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H&E staining of nerve tissue in the three groups at each time point (x400). (A-D) The PCL-amnion group. (E-H) The chitosan group. (I-L) The control group. Scale bar = 50 μm. https://doi.org/10.1371/journal.pone.0244301.g004
Source publication
Adhesion and scarring after neural surgery are detrimental to nerve regeneration and functional recovery. Amniotic membranes have been used in tissue repair due to their immunogenicity and richness in cytokines. In this study, an electrospun polycaprolactone (PCL)-amnion nanofibrous membrane was prepared for the treatment of sciatic nerve compressi...
Contexts in source publication
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... large amount of inflammatory cells infiltration around the nerve fibers. In the PCL-amnion group, inflammatory cells were confined to the superficial layer of the epineurium (Fig 4A). In the chitosan group ( and control group (Fig 4I), more inflammatory cells and scattered multinucleated giant cells were observed. ...
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... the PCL-amnion group, inflammatory cells were confined to the superficial layer of the epineurium (Fig 4A). In the chitosan group ( and control group (Fig 4I), more inflammatory cells and scattered multinucleated giant cells were observed. TEM images showed that there was axonal sprouting around the compressed section in the PCL-amnion group and chitosan group, which was surrounded by perineurial cells with a few mitochondria, microfilaments, microtubules, and vesicles ( Fig 5A and 5E). ...
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... the 4th week, the inflammatory reaction and myelin sheath swelling were alleviated in all rats. Compared with the control group ( Fig 4J), there were fewer inflammatory cells in the PCL-amnion group ( Fig 4B) and chitosan group (Fig 4F). In the PCL-amnion group (Fig 5B), the myelin sheath was thicker than that of the chitosan group ( Fig 5F) and regular regenerated axons with organelles were observed. ...
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... the 4th week, the inflammatory reaction and myelin sheath swelling were alleviated in all rats. Compared with the control group ( Fig 4J), there were fewer inflammatory cells in the PCL-amnion group ( Fig 4B) and chitosan group (Fig 4F). In the PCL-amnion group (Fig 5B), the myelin sheath was thicker than that of the chitosan group ( Fig 5F) and regular regenerated axons with organelles were observed. ...
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... the 4th week, the inflammatory reaction and myelin sheath swelling were alleviated in all rats. Compared with the control group ( Fig 4J), there were fewer inflammatory cells in the PCL-amnion group ( Fig 4B) and chitosan group (Fig 4F). In the PCL-amnion group (Fig 5B), the myelin sheath was thicker than that of the chitosan group ( Fig 5F) and regular regenerated axons with organelles were observed. ...
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... the 8th week, demyelination was significantly alleviated in all groups. There were more regenerated nerve fibers with thin myelin in the PCL-amnion group ( Fig 4C) and chitosan group ( Fig 4G) compared with the control group ( Fig 4K). TEM images presented significant myelinated fibers regeneration in the PCL-amnion group ( Fig 5C) and chitosan group (Fig 5G). ...
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... the 8th week, demyelination was significantly alleviated in all groups. There were more regenerated nerve fibers with thin myelin in the PCL-amnion group ( Fig 4C) and chitosan group ( Fig 4G) compared with the control group ( Fig 4K). TEM images presented significant myelinated fibers regeneration in the PCL-amnion group ( Fig 5C) and chitosan group (Fig 5G). ...
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... the 8th week, demyelination was significantly alleviated in all groups. There were more regenerated nerve fibers with thin myelin in the PCL-amnion group ( Fig 4C) and chitosan group ( Fig 4G) compared with the control group ( Fig 4K). TEM images presented significant myelinated fibers regeneration in the PCL-amnion group ( Fig 5C) and chitosan group (Fig 5G). ...
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... the control group, the diameter of axons became smaller and connective tissue hyperplasia was observed (Fig 5K). At the 12th week, there were abundant regenerated axons and thick myelin formed in the PCL-amnion group ( Fig 4D). As shown in the TEM image (Fig 5D), the nerve fibers were surrounded by intact myelin and Schwann cells with normal cellular structure. ...
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... small number of myelinated fibers were assembled into bundles. In the chitosan group ( Fig 4H) and control group (Fig 4L), the surface of the nerves was not as smooth as the PCL-amnion group. Moreover, although nerve fibers were orderly arranged, the diameter and myelin were thinner and the wrapped perineurium was less compact than that in the PCL-amnion group. ...
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... small number of myelinated fibers were assembled into bundles. In the chitosan group ( Fig 4H) and control group (Fig 4L), the surface of the nerves was not as smooth as the PCL-amnion group. Moreover, although nerve fibers were orderly arranged, the diameter and myelin were thinner and the wrapped perineurium was less compact than that in the PCL-amnion group. ...
Citations
... Depending on the tissue-specific applications, synthetic and/or natural polymer-based electrospun layers are used to cover the surface of the AM. In this present review, we highlight that, apart from four studies [74,[84][85][86], these composite membranes were all performed using decellularized or de-epithelialized AMs. Additionally, we emphasize that all the studies dedicated to these hybrid membranes focused on the AM and no composite membrane using amniochorionic membrane has been performed to date. ...
... Both synthetic and natural polymers were used as secondary materials to create electrospun multilayered composite AM (Table 1). The synthetic electrospun polymers were polycaprolactone (PCL) [74,84,86,88,89,[97][98][99], poly(lactic-co-glycolic acid) (PLGA) [90,91,97], poly(lactic acid) (PLA) [97], and poly-(Llactide-co-E-caprolactone) (PCLC) [85]. They were all biodegradable and biocompatible synthetic polymers. ...
... When mentioned, nanofibers were either electrospun on the basement membrane side of the de-epithelized or decellularized AM [95,96] or spread onto the stromal side of the AM [97]. Both sides of the AM were electrospun to construct the three-layer composite membrane [74,[84][85][86] (Figure 2). The synthetic electrospun polymers were polycaprolactone (PCL) [74,84,86,88,89,[97][98][99], poly(lactic-co-glycolic acid) (PLGA) [90,91,97], poly(lactic acid) (PLA) [97], and poly-(L-lactide-co-E-caprolactone) (PCLC) [85]. ...
The amniotic membrane (AM) is the innermost part of the fetal placenta, which surrounds and protects the fetus. Due to its structural components (stem cells, growth factors, and proteins), AMs display unique biological properties and are a widely available and cost-effective tissue. As a result, AMs have been used for a century as a natural biocompatible dressing for healing corneal and skin wounds. To further increase its properties and expand its applications, advanced hybrid materials based on AMs have recently been developed. One existing approach is to combine the AM with a secondary material to create composite membranes. This review highlights the increasing development of new multilayer composite-based AMs in recent years and focuses on the benefits of additive manufacturing technologies and electrospinning, the most commonly used strategy, in expanding their use for tissue engineering and clinical applications. The use of AMs and multilayer composite-based AMs in the context of nerve regeneration is particularly emphasized and other tissue engineering applications are also discussed. This review highlights that these electrospun multilayered composite membranes were mainly created using decellularized or de-epithelialized AMs, with both synthetic and natural polymers used as secondary materials. Finally, some suggestions are provided to further enhance the biological and mechanical properties of these composite membranes.
... Too, numerous studies on cross-linked scaffolds and the physico-chemical properties of the surface have shown reductions in the incidence of immunogenicity. Therefore, it is expected that after implantation in the body, no inflammatory or macrophage response would be produced; except for the scar caused in the surgical site [11,25,108,[110][111][112][113][114][115][116][117]. ...
Heart valve disorders (HVD) caused by medical complications like calcification, thrombosis and infective endocarditis are a reason for cardiac dysfunctionality. The main aim of the present study was to develop a 3D polymeric antibacterial heart valve to prevent endocarditis and infection at the surgical site, through heart valve tissue engineering (HVTE), as a novel approach for the treatment of HVD. In this regard, using a 3D printed designed mold, a scaffold of poly glycerol sebacate: polycaprolactone: gelatin (50:40:10) containing ciprofloxacin, a broad-spectrum antibacterial drug, was made using melt molding method (D1 scaffold). Then, a layer of PGS-gelatin was coated on the optimized scaffold using a dip coating and EDC-NHS cross-linking agent (D2 scaffold). Based on the results, the D1 presented a 21.17 ± 0.8° contact angle while in D2 it was 37.49 ± 1.3°. The calcification rate also showed a lower amount of calcium and phosphorus deposition on the cross-linked surface of D2 (6.12 ± 0.35 µg mg⁻¹) compared with D1 (14.2 ± 1.27 µg mg⁻¹). D2 also demonstrated a remarkable antibacterial activity which was effective against Gram-negative and Gram-positive bacteria. The in vitro release profile showed that D2 can release ciprofloxacin gradually and continuously for over 140 h. The D2 showed a non-thrombogenic interface based on blood compatibility testing. Cell study results assessed by the Alamar Blue, Calcein-AM, and Hoechst stain assay, revealed that the human cardiac fibroblasts grew well on D2 compared to D1. The results of the present study support the main idea of creating an antibacterial and biocompatible 3D biomimetic heart valve for HVTE.
Graphical Abstract
... Polycaprolactone (PCL) is a polymer prepared by the polymerization of e-caprolactone monomers, a reaction that is catalyzed through metal anion complexes. PCL shows favorable biocompatibility and biodegradability and has been utilized in synthetic skin materials, implanted bone screws, and intravascular stents [216] . PCL is a semi-crystalline linear aliphatic polyester with a low melting point (about 60 C) and a low T g (roughly 60 C), making it easy to manufacture; however, the low melting point limits the potential applications, and it is also hydrophobic [217] . ...
... 2 Adhesion mainly results from the excessive aggregation of fibrous tissue around the nerve, 3 which can cause neurodegenerative changes at the distal end of the nerve adhesion. [4][5][6] Clinically, external neurolysis is the standard operation for an established nerve adhesion; [7][8][9] to protect it against recurring adhesion, a muscle flap, adipofascial flap, or an autogenous vein is needed to cover or wrap the injured nerve. [10][11][12][13] Despite this, recurring adhesion remains a challenging issue in the clinical setting. ...
... 14 Therefore, some researchers have developed biological materials to prevent peripheral nerve adhesion. For instance, human amniotic fluid 15 or amniotic membrane, 16 acellular matrix films, 17 electrospun polycaprolactone (PCL)-amnion nanofibrous membranes, 5 absorbable nerve ducts, 18 and hydrogel 19 are some materials being developed. However, these materials are still at the experimental research stage due to the drawbacks of immunogenicity, infection risk, limitation of nerve slip, difficulty in obtaining methods, and different anti-adhesion abilities and therapeutic effects due to different target organs. ...
... However, these materials are still at the experimental research stage due to the drawbacks of immunogenicity, infection risk, limitation of nerve slip, difficulty in obtaining methods, and different anti-adhesion abilities and therapeutic effects due to different target organs. 5,[15][16][17][18][19] In the study, we propose a novel therapeutic strategy to prevent nerve adhesion, namely, overexpression of heat shock protein (HSP) 72 by a photothermal material stimulating the nerve and its surrounding tissue may attenuate peripheral nerve adhesion. Zhou et al have demonstrated in animal models of renal fibrosis that overexpressed HSP72 inhibits fibroblast proliferation and differentiation by blocking the signal transducer and activator of transcription (STAT3) signaling pathway. ...
Purpose
Peripheral nerve adhesion occurs following injury and surgery. Functional impairment leading by peripheral nerve adhesion remains challenging for surgeons. Local tissue overexpression of heat shock protein (HSP) 72 can reduce the occurrence of adhesion. This study aims to develop a photothermal material polydopamine nanoparticles@Hyaluronic acid methacryloyl hydrogel (PDA NPs@HAMA) and evaluate their efficacy for preventing peripheral nerve adhesion in a rat sciatic nerve adhesion model.
Materials and Methods
PDA NPs@HAMA was prepared and characterized. The safety of PDA NPs@HAMA was evaluated. Seventy-two rats were randomly assigned to one of the following four groups: the control group; the hyaluronic acid (HA) group; the polydopamine nanoparticles (PDA) group and the PDA NPs@HAMA group (n = 18 per group). Six weeks after surgery, the scar formation was evaluated by adhesion scores and biomechanical and histological examinations. Nerve function was assessed with electrophysiological examination, sensorimotor analysis and gastrocnemius muscle weight measurements.
Results
There were significant differences in the score on nerve adhesion between the groups (p < 0.001). Multiple comparisons indicated that the score was significantly lower in the PDA NPs@HAMA group (95% CI: 0.83, 1.42) compared with the control group (95% CI: 1.86, 2.64; p = 0.001). Motor nerve conduction velocity and muscle compound potential of the PDA NPs@HAMA group were higher than the control group’s. According to immunohistochemical analysis, the PDA NPs@HAMA group expressed more HSP72, less α-smooth muscle actin (α-SMA), and had fewer inflammatory reactions than the control group.
Conclusion
In this study, a new type of photo-cured material with a photothermic effect was designed and synthesized-PDA NPs@HAMA. The photothermic effect of PDA NPs@HAMA protected the nerve from adhesion to preserve the nerve function in the rat sciatic nerve adhesion model. This effectively prevented adhesion-related damage.
... In order to reduce adhesion and promote nerve repair following peripheral nerve injury surgery, we have invented a novel biomaterial named as PCL-amnion nanofibrous membrane. Our previous study demonstrated that electrospun PCL-amnion nanofibrous membranes obviously alleviate tissue adhesion following neural surgery and accelerate nerve regeneration in a rat model of sciatic nerve compression in order to determine whether this new type of biomaterial can exert beneficial effects in chronic nerve injury animal model (29). In the current study, we explore the effect of PCL-amnion nanofibrous membrane on nerve regeneration and scarring formation at the nerve repair for the recovery of nerve function in a rat sciatic nerve transection model in order to determine whether this new type of biomaterial can exert beneficial effects in acute nerve injury animal model. ...
... As the solution was ejected from the needle, charged PCL nanofibers traversed a distance of 15 cm and were deposited on the two surfaces of the freeze-dried amnions. The PCL-amnion nanofibrous membranes were dried overnight in a vacuum (29). The PCL-amnion nanofibrous membranes were sterilized by cobalt 60 irradiation before use (30). ...
Functional recovery after peripheral nerve injury repair is typically unsatisfactory. An anastomotically poor microenvironment and scarring at the repair site are important factors impeding nerve regeneration. In this study, an electrospun poly-e-caprolactone (PCL)-amnion nanofibrous membrane comprising an amnion membrane and nonwoven electrospun PCL was used to wrap the sciatic nerve repair site in the rat model of a sciatic nerve transection. The effect of the PCL-amnion nanofibrous membrane on improving nerve regeneration and preventing scarring at the repair site was evaluated by expression of the inflammatory cytokine, sciatic functional index (SFI), electrophysiology, and histological analyses. Four weeks after repair, the degree of nerve adhesion, collagen deposition, and intraneural macrophage invasion of the PCL-amnion nanofibrous membrane group were significantly decreased compared with those of the Control group. Moreover, the PCL-amnion nanofibrous membrane decreased the expression of pro-inflammatory cytokines such as interleukin(IL)-6, Tumor Necrosis Factor(TNF)-a and the number of pro-inflammatory M1 macrophages, and increased the expression of anti-inflammatory cytokine such as IL-10, IL-13 and anti-inflammatory M2 macrophages. At 16 weeks, the PCL-amnion nanofibrous membrane improved functional recovery, including promoting nerve Schwann cell proliferation, axon regeneration, and reducing the time of muscle denervation. In summary, the PCL-amnion nanofibrous membrane effectively improved nerve regeneration and prevent fibrosis after nerve repair, which has good clinical application prospect for tissue repair.
... Additionally, amnion tubes were manufactured to cover the gap and edges of the nerve with favorable functional in vivo results [187][188][189]. Recently, an electrospun polycaprolactone-amnion nanofibrous membrane showed satisfying results for the treatment of sciatic nerve compression in a rat model [190]. ...
An important component of tissue engineering (TE) is the supporting matrix upon which cells and tissues grow, also known as the scaffold. Scaffolds must easily integrate with host tissue and provide an excellent environment for cell growth and differentiation. Human amniotic membrane (hAM) is considered as a surgical waste without ethical issue, so it is a highly abundant, cost-effective, and readily available biomaterial. It has biocompatibility, low immunogenicity, adequate mechanical properties (permeability, stability, elasticity, flexibility, resorbability), and good cell adhesion. It exerts anti-inflammatory, antifibrotic, and antimutagenic properties and pain-relieving effects. It is also a source of growth factors, cytokines, and hAM cells with stem cell properties. This important source for scaffolding material has been widely studied and used in various areas of tissue repair: corneal repair, chronic wound treatment, genital reconstruction, tendon repair, microvascular reconstruction, nerve repair, and intraoral reconstruction. Depending on the targeted application, hAM has been used as a simple scaffold or seeded with various types of cells that are able to grow and differentiate. Thus, this natural biomaterial offers a wide range of applications in TE applications. Here, we review hAM properties as a biocompatible and degradable scaffold. Its use strategies (i.e., alone or combined with cells, cell seeding) and its degradation rate are also presented.
Polymeric materials have gained immense significance in the field of biomedicine. Among these materials, poly(ε-caprolactone) (PCL) stands out as a prominent biocompatible and biodegradable polyester. This polymer has become extremely attractive in various fields due to its versatile properties and potential application in regenerative medicine, tissue engineering, and drug delivery. The unique combination of the desirable properties of PCL such as non-toxicity, low melting point and glass transition temperature, mechanical strength, compatibility with other polymers and therapeutic agents, and ease of processability makes this synthetic polymer an ideal material for a wide range of applications. Due to its ability to facilitate cell attachment and proliferation, mechanical compatibility with biological tissues, and controlled release of therapeutic agents, PCL is utilized for the fabrication of implants, scaffolds, and drug delivery systems. Herein, we aimed to provide the current state-of-the-art regarding PCL-based formulations including nanoparticles, microparticles, nanofibers, micelles, and films, and their diverse biomedical applications in tissue engineering, wound healing, drug delivery, and regenerative medicine. Furthermore, we discuss the active ingredients, composition, investigation status, and route of administration of these formulations. This paper also delves into various methods of preparing PCL-based formulations, including conventional techniques such as electrospinning and solvent casting as well as emerging methods, namely 3D printing, self-assembly, and microfluidics approaches, shedding light on their advantages and limitations. Commercial biomedical applications are another area that is addressed. Overall, this paper provides valuable insights into the advancements and potential of this biodegradable polymer in the biomedical field.
Graphical abstract
Nervous system plays a dynamic role in communicating information from the brain to body parts through central and peripheral nerves. Significant destruction to the nerve system instigates loss of sensor and motor functions. The regeneration of such damaged nerve is essential for retaining its functionality. It requires the scaffold, which acts as an aqueduct between the distal and proximal ends during regeneration. The present review is mainly concerned with the design aspects of fabricating nerve guidance conduits (NGCs) for rectifying injured peripheral nerves using advanced materials and manufacturing methods. A detailed review is presented on the biological and structural properties of nerve conduits. The different design features of the NGCs are elaborated concerning biocompatibility, cell adhesion, and proliferation enhancement. The various biocompatible materials and additives used for fabricating nerve conduits are elaborately discussed. The application of machine learning is elaborated at different stages in developing the NGCs. In addition, challenges and futuristic aspects for improving scaffold properties in repairing and regenerating peripheral nerve injuries are explicated.
Peripheral nerve injury is a clinically common injury that causes sensory dysfunction and locomotor system degeneration, which seriously affects the quality of the patients’ daily life. Long gapped defects in large nerve are difficult to repair via surgery and limited donor source of autologous nerve greatly challenges the successful nerve repair by transplantation. Significantly, remarkable progress has been made in repairing the peripheral nerve injury using artificial nerve grafts and a variety of products for peripheral nerve repair have emerged been approved globally in recent years. The raw materials of these commercial products includes natural/synthetic polymers, extracellular matrix. Despite a lot of effort, the desirable functional recovery still remains great challenges in long gapped nerve defects. Thus this review discusses the recent development of tissue engineering products for peripheral nerve repair and the design of bionic grafts improving the local microenvironment for accelerating nerve regeneration against locomotor disorder, which may provide potential strategies for the repair of long gaps or thick nerve defects by multifunctional biomaterials.
