerve crush. Furthermore, RT-qPCR analysis of nerve segments revealed that the anti-inflammatory and neurotrophic effects of ibuprofen may still be observed 21 days after implantation. This suggests that the formulation developed in this work could have potential to improve nerve regeneration in vivo.

Tailored biomedical materials for wound healing

Wound healing is a long-term, multi-stage biological process that mainly includes haemostatic, inflammatory, proliferative and tissue remodelling phases. Controlling infection and inflammation and promoting tissue regeneration can contribute well to wound healing. Smart biomaterials offer significant advantages in wound healing because of their ability to control wound healing in time and space. Understanding how biomaterials are designed for different stages of wound healing will facilitate future personalized material tailoring for different wounds, making them beneficial for wound therapy. This review summarizes the design approaches of biomaterials in the field of anti-inflammatory, antimicrobial and tissue regeneration, highlights the advanced precise control achieved by biomaterials in different stages of wound healing and outlines the clinical and practical applications of biomaterials in wound healing.

Bletilla striata composite nanofibrous membranes prepared by emulsion electrospinning for enhanced healing of diabetic wounds

Diabetic wounds impose enormous distress and financial burden on patients, and finding effective dressings to manage wounds is critical. As a Chinese herbal medicine with a long history of Clinical application, Bletilla striata has significant medicinal effects in the therapy of various wounds. In this study, PLA and the pharmacodynamic substances of Bletilla striata were prepared into fibrous scaffolds by emulsion electrospinning technology for the management of diabetic wounds in mice. The results of scanning electron microscopy showed that the core-shell structure fibre was successfully obtained by emulsion electrospinning. The fibre membrane exhibited excellent water absorption capability and water vapor transmission rate, could inhibit the growth of Staphylococcus aureus and Pseudomonas aeruginosa, had good compatibility, and achieved excellent healing effect on diabetic wounds. Especially in the in vivo wound healing experiment, the wound healing rate of composite fibre membrane treatment reached 98.587 ± 2.149% in 16 days. This work demonstrated the good therapeutic effect of the developed fibrous membrane to diabetic wound, and this membrane could be potentially applied to chronic wound healing.

Wound healing efficacy of curcumin-loaded sandalwood bark-derived carbon nanosphere/PVA nanofiber matrix

The present investigation deals with the evaluation of the wound healing efficacy of sandalwood bark-derived carbon nanospheres loaded with curcumin-embedded polyvinyl alcohol (PVA) nanofiber membranes (NF). Carbon nanospheres (CNS) were prepared by pyrolyzing sandal wood bark powder at 750 °C. The morphology was confirmed by field emission scanning electron micrographs and a rich amount of carbon was confirmed by the energy dispersive X-ray technique. Curcumin, an active wound healing drug was loaded onto synthesized CNS and confirmed by ATR-IR studies. Drug-loaded CNS were anchored in a PVA matrix via electrospun nanofiber fabrication. The fabricated nanofiber membranes were characterized and evaluated for wound healing efficiency. The cytotoxicity assay proved the non-toxic nature of the prepared PVA/CNS-curcumin-loaded NF. Membranes with active CNS/drug showed better antimicrobial activity against S. aureus and E. coli, which was estimated using the zone of inhibition (ZOI) test. The in vitro scratch wound healing assay of prepared PVA/CNS-curcumin nanofibers was efficient enough and showed 92 to 98% wound closure, which was greater than the control (without drug) nanofiber membranes. The PVA nanofiber matrix with interconnected structure and carbon nanostructures together enhanced the wound healing efficacy of the considered wound healing membrane, which is a promising novel approach for future wound healing patches.

Pilot Study of Cytoprotective Mechanisms of Selenium Nanorods (SeNrs) under Ischemia-like Conditions on Cortical Astrocytes

The cytoprotective properties of the trace element selenium, its nanoparticles, and selenium nanocomplexes with active compounds are shown using a number of models. To date, some molecular mechanisms of the protective effect of spherical selenium nanoparticles under the action of ischemia/reoxygenation on brain cells have been studied. Among other things, the dependence of the effectiveness of the neuroprotective properties of nanoselenium on its diameter, pathways, and efficiency of penetration into astrocytes was established. In general, most research in the field of nanomedicine is focused on the preparation and study of spherical nanoparticles of various origins due to the ease of their preparation; in addition, spherical nanoparticles have a large specific surface area. However, obtaining and studying the mechanisms of action of nanoparticles of a new form are of great interest since nanorods, having all the positive properties of spherical nanoparticles, will also have a number of advantages. Using the laser ablation method, we managed to obtain and characterize selenium nanorods (SeNrs) with a length of 1 μm and a diameter of 100 nm. Using fluorescence microscopy and inhibitory analysis, we were able to show that selenium nanorods cause the generation of Ca2+ signals in cortical astrocytes in an acute experiment through the mobilization of Ca2+ ions from the thapsigargin-sensitive pool of the endoplasmic reticulum. Chronic use of SeNrs leads to a change in the expression pattern of genes encoding proteins that regulate cell fate and protect astrocytes from ischemia-like conditions and reoxygenation through the inhibition of a global increase in the concentration of cytosolic calcium ([Ca2+]i). An important component of the cytoprotective effect of SeNrs during ischemia/reoxygenation is the induction of reactive A2-type astrogliosis in astrocytes, leading to an increase in both baseline and ischemia/reoxygenation-induced phosphoinositide 3-kinase (PI3K) activity and suppression of necrosis and apoptosis. The key components of this cytoprotective action of SeNrs are the actin-dependent process of endocytosis of nanoparticles into cells and activation of the Ca2+ signaling system of astrocytes.

Antimicrobial Activities of Polyethylene Terephthalate-Waste-Derived Nanofibrous Membranes Decorated with Green Synthesized Ag Nanoparticles

Thermoplastic polymers are one of the synthetic materials produced with high tonnage in the world and are so omnipresent in industries and everyday life. One of the most important polymeric wastes is polyethylene terephthalate (PET), and the disposal of used PET bottles is an unsolved environmental problem, and many efforts have been made to find practical solutions to solve it. In this present work, nanofibrous membranes were produced from waste PET bottles using the electrospinning process. The surface of membranes was modified using NaOH and then decorated with green synthesized Ag nanoparticles (10 ± 2 nm) using an in situ chemical reduction method. The morphology, size, and diameter of the Ag nanoparticles decorating the nanofibers were characterized through transmission electron microscopy (TEM), a field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and UV-visible spectroscopy techniques. Finally, the antimicrobial activity of the nanofibrous membranes was tested against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus using disc diffusion and colony-forming count methods. The growth of bacteria was not affected by the pure nanofibrous membranes, while the Ag-decorated samples showed inhibition zones of 17 ± 1, 16 ± 1, and 14 ± 1 mm for Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, respectively. The planktonic culture results of Pseudomonas aeruginosa showed that the membranes had a relatively low inhibitory effect on its growth. The obtained results showed that Pseudomonas aeruginosa has a relatively low ability to form biofilms on the nanostructured membranes too. A good agreement was observed between the data of biofilm formation and the planktonic cultures of bacteria. The plastic-waste-derived PET/Ag nanocomposite membranes can be used for wound dressings, air filters, and water purification applications.

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.

Research Progress of Design Drugs and Composite Biomaterials in Bone Tissue Engineering

Bone, like most organs, has the ability to heal naturally and can be repaired slowly when it is slightly injured. However, in the case of bone defects caused by diseases or large shocks, surgical intervention and treatment of bone substitutes are needed, and drugs are actively matched to promote osteogenesis or prevent infection. Oral administration or injection for systemic therapy is a common way of administration in clinic, although it is not suitable for the long treatment cycle of bone tissue, and the drugs cannot exert the greatest effect or even produce toxic and side effects. In order to solve this problem, the structure or carrier simulating natural bone tissue is constructed to control the loading or release of the preparation with osteogenic potential, thus accelerating the repair of bone defect. Bioactive materials provide potential advantages for bone tissue regeneration, such as physical support, cell coverage and growth factors. In this review, we discuss the application of bone scaffolds with different structural characteristics made of polymers, ceramics and other composite materials in bone regeneration engineering and drug release, and look forward to its prospect.

Bioactive Nanostructured Scaffold-Based Approach for Tendon and Ligament Tissue Engineering

An effective therapeutic strategy to treat tendon or ligament injury continues to be a clinical challenge due to the limited natural healing capacity of these tissues. Furthermore, the repaired tendons or ligaments usually possess inferior mechanical properties and impaired functions. Tissue engineering can restore the physiological functions of tissues using biomaterials, cells, and suitable biochemical signals. It has produced encouraging clinical outcomes, forming tendon or ligament-like tissues with similar compositional, structural, and functional attributes to the native tissues. This paper starts by reviewing tendon/ligament structure and healing mechanisms, followed by describing the bioactive nanostructured scaffolds used in tendon and ligament tissue engineering, with emphasis on electrospun fibrous scaffolds. The natural and synthetic polymers for scaffold preparation, as well as the biological and physical cues offered by incorporating growth factors in the scaffolds or by dynamic cyclic stretching of the scaffolds, are also covered. It is expected to present a comprehensive clinical, biological, and biomaterial insight into advanced tissue engineering-based therapeutics for tendon and ligament repair.

Synthesis of oxidized sodium alginate and its electrospun bio-hybrids with zinc oxide nanoparticles to promote wound healing

Electrospun fibers provide a promising platform for wound healing; however, they lack requisite characteristics for wound repair, including antibacterial and anti-inflammatory properties and angiogenic ability. Sodium alginate (SA) is being used for different types of applications. However, the poor spinnability of SA restricts its applications. The objectives of this study were three-fold: a) to synthesize oxidized sodium alginate (OSA) to improve its spinnability, b) to fabricate composite fibrous membranes by blending OSA along with zinc oxide nanoparticles (ZnO-NPs), and c) to decipher antibacterial and anti-inflammatory properties as well as biocompatibility of membranes in vitro and in vivo. OSA displaying different oxidation degrees (Dox (%)) was synthesized by varying the molar ratio of sodium periodate to SA. OSA (Dox, ∼48 %) afforded smooth and uniform fibers; 0.5 wt% of adipic dihydrazide (ADH) evolved into structurally stable and water-insoluble membranes. Composite fibrous membranes containing 2 wt% of ZnO-NPs displayed good biocompatibility and bactericidal effect against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in vitro. In addition, composite membranes showed remarkable epithelialization, neovascularization, and anti-inflammatory response than that of the membranes devoid of ZnO-NPs. Conclusively, these composite fibrous membranes may have broad implications for wound healing applications.

Preparation and Investigation of Thermally Annealed Zein-Propolis Electrospun Nanofibers for Biomedical Applications

Zein, a corn-derived protein, has a variety of applications ranging from drug delivery to tissue engineering and wound healing. This work aims to develop a biocompatible scaffold for dermal applications based on thermally annealed electrospun propolis-loaded zein nanofibers. Pristine fibers' biocompatibility is determined in vitro. Next, propolis from Melipona quadrifasciata is added to the fibers at different concentrations (5% to 25%), and the scaffolds are studied. The physicochemical properties of zein/propolis precursor dispersions are evaluated and the results are correlated to the fibers' properties. Due to zein's and propolis' very favorable interactions, which are responsible for the increase in the dispersions surface tension, nanometric size ribbon-like fibers ranging from 420 to 575 nm are obtained. The fiber's hydrophobicity is not dependent on propolis concentration and increases with the annealing procedure. Propolis inhibitory concentration (IC₅₀ ) is determined as 61.78 µg mL^-1 . When loaded into fibers, propolis is gradually delivered to cells as Balb/3T3 fibroblasts and are able to adhere, grow, and interact with pristine and propolis-loaded fibers, and cytotoxicity is not observed. Therefore, the zein-propolis nanofibers are considered biocompatible and safe. The results are promising and provide prospects for the development of wound-healing nanofiber patches-one of propolis' main applications.

Study of nerve cell regeneration on nanofibers containing cerium oxide nanoparticles in a spinal cord injury model in rats

Since the CNS is unable to repair itself via neuronal regeneration in adult mammals, alternative therapies need to be found. The use of cerium oxide nanoparticles to repair nerve damage could be a promising approach for spinal cord reconstruction. In this study, we constructed a scaffold containing cerium oxide nanoparticles (Scaffold-CeO₂) and investigated the rate of nerve cell regeneration in a rat model of spinal cord injury. The scaffold of gelatin and polycaprolactone was synthesized, and a gelatin solution containing cerium oxide nanoparticles was attached to the scaffold. For the animal study, 40 male Wistar rats were randomly divided into 4 groups (n = 10): (a) Control; (b) Spinal cord injury (SCI); (c) Scaffold (SCI + scaffold without CeO₂ nanoparticles); (d) Scaffold-CeO₂ (SCI + scaffold containing CeO₂ nanoparticles). After creation of a hemisection SCI, scaffolds were placed at the site of injury in groups c and d, and after 7 weeks the rats were subjected to behavioral tests and then sacrificed for preparation of the spinal cord tissue to measure the expression of G-CSF, Tau and Mag proteins by Western blotting and Iba-1 protein by immunohistochemistry. The result of behavioral tests confirmed motor improvement and pain reduction in the Scaffold-CeO₂ group compared to the SCI group. Decreased expression of Iba-1 and higher expression of Tau and Mag in the Scaffold-CeO₂ group compared to the SCI group could be the result of nerve regeneration caused by the scaffold containing CeONPs as well as relief of pain symptoms.

Drug Delivery Systems in Regenerative Medicine: An Updated Review

Modern drug discovery methods led to evolving new agents with significant therapeutic potential. However, their properties, such as solubility and administration-related challenges, may hinder their benefits. Moreover, advances in biotechnology resulted in the development of a new generation of molecules with a short half-life that necessitates frequent administration. In this context, controlled release systems are required to enhance treatment efficacy and improve patient compliance. Innovative drug delivery systems are promising tools that protect therapeutic proteins and peptides against proteolytic degradation where controlled delivery is achievable. The present review provides an overview of different approaches used for drug delivery.

Polymeric Materials, Advances and Applications in Tissue Engineering: A Review

Tissue Engineering (TE) is an interdisciplinary field that encompasses materials science in combination with biological and engineering sciences. In recent years, an increase in the demand for therapeutic strategies for improving quality of life has necessitated innovative approaches to designing intelligent biomaterials aimed at the regeneration of tissues and organs. Polymeric porous scaffolds play a critical role in TE strategies for providing a favorable environment for tissue restoration and establishing the interaction of the biomaterial with cells and inducing substances. This article reviewed the various polymeric scaffold materials and their production techniques, as well as the basic elements and principles of TE. Several interesting strategies in eight main TE application areas of epithelial, bone, uterine, vascular, nerve, cartilaginous, cardiac, and urinary tissue were included with the aim of learning about current approaches in TE. Different polymer-based medical devices approved for use in clinical trials and a wide variety of polymeric biomaterials are currently available as commercial products. However, there still are obstacles that limit the clinical translation of TE implants for use wide in humans, and much research work is still needed in the field of regenerative medicine.

Regeneration of sciatic nerve injury through nanofiber neural guidance channels containing collagen hydrogel and acetyl L carnitine: An in vitro and in vivo study

Unlike the central nervous system (CNS), peripheral nervous system (PNS) injuries are partially repairable. Nerve guidance channels (NGCs) have been shown to improve the level of nerve repair after injury. In the present study, we developed a nanofiber NGC for the delivery of acetyl L carnitine (ALC) in a rat model of sciatic nerve injury. NGCs were produced by electrospinning a polymer blend of polycaprolacton and gelatin. The physicochemical and biological properties of developed scaffolds were investigated using Scanning electron microscopy, surface hydrophilicity measurement, porosity measurement, tensile strength studies, cell viability assay, and cell attachment assay. ALC was included in the collagen hydrogels at three weight ratios of 1%, 3%, and 5%. Cell viability assay showed that the hydrogels containing 5% ALC demonstrated a more favorable effect on PC-12 metabolic activity. Therefore, this concentration was chosen to treat PNS injury. The NGCs were implanted in rats and then their lumen was filled with collagen hydrogel + 5%ALC. The results of histopathological examinations and functional recovery studies showed that NGCs filled with ALC containing hydrogel have significant recovery potential compared to NGCs loaded with collagen hydrogels without ALC. Our results support the potential use of ALC-delivering NGCs in the treatment of peripheral nerve injury in the clinic.

Preparation of PLGA-Coated Porous Silica Nanofibers for Drug Release

Fibrous materials have unique applications in drug release and biomedical fields. This study reports on the preparation of porous silica nanofibers, using organic nanofibers as templates, and their use for drug release. Different from the commonly used electrospinning method, the organic nanofibers are produced via a self-assembly approach between melamine and benzene-1,3,5-tricarboxylic acid. Silica is then coated on the organic nanofibers via homogenization in a silica sol, a freeze-drying process, and then a sol-gel process. In order to regulate the surface area and mesopore volume of silica nanofibers, cetyltrimethyl ammonium bromide at different concentrations is used as template in the sol-gel process. With the removal of organic nanofibers and the surfactant by calcination, porous silica nanofibers are generated and then assessed as a scaffold for controlled drug release with ketoprofen as a model drug. Poly (D, L-lactide-co-glycolide) is coated on the silica nanofibers to achieve slow burst release and prolonged cumulative release of 25 days. This study demonstrates an effective method of preparing hollow silica nanofibers and the use of such nanofibers for long-term release with high drug loading.

Synthesis and Characterization of PU/PLCL/CMCS Electrospun Scaffolds for Skin Tissue Engineering

As tissue regeneration material, electrospun fibers can mimic the microscale and nanoscale structure of the natural extracellular matrix (ECM), which provides a basis for cell growth and achieves organic integration with surrounding tissues. At present, the challenge for researchers is to develop a bionic scaffold for the regeneration of the wound area. In this paper, polyurethane (PU) is a working basis for the subsequent construction of tissue-engineered skin. poly(L-lactide-co-caprolactone) (PLCL)/carboxymethyl chitosan (CMCS) composite fibers were prepared via electrospinning and cross-linked by glutaraldehyde. The effect of CMCS content on the surface morphology, mechanical properties, hydrophilicity, swelling degree, and cytocompatibility were explored, aiming to assess the possibility of composite scaffolds for tissue engineering applications. The results showed that randomly arranged electrospun fibers presented a smooth surface. All scaffolds exhibited sufficient tensile strength (5.30-5.60 MPa), Young's modulus (2.62-4.29 MPa), and swelling degree for wound treatment. The addition of CMCS improved the hydrophilicity and cytocompatibility of the scaffolds.

Electrospun Poly(acrylic acid-co-4-styrene sulfonate) as Potential Drug-Eluting Scaffolds for Targeted Chemotherapeutic Delivery Systems on Gastric (AGS) and Breast (MDA-Mb-231) Cancer Cell Lines

Potential drug-eluting scaffolds of electrospun poly(acrylic acid-co-styrene sulfonate) P(AA-co-SS) in clonogenic assays using tumorigenic gastric and ovarian cancer cells were tested in vitro. Electrospun polymer nanofiber (EPnF) meshes of PAA and PSSNa homo- and P(AA-co-SS) copolymer composed of 30:70, 50:50, 70:30 acrylic acid (AA) and sodium 4-styrene sulfonate (SSNa) units were performed by electrospinning (ES). The synthesis, structural and morphological characterization of all EPnF meshes were analyzed by optical and electron microscopy (SEM-EDS), infrared spectroscopy (FTIR), contact angle, and X-ray diffraction (XRD) measurements. This study shows that different ratio of AA and SSNa of monomers in P(AA-co-SS) EPnF play a crucial role in clonogenic in vitro assays. We found that 50:50 P(AA-co-SS) EPnF mesh loaded with antineoplastic drugs can be an excellent suppressor of growth-independent anchored capacities in vitro assays and a good subcutaneous drug delivery system for chemotherapeutic medication in vivo model for surgical resection procedures in cancer research.

Fabrication and characterization of super-hydrophilic poly (ε-caprolactone)/hydroxypropyl methylcellulose (HPMC) based composite electrospun membranes for tissue engineering applications

Tissue engineering (TE) employs scaffolds as a structural support for initially seeding of cells followed by development of new tissues. Electrospun scaffolds generally function as a template of native extracellular matrix (ECM). The chemical composition of the scaffold and its surface morphology strongly influence the interaction between various cell types and materials. In this work, PCL and PCL/HPMC-based composite membranes with varying concentrations of HPMC (20-30% by weight) were fabricated using electrospinning technique. The membranes were evaluated for their surface, physio-chemical and biological properties. It was observed probably for the first time that blending of HPMC with PCL produced super-hydrophilic scaffolds. DSC studies confirmed the semi- crystalline nature of HPMC. PCL/HPMC composite scaffolds are found biocompatible from cytotoxicity assay. From the cell culture studies (apoptosis), PCL/HPMC composite scaffolds did not inhibit the adhesion of L929 cells due to their super-hydrophilic nature. The cell adhesion and spreading varied with HPMC concentration. PCL/HPMC (70/30) membranes showed highest cell adhesion among others due to its porous structure.

Extracellular matrix mechanobiology in cancer cell migration

The extracellular matrix (ECM) is pivotal in modulating tumor progression. Besides chemically stimulating tumor cells, it also offers physical support that orchestrates the sequence of events in the metastatic cascade upon dynamically modulating cell mechanosensation. Understanding this translation between matrix biophysical cues and intracellular signaling has led to rapid growth in the interdisciplinary field of cancer mechanobiology in the last decade. Substantial efforts have been made to develop novel in vitro tumor mimicking platforms to visualize and quantify the mechanical forces within the tissue that dictate tumor cell invasion and metastatic growth. This review highlights recent findings on tumor matrix biophysical cues such as fibrillar arrangement, crosslinking density, confinement, rigidity, topography, and non-linear mechanics and their implications on tumor cell behavior. We also emphasize how perturbations in these cues alter cellular mechanisms of mechanotransduction, consequently enhancing malignancy. Finally, we elucidate engineering techniques to individually emulate the mechanical properties of tumors that could help serve as toolkits for developing and testing ECM-targeted therapeutics on novel bioengineered tumor platforms. STATEMENT OF SIGNIFICANCE: Disrupted ECM mechanics is a driving force for transitioning incipient cells to life-threatening malignant variants. Understanding these ECM changes can be crucial as they may aid in developing several efficacious drugs that not only focus on inducing cytotoxic effects but also target specific matrix mechanical cues that support and enhance tumor invasiveness. Designing and implementing an optimal tumor mimic can allow us to predictively map biophysical cue-modulated cell behaviors and facilitate the design of improved lab-grown tumor models with accurately controlled structural features. This review focuses on the abnormal changes within the ECM during tumorigenesis and its implications on tumor cell-matrix mechanoreciprocity. Additionally, it accentuates engineering approaches to produce ECM features of varying levels of complexity which is critical for improving the efficiency of current engineered tumor tissue models.

Electrospinning of botanicals for skin wound healing

Being the first barrier between the human body and external environments, our skin is highly vulnerable to injuries. As one of the conventional therapies, botanicals prepared in different topical formulations have been applied as medical care for centuries. With the current increase of clinical requirements, applications of botanicals are heading towards nanotechnologies, typically fused with electrospinning that forms nanofibrous membranes suitable for skin wound healing. In this review, we first introduced the main process of wound healing, and then presented botanicals integrated into electrospun matrices as either loaded drugs, or carriers, or membrane coatings. In addition, by addressing functional features of individual botanicals in the healing of injured skin, we further discussed the bioactivity of botanical electrospun membranes in relevant to the medical issues solved in the process of wound healing. As achieved by pioneer studies, due to infrequent adverse effects and the diversity in resources of natural plants, the development of electrospun products based on botanicals is gaining greater attention. However, investigations in this field have mainly focused on different methodologies used in the preparation of nanofibrous membranes containing botanicals, their translation into clinical practices remains unaddressed. Accordingly, we propose that potential clinical applications of botanical electrospun membranes require not only the further expansion and understanding of botanicals, but also an establishment of standard criteria for the evaluation of wound healing and evolutions of technologies to support the large-scale manufacturing industry.

Chitosan-based scaffolds as drug delivery systems in bone tissue engineering

The bone tissue engineering approach for treating large bone defects becomes necessary when the tissue damage surpasses the threshold of the inherent regenerative ability of the human body. A myriad of natural biodegradable polymers and scaffold fabrication techniques have emerged in the last decade. Chitosan (CS) is especially attractive as a bone scaffold material to support cell attachment and proliferation and mineralization of the bone matrix. The primary amino groups in CS are responsible for properties such as controlled drug release, mucoadhesion, in situ gelation, and transfection. CS-based smart drug delivery scaffolds that respond to environmental stimuli have been reported to have a localized sustained delivery of drugs in the large bone defect area. This review outlines the recent advances in the fabrication of CS-based scaffolds as a pharmaceutical carrier to deliver drugs such as antibiotics, growth factors, nucleic acids, and phenolic compounds for bone tissue regeneration.

Prospects and Challenges of Electrospun Cell and Drug Delivery Vehicles to Correct Urethral Stricture

Current therapeutic modalities to treat urethral strictures are associated with several challenges and shortcomings. Therefore, significant strides have been made to develop strategies with minimal side effects and the highest therapeutic potential. In this framework, electrospun scaffolds incorporated with various cells or bioactive agents have provided promising vistas to repair urethral defects. Due to the biomimetic nature of these constructs, they can efficiently mimic the native cells’ niches and provide essential microenvironmental cues for the safe transplantation of multiple cell types. Furthermore, these scaffolds are versatile platforms for delivering various drug molecules, growth factors, and nucleic acids. This review discusses the recent progress, applications, and challenges of electrospun scaffolds to deliver cells or bioactive agents during the urethral defect repair process. First, the current status of electrospinning in urethral tissue engineering is presented. Then, the principles of electrospinning in drug and cell delivery applications are reviewed. Finally, the recent preclinical studies are summarized and the current challenges are discussed.

Smart Thermoresponsive Electrospun Nanofibers with On-Demand Release of Carbon Quantum Dots for Cellular Uptake

Developing a smart responsive surface for on-demand delivery of organic, inorganic, and biological cargo in vitro cellular uptake is always in constant demand. Herein, we present carbon quantum dot (CQD)-loaded (poly(N-isopropylacrylamide) (PNIPAAm)/poly(methyl methacrylate (PMMA)) blend nanofiber sheets having a thermoresponsive nature. As a model cargo, fluorescent CQDs are used for the demonstration of the on-demand delivery mechanism. In addition, a thermoresponsive nature is produced by the PNIPAAm polymer in the nanofiber matrix while the PMMA polymer provides extra stability and firmness to the nanofibers against the sudden dissolution of the nanofibers in aqueous media. The synthesis of CQDs and their loading into a blend nanofiber matrix are confirmed using fluorescence spectrophotometry, transmission electron microscopy, and fluorescence microscopy. The morphologies and diameters of the nanofibers are analyzed by scanning electron microscopy. Burst effect analysis proves that 30% (w/w) PNIPAAm-containing nanofibers possess the highest stability with the least dissolution in aqueous media. Thermoresponsiveness of the nanofibers is further confirmed through water contact angle measurements. Quantitative fluorescence results show that more than 80% of loaded CQDs can be released upon thermal stimulation. The fluorescence micrographs reveal that the blend nanofiber sheets can effectively improve the cellular uptake of CQDs by simply increasing the local concentrations via applying thermal stimulation as the released mechanism.

Development of high resilience spiral wound suture-embedded gelatin/PCL/heparin nanofiber membrane scaffolds for tendon tissue engineering

This study develops a spiral wound scaffold based on gelatin/PCL/heparin (GPH) nanofiber membranes for tendon tissue engineering. By embedding sutures in dual layers of aligned GPH nanofiber membranes, prepared from mixed electrospinning of gelatin and PCL/heparin solutions, we fabricate a high resilience scaffold intended for the high loading environment experienced by tendons. The basic fibroblast growth factor (bFGF) was anchored to GPH scaffold through bioaffinity between heparin and bFGF, aim to provide biological cues for maintenance of tenogenic phenotype. In addition, the aligned nanofiber morphology is expected to provide physical cues toward seeded tenocytes. With sustained release of bFGF, GPH-bFGF can enhance proliferation, up-regulate tenogenic gene expression, and increase synthesis of tendon-specific proteins by tenocytes in vitro. Furthermore, by properly maintaining tendon phenotypes, GPH-bFGF/tenocytes constructs showed improved mechanical properties over GPH-bFGF. From in vivo study using GPH-bFGF/tenocytes constructs to repair rabbit Achilles tendon defects, neotendon tissue formation was confirmed from histological staining and biomechanical analysis. These findings collectively demonstrate that the newly designed GPH-bFGF scaffold could provide a niche for inducing tendon tissue regeneration by effectively restoring the tendon tissue structure and function.

Recent Advances in Designing Fibrous Biomaterials for the Domain of Biomedical, Clinical, and Environmental Applications

Unique properties and potential applications of nanofibers have emerged as innovative approaches and opportunities in the biomedical, healthcare, environmental, and biosensor fields. Electrospinning and centrifugal spinning strategies have gained considerable attention among all kinds of strategies to produce nanofibers. These techniques produce nanofibers with high porosity and surface area, adequate pore architecture, and diverse chemical compositions. The extraordinary characteristics of nanofibers have unveiled new gates in nanomedicine to establish innovative fiber-based formulations for biomedical use, healthcare, and a wide range of other applications. The present review aims to provide a comprehensive overview of nanofibers and their broad range of applications, including drug delivery, biomedical scaffolds, tissue/bone-tissue engineering, dental applications, and environmental remediation in a single place. The review begins with a brief introduction followed by potential applications of nanofibers. Finally, the future perspectives and current challenges of nanofibers are demonstrated. This review will help researchers to engineer more efficient multifunctional nanofibers with improved characteristics for their effective use in broad areas. We strongly believe this review is a reader's delight and will help in dealing with the fundamental principles and applications of nanofiber-based scaffolds. This review will assist students and a broad range of scientific communities to understand the significance of nanofibers in several domains of nanotechnology, nanomedicine, biotechnology, and environmental remediation, which will set a benchmark for further research.

Spermidine Crosslinked Gellan Gum-Based “Hydrogel Nanofibers” as Potential Tool for the Treatment of Nervous Tissue Injuries: A Formulation Study

Purpose

Aim of the work was to develop a potential neural scaffold, endowed with neuroprotective and neuroregenerative potential, to be applied at the site of nervous tissue injuries: nanofibers, consisting of gellan gum (GG), spermidine (SP) and gelatin (GL), were prepared via electrospinning. SP was selected for its neuroprotective activity and cationic nature that makes it an ideal GG cross-linking agent. GL was added to improve the scaffold bioactivity.

Methods

Mixtures, containing 1.5% w/w GG and increasing SP concentrations (0–0.125% w/w), were prepared to investigate GG/SP interaction and, thus, to find the best mixture to be electrospun. Mixture rheological and mechanical properties were assessed. The addition of 0.1% w/w GL was also investigated. The most promising GG/SP/GL mixtures were added with poly(ethylene oxide) (PEO) and poloxamer (P407) and, then, electrospun. The resulting fibers were characterized in terms of size and mechanical properties and fiber morphology was observed after soaking in water for 24 hours. Nanofiber biocompatibility was assessed on Schwann cells.

Results

More and more structured GG/SP mixtures were obtained by increasing SP concentration, proving its cross-linking potential. After blending with PEO and P407, the mixture consisting of 1.5% w/w GG, 0.05% w/w SP and 0.1% w/w GL was electrospun. The resulting nanofibers appeared homogenous and characterized by a plastic behavior, suggesting a good mechanical resistance when applied at the injury site. Nanofibers were insoluble in aqueous media and able to form a thin gel layer after hydration. GG/SP/GL nanofibers showed a higher compatibility with Schwann cells than GG/SP ones.

Conclusion

SP and GL allowed the production of homogenous GG-based nanofibers, which preserved their structure after contact with aqueous media and showed a good compatibility with a neural cell line. After local application at the injury site, nanofibers should support and guide axonal outgrowth, releasing SP in a controlled manner.

Electrospun Antibacterial Composites for Cartilage Tissue Engineering

Implantation of biomaterials capable of the controlled release of antibacterials during articular cartilage repair may prevent postoperative infections. Herein, biomaterials are prepared with biomimetic architectures (nonwoven mats of fibers) via electrospinning that are composed of poly(ɛ-caprolactone), poly(lactic acid), and Bombyx mori silk fibroin (with varying ratios) and, optionally, an antibiotic drug (cefixime trihydrate). The composition, morphology, and mechanical properties of the nanofibrous mats are characterized using scanning electron microscope, Fourier transform infrared spectroscopy, and tensile testing. The nonwoven mats have nanoscale fibers (typical diameters of 324-725 nm) and are capable of controlling the release profiles of the drug, with antibacterial activity against Gram +ve and Gram -ve bacteria (two common strains of human pathogenic bacteria, Staphylococcus aureus and Escherichia coli) under in vitro static conditions. The drug loaded nanofiber mats display cytocompatibility comparable to pure poly(ɛ-caprolactone) nanofibers when cultured with National Institutes of Health (NIH) NIH-3T3 fibroblast cell line and have long-term potential for clinical applications in the field of pharmaceutical sciences.

Functionalization of Electrospun Nanofiber for Bone Tissue Engineering

Bone-tissue engineering is an alternative treatment for bone defects with great potential in which scaffold is a critical factor to determine the effect of bone regeneration. Electrospun nanofibers are widely used as scaffolds in the biomedical field for their similarity with the structure of the extracellular matrix (ECM). Their unique characteristics are: larger surface areas, porosity and processability; these make them ideal candidates for bone-tissue engineering. This review briefly introduces bone-tissue engineering and summarizes the materials and methods for electrospining. More importantly, how to functionalize electrospun nanofibers to make them more conducive for bone regeneration is highlighted. Finally, the existing deficiencies of functionalized electrospun nanofibers for promoting osteogenesis are proposed. Such a summary can lay the foundation for the clinical practice of functionalized electrospun nanofibers.

Polysaccharides, as biological macromolecule-based scaffolding biomaterials in cornea tissue engineering: A review

Corneal-related diseases and injuries are the leading causes of vision loss, estimated to affect over 10 million people worldwide. Currently, cadaveric corneal grafts are considered the gold standard of treatment to restore cornea-related vision. However, this treatment modality faces different challenges such as donor shortage and graft failure. Therefore, the need for alternative solutions continues to grow. Tissue engineering has dramatically progressed to produce artificial cornea implants in order to repair, regenerate, or replace the damaged cornea. In this regard, a variety of polysaccharides such as cellulose, chitosan, alginate, agarose, and hyaluronic acid have been widely explored as scaffolding biomaterials for the production of tissue-engineered cornea. These polymers are known for their excellent biocompatibility, versatile properties, and processability. Recent progress and future perspectives of polysaccharide-based biomaterials in cornea tissue engineering is reviewed here.

Cold atmospheric plasma modification and electrical conductivity induction in gelatin/polyvinylidene fluoride nanofibers for neural tissue engineering

BACKGROUND

This research follows some investigations through neural tissue engineering, including fabrication, surface treatment, and evaluation of novel self-stimuli conductive biocompatible and degradable nanocomposite scaffolds.

METHODS

Gelatin as a biobased material and polyvinylidene fluoride (PVDF) as a mechanical, electrical, and piezoelectric improvement agent were co-electrospun. In addition, polyaniline/graphene (PAG) nanoparticles were synthesized and added to gelatin solutions in different percentages to induce electrical conductivity. After obtaining optimum PAG percentage, cold atmospheric plasma (CAP) treatment was applied over the best samples by different plasma variable parameters. Finally, the biocompatibility of the scaffolds was analyzed and approved by in vitro tests using two different PC12 and C6 cell lines. In the present study the morphology, FTIR, dynamic light scattering, mechanical properties, wettability, contact angle tests, differential scanning calorimetric, rate of degradation, conductivity, biocompatibility, gene expression, DAPI staining, and cell proliferation were investigated.

RESULTS

The PAG percentage optimization results revealed fiber diameter reduction, conductivity enhancement, young's modulus improvement, hydrophilicity devaluation, water uptake decrement, and degradability reduction in electrospun nanofibers by increasing the PAG concentration. Furthermore, ATR-FTIR, FE-SEM, AFM, and contact angle tests revealed that helium CAP treatment improves scaffold characterizations for 90 seconds in duration time. Furthermore, the results of the MTT assay, FE-SEM, DAPI staining, and RT-PCR revealed that samples containing 2.5% w/w of PAG are the most biocompatible, and CAP treatment increases cell proliferation and improves neural gene expression in the differentiation medium.

CONCLUSIONS

According to the results, the samples with the 2.5% w/w of PAG could provide a suitable matrix for neural tissue engineering in terms of physicochemical and biological.

Bipolar Metal Flexible Electrospun Fibrous Membrane Based on Metal-Organic Framework for Gradient Healing of Tendon-to-Bone Interface Regeneration

Metal ions play a significant role in tissue repair, with widely application in clinical treatment. However, the therapeutic effect of metal ions is always limited due to metabolization and narrow repair capability. Here, a bipolar metal flexible electrospun fibrous membrane based on a metal-organic framework (MOF), which is bioinspired by the gradient structure of the tendon-to-bone interface, with a combination of regulating osteoblasts differentiation and angiogenesis properties, is constructed successfully by a continuous electrospinning technique and matching the longitudinal space morphology for synchronous regeneration. Furthermore, the MOF, acting as carriers, can not only achieve the sustainable release of metal ions, but promote the osteogenesis and tenogenesis on the scaffold. The in vitro data show that this novel hierarchical structure can accelerate the tenogenesis, the biomineralization, and angiogenesis. Moreover, in the in vivo experiment, the flexible fibrous membrane can promote tendon and bone tissue repair, and fibrocartilage reconstruction, to realize the multiple tissue synchronous regeneration at the damaged tendon-to-bone interface. Altogether, this newly developed bipolar metal flexible electrospun fibrous membrane based on a MOF, as a new biomimetic flexible scaffold, has great potential in reconstruct the tissue damage, especially gradient tissue damage.

Bone Morphogenetic Protein-, Antimicrobial Agent-, and Analgesic-Incorporated Nanofibrous Scaffolds for the Therapy of Alveolar Clefts

An alveolar cleft is a bone defect in the maxillary arch. Although the use of autologous iliac bone grafts to repair alveolar clefts is the preferred treatment method, donor-site morbidity remains a concern. In this study, we incorporated bone morphogenetic protein (BMP), an antimicrobial agent, and an analgesic into nanofibrous scaffolds for alveolar cleft therapy. Three-dimensional (3D) printing and coaxial electrospinning techniques were used to fabricate the scaffolds. BMP-2, ketorolac, and amoxicillin were used as the growth factor, analgesic, and antimicrobial agent, respectively. The in vitro properties of the nanofibrous scaffolds were characterized, and in vivo efficacy was evaluated in a rat alveolar-cleft model. The empirical data indicated that the biomolecule-incorporated scaffolds offered extended discharge of BMP-2, amoxicillin, and ketorolac for >4 weeks. The animal test outcomes also demonstrated favorable bone healing at the cleft site. Biomolecule- and drug-incorporated nanofibrous scaffolds demonstrated their efficacy in alveolar cleft treatment.

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.