PLGA nanofiber membranes loaded with epigallocatechin-3-O-gallate are beneficial to prevention of postsurgical adhesions

Advanced postoperative tissue antiadhesive membranes enabled with electrospun nanofibers

Tissue adhesion is one of the most common postoperative complications, which is frequently accompanied by inflammation, pain, and even dyskinesia, significantly reducing the quality of life of patients. Thus, to prevent the formation of tissue adhesions, various strategies have been explored. Among these methods, placing anti-adhesion membranes over the injured site to separate the wound from surrounding tissues is a simple and prominently favored method. Recently, electrospun nanofibers have been the most frequently investigated antiadhesive membranes due to their tunable porous structure and high porosities. They not only can act as an essential barrier and functional carrier system but also allow for high permeability and nutrient transport, showing great potential for preventing tissue adhesion. Herein, we provide a short review of the most recent applications of electrospun nanofibrous antiadhesive membranes in tendons, the abdominal cavity, dural sac, pericardium, and meninges. Firstly, each section highlights the most representative examples and they are sorted based on the latest progress of related research. Moreover, the design principles, preparation strategies, overall performances, and existing problems are highlighted and evaluated. Finally, the current challenges and several future ways to develop electrospun nanofibrous antiadhesive membranes are proposed. The systematic discussion and proposed directions can shed light on ideas and guide the reasonable design of electrospun nanofibrous membranes, contributing to the development of exceptional tissue anti-adhesive materials in the foreseeable future.

Antiadhesive Nanofibrous Materials for Medicine: Preventing Undesirable Tissue Adhesions

Undesirable postoperative tissue adhesions remain among the most common complications after surgery. Apart from pharmacological antiadhesive agents, various physical barriers have been developed in order to prevent postoperative tissue adhesions. Nevertheless, many introduced materials suffer from shortcomings during in vivo application. Thus, there is an increasing need to develop a novel barrier material. However, various challenging criteria have to be met, so this issue pushes the research in materials to its current limits. Nanofibers play a major role in breaking the wall of this issue. Due to their properties, such as a large surface area for functionalization, tunable degradation rate, or the possibility of layering individual nanofibrous materials, it is feasible to create an antiadhesive surface while maintaining biocompatibility. There are many ways to produce nanofibrous material; electrospinning is the most used and versatile technique. This review reveals the different approaches and puts them into context.

The potential of functionalized dressing releasing flavonoids facilitates scar-free healing

Scars are pathological marks left after an injury heals that inflict physical and psychological harm, especially the great threat to development and aesthetics posed by oral and maxillofacial scars. The differential expression of genes such as transforming growth factor-β, local adherent plaque kinase, and yes-related transcriptional regulators at infancy or the oral mucosa is thought to be the reason of scarless regenerative capacity after tissue defects. Currently, tissue engineering products for defect repair frequently overlook the management of postoperative scars, and inhibitors of important genes alone have negative consequences for the organism. Natural flavonoids have hemostatic, anti-inflammatory, antioxidant, and antibacterial properties, which promote wound healing and have anti-scar properties by interfering with the transmission of key signaling pathways involved in scar formation. The combination of flavonoid-rich drug dressings provides a platform for clinical translation of compounds that aid in drug disintegration, prolonged release, and targeted delivery. Therefore, we present a review of the mechanisms and effects of flavonoids in promoting scar-free regeneration and the application of flavonoid-laden dressings.

Prevention of Postsurgical Abdominal Adhesion Using Electrospun TPU Nanofibers in Rat Model

Intra-abdominal adhesions following surgery are a challenging problem in surgical practice. This study fabricated different thermoplastic polyurethane (TPU) nanofibers with different average diameters using the electrospinning method. The conditions were evaluated by scanning electron microscopy (SEM), atomic force microscope (AFM), and Fourier transform infrared spectrometer (FTIR) analysis. A static tensile test was applied using a strength testing device to assess the mechanical properties of the electrospun scaffolds. By changing the effective electrospinning parameters, the best quality of nanofibers could be achieved with the lowest bead numbers. The electrospun nanofibers were evaluated in vivo using a rat cecal abrasion model. The macroscopic evaluation and the microscopic study, including the degree of adhesion and inflammation, were investigated after three and five weeks. The resultant electrospun TPU nanofibers had diameters ranging from about 200 to 1000 nm. The diameters and morphology of the nanofibers were significantly affected by the concentration of polymer. Uniform TPU nanofibers without beads could be prepared by electrospinning through reasonable control of the process concentration. These nanofibers' biodegradability and antibacterial properties were investigated by weight loss measurement and microdilution methods, respectively. The purpose of this study was to provide electrospun nanofibers having biodegradability and antibacterial properties that prevent any adhesions or inflammation after pelvic and abdominal surgeries. The in vivo experiments revealed that electrospun TPU nanofibers reduced the degree of abdominal adhesions. The histopathological study confirmed only a small extent of inflammatory cell infiltration in the 8% and 10% TPU. Conclusively, nanofibers containing 8% TPU significantly decreased the incidence and severity of postsurgical adhesions, and it is expected to be used in clinical applications in the future.

Polyphenols-loaded electrospun nanofibers in bone tissue engineering and regeneration

Bone is a complex structure with unique cellular and molecular process in its formation. Bone tissue regeneration is a well-organized and routine process at the cellular and molecular level in humans through the activation of biochemical pathways and protein expression. Though many forms of biomaterials have been applied for bone tissue regeneration, electrospun nanofibrous scaffolds have attracted more attention among researchers with their physicochemical properties such as tensile strength, porosity, and biocompatibility. When drugs, antibiotics, or functional nanoparticles are taken as additives to the nanofiber, its efficacy towards the application gets increased. Polyphenol is a versatile green/phytochemical small molecule playing a vital role in several biomedical applications, including bone tissue regeneration. When polyphenols are incorporated as additives to the nanofibrous scaffold, their combined properties enhance cell attachment, proliferation, and differentiation in bone tissue defect. The present review describes bone biology encompassing the composition and function of bone tissue cells and exemplifies the series of biological processes associated with bone tissue regeneration. We have highlighted the molecular mechanism of bioactive polyphenols involved in bone tissue regeneration and specified the advantage of electrospun nanofiber as a wound healing scaffold. As the polyphenols contribute to wound healing with their antioxidant and antimicrobial properties, we have compiled a list of polyphenols studied, thus far, for bone tissue regeneration along with their in vitro and in vivo experimental biological results and salient observations. Finally, we have elaborated on the importance of polyphenol-loaded electrospun nanofiber in bone tissue regeneration and discussed the possible challenges and future directions in this field.

Applications of Electrospun Nanofibers with Antioxidant Properties: A Review

Antioxidants can be encapsulated to enhance their solubility or bioavailability or to protect them from external factors. Electrospinning has proven to be an excellent option for applications in nanotechnology, as electrospun nanofibers can provide the necessary environment for antioxidant encapsulation. Forty-nine papers related to antioxidants loaded onto electrospun nanofibers were categorized and reviewed to identify applications and new trends. Medical and food fields were commonly proposed for the newly obtained composites. Among the polymers used as a matrix for the electrospinning process, synthetic poly (lactic acid) and polycaprolactone were the most widely used. In addition, natural compounds and extracts were identified as antioxidants that help to inhibit free radical and oxidative damage in tissues and foods. The most recurrent active compounds used were tannic acid (polyphenol), quercetin (flavonoid), curcumin (polyphenol), and vitamin B6 (pyridoxine). The incorporation of active compounds in nanofibers often improves their bioavailability, giving them increased stability, changing the mechanical properties of polymers, enhancing nanofiber biocompatibility, and offering novel properties for the required field. Although most of the polymers used were synthetic, natural polymers such as silk fibroin, chitosan, cellulose, pullulan, polyhydroxybutyrate, and zein have proven to be proper matrices for this purpose.

Nanochemoprevention with therapeutic benefits: An updated review focused on epigallocatechin gallate delivery

Epigallocatechin gallate (EGCG) is a natural phenolic compound found in many plants, especially in green tea, which is a popular and restorative beverage with many claimed health benefits such as antioxidant, anti-cancer, anti-microbial, anti-diabetic, and anti-obesity activities. Despite its great curative potential, the poor bioavailability of EGCG restricts its clinical applcation. However, nanoformulations of EGCG are emerging as new alternatives to traditional formulations. This review focuses on the nanochemopreventive applications of various EGCG nanoparticles such as lipid-based, polymer-based, carbohydrate-based, protein-based, and metal-based nanoparticles. EGCG hybridized with these nanocarriers is capable of achieving advanced functions such as targeted release, active targeting, and enhanced penetration, ultimately increasing the bioavailability of EGCG. In addition, this review also summarizes the challenges for the use of EGCG in therapeutic applications, and suggests future directions for progress.

Single Local Injection of Epigallocatechin Gallate-Modified Gelatin Attenuates Bone Resorption and Orthodontic Tooth Movement in Mice

Osteoclastic bone resorption enables orthodontic tooth movement (OTM) in orthodontic treatment. Previously, we demonstrated that local epigallocatechin gallate (EGCG) injection successfully slowed the rate of OTM; however, repeat injections were required. In the present study, we produced a liquid form of EGCG-modified gelatin (EGCG-GL) and examined the properties of EGCG-GL with respect to prolonging EGCG release, NF-E2-related factor 2 (Nrf2) activation, osteoclastogenesis inhibition, bone destruction, and OTM. We found EGCG-GL both prolonged the release of EGCG and induced the expression of antioxidant enzyme genes, such as heme oxygenase 1 (Hmox1) and glutamate-cysteine ligase (Gclc), in the mouse macrophage cell line, RAW264.7. EGCG-GL attenuated intracellular reactive oxygen species (ROS) levels were induced by the receptor activator of nuclear factor-kB ligand (RANKL) and inhibited RANKL-mediated osteoclastogenesis in vitro. An animal model of bone destruction, induced by repeat Lipopolysaccharide (LPS)-injections into the calvaria of male BALB/c mice, revealed that a single injection of EGCG-GL on day-1 could successfully inhibit LPS-mediated bone destruction. Additionally, experimental OTM of maxillary first molars in male mice was attenuated by a single EGCG-GL injection on day-1. In conclusion, EGCG-GL prolongs the release of EGCG and inhibits osteoclastogenesis via the attenuation of intracellular ROS signaling through the increased expression of antioxidant enzymes. These results indicate EGCG-GL would be a beneficial therapeutic approach both in destructive bone disease and in controlling alveolar bone metabolism.

Fabrication and hemocompatibility assessment of novel polyurethane-based bio-nanofibrous dressing loaded with honey and Carica papaya extract for the management of burn injuries

Management of burn injury is an onerous clinical task since it requires continuous monitoring and extensive usage of specialized facilities. Despite rapid improvizations and investments in burn management, >30% of victims hospitalized each year face severe morbidity and mortality. Excessive loss of body fluids, accumulation of exudate, and the development of septic shock are reported to be the main reasons for morbidity in burn victims. To assist burn wound management, a novel polyurethane (PU)-based bio-nanofibrous dressing loaded with honey (HN) and Carica papaya (PA) fruit extract was fabricated using a one-step electrospinning technique. The developed dressing material had a mean fiber diameter of 190±19.93 nm with pore sizes of 4–50 µm to support effective infiltration of nutrients and gas exchange. The successful blending of HN- and PA-based active biomolecules in PU was inferred through changes in surface chemistry. The blend subsequently increased the wettability (14%) and surface energy (24%) of the novel dressing. Ultimately, the presence of hydrophilic biomolecules and high porosity enhanced the water absorption ability of the PU-HN-PA nanofiber samples to 761.67% from 285.13% in PU. Furthermore, the ability of the bio-nanofibrous dressing to support specific protein adsorption (45%), delay thrombus formation, and reduce hemolysis demonstrated its nontoxic and compatible nature with the host tissues. In summary, the excellent physicochemical and hemocompatible properties of the developed PU-HN-PA dressing exhibit its potential in reducing the clinical complications associated with the treatment of burn injuries.

Characterization of nanostructured ureteral stent with gradient degradation in a porcine model

A tubular poly(ε-caprolactone) (PCL)/poly(lactide-co-glycolide) (PLGA) ureteral stent composed of nanofibers with micropores was fabricated by double-needle electrospinning. The stent was ureteroscopically inserted into six Changbai pigs, and the commercial polyurethane Shagong^® stent was inserted into four pigs as control. Intravenous pyelography revealed that the PCL/PLGA stent gradually degraded from the distal end to proximal terminal, and all stents were completely degraded at 10 weeks post-insertion. No significant difference was observed in hydronephrosis severity between the two groups. The levels of serum creatinine and urine pH remained similar throughout the study in the two groups, but the number of white blood cells in the urine was significantly higher in the Shagong^® stent group. On Day 70, histological evaluation indicated equivalent histological severity scores in the middle and distal ureter sections and bladder in the two groups. However, the PCL/PLGA stent-implanted pigs had significantly lower mean severity scores in the kidney and proximal ureter sites. These data revealed that the PCL/PLGA stent degraded in a controlled manner, did not induce obstruction, and had a lower urothelial impact in comparison to the Shagong^® stent, indicating that the stent exhibited great potential for clinical application.

Stimulated myoblast differentiation on graphene oxide-impregnated PLGA-collagen hybrid fibre matrices

Background

Electrospinning is a simple and effective method for fabricating micro- and nanofiber matrices. Electrospun fibre matrices have numerous advantages for use as tissue engineering scaffolds, such as high surface area-to-volume ratio, mass production capability and structural similarity to the natural extracellular matrix (ECM). Therefore, electrospun matrices, which are composed of biocompatible polymers and various biomaterials, have been developed as biomimetic scaffolds for the tissue engineering applications. In particular, graphene oxide (GO) has recently been considered as a novel biomaterial for skeletal muscle regeneration because it can promote the growth and differentiation of myoblasts. Therefore, the aim of the present study was to fabricate the hybrid fibre matrices that stimulate myoblasts differentiation for skeletal muscle regeneration.

Results

Hybrid fibre matrices composed of poly(lactic-co-glycolic acid, PLGA) and collagen (Col) impregnated with GO (GO-PLGA-Col) were successfully fabricated using an electrospinning process. Our results indicated that the GO-PLGA-Col hybrid matrices were comprised of randomly-oriented continuous fibres with a three-dimensional non-woven porous structure. Compositional analysis showed that GO was dispersed uniformly throughout the GO-PLGA-Col matrices. In addition, the hydrophilicity of the fabricated matrices was significantly increased by blending with a small amount of Col and GO. The attachment and proliferation of the C2C12 skeletal myoblasts were significantly enhanced on the GO-PLGA-Col hybrid matrices. Furthermore, the GO-PLGA-Col matrices stimulated the myogenic differentiation of C2C12 skeletal myoblasts, which was enhanced further under the culture conditions of the differentiation media.

Conclusions

Taking our findings into consideration, it is suggested that the GO-PLGA-Col hybrid fibre matrices can be exploited as potential biomimetic scaffolds for skeletal tissue engineering and regeneration because these GO-impregnated hybrid matrices have potent effects on the induction of spontaneous myogenesis and exhibit superior bioactivity and biocompatibility.