Electrospun polyamide-6/chitosan nanofibers reinforced nano-hydroxyapatite/polyamide-6 composite bilayered membranes for guided bone regeneration

Application of mesenchymal stem/stromal cells in periodontal regeneration: Opportunities and challenges

Guided tissue regeneration (GTR) has been widely used in the periodontal treatment of intrabony and furcation defects for nearly four decades. The treatment outcomes have shown effectiveness in reducing pocket depth, improving attachment gain and bone filling in periodontal tissue. Although applying GTR could reconstruct the periodontal tissue, the surgical indications are relatively narrow, and some complications and race ethic problems bring new challenges. Therefore, it is challenging to achieve a consensus concerning the clinical benefits of GTR. With the appearance of stem cell-based regenerative medicine, mesenchymal stem/stromal cells (MSCs) have been considered a promising cell resource for periodontal regeneration. In this review, we highlight preclinical and clinical periodontal regeneration using MSCs derived from distinct origins, including non-odontogenic and odontogenic tissues and induced pluripotent stem cells, and discuss the transplantation procedures, therapeutic mechanisms, and concerns to evaluate the effectiveness of MSCs.

Barrier Membrane with Janus Function and Structure for Guided Bone Regeneration

Guided bone regeneration (GBR) technology has been demonstrated to be an effective method for reconstructing bone defects. A membrane is used to cover the bone defect to stop soft tissue from growing into it. The biosurface design of the barrier membrane is key to the technology. In this work, an asymmetric functional gradient Janus membrane was designed to address the bidirectional environment of the bone and soft tissue during bone reconstruction. The Janus membrane was simply and efficiently prepared by the multilayer self-assembly technique, and it was divided into the polycaprolactone isolation layer (PCL layer, GBR-A) and the nanohydroxyapatite/polycaprolactone/polyethylene glycol osteogenic layer (HAn/PCL/PEG layer, GBR-B). The morphology, composition, roughness, hydrophilicity, biocompatibility, cell attachment, and osteogenic mineralization ability of the double surfaces of the Janus membrane were systematically evaluated. The GBR-A layer was smooth, dense, and hydrophobic, which could inhibit cell adhesion and resist soft tissue invasion. The GBR-B layer was rough, porous, hydrophilic, and bioactive, promoting cell adhesion, proliferation, matrix mineralization, and expression of alkaline phosphatase and RUNX2. In vitro and in vivo results showed that the membrane could bind tightly to bone, maintain long-term space stability, and significantly promote new bone formation. Moreover, the membrane could fix the bone filling material in the defect for a better healing effect. This work presents a straightforward and viable methodology for the fabrication of GBR membranes with Janus-based bioactive surfaces. This work may provide insights for the design of biomaterial surfaces and treatment of bone defects.

Chitosan-based biomaterials promote bone regeneration by regulating macrophage fate

The development of various osteogenic biomaterials has not only promoted the development of bone tissue engineering but also provided more possibilities for bone defect repair. However, most previous studies have focused on the interaction of biomaterials on endogenous or exogenous stem cells involved in the bone regeneration process while neglecting the effect of changes in the immune microenvironment of bone defect sites on bone regeneration after biomaterial implantation into the host. With the development of bone immunology, the role of various immune cells, especially macrophages, in bone regeneration has gradually attracted the attention of researchers. An increasing number of studies have begun to target macrophages to better promote bone regeneration by modulating the fate of macrophages in a spatiotemporally ordered manner to mimic the changes in the immune microenvironment of bone defect sites during the natural repair process of bone tissue. Chitosan is one of the most abundant natural polysaccharides in the world. In recent years, various chitosan-based biomaterials have been widely used in macrophage fate modulation and bone regeneration. In this review, we review the interaction between macrophages and scaffold materials, general information about chitosan, the modulation of macrophage fate by chitosan-based biomaterials, and their application in bone regeneration.

Tailoring Biomaterials Ameliorate Inflammatory Bone Loss

Inflammatory diseases, such as rheumatoid arthritis, periodontitis, chronic obstructive pulmonary disease, and celiac disease, disrupt the delicate balance between bone resorption and formation, leading to inflammatory bone loss. Conventional approaches to tackle this issue encompass pharmaceutical interventions and surgical procedures. Nevertheless, pharmaceutical interventions exhibit limited efficacy, while surgical treatments impose trauma and significant financial burden upon patients. Biomaterials show outstanding spatiotemporal controllability, possess a remarkable specific surface area, and demonstrate exceptional reactivity. In the present era, the advancement of emerging biomaterials has bestowed upon more efficacious solutions for combatting the detrimental consequences of inflammatory bone loss. In this review, the advances of biomaterials for ameliorating inflammatory bone loss are listed. Additionally, the advantages and disadvantages of various biomaterials-mediated strategies are summarized. Finally, the challenges and perspectives of biomaterials are analyzed. This review aims to provide new possibilities for developing more advanced biomaterials toward inflammatory bone loss.

Advances in guided bone regeneration membranes: a comprehensive review of materials and techniques

Guided tissue/bone regeneration (GTR/GBR) is a widely used technique in dentistry to facilitate the regeneration of damaged bone and tissue, which involves guiding materials that eventually degrade, allowing newly created tissue to take its place. This comprehensive review the evolution of biomaterials for guided bone regeneration that showcases a progressive shift from non-resorbable to highly biocompatible and bioactive materials, allowing for more effective and predictable bone regeneration. The evolution of biomaterials for guided bone regeneration GTR/GBR has marked a significant progression in regenerative dentistry and maxillofacial surgery. Biomaterials used in GBR have evolved over time to enhance biocompatibility, bioactivity, and efficacy in promoting bone growth and integration. This review also probes into several promising fabrication techniques like electrospinning and latest 3D printing fabrication techniques, which have shown potential in enhancing tissue and bone regeneration processes. Further, the challenges and future direction of GTR/GBR are explored and discussed.

Absorbable calcium and phosphorus bioactive membranes promote bone marrow mesenchymal stem cells osteogenic differentiation for bone regeneration

Large segmental bone defects are commonly operated with autologous bone grafting, which has limited bone sources and poses additional surgical risks. In this study, we fabricated poly(lactide-co-glycolic acid) (PLGA)/β-tricalcium phosphate (β-TCP) composite membranes by electrostatic spinning and further promoted osteogenesis by regulating the release of β-TCP in the hope of replacing autologous bone grafts in the clinical practice. The addition of β-TCP improved the mechanical strength of PLGA by 2.55 times. Moreover, β-TCP could accelerate the degradation of PLGA and neutralize the negative effects of acidification of the microenvironment caused by PLGA degradation. In vitro experiments revealed that PLGA/TCP10 membranes are biocompatible and the released β-TCP can modulate the activity of osteoblasts by enhancing the calcium ions concentration in the damaged area and regulating the pH of the local microenvironment. Simultaneously, an increase in β-TCP can moderate the lactate content of the local microenvironment, synergistically enhancing osteogenesis by promoting the tube-forming effect of human umbilical vein endothelial cells. Therefore, it is potential to utilize PLGA/TCP bioactive membranes to modulate the microenvironment at the site of bone defects to promote bone regeneration.

Tough physically crosslinked poly(vinyl alcohol)-based hydrogels loaded with collagen type I to promote bone regeneration in vitro and in vivo

Poly(vinyl alcohol) (PVA) hydrogels exhibit great potential as ideal biomaterials for tissue engineering, owing to their non-toxicity, high water content, and strong biocompatibility. However, limited mechanical strength and low bioactivity have constrained their application in bone tissue engineering. In this study, we have developed a tough PVA-based hydrogel using a facile physical crosslinking method, comprising of PVA, tannic acid (TA), and hydroxyapatite (HA). Systematic experiments were conducted to examine the physicochemical properties of PVA/HA/TA hydrogels, including their compositions, microstructures, and mechanical and rheological properties. The results demonstrated that the PVA/HA/TA hydrogels possessed the porous microstructures and excellent mechanical properties. Furthermore, collagen type I (ColI) was used to further improve the biocompatibility and bioactivity of PVA/HA/TA hydrogels. In vitro experiments revealed that PVA/HA/TA/COL hydrogel could offer a suitable microenvironment for the growth of MC3T3-E1 cells and promote their osteogenic differentiation. Meanwhile, the PVA/HA/TA/COL hydrogel demonstrated the ability to promote bone regeneration and osteointegration in a rat femoral defect model. This study provides a potential strategy for the use of PVA-based hydrogels in bone tissue engineering.

Hydroxyapatite/Polyurethane Scaffolds for Bone Tissue Engineering

Polyurethane (PU) and PU ceramic scaffolds are the principal materials investigated for developing synthetic bone materials due to their excellent biocompatibility and biodegradability. PU has been combined with calcium phosphate (such as hydroxyapatite [HA] and tricalcium phosphate) to prepare scaffolds with enhanced mechanical properties and biocompatibility. This article reviews the latest progress in the design, synthesis, modification, and biological attributes of HA/PU scaffolds for bone tissue engineering. Diverse HA/PU scaffolds have been proposed and discussed in terms of their osteogenic, antimicrobial, biocompatibility, and bioactivities. The application progress of HA/PU scaffolds in bone tissue engineering is predominantly introduced, including bone repair, bone defect filling, drug delivery, and long-term implants.

Engineering periodontal tissue interfaces using multiphasic scaffolds and membranes for guided bone and tissue regeneration

Periodontal diseases are one of the greatest healthcare burdens worldwide. The periodontal tissue compartment is an anatomical tissue interface formed from the periodontal ligament, gingiva, cementum, and bone. This multifaceted composition makes tissue engineering strategies challenging to develop due to the interface of hard and soft tissues requiring multiphase scaffolds to recreate the native tissue architecture. Multilayer constructs can better mimic tissue interfaces due to the individually tuneable layers. They have different characteristics in each layer, with modulation of mechanical properties, material type, porosity, pore size, morphology, degradation properties, and drug-releasing profile all possible. The greatest challenge of multilayer constructs is to mechanically integrate consecutive layers to avoid delamination, especially when using multiple manufacturing processes. Here, we review the development of multilayer scaffolds that aim to recapitulate native periodontal tissue interfaces in terms of physical, chemical, and biological characteristics. Important properties of multiphasic biodegradable scaffolds are highlighted and summarised, with design requirements, biomaterials, and fabrication methods, as well as post-treatment and drug/growth factor incorporation discussed.

Green synthetic sodium alginate-glycerol-MXene nanocomposite membrane with excellent flexibility and mineralization ability for guided bone regeneration

Developing a novel bioactive material as a barrier membrane for guided bone regeneration (GBR) surgery remains challenging. As a new member of two-dimensional (2D) material family, MXene is a promising candidate component for barrier membranes due to its high specific surface area and osteogenic differentiation ability. In this work, a green and simple SA/glycerol/MXene (SgM) composite membrane was prepared via solvent casting method by using sodium alginate (SA) and MXene (M) as raw materials while employing glycerol (g) as a plasticizer. The addition of glycerol significantly increased the elongation at the break of SA from 10%-20% to 240%-360%, while the introduction of MXene promoted the deposition of calcium and phosphorus to form hydroxyapatite. At the same time, the roughness of the SgM composite membrane is apparently improved, which is conducive to cell adhesion and proliferation. This work provides a basis for further research on SgM composite membrane as GBR membrane for the treatment of bone defects.

Barrier membranes for periodontal guided bone regeneration: a potential therapeutic strategy

Periodontal disease is one of the most common oral diseases with the highest incidence world-wide. In particular, the treatment of periodontal bone defects caused by periodontitis has attracted extensive attention. Guided bone regeneration (GBR) has been recognized as advanced treatment techniques for periodontal bone defects. GBR technique relies on the application of barrier membranes to protect the bone defects. The commonly used GBR membranes are resorbable and non-resorbable. Resorbable GBR membranes are divided into natural polymer resorbable membranes and synthetic polymer resorbable membranes. Each has its advantages and disadvantages. The current research focuses on exploring and improving its preparation and application. This review summarizes the recent literature on the application of GBR membranes to promote the regeneration of periodontal bone defects, elaborates on GBR development strategies, specific applications, and the progress of inducing periodontal bone regeneration to provide a theoretical basis and ideas for the future application of GBR membranes to promote the repair of periodontal bone defects.

Hydrogel-Loaded Exosomes: A Promising Therapeutic Strategy for Musculoskeletal Disorders

Clinical treatment strategies for musculoskeletal disorders have been a hot research topic. Accumulating evidence suggests that hydrogels loaded with MSC-derived EVs show great potential in improving musculoskeletal injuries. The ideal hydrogels should be capable of promoting the development of new tissues and simulating the characteristics of target tissues, with the properties matching the cell-matrix constituents of autologous tissues. Although there have been numerous reports of hydrogels loaded with MSC-derived EVs for the repair of musculoskeletal injuries, such as intervertebral disc injury, tendinopathy, bone fractures, and cartilage injuries, there are still many hurdles to overcome before the clinical application of modified hydrogels. In this review, we focus on the advantages of the isolation technique of EVs in combination with different types of hydrogels. In this context, the efficacy of hydrogels loaded with MSC-derived EVs in different musculoskeletal injuries is discussed in detail to provide a reference for the future application of hydrogels loaded with MSC-derived EVs in the clinical treatment of musculoskeletal injuries.

Multifunctional electrospun nanofibrous scaffold enriched with alendronate and hydroxyapatite for balancing osteogenic and osteoclast activity to promote bone regeneration

Electrospun composite nanofiber scaffolds are well known for their bone and tissue regeneration applications. This research is focused on the development of PVP and PVA nanofiber composite scaffolds enriched with hydroxyapatite (HA) nanoparticles and alendronate (ALN) using the electrospinning technique. The developed nanofiber scaffolds were investigated for their physicochemical as well as bone regeneration potential. The results obtained from particle size, zeta potential, SEM and EDX analysis of HA nanoparticles confirmed their successful fabrication. Further, SEM analysis verified nanofiber's diameters within 200-250 nm, while EDX analysis confirmed the successful incorporation of HA and ALN into the scaffolds. XRD and TGA analysis revealed the amorphous and thermally stable nature of the nanofiber composite scaffolds. Contact angle, FTIR analysis, Swelling and biodegradability studies revealed the hydrophilicity, chemical compatibility, suitable water uptake capacity and increased in-vitro degradation making it appropriate for tissue regeneration. The addition of HA into nanofiber scaffolds enhanced the physiochemical properties. Additionally, hemolysis cell viability, cell adhesion and proliferation by SEM as well as confocal microscopy and live/dead assay results demonstrated the non-toxic and biocompatibility behavior of nanofiber scaffolds. Alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) assays demonstrated osteoblast promotion and osteoclast inhibition, respectively. These findings suggest that developed HA and ALN-loaded PVP/PVA-ALN-HA nanofiber composite scaffolds hold significant promise for bone regeneration applications.

Current application and modification strategy of marine polysaccharides in tissue regeneration: A review

Marine polysaccharides (MPs) are exceptional bioactive materials that possess unique biochemical mechanisms and pharmacological stability, making them ideal for various tissue engineering applications. Certain MPs, including agarose, alginate, carrageenan, chitosan, and glucan have been successfully employed as biological scaffolds in animal studies. As carriers of signaling molecules, scaffolds can enhance the adhesion, growth, and differentiation of somatic cells, thereby significantly improving the tissue regeneration process. However, the biological benefits of pure MPs composite scaffold are limited. Therefore, physical, chemical, enzyme modification and other methods are employed to expand its efficacy. Chemically, the structural properties of MPs scaffolds can be altered through modifications to functional groups or molecular weight reduction, thereby enhancing their biological activities. Physically, MPs hydrogels and sponges emulate the natural extracellular matrix, creating a more conducive environment for tissue repair. The porosity and high permeability of MPs membranes and nanomaterials expedite wound healing. This review explores the distinctive properties and applications of select MPs in tissue regeneration, highlighting their structural versatility and biological applicability. Additionally, we provide a brief overview of common modification strategies employed for MP scaffolds. In conclusion, MPs have significant potential and are expected to be a novel regenerative material for tissue engineering.

Janus functional electrospun polyurethane fibrous membranes for periodontal tissue regeneration

The guided tissue regeneration (GTR) technique with GTR membranes is an efficient method for repairing periodontal defects. Conventional periodontal membranes act as physical barriers that resist the growth of fibroblasts, epithelial cells, and connective tissue. However, they cannot facilitate the regeneration of periodontal tissue. To address this issue, the exploitation of novel GTR membranes with bioactive functions based on therapeutic requirements is critical. Herein, we exploited a biodegradable bilayer polyurethane fibrous membrane by uniaxial electrostatic spinning to construct two sides with Janus properties by integrating the bioactive molecule dopamine (DA) and antimicrobial Gemini quaternary ammonium salt (QAS). The DA-containing side, located inside the injury, can effectively promote cell adhesion and mesenchymal stem cell growth as well as support mineralization and antioxidant properties, which are beneficial for bone regeneration. The QAS-containing side, located on the outer surface of the injury, endows antibacterial properties and limits fibroblast adhesion and growth on its surface owing to its strong hydrophilicity. An in vivo study demonstrates that the Janus polyurethane fibrous membrane can significantly promote the regeneration of periodontal defects in rats. Owing to its superior mechanical properties and biocompatibility, this polyurethane fibrous membrane has potential applications in the field of periodontal regeneration.

Biodegradable and biocompatible alginate/gelatin/MXene composite membrane with efficient osteogenic activity and its application in guided bone regeneration

Guided bone regeneration (GBR) utilizes a barrier membrane to maintain the osteogenic space and promote osseointegration of the implants. Developing a novel biomaterial to meet the mechanical and biological performance requirements of GBR membrane (GBRM) remains a huge challenge. Here, the sodium alginate (SA, S)/gelatin (G)/MXene (M) composite membrane (SGM) was prepared by combining sol-gel and freeze-drying processes. The incorporation of MXene improved the mechanical properties and hydrophilicity of the SA/G (SG) membrane, and also enhanced its cell proliferation and osteogenic differentiation. More importantly, when the concentration of MXene is 0.25%W/V, the SGM composite membrane exhibited the best tensile strength (40 MPa), high swelling rate (1012%), and appropriate degradation rate (40%). Meanwhile, the biological improvements were more significant. Therefore, the appropriate amount addition of MXene has a positive and obvious effect on the improvements of the mechanical properties, biocompatibility, and osteogenic induction of the SG composite membranes. This work provides a more extendable development idea for the application of SGM composite membrane as GBRM.

Bilayer scaffolds/membranes for bone tissue engineering applications: A systematic review

OBJECTIVE

This systematic review evaluates the purpose, materials, physio-mechanical, and biological effects of bilayer scaffolds/membranes used for bone tissue engineering applications.

METHODS

A comprehensive electronic search of English-language literature from 2012 to October 2022 was conducted in PubMed, Scopus, ScienceDirect, and Google Scholar online databases according to the PRISMA 2020 guidelines. The quality of animal studies was evaluated through the SYRCLE's risk of bias tool.

RESULTS

A total of 77 studies were sought for retrieval, and 39 studies met the inclusion criteria. According to the synthesis results, most bilayers had a dense barrier layer that prevented connective tissue penetration and a loose osteogenic layer that supported cell migration and osteogenesis. PLGA, PCL, and chitosan were the most common polymers in the barrier layers, while the most utilized polymers in osteogenic layers were PLGA and gelatin. Electrospinning and solvent casting were the most common fabrication methods to design the bilayer structures. Many studies reported higher biological results for bilayers compared to their single layers. Also, fabricated bilayers' in vitro osteogenesis and in vivo new bone formation were significantly superior or at least comparable to the frequently used commercial membranes.

CONCLUSION

1) Bilayers with two distinct layers and different materials, porosities, mechanical properties, and biological behavior can significantly improve heterogeneous bone regeneration; 2) the addition of ceramics and/or drugs to the osteogenic layer enhances the osteogenic properties of the bilayers; 3) fabrication method and pore size of the layers play an important role in determining the mechanical and biological behavior of them.

Nanohydroxyapatite in dentistry: A comprehensive review

Enamel, being the hardest and the highest mineralized tissue of the human body, contains nearly 96% inorganic components and 4% organic compounds and water. Dentin contains 65% inorganic components and 35% organic and water content. The translucency and white appearance of enamel are attributed to Hydroxyapatite (HA), which constitutes the major part of the inorganic component of dental hard tissue. With the advent of nanotechnology, the application of Nanohydroxyapatite (nHA) has piqued interest in dentistry due to its excellent mechanical, physical, and chemical properties. Compared to HA, nHA is found to have superior properties such as increased solubility, high surface energy and better biocompatibility. This is due to the morphological and structural similarity of nanosized hydroxyapatite particles to tooth hydroxyapatite crystals. These nanoparticles have been incorporated into various dental formulations for different applications to ensure comprehensive oral healthcare. To prevent dental caries, several nHA based dentifrices, mouth rinsing solutions and remineralizing pastes have been developed. nHA-based materials, such as nanocomposites, nano impression materials, and nanoceramics, have proven to be very effective in restoring tooth deformities (decay, fracture, and tooth loss). The nHA coating on the surface of the dental implant helps it bind to the bone by forming a biomimetic coating. A recent innovative strategy involves using nHA to reduce dentinal hypersensitivity and to reconstruct periodontal bone defects. The purpose of the present review is to discuss the different applications of nHA in dentistry, especially in preventive and restorative dentistry, dental implantology, bleaching and dentine hypersensitivity management.

Electrospun PA6 Nanofibers Bearing the CeO2 Dephosphorylation Catalyst

Two types of CeO₂ nanoparticles (CeNPs) prepared by low-temperature (<100 °C) precipitation methods in water were successfully immobilized in a matrix of electrospun PA6 nanofibers. The colloidal solutions of CeNPs in AcOH were directly mixed with the polymer solution before the needle electrospinning process, thereby achieving their good dispersion in the nanofibers. CeNPs embedded in the structure and on the surface of nanofibers exposing their reactive surfaces showed robust dephosphorylation catalytic activity, as demonstrated by monitoring the hydrolytic cleavage of three phosphodiester molecules (p-NP-TMP, p-NPPC, BNPP) in water by the HPLC method. This procedure allowed us to study the kinetics and mechanism of the hydrolytic cleavage and the ability of immobilized CeNPs to cleave different types of P-O bonds. One of the main hydrolysis products, p-nitrophenol, was effectively adsorbed on PA6 nanofibers, which may allow the selective separation of the degradation products after hydrolysis.

Recent Advancements in Electrospun Chitin and Chitosan Nanofibers for Bone Tissue Engineering Applications

Treatment of large segmental bone loss caused by fractures, osteomyelitis, and non-union results in expenses of around USD 300,000 per case. Moreover, the worst-case scenario results in amputation in 10% to 14.5% of cases. Biomaterials, cells, and regulatory elements are employed in bone tissue engineering (BTE) to create biosynthetic bone grafts with effective functionalization that can aid in the restoration of such fractured bones, preventing amputation and alleviating expenses. Chitin (CT) and chitosan (CS) are two of the most prevalent natural biopolymers utilized in the fields of biomaterials and BTE. To offer the structural and biochemical cues for augmenting bone formation, CT and CS can be employed alone or in combination with other biomaterials in the form of nanofibers (NFs). When compared with several fabrication methods available to produce scaffolds, electrospinning is regarded as superior since it enables the development of nanostructured scaffolds utilizing biopolymers. Electrospun nanofibers (ENFs) offer unique characteristics, including morphological resemblance to the extracellular matrix, high surface-area-to-volume ratio, permeability, porosity, and stability. This review elaborates on the recent strategies employed utilizing CT and CS ENFs and their biocomposites in BTE. We also summarize their implementation in supporting and delivering an osteogenic response to treat critical bone defects and their perspectives on rejuvenation. The CT- and CS-based ENF composite biomaterials show promise as potential constructions for bone tissue creation.

Bifunctional electrospun poly (L-lactic acid) membranes incorporating black phosphorus nanosheets and nano-zinc oxide for enhanced biocompatibility and antibacterial properties in catheter materials

For several decades, urinary tract infections caused by catheter-associated devices have negatively impacted not only medical device utilization, but also patient health. As such, the creation of catheter materials with both superior biocompatibility and antibacterial properties has become necessary. This study aimed to produce electrospun membranes based on polylactic acid (PLA) with the incorporation of black phosphorus nanosheets (BPNS) and nano-zinc oxide (nZnO) particles, as well as a mixture of both, in order to design bifunctional membranes with enhanced bioactivity and antibacterial features. The optimum spinning process was determined through examination of various PLA mass concentrations, spinning solution propelling speeds, and receiving drum rotating speeds, with emphasis on the mechanical properties of PLA membranes. Additionally, the antibacterial properties and cytocompatibility of the ZnO-BP/PLA antibacterial membranes were explored. Results demonstrated that the ZnO-BP/PLA antibacterial membranes displayed a rich porous structure, with uniform distribution of nZnO particles and BPNS. With the increase of polylactic acid concentration and the decrease of spinning solution advancing and drum rotation speeds, the mechanical properties of the fiber membrane were significantly improved. Furthermore, the composite membranes exhibited remarkable photothermal therapy (PTT) capabilities when aided by the synergistic effect of BP nanosheets and ZnO. This was achieved through near-infrared (NIR) irradiation, which not only dissipated the biofilm but also enhanced the release capability of Zn²⁺. Consequently, the composite membrane demonstrated an improved inhibitory effect on both Escherichia coli and Staphylococcus aureus. The results of cytotoxicity and adhesion experiments also indicated good cytocompatibility, with cells growing normally on the surface of the ZnO-BP/PLA antibacterial membrane. Overall, these findings validate the utilization of both BPNS and n-ZnO fillers in the creation of novel bifunctional PLA-based membranes, which possess both biocompatibility and antibacterial properties for interventional catheter materials.

In situ titanium phosphate formation on a titanium implant as ultrahigh bonding with nano-hydroxyapatite coating for rapid osseointegration

Titanium (Ti) has been widely used as a dental implant material due to its excellent mechanical property and good biocompatibility. However, its poor biological activity severely limits its ability to bond with bony tissues. To ameliorate this situation, a preparation method of ultra-high bonding nano-hydroxyapatite (n-HA) coating on the Ti surface is urgently needed. Here, Ti phosphate/n-HA (TiP-Ca) composite coatings with ultra-high bonding were prepared by a two-step hydrothermal treatment. The TiP coating was first formed in situ on the pure Ti substrate and then n-HA crystals further grew on the TiP surface. The formation mechanism of composite coating and reasons for increased bonding strength were systematically investigated. The results show that the TiP-Ca coating remains stable and exhibits an ultra-high bonding strength with the Ti implant (up to 783.30 ± 207.46 N). An effective solution was designed to address the problems of easy peel off. Cell experiments showed that TiP-Ca could promote the adhesion of MC3T3-E1 and expression of OCN, Runx2, and ALP. In vivo evaluation further confirmed that the TiP-Ca composite coating significantly enhanced osseointegration. The designed coating shows great potential in clinical application of implants.

Advanced materials and technologies for oral diseases

Oral disease, as a class of diseases with very high morbidity, brings great physical and mental damage to people worldwide. The increasing burden and strain on individuals and society make oral diseases an urgent global health problem. Since the treatment of almost all oral diseases relies on materials, the rapid development of advanced materials and technologies has also promoted innovations in the treatment methods and strategies of oral diseases. In this review, we systematically summarized the application strategies in advanced materials and technologies for oral diseases according to the etiology of the diseases and the comparison of new and old materials. Finally, the challenges and directions of future development for advanced materials and technologies in the treatment of oral diseases were refined. This review will guide the fundamental research and clinical translation of oral diseases for practitioners of oral medicine.

Extracellular-matrix-mimicked 3D nanofiber and hydrogel interpenetrated wound dressing with a dynamic autoimmune-derived healing regulation ability based on wound exudate

Dynamic regulation of wound physiological signals is the basis of wound healing. Conventional biomaterials delivering growth factors to drive wound healing leads to the passive repair of soft tissues because of the mismatch of wound healing stages. Meanwhile, the bioactivity of wound exudate is often restricted by oxidation and bacterial contamination. Herein, an extracellular matrix mimicked nanofiber/hydrogel interpenetrated network (NFHIN) was constructed with a 3D nanofibrous framework for cell immigration, and interfiled aerogel containing cross-linked hyaluronic acid and hyperbranched polyamidoamine to balance the wound microenvironment. The aerogel can collect wound exudate and transform into a polycationic hydrogel with contact-killing effects even against intracellular pathogens (bactericidal rate > 99.9% in 30 min) and real-time scavenging property of reactive oxygen species. After co-culturing with the NFHIN, the bioactivity of fibroblast in theex vivoblister fluid was improved by 389.69%. The NFHIN showed sustainable exudate management with moisture-vapor transferring rate (6000 g m^-2×24 h), equilibrium liquid content (75.3%), Young's modulus (115.1 ± 7 kPa), and anti-tearing behavior similar to human skin. The NFHIN can collect and activate wound exudate, turning it from a clinical problem to an autoimmune-derived wound regulation system, showing potential for wound care in critical skin diseases.

Strategies of cell and cell-free therapies for periodontal regeneration: the state of the art

BACKGROUND

Periodontitis often causes irrevocable destruction of tooth-supporting tissues and eventually leads to tooth loss. Currently, stem cell-based tissue engineering has achieved a favorable result in regenerating periodontal tissues. Moreover, cell-free therapies that aim to facilitate the recruitment of resident repair cell populations to injured sites by promoting cell mobilization and homing have become alternative options to cell therapy.

MAIN TEXT

Cell aggregates (e.g., cell sheets) retain a large amount of extracellular matrix which can improve cell viability and survival rates after implantation in vivo. Electrostatic spinning and 3D bioprinting through fabricating specific alignments and interactions scaffold structures have made promising outcomes in the construction of a microenvironment conducive to periodontal regeneration. Cell-free therapies with adding biological agents (growth factors, exosomes and conditioned media) to promote endogenous regeneration have somewhat addressed the limitations of cell therapy.

CONCLUSION

Hence, this article reviews the progress of stem cell-based tissue engineering and advanced strategies for endogenous regeneration based on stem cell derivatives in periodontal regeneration.

Layer-by-layer assembly of peptides-decorated coaxial nanofibrous membranes with antibiofilm and visual pH sensing capability

The countermeasure of biofilm infections leaving a challenge due to a dense antibiotic-resistant barrier formed by extracellular polymeric substances (EPS). Although antibiotic alternative methods have been developed to combat biofilms, develop effective remedies coupling with timely feedback about the therapeutic effect are still in urgent demand. To this end, we construct an intelligent coaxial electrospun nanofibrous membranes (ENMs) that integrated therapy of infections and in situ visualized diagnosis. Specifically, pH-sensitive alizarin was incorporated into polyamide 6 to subtly consist core layer and curcumin (Cur) was formulated with degradable polyglycolic acid (PGA) to composed of the shell layer. The shell layer can gradually release curcumin along with the degradation of PGA. Moreover, epsilon-poly-_L-lysine (ε-PL) was deposited on coaxial ENMs via layer-by-layer self-assembly technique to disturb EPS integrity. As a result of the treatment, two different Gram-positive and Gram-negative bacteria displayed increased susceptibility to the drug hybrids. The degradation of PGA would trigger a sustained release of Cur and ε-PL, and once the core layer exposing, the acidic microenvironment of Staphylococcus aureus and Pseudomonas aeruginosa biofilm could be detected in situ by emerging visualized color change to timely feedback. Besides, the ENMs showed good biocompatibility. It paves a feasible and effective avenue for constructing a facile treatment and diagnosis platform for wound biofilm infections.

Electrospun Nanofiber Composites for Drug Delivery: A Review on Current Progresses

A medication’s approximate release profile should be sustained in order to generate the desired therapeutic effect. The drug’s release site, duration, and rate must all be adjusted to the drug’s therapeutic aim. However, when designing drug delivery systems, this may be a considerable hurdle. Electrospinning is a promising method of creating a nanofibrous membrane since it enables drugs to be placed in the nanofiber composite and released over time. Nanofiber composites designed through electrospinning for drug release purposes are commonly constructed of simple structures. This nanofiber composite produces matrices with nanoscale fiber structure, large surface area to volume ratio, and a high porosity with small pore size. The nanofiber composite’s large surface area to volume ratio can aid with cell binding and multiplication, drug loading, and mass transfer processes. The nanofiber composite acts as a container for drugs that can be customized to a wide range of drug release kinetics. Drugs may be electrospun after being dissolved or dispersed in the polymer solution, or they can be physically or chemically bound to the nanofiber surface. The composition and internal structure of the nanofibers are crucial for medicine release patterns.

The applications of polysaccharides in dentistry

Polysaccharides are natural polymers widely present in animals, plants, and several microorganisms. Polysaccharides have remarkable properties, including easy extractions, degradability, and renewability, and have no apparent toxicity, making them ideal for biomedical applications. Moreover, polysaccharides are suitable for repairing oral tissue defects and treating oral diseases due to their excellent biocompatibility, biosafety, anti-inflammatory, and antibacterial properties. The oral cavity is a relatively complex environment vulnerable to numerous conditions, including soft tissue diseases, hard tissue disorders, and as well as soft and hard tissue diseases, all of which are complex to treat. In this article, we reviewed different structures of natural polysaccharides with high commercial values and their applications in treating various oral disease, such as drug delivery, tissue regeneration, material modification, and tissue repair.

Mechanically and biologically enhanced 3D-printed HA/PLLA/dECM biocomposites for bone tissue engineering

Poly (L-lactic acid) (PLLA)-based biocomposites have been used in tissue engineering applications because of their reasonable biocompatibility and mechanical properties. However, the imperfect bioactive and mechanical properties of the composite make it difficult to be used in the region of bone defects that require high load-bearing. Therefore, this study introduced two fabricating strategies to induce mechanically and biologically enhanced hydroxyapatite (HA)/PLLA biocomposites. By introducing an in situ plasma treatment, which was simultaneously applied during the 3D-printing process, followed by the thermal annealing process, the flexural modulus of the composite was increased by 2.1-fold compared to the normal HA/PLLA composite. Furthermore, using the combinational process, efficient coating of bioactive material [decellularized extracellular matrix (dECM) derived from porcine bones] was possible. The fabricated biocomposite scaffold was assessed for various in vitro cellular activities such as cell proliferation and osteogenic activity. Based on the mechanical and biological studies, the HA/PLLA/dECM biocomposite scaffold is one of the promising scaffolds that can be applied in bone tissue regeneration.

Applications of Chitosan in Surgical and Post-Surgical Materials

The continuous advances in surgical procedures require continuous research regarding materials with surgical applications. Biopolymers are widely studied since they usually provide a biocompatible, biodegradable, and non-toxic material. Among them, chitosan is a promising material for the development of formulations and devices with surgical applications due to its intrinsic bacteriostatic, fungistatic, hemostatic, and analgesic properties. A wide range of products has been manufactured with this polymer, including scaffolds, sponges, hydrogels, meshes, membranes, sutures, fibers, and nanoparticles. The growing interest of researchers in the use of chitosan-based materials for tissue regeneration is obvious due to extensive research in the application of chitosan for the regeneration of bone, nervous tissue, cartilage, and soft tissues. Chitosan can serve as a substance for the administration of cell-growth promoters, as well as a support for cellular growth. Another interesting application of chitosan is hemostasis control, with remarkable results in studies comparing the use of chitosan-based dressings with traditional cotton gauzes. In addition, chitosan-based or chitosan-coated surgical materials provide the formulation with antimicrobial activity that has been highly appreciated not only in dressings but also for surgical sutures or meshes.

Marine Biopolymers as Bioactive Functional Ingredients of Electrospun Nanofibrous Scaffolds for Biomedical Applications

Marine biopolymers, abundantly present in seaweeds and marine animals, feature diverse structures and functionalities, and possess a wide range of beneficial biological activities. Characterized by high biocompatibility and biodegradability, as well as unique physicochemical properties, marine biopolymers are attracting a constantly increasing interest for the development of advanced systems for applications in the biomedical field. The development of electrospinning offers an innovative technological platform for the production of nonwoven nanofibrous scaffolds with increased surface area, high encapsulation efficacy, intrinsic interconnectivity, and structural analogy to the natural extracellular matrix. Marine biopolymer-based electrospun nanofibrous scaffolds with multifunctional characteristics and tunable mechanical properties now attract significant attention for biomedical applications, such as tissue engineering, drug delivery, and wound healing. The present review, covering the literature up to the end of 2021, highlights the advancements in the development of marine biopolymer-based electrospun nanofibers for their utilization as cell proliferation scaffolds, bioadhesives, release modifiers, and wound dressings.

A long-lasting guided bone regeneration membrane from sequentially functionalised photoactive atelocollagen

The fast degradation of collagen-based membranes in the biological environment remains a critical challenge, resulting in underperforming Guided Bone Regeneration (GBR) therapy leading to compromised clinical results. Photoactive atelocollagen (AC) systems functionalised with ethylenically unsaturated monomers, such as 4-vinylbenzyl chloride (4VBC), have been shown to generate mechanically competent materials for wound healing, inflammation control and drug delivery, whereby control of the molecular architecture of the AC network is key. Building on this platform, the sequential functionalisation with 4VBC and methacrylic anhydride (MA) was hypothesised to generate UV-cured AC hydrogels with reduced swelling ratio, increased proteolytic stability and barrier functionality for GBR therapy. The sequentially functionalised atelocollagen precursor (SAP) was characterised via TNBS and ninhydrin colourimetric assays, circular dichroism and UV-curing rheometry, which confirmed nearly complete consumption of collagen's primary amino groups, preserved triple helices and fast (< 180 s) gelation kinetics, respectively. Hydrogel's swelling ratio and compression modulus were adjusted depending on the aqueous environment used for UV-curing, whilst the sequential functionalisation of AC successfully generated hydrogels with superior proteolytic stability in vitro compared to both 4VBC-functionalised control and the commercial dental membrane Bio-Gide®. These in vitro results were confirmed in vivo via both subcutaneous implantation and a proof-of-concept study in a GBR calvarial model, indicating integrity of the hydrogel and barrier defect, as well as tissue formation following 1-month implantation in rats. STATEMENT OF SIGNIFICANCE: Collagen-based membranes remain a key component in Guided Bone Regeneration (GBR) therapy, but their properties, e.g. proteolytic stability and soft tissue barrier functionality, are still far from optimal. This is largely attributed to the complex molecular configuration of collagen, which makes chemical accessibility and structure-function relations challenging. Here, we fabricated a UV-cured hydrogel network of atelocollagen, whereby triple helices were sequentially functionalised with two distinct ethylenically unsaturated monomers. The effects of the sequential functionalisation and UV-curing on the macroscopic properties, degradation behaviour and GBR capability were investigated in vitro and in vivo. The results highlight the key role of the sequential functionalisation and provide important insights for the design of future, longer-lasting resorbable membranes for GBR therapy.

Engineering Electrospun Nanofibers for the Treatment of Oral Diseases

With the increase of consumption of high-sugar foods, beverages, tobacco, and alcohol, the incidence rate of oral diseases has been increasing year by year. Statistics showed that the prevalence of oral diseases such as dental caries, dental pulpal disease, and periodontal disease has reached as high as 97% in 2015 in China. It is thus urgent to develop functional materials or products for the treatment of oral diseases. Electrospinning has been a widely used technology that is capable of utilizing polymer solution to generate micro/nano fibers under an appropriate high voltage condition. Owing to their excellent structures and biological performances, materials prepared by electrospinning technology have been used for a wide range of oral-related applications, such as tissue restoration, controlled drug release, anti-cancer, etc. In this regard, this article reviews the application and progress of electrospun nanofibers to various oral diseases in recent years. Firstly, engineering strategies of a variety of nanofiber structures together with their resultant functions will be introduced. Then, biological functions of electrospun nanofibers as well as their applications in the treatment of oral diseases are summarized and demonstrated. Finally, the development viewpoint of functional nanofibers is prospected, which is expected to lay the foundation and propose the direction for further clinical application.

A bioinspired Janus polyurethane membrane for potential periodontal tissue regeneration

Guided tissue regeneration (GTR) is the main therapeutic method for periodontal tissue regeneration. The key to the GTR strategy is the membrane which can assist the reconstruction of bone tissue in the periodontal defect and prevent the migration of epithelium and fibroblasts to the defect. However, the existing periodontal membrane cannot effectively promote periodontal tissue regeneration due to the limited bioactivity and physicochemical function. Here, we developed a bioinspired degradable polyurethane membrane with Janus surface morphology by integrating bioactive dopamine (DA) and an antibacterial Gemini quaternary ammonium salt (QAS). The Janus surface of the membrane is fabricated through spontaneous microphase separation, resulting from the different migration of functional segments between the air-contact upper surface with enriched antibacterial QAS and the substrate-contact bottom with enriched bioactive DA. The smooth surface of the upper membrane used to face the soft tissues can reduce cell adhesion to suppress the migration of fibroblasts, while the rough surface with a topological micro-pit structure of the bottom side facing the bone has excellent function of autonomic mineralization and cell adhesion to promote bone tissue reconstruction. In addition, the membrane containing the antibacterial QAS shows excellent antibacterial effect on common oral pathogens, such as S. aureus and S. mutans. Moreover, the specific dopamine group also endows the membrane with excellent antioxidant efficiency. In vivo research shows that this Janus polyurethane membrane can effectively promote periodontal tissue regeneration in a rat periodontal defect model. Combined with its excellent mechanical properties and biocompatibility, the polyurethane membrane is a promising material for potential periodontal tissue regeneration.

A Review on Electrospun Nanofibers Based Advanced Applications: From Health Care to Energy Devices

Electrospun nanofibers have been exploited in multidisciplinary fields with numerous applications for decades. Owing to their interconnected ultrafine fibrous structure, high surface-to-volume ratio, tortuosity, permeability, and miniaturization ability along with the benefits of their lightweight, porous nanofibrous structure, they have been extensively utilized in various research fields for decades. Electrospun nanofiber technologies have paved unprecedented advancements with new innovations and discoveries in several fields of application including energy devices and biomedical and environmental appliances. This review article focused on providing a comprehensive overview related to the recent advancements in health care and energy devices while emphasizing on the importance and uniqueness of utilizing nanofibers. A brief description regarding the effect of electrospinning techniques, setup modifications, and parameters optimization on the nanofiber morphology was also provided. The article is concluded with a short discussion on current research challenges and future perspectives.

Engineered bone tissues using biomineralized gelatin methacryloyl/sodium alginate hydrogels

At present, the treatment of bone defect is one of the most concerned problems in biomedical fields. Despite the wide variety of scaffolds, there is a challenge to select materials that can mimic the structural integrity and biocompatibility of natural bone. In our study, gelatin methacryloyl (GelMA) and sodium alginate (Alg) were used to prepare three-dimensional (3D) GelMA/Alg hybrid hydrogel, which can simulate the structure and biological function of natural extracellular matrix due to their high water content and porous structure. The interconnected and homogeneous pores of the scaffold facilitate the transport of nutrients during the bone regeneration. Then hydroxyapatite (HA) coated GelMA/Alg (GelMA/Alg-HA) hydrogel was obtained by sequential mineralization. The mineralized hydrogel was obtained by immersing hydrogel alternately in a solution of calcium and phosphorus at 37 °C. The hydrogel was modified with a coating of HA under a mild condition. The calcium crosslinked Alg could provide nucleation sites for HA crystals. And the sequential mineralization will improve the physical properties and osteoinductivity of the hydrogels by introducing HA, which is similar to the mineral component of natural bone. Analytical results confirmed that the HA particles were uniformly distributed in the surface of the hydrogels and the mineral contents were about 40% after three cycles. The compressive strength was improved from 22.43 ± 6.39 to 131.03 ± 9.26 kPa. In addition, MC3T3-E1 cell co-culture experiments shown that the mineralized GelMA/Alg-HA hybrid hydrogel possess good biocompatibility, which is conducive to the growth of new bone tissue and bone repair.

Preparation and characterization of a novel composite membrane of natural silk fiber/nano-hydroxyapatite/chitosan for guided bone tissue regeneration

Natural silk fiber (SF) was introduced into the chitosan/nano-hydroxyapatite (CS/n-HA) system to fabricate a novel guided bone tissue regeneration (GBR) membrane. The effect of different treatment methods (degummed, un-degummed, or dissolved SF) and different contents of SF on the properties of the CS/n-HA composite membrane was investigated. Results demonstrated that the degummed SF/CS/n-HA composite membrane with a weight ratio of 2:6:2 possessed the highest mechanical strength, where SF supported the composite membrane as a skeleton frame in the form of primeval state, while the un-degummed SF and dissolved SF had weaker reinforce effect due to the poor interface or poor interaction between SF and CS, and the dissolved SF/CS/n-HA composite membrane displayed the fastest degradation. However, the three SF could all improve the cell biocompatibility of the CS/n-HA composite membrane. Conclusively, the study revealed that degummed SF could in situ reinforce the CS/n-HA composite membrane with a simple and green processing method, which would provide an important guidance significant to develop a novel GBR membrane.

A new cancellous bone material of silk fibroin/cellulose dual network composite aerogel reinforced by nano-hydroxyapatite filler

Composites materials comprised of biopolymeric aerogel matrices and inorganic nano-hydroxyapatite (n-HA) fillers have received considerable attention in bone engineering. Although with significant progress in aerogel-based biomaterials, the brittleness and low strengths limit the application. The improvements in toughness and mechanical strength of aerogel-based biomaterials are in great need. In this work, an alkali urea system was used to dissolve, regenerate and gelate cellulose and silk fibroin (SF) to prepare composite aerosol. A dual network structure was shaped in the composite aerosol materials interlaced by sheet-like SF and reticular cellulose wrapping n-HA on the surface. Through uniaxial compression, the density of the composite aerogel material was close to the one of natural bone, and mechanical strength and toughness were high. Our work indicates that the composite aerogel has the same mechanical strength range as cancellous bone when the ratio of cellulose, n-HA and SF being 8:1:1. In vitro cell culture showed HEK-293T cells cultured on composite aerogels had high ability of adhesion, proliferation and differentiation. Totally, the presented biodegradable composite aerogel has application potential in bone tissue engineering.

Biopolymers Hybrid Particles Used in Dentistry

This literature review provides an overview of the fabrication and application of biopolymer hybrid particles in dentistry. A total of 95 articles have been included in this review. In the review paper, the common inorganic particles and biopolymers used in dentistry are discussed in general, and detailed examples of inorganic particles (i.e., hydroxyapatite, calcium phosphate, and bioactive glass) and biopolymers such as collagen, gelatin, and chitosan have been drawn from the scientific literature and practical work. Among the included studies, calcium phosphate including hydroxyapatite is the most widely applied for inorganic particles used in dentistry, but bioactive glass is more applicable and multifunctional than hydroxyapatite and is currently used in clinical practice. Today, biopolymer hybrid particles are receiving more attention as novel materials for several applications in dentistry, such as drug delivery systems, bone repair, and periodontal regeneration surgery. The literature published on the biopolymer gel-assisted synthesis of inorganic particles for dentistry is somewhat limited, and therefore, this article focuses on reviewing and discussing the biopolymer hybrid particles used in dentistry.