This study presents a dual-layer artificial dura mater, a hierarchically structured fibrous membrane composed of poly(p-dioxanone) (PPDO) and bioactive glass (BG), fabricated using electrospinning and melt-casting techniques. Designed to address the challenges of dura mater repair, the membrane features a dense outer PPDO layer for mechanical resilience and an electrospun inner layer embedded with BG to enable controlled ion release, promoting tissue regeneration and angiogenesis. We evaluated the fibrous membrane's surface morphology, mechanical properties, hydrophilicity, and in vitro degradation, demonstrating that increasing BG content enhances hydrophilicity, reduces crystallinity, and modulates degradation kinetics. In vitro assays using L929 fibroblasts and human umbilical vein endothelial cells reveal that the PPDO/BG membrane not only supports cell adhesion and proliferation but also fosters a pro-angiogenic environment through the controlled release of bioactive silicon ions. In vivo implantation in a rat dura mater defect model further validates its therapeutic potential, showing reduced adhesion, improved tissue integration, and enhanced vascularization, with the PBD-3 variant exhibiting superior performance due to its optimized BG composition. The synergistic effects of bioactive ion release, mechanical stability, and biocompatibility establish the PPDO/BG membrane as a highly promising dura mater substitute, offering a bioengineered solution for neurosurgical applications aimed at functional tissue regeneration.

Effective wound healing requires precise immune regulation, including infection clearance to prevent excessive immune cell activation and polarization of macrophages. Therapeutic systems with combined immunomodulatory effects are crucial. Photodynamic therapy (PDT) is a promising antimicrobial treatment(AIE), with photosensitizers (PSs) playing a central role. The PSs with aggregation-induced emission can efficiently generate reactive oxygen species (ROS) in the aggregated state, making them workable in high concentration. Introduction of a biocompatible carrier is beneficial for the PSs' immobilization and distribution and hydrogels are excellent candidates. It is pursuing to design a PS-hydrogel system with synergetic effect. Type II PSs can generate singlet oxygen under sufficient oxygen. Macroporous hydrogels (MPHs) own superiorities in matter transport and immune cell adhesion reduction. Herein, an AIE-PS, TCSPy+ was designed. With its nanoparticles (NPs), an MPH dressing was developed using a facile extrusion-sequential-photo-crosslinking method based on PEGDA and GelMA. In vitro and in vivo studies demonstrated that TCSPy+@MPH dressing exhibited superior antibacterial activity compared to non-porous hydrogel-based one, significantly inhibiting excessive immune cell activation and polarization of macrophages. The macroporous structure also facilitated inflammatory exudates removal. The synergetic effect with the combined immunomodulation ability allows the dressing to efficiently treat infected wounds, offering an effective strategy to design advanced therapeutic systems for tissue regeneration and immune regulation.

Dural injuries often result in severe complications such as cerebrospinal fluid (CSF) leakage, intracranial infections, and brain herniation, which significantly impact patient recovery and quality of life. Conventional dural repair materials, which rely on suturing to peripheral tissues, fail to promote tissue regeneration and provide sufficient CSF leakage prevention, leading to suboptimal outcomes. To address these limitations, we developed a Janus adhesive bio-patch with both antibacterial and pro-angiogenic properties to enhance dura mater repair. This bio-patch consisted of a polyacrylic acid (PAA) adhesive gel layer loaded with vancomycin and magnesium carbonate (MgCO3), integrated onto a small intestinal submucosa (SIS) extracellular matrix. It exhibited a burst strength of 20.50±2.89kPa, effectively sealing CSF leaks, while demonstrating excellent antibacterial efficacy (∼99%) and significant enhanced angiogenesis (3.47-fold higher than the control). In rat, rabbit, and dog dural injury models, the bio-patch adhered seamlessly to the injury site, successfully preventing leaks and promoting tissue regeneration. These results highlighted the Janus adhesive bio-patch as a promising solution for improving dural repair in neurosurgery, offering a safer and more effective alternative to conventional suturing techniques.

The dura mater, the furthest and strongest layer of the meninges, is crucial for protecting the brain and spinal cord. Its biomechanical behavior is vital, as any alterations can compromise biological functions. In recent decades, interest in the dura mater has increased due to the need for hermetic closure of dural defects prompting the development of several substitutes. Collagen-based dural substitutes are common commercial options, but they lack the complex biological and structural elements of the native dura mater, impacting regeneration and potentially causing complications like wound/postoperative infection and cerebrospinal fluid (CSF) leakage. To face this issue, recent tissue engineering approaches focus on creating biomimetic dura mater substitutes. The objective of this review is to discuss whether mimicking the mechanical properties of native tissue or ensuring high biocompatibility and bioactivity is more critical in developing effective dural substitutes, or if both aspects should be systematically linked. After a brief description of the properties and architecture of the native cranial dura, we describe the advantages and limitations of biomimetic dura mater substitutes to better understand their relevance. In particular, we consider biomechanical properties' impact on dura repair's effectiveness. Finally, the obstacles and perspectives for developing the ideal dural substitute are explored.

This study examines cranial dura mater's structural and mechanical heterogeneity, focusing on the distinct properties between the sulcus and gyrus regions. Microscale analyses using two-photon microscopy and atomic force microscopy (AFM) revealed significant regional differences in thickness (p < 0.05), with sulcus dura being 1.34 times thicker than gyrus dura. Differences in effective Young's modulus were observed, with values of 6.75 ± 5.12 kPa in the sulcus and 10.48 ± 7.13 kPa in the gyrus. These findings highlight the dura mater's pronounced variability in stiffness and anisotropy, with the periosteal layer being substantially stiffer than the meningeal layer. These results underscore the critical role of collagenous architecture in determining dura's mechanical behavior, particularly in the transfer of loads across the brain. This study provides valuable insights into the functional heterogeneity of the dura mater and emphasizes the importance of these variations in the design of biomimetic dural grafts. The quantitative data generated in this study has significant implications for enhancing the biofidelity of computational models used in brain biomechanics and advancing tissue engineering strategies to develop dural substitutes. STATEMENT OF SIGNIFICANCE: This study presents a comprehensive analysis of the structural and mechanical heterogeneity of cranial dura mater at the nanoscale, focusing on the differences between sulcus and gyrus regions. By employing advanced techniques such as atomic force microscopy (AFM) and two photon microscopies, the findings are crucial for understanding the dura's protective functions and its role in load transfer across the brain. The implications of this study are significant for the development of biomimetic dural grafts, as it offers detailed quantitative data necessary for designing grafts that closely mimic the native dura's structural and mechanical. Additionally, this research could help develop more accurate finite element models (FEM) to study traumatic brain injuries (TBI) and brain dynamics.

During transsphenoidal surgery to remove pituitary adenomas, the structures of the skull base consisting of the dura mater and skull base bones are destroyed, making it crucial to restore the natural structure of the skull base. We crafted a dual-layer Janus fiber membrane utilizing the layer-by-layer electrospinning technique, comprising an osteoblast layer and a leak-proof antimicrobial layer. Specifically, RPG-1%PCPP radially aligned nanofibrous membranes (osteoblasts) can promote directional cell migration and facilitate cellular osteogenic differentiation. TPC nanofibrous membranes (leak-proof antimicrobial layer) can prevent fluid leakage while releasing antimicrobials for resisting bacterial infections. Bacteriostatic tests showed that cefazolin had a good inhibitory ability against both E. coli and S. aureus. RT-PCR showed that radial fiber membrane loaded with PCPP promoted the expression of ALP and BMP-2 genes, thereby promoting osteogenic differentiation of cells. Animal experiments showed that the BV/TV in the TPC/RPG-1%PCPP fiber membrane group was significantly higher than that in the blank group, indicating that TPC/RPG-1%PCPP could promote bone tissue regeneration.

Infection after craniocerebral operation has always been a very focused problem, and dural closure can reduce perioperative infection by reducing drainage volume and subcutaneous effusion, so how to effectively perform dural closure seems to be a small but not negligible problem.

We proposed a classification and grading system for dural incisions based on the type and degree of suture, and based on the system, a standardized operation process for ADS (absorbable dural sealant) was developed. Then, we conducted a retrospective study. We divided the included patients into 3 groups. Normalized group follows the ADS standard use process proposed by us, while Empirical group does not meet or only partially meets the ADS standard use process, or uses ADS based on its own experience, and Non-sealant group were patients who did not use ADS. And perioperative infection was used as the primary assessment metric to verify the effectiveness of ADS in blocking the dural membrane, and to try to propose a standardized use plan.

A retrospective collection of 383 patients' clinical data was conducted between October 2019 and April 2023 in the Department of Neurosurgery of Qilu Hospital of Shandong University. Of them, 128 belonged to the non-sealant group, 126 to the normalized group, and 129 to the empirical group. In our study, we discovered that, in comparison to the normalized group, postoperative cerebral infection rose by 17.2 % (OR = 2.437, P = 0.004) and 21.9 % (OR = 3.227, P < 0.001), respectively, in the empirical group and non-sealant group. In comparison to the normalized group, the empirical group and non-sealant group experienced a 13.2 % (OR = 1.882, P = 0.037) and 24.8 % (OR = 3.346, P < 0.001) increase in subcutaneous effusion development, respectively. Furthermore, when compared to the normalized group, the empirical group's (β = 48.556, P = 0.003) and non-sealant group's (β = 91.960, P < 0.001) subcutaneous or epidural drainage volume was significantly higher.

Correct and standardized use of ADS can improve the watertight suturing of the dura mater and reduce the incidence of postoperative complications such as infection, and is of great significance for perioperative management of neurosurgery.

Cerebrospinal fluid (CSF) leakage caused by accidents or diseases resulting from traumatic brain injury, inflammation, tumor erosion and surgery can lead to many complications. In this study, a multifunctional composite double-layer hydrogel was designed by simulating the structure of native dura mater, which was composed of polyacrylic acid (PAA), polyethyleneimine (PEI), sodium alginate (SA), β-cyclodextrin (β-CD) and edaravone (Ed). The PAA/PEI layer had strong wet adhesion characteristics, while the PEI/SA@β-CD/Ed layer exhibited significant antioxidant, drug release and biocompatibility properties. By controlling the concentration of Ca2+, the gelation time can be adjusted rapidly within 95-215 s. Specifically, the final PAA/PEI/SA@β-CD/Ed composite hydrogel exhibited a porous network structure with high porosity and low swelling rate, improved tensile strength, sufficient biodegradability, favourable adhesion performance, enhanced DPPH and ABTS radicals scavenging abilities, and sustained Ed release capacity. In addition, the resulting hydrogel also showed excellent biocompatibility and protective effect on H2O2-induced oxidative damage in SH-SY5Y cells. These results preliminarily suggested that the PAA/PEI/SA@β-CD/Ed composite hydrogel would appear to be a promising candidate for dural repair.

The dura trauma or large defects due to neurosurgical procedures can result in potential complications. Dural replacements have proven effective to reduce the risk of seizures, meningitis, cerebrospinal fluid leakage, cerebral herniation, and infection. Although various artificial dural patches have been developed, addressing iatrogenic infections and cerebral adhesions resulting from patches implantation remains a challenge. This study employed a network interpenetration modification strategy to introduce super-hydrophilic and super-lubricity zwitterionic hydrogel coatings on polyurethane Neuro-Patch® (NP®) dura mater patch. The successful modification with the hydrogel coating preserved the intrinsic properties of the NP®, such as their anti-leakage and tensile strength capabilities, while effectively reducing biofouling on the surface of the patches. Additionally, by constructing subdural implantation for each dura mater substitute in rabbits, we observed that artificial dura mater patches modified with the hydrogel coating effectively reduced the incidence of postoperative cerebral adhesions and infections. This suggests a promising application prospect of the hydrogel coating in dural repair. STATEMENT OF SIGNIFICANCE: The development of dural substitutes with anti-leakage, anti-adhesion and anti-infection functions is the key to the treatment of dural defects and cerebrospinal fluid leakage during trauma or neurosurgery. In this study, the amphoteric ionic hydrogel coating was firmly modified on the surface of polyurethane with a mild modification process to give the patch super-hydrophilic and super-lubricating properties. The adhesion of non-specific proteins and bacteria is effectively reduced. The rabbit dural defect repair model showed that the introduction of zwitterionic hydrogel coating effectively reduced the occurrence of postoperative infection, and no tissue adhesion was observed. Taken together, this study offers a promising way to enhance the performance of artificial dural patches, potentially benefiting patients undergoing neurosurgery.

Postoperative adhesions commonly form in various tissues, resulting in serious implications and an increased risk of secondary surgery. The application of anti-adhesion films as physical barriers has proven effective in reducing adhesion incidence and severity. However, existing anti-adhesion films require manual deployment during minimally invasive surgery, posing inconvenience and possibility of further injury. To address these limitations, we have developed an intelligent anti-adhesion film based on shape memory polyurethane. In this work, a linear shape memory polyurethane (ISO2-PU), incorporating hexamethylene isocyanate and isosorbitol as hard segments and poly(D, L-lactic acid) macrodiol as soft segments, was fabricated into an anti-adhesion film. The favorable shape memory effect of the ISO2-PU film ensures its convenient delivery and automatic unfolding, as revealed by a simulation experiment for endoscopic surgical implantation. Furthermore, the glass transition temperature (Tg) close to body temperature endows the ISO2-PU film with good mechanical compliance, thus ensuring a reliable fit with the wounded tissue to avoid undesired folding. Finally, in vivo experiments using a rat cecal abdominal wall injury model demonstrated that the combination of reliable fit, appropriate degradation rate, and good cytocompatibility promises the ISO2-PU film with high anti-adhesion efficacy. This work validates the concept of shape memory anti-adhesion barrier and expands future directions for advanced anti-adhesion biomaterials. STATEMENT OF SIGNIFICANCE: Postoperative adhesions are a common complication that occurs widely after various surgeries. This work developed an intelligent anti-adhesion film based on a linear shape memory polyurethane (ISO2-PU). This film is featured with remarkable shape memory effect and mechanical compliance at body temperature, appropriate degradability, and good cytocompatibility. These merits ensure convenient delivery and smart unfolding of ISO2-PU film during minimally invasive surgery and favorable postoperative anti-adhesion efficacy. The results validate the concept of shape memory anti-adhesion barrier and paves a way for designing next-generation anti-adhesion biomaterials.

Traumatic brain injury is a serious medical condition that can be attributed to falls, motor vehicle accidents, sports injuries and acts of violence, causing a series of neural injuries and neuropsychiatric symptoms. However, limited accessibility to the injury sites, complicated histological and anatomical structure, intricate cellular and extracellular milieu, lack of regenerative capacity in the native cells, vast variety of damage routes, and the insufficient time available for treatment have restricted the widespread application of several therapeutic methods in cases of central nervous system injury. Tissue engineering and regenerative medicine have emerged as innovative approaches in the field of nerve regeneration. By combining biomaterials, stem cells, and growth factors, these approaches have provided a platform for developing effective treatments for neural injuries, which can offer the potential to restore neural function, improve patient outcomes, and reduce the need for drugs and invasive surgical procedures. Biomaterials have shown advantages in promoting neural development, inhibiting glial scar formation, and providing a suitable biomimetic neural microenvironment, which makes their application promising in the field of neural regeneration. For instance, bioactive scaffolds loaded with stem cells can provide a biocompatible and biodegradable milieu. Furthermore, stem cells-derived exosomes combine the advantages of stem cells, avoid the risk of immune rejection, cooperate with biomaterials to enhance their biological functions, and exert stable functions, thereby inducing angiogenesis and neural regeneration in patients with traumatic brain injury and promoting the recovery of brain function. Unfortunately, biomaterials have shown positive effects in the laboratory, but when similar materials are used in clinical studies of human central nervous system regeneration, their efficacy is unsatisfactory. Here, we review the characteristics and properties of various bioactive materials, followed by the introduction of applications based on biochemistry and cell molecules, and discuss the emerging role of biomaterials in promoting neural regeneration. Further, we summarize the adaptive biomaterials infused with exosomes produced from stem cells and stem cells themselves for the treatment of traumatic brain injury. Finally, we present the main limitations of biomaterials for the treatment of traumatic brain injury and offer insights into their future potential.

Typically occurring after trauma or neurosurgery treatments, dura mater defect and the ensuing cerebrospinal fluid (CSF) leakage could lead to a number of serious complications and even patient's death. Although numerous natural and synthetic dura mater substitutes have been reported, none of them have been able to fulfill the essential properties, such as anti-adhesion, leakage blockage, and pro-dura rebuilding. In this study, we devised and prepared a series of robust and biodegradable hydroxyapatite/poly(lactide-co-ε-caprolactone) (nHA/PLCL) membranes for dura repair via an electrospinning technique. In particular, PLLA/PCL (80/20) was selected for electrospinning due to its mechanical properties that most closely resembled natural dural tissue. Studies by SEM, XRD, water contact angle and in vitro degradation showed that the introduction of nHA would destroy PLCL's crystalline structure, which would further affect the mechanical properties of the nHA/PLCL membranes. When the amount of nHA added increased, so did the wettability and in vitro degradation rate, which accelerated the release of nHA. In addition, the high biocompatibility of nHA/PLCL membranes was demonstrated by in vitro cytotoxicity data. The in vivo rabbit dura repair model results showed that nHA/PLCL membranes provided a strong physical barrier to stop tissue adhesion at dura defects. Meanwhile, the nHA/PLCL and commercial group's CSF had a significantly lower number of inflammatory cells than the control groups, validating the nHA/PLCL's ability to effectively lower the risk of intracranial infection. Findings from H&E and Masson-trichrome staining verified that the nHA/PLCL electrospun membrane was more favorable for fostering dural defect repair and skull regeneration. Moreover, the relative molecular weight of PLCL declined dramatically after 3 months of implantation, according to the results of the in vivo degradation test, but it retained the fiber network structure and promoted tissue growth, demonstrating the good stability of the nHA/PLCL membranes. Collectively, the nHA/PLCL electrospun membrane presents itself as a viable option for dura repair.

Repair of bone defects exceeding a critical size has been always a big challenge in clinical practice. Tissue engineering has exhibited great potential to effectively repair the defects with less adverse effect than traditional bone grafts, during which how to induce vascularized bone formation has been recognized as a critical issue. Therefore, recently many studies have been launched to attempt to promote osteogenesis-angiogenesis coupling. This review summarized comprehensively and explored in depth current efforts to ameliorate the coupling of osteogenesis and angiogenesis from four aspects, namely the optimization of scaffold components, modification of scaffold structures, loading strategies for bioactive substances, and employment tricks for appropriate cells. Especially, the advantages and the possible reasons for every strategy, as well as the challenges, were elaborated. Furthermore, some promising research directions were proposed based on an in-depth analysis of the current research. This paper will hopefully spark new ideas and approaches for more efficiently boosting new vascularized bone formations.

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.

The dura mater, as the crucial outermost protective layer of the meninges, plays a vital role in safeguarding the underlying brain tissue. Neurosurgeons face significant challenges in dealing with trauma or large defects in the dura mater, as they must address the potential complications, such as wound infections, pseudomeningocele formation, cerebrospinal fluid leakage, and cerebral herniation. Therefore, the development of dural substitutes for repairing or reconstructing the damaged dura mater holds clinical significance. In this review we highlight the progress in the development of dural substitutes, encompassing autologous, allogeneic, and xenogeneic replacements, as well as the polymeric-based dural substitutes fabricated through various scaffolding techniques. In particular, we explore the development of composite materials that exhibit improved physical and biological properties for advanced dural substitutes. Furthermore, we address the challenges and prospects associated with developing clinically relevant alternatives to the dura mater.

The dura mater is the final barrier against cerebrospinal fluid leakage and plays a crucial role in protecting and supporting the brain and spinal cord. Head trauma, tumor resection and other traumas damage it, requiring artificial dura mater for repair.  However, surgical tears are often unavoidable. To address these issues, the ideal artificial dura mater should have biocompatibility, anti-leakage, and self-healing properties. Herein, this work has used biocompatible polycaprolactone diol as the soft segment and introduced dynamic disulfide bonds into the hard segment, achieving a multifunctional polyurethane (LSPU-2), which integrated the above mentioned properties required in surgery. In particular, LSPU-2 matches the mechanical properties of the dura mater and the biocompatibility tests with neuronal cells demonstrate extremely low cytotoxicity and do not cause any negative skin lesions. In addition, the anti-leakage properties of the LSPU-2 are confirmed by the water permeability tester and the 900 mm H2 O static pressure test with artificial cerebrospinal fluid. Due to the disulfide bond exchange and molecular chain mobility, LSPU-2 could be completely self-healed within 115 min at human body temperature. Thus, LSPU-2 comprises one of the most promising potential artificial dura materials, which is essential for the advancement of artificial dura mater and brain surgery.

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

Postoperative adhesion (POA) widely occurs in soft tissues and usually leads to chronic pain, dysfunction of adjacent organs and some acute complications, seriously reducing patients' quality of life and even being life-threatening. Except for adhesiolysis, there are few effective methods to release existing adhesion. However, it requires a second operation and inpatient care and usually triggers recurrent adhesion in a great incidence. Hence, preventing POA formation has been regarded as the most effective clinical strategy. Biomaterials have attracted great attention in preventing POA because they can act as both barriers and drug carriers. Nevertheless, even though much reported research has been demonstrated their efficacy on POA inhibition to a certain extent, thoroughly preventing POA formation is still challenging. Meanwhile, most biomaterials for POA prevention were designed based on limited experiences, not a solid theoretical basis, showing blindness. Hence, we aimed to provide guidance for designing anti-adhesion materials applied in different soft tissues based on the mechanisms of POA occurrence and development. We first classified the postoperative adhesions into four categories according to the different components of diverse adhesion tissues, and named them as "membranous adhesion", "vascular adhesion", "adhesive adhesion" and "scarred adhesion", respectively. Then, the process of the occurrence and development of POA were analyzed, and the main influencing factors in different stages were clarified. Further, we proposed seven strategies for POA prevention by using biomaterials according to these influencing factors. Meanwhile, the relevant practices were summarized according to the corresponding strategies and the future perspectives were analyzed.

Dural defects are common in spinal and cranial neurosurgery. A series of complications, such as cerebrospinal fluid leakage, occur after rupture of the dura. Therefore, treatment strategies are necessary to reduce or avoid complications. This review comprehensively summarizes the common causes, risk factors, clinical complications, and repair methods of dural defects. The latest research progress on dural repair methods and materials is summarized, including direct sutures, grafts, biomaterials, non-biomaterial materials, and composites formed by different materials. The characteristics and efficacy of these dural substitutes are reviewed, and these materials and methods are systematically evaluated. Finally, the best methods for dural repair and the challenges and future prospects of new dural repair materials are discussed.

Dural defects are a common problem in neurosurgical procedures and should be repaired to avoid complications such as cerebrospinal fluid leakage, brain swelling, epilepsy, intracranial infection, and so on. Various types of dural substitutes have been prepared and used for the treatment of dural defects. In recent years, electrospun nanofibers have been applied for various biomedical applications, including dural regeneration, due to their interesting properties such as a large surface area to volume ratio, porosity, superior mechanical properties, ease of surface modification, and, most importantly, similarity with the extracellular matrix (ECM). Despite continuous efforts, the development of suitable dura mater substrates has had limited success. This review summarizes the investigation and development of electrospun nanofibers with particular emphasis on dura mater regeneration. The objective of this mini-review article is to give readers a quick overview of the recent advances in electrospinning for dura mater repair.

The osteochondral defect repair has been most extensively studied due to the rising demand for new therapies to diseases such as osteoarthritis. Tissue engineering has been proposed as a promising strategy to meet the demand of simultaneous regeneration of both cartilage and subchondral bone by constructing integrated gradient tissue-engineered osteochondral scaffold (IGTEOS). This review brought forward the main challenges of establishing a satisfactory IGTEOS from the perspectives of the complexity of physiology and microenvironment of osteochondral tissue, and the limitations of obtaining the desired and required scaffold. Then, we comprehensively discussed and summarized the current tissue-engineered efforts to resolve the above challenges, including architecture strategies, fabrication techniques and in vitro/in vivo evaluation methods of the IGTEOS. Especially, we highlighted the advantages and limitations of various fabrication techniques of IGTEOS, and common cases of IGTEOS application. Finally, based on the above challenges and current research progress, we analyzed in details the future perspectives of tissue-engineered osteochondral construct, so as to achieve the perfect reconstruction of the cartilaginous and osseous layers of osteochondral tissue simultaneously. This comprehensive and instructive review could provide deep insights into our current understanding of IGTEOS.

Nano-hydroxyapatite (n-HAp) is similar to human bone mineral in structure and biochemistry and is, therefore, widely used as bone biomaterial and a drug carrier. Further, n-HAp composite scaffolds have a great potential role in bone regeneration. Loading bioactive factors and drugs onto n-HAp composites has emerged as a promising strategy for bone defect repair in bone tissue engineering. With local delivery of bioactive agents and drugs, biological materials may be provided with the biological activity they lack to improve bone regeneration. This review summarizes classification of n-HAp composites, application of n-HAp composite scaffolds loaded with bioactive factors and drugs in bone tissue engineering and the drug loading methods of n-HAp composite scaffolds, and the research direction of n-HAp composite scaffolds in the future is prospected.