Biocompatible alginate/nano bioactive glass ceramic composite scaffolds for periodontal tissue regeneration

Advanced alginate/58S bioactive glass inks with enhanced printability, mechanical strength, and cytocompatibility for soft tissue engineering

Alginate-based hydrogels are promising biomaterials for extrusion-based bioprinting; however, their poor mechanical properties, printability, and shape integrity limit their utility in mimicking complex tissues and organs. In this study, a novel sodium alginate (Alg)/58S bioactive glass (BG)-based ink was developed for soft tissue engineering applications. The inks were characterised for shear-thinning, flowability, and shape integrity by printing various structures, including single filaments (0° and 90° nozzle movement), scaffolds, and rings. The ABG10 ink (10 wt% 58S BG in Alg) exhibited superior printability, achieving a printing accuracy of over 90 %, compared to a printing accuracy of 30-40 % for pure Alg. Fourier transform infrared spectroscopy revealed interactions between 58S BG and the Alg matrix, while scanning electron microscopy characterised the 58S BG morphology within the matrix. The storage modulus increased from 767 (pure Alg) to 13,604 Pa (ABG10), while compressive strength rose from 23 ± 3 to 43 ± 4 kPa (58 % enhancement). The cytocompatibility of the inks was assessed using an MTT assay (with SH-SY5Y cells), which confirmed that ABG10 ink supports cell viability. Overall, ABG10 hydrogel-based inks exhibited enhanced shear-thinning behaviour, printability, mechanical strength, and cytocompatibility, which could help to develop patient-specific soft tissues.

Freeze-Cast Composites of Alginate/Pyrophosphate-Stabilized Amorphous Calcium Carbonate: From the Nanoscale Structuration to the Macroscopic Properties

Pyrophosphate-stabilized amorphous calcium carbonates (PyACC) are promising compounds for bone repair due to their ability to release calcium, carbonate, and phosphate ions following pyrophosphate hydrolysis. However, shaping these metastable and brittle materials using conventional methods remains a challenge, especially in the form of macroporous scaffolds, yet essential to promote cell colonization. To overcome these limitations, this article describes for the first time the design and multiscale characterization of freeze-cast alginate (Alg)-PyACC nanocomposite scaffolds. The study initially focused on the synthesis of Alg-PyACC powder through in situ coprecipitation. The presence of alginate chains in the vicinity of the PyACC was shown to affect both the powder reactivity and the release of calcium ions when placed in water (XRD, chemical titrations). In vitro cellular assays confirmed the biocompatibility of Alg-PyACC powder, supporting its use as a filler in scaffolds for bone substitutes. In a second step, the freeze-casting process was carried out using these precursor powders with varying rates of inorganic fillers. The resulting scaffolds were compared in terms of pore size and gradient (via SEM, X-ray microtomography, and mercury intrusion porosimetry). All scaffolds exhibited a pore size gradient oriented along the solidification axis, featuring unidirectional, lamellar, and interconnected pores. Interestingly, we found that the pore size and wall thickness could be controlled by the filler rate. This effect was attributed to the in situ cross-linking of alginate chains by released Ca2+ ions from the fillers, which increased viscosity, affecting temperature-driven segregation during the freezing step. Different multiscale organizations of the porosity and spatial distribution of fillers (FEG-SEM) were correlated with changes in the scaffold mechanical properties (tested via uniaxial compression). With such tunable porous and mechanical properties, Alg-PyACC composite scaffolds present attractive opportunities for specific bone substitute applications.

Role of periodontal ligament fibroblasts in periodontitis: pathological mechanisms and therapeutic potential

Periodontal ligament fibroblasts (PDLFs) play a crucial role in the etiology of periodontitis and periodontal tissue regeneration. In healthy periodontal tissues, PDLFs maintain the homeostasis of periodontal soft and hard tissues as well as the local immune microenvironment. PDLFs also have the potential for multidirectional transdifferentiation and are involved in periodontal tissue regeneration. On the other hand, PDLFs can become dysfunctional and acquire an inflammatory phenotype to secret various inflammatory cytokines when affected by pathological factors. These cytokines further trigger immune and inflammatory events, and lead to destruction of periodontal soft and hard tissues as well as damage to the regenerative potential of PDLFs. This review summarizes the physiological functions of PDLFs. Meanwhile, this review also highlights recent insights into the pathological mechanisms driving the development of periodontitis through dysfunctional PDLFs and the negative impact on periodontal tissue regeneration. Additionally, this paper summarizes strategies for targeting PDLFs to treat periodontitis, involving blocking multiple stages of the inflammatory response induced by PDLFs and promoting the multidirectional transdifferentiation of PDLFs. Future research directions are proposed to address important questions that have not yet been answered in this field. This article provides a reference for understanding the important role of PDLFs in the pathological mechanisms of periodontitis and for developing new strategies for targeting PDLFs in periodontitis treatment.

Synthesis, Characterization and Osteogenic Properties of Chitin-Polydioxanone Composite Gel

In this study, we have developed a Chitin(Ch)-Poly(dioxanone)(PDO) gel system, which can be potentially used for tissue engineering. Hydrogel has been widely used in biomedical applications for its tuneable properties and biocompatibility. Chitin (Ch) is a natural biopolymer used for its ability to mimic the natural extracellular matrix due to its N-acetyl glucosamine structural units. Poly (dioxanone) (PDO) is a FDA-approved synthetic biopolymer known for its mechanical properties, good biocompatibility, and poor inflammatory response. Based on this, we have developed Ch-PDO composite gel using simple regeneration chemistry and characterized it using FT-IR and SEM. The developed composite gel showed improved gel strength, good swelling ability, and controlled degradation behaviour. It also showed good inject ability with shear thinning properties and hemocompatibility. Further, the biocompatibility and cell adhesion studies of the prepared gels were studied using dental follicle stem cells (DFSCs). The prepared Ch-PDO gel was biocompatible and showed DFSCs cell attachment. Osteogenic mineralization, RUNX2 and OPN expression of the prepared Ch and Ch-PDO gel was studied and Ch-PDO gel showed an enhanced mineralization and RUNX2 and OPN expression showed enhanced osteogenic activity in Ch-PDO. Therefore, the developed chitin-PDO gel could be potentially used for bone tissue engineering.

Strontium doped 58S bioglass incorporated chitosan/gelatin porous scaffold for bone tissue engineering applications

Bioglass (Bg) is accepted as a revolutionary material, and doping with strontium (Sr) ions in the Bg network exhibits improved biofunctionality towards bone tissue regeneration and inhibits osteoclast formation. Keeping this in view, the present study focused on the development of chitosan (CS)/gelatin (GE) porous scaffolds incorporated with Sr-doped Bg nanoparticles (nSrBg) for bone tissue engineering applications. The SEM analysis of the fabricated scaffold exhibited that it possessed a homogenous microstructure with an interconnected porous network having pore sizes of 100-300 μm. A swelling of <6-fold and a degradation rate under 50 % were achieved. The compression test revealed that nSrBg improved the strength of the composite to 1.15 MPa. In vitro bioactivity assays suggested the presence of nSrBg enhanced the bone-like deposition of the apatite layer, which possessed cell-supportive properties, allowing the cells to attach and proliferate over the scaffold surface. MTT assay and live-dead staining revealed that the nSrBg enhanced the proliferation of the cells up to 0.48 OD. The ALP assay suggested that the nSrBg addition improved the osteogenic potential until 0.70 OD. Overall, the fabricated scaffold showed superior mechanical and biological properties that can be a promising platform for bone tissue regeneration.

Using hardystonite as a biomaterial in biomedical and bone tissue engineering applications

Widespread adoption for substitutes of artificial bone grafts based on proper bioceramics has been generated in recent years. Among them, calcium-silicate-based bioceramics, which possess osteoconductive properties and can directly attach to biological organs, have attracted substantial attention for broad ranges of applications in bone tissue engineering. Approaches exist for a novel strategy to promote the drawbacks of bioceramics such as the incorporation of Zn2+, Mg2+, and Zr4+ ions into calcium-silicate networks, and the improvement of their physical, mechanical, and biological properties. Recently, hardystonite (Ca2ZnSi2O7) bioceramics, as one of the most proper calcium-silicate-based bioceramics, has presented excellent biocompatibility, bioactivity, and interaction. Due to its physical, mechanical, and biological behaviors and ability to be shaped utilizing a variety of fabrication techniques, hardystonite possesses the potential to be applied in biomedical and tissue engineering, mainly bone tissue engineering. A notable potential exists for the newly developed bioceramics to help therapies supply clinical outputs. The promising review paper has been presented by considering major aims to summarize and discuss the most applicable studies carried out for its physical, mechanical, and biological behaviors.

Limitations, challenges and prospective solutions for bioactive glasses-based nanocomposites for dental applications: A critical review

Several nanomaterials have been recently used to overcome various challenges in the dental domain. Bioactive glasses, a class of bioceramics, with their outstanding properties including but not limited to their strong biocompatibility, antibacterial characteristics, and bioactivity inside the body's internal milieu have made them valuable biomaterials in a variety of dental domains. The utilization of nanomaterials has improved the performance of teeth, and the incorporation of bioactive glasses has the field of dentistry at an unsurpassed level in different categories such as esthetic and restorative dentistry, periodontics and dental implants, orthodontics, and endodontics. The current study discusses the most recent developments of the bioactive glasses' creation and implementation for dental applications, as well as the challenges and opportunities still facing the field. This work provides an overview of the current obstacles and potential future prospects for bioactive glasses-based nanocomposites to improve their dental uses. It also emphasizes the great potential synergistic effects of bioactive glasses used with other nanomaterials for dental applications.

Porous calcium silicate bioactive material-alginate composite for bone regeneration

Bone tissue engineering aims to address bone-related problems that arise from trauma, infection, tumors, and surgery. Polymer and calcium silicate bioactive material (BM) based composites are commonly preferred as potential materials for bone treatment. However, the polymer has low bioactivity, thus, the current work aims to prepare a composite scaffold based on BM-sodium alginate (Alg) by varying the Alg percentage to optimize the porous nature of the composite. Primarily, the BM was synthesized by a simple precipitation method using rice husk and eggshell as the precursors of silica and calcium, while the BM-Alg composite was prepared by a facile cross-linking approach. The BM-Alg composite was studied using XRD, FTIR, SEM, and BET techniques. Further, an in vitro bioactivity study was performed in simulated body fluid (SBF) which shows hydroxyapatite formation. The in vitro haemolysis study displayed less than 5% haemolysis. Subsequently, the angiogenesis study was carried out using the ex ovo CAM model which reveals enhanced neovascularization. The MG-63 cells were used to study the biocompatibility, and they displayed a non-toxic nature at a concentration of 10 mg mL-1. Further, the in vivo biocompatibility results also reveal its non-toxic nature. Thus, the BM-Alg composite acts as a potential biocompatible material for bone tissue engineering applications.

Nanotechnology in tissue engineering: expanding possibilities with nanoparticles

Tissue engineering is a multidisciplinary field that merges engineering, material science, and medical biology in order to develop biological alternatives for repairing, replacing, maintaining, or boosting the functionality of tissues and organs. The ultimate goal of tissue engineering is to create biological alternatives for repairing, replacing, maintaining, or enhancing the functionality of tissues and organs. However, the current landscape of tissue engineering techniques presents several challenges, including a lack of suitable biomaterials, inadequate cell proliferation, limited methodologies for replicating desired physiological structures, and the unstable and insufficient production of growth factors, which are essential for facilitating cell communication and the appropriate cellular responses. Despite these challenges, there has been significant progress made in tissue engineering techniques in recent years. Nanoparticles hold a major role within the realm of nanotechnology due to their unique qualities that change with size. These particles, which provide potential solutions to the issues that are met in tissue engineering, have helped propel nanotechnology to its current state of prominence. Despite substantial breakthroughs in the utilization of nanoparticles over the past two decades, the full range of their potential in addressing the difficulties within tissue engineering remains largely untapped. This is due to the fact that these advancements have occurred in relatively isolated pockets. In the realm of tissue engineering, the purpose of this research is to conduct an in-depth investigation of the several ways in which various types of nanoparticles might be put to use. In addition to this, it sheds light on the challenges that need to be conquered in order to unlock the maximum potential of nanotechnology in this area.

Multi-functional bandage - bioactive glass/metal oxides/alginate composites based regenerative membrane facilitating re-epithelialization in diabetic wounds with sustained drug delivery and anti-bactericidal efficacy

Chronic wounds, especially diabetic, foot and pressure ulcers are a major health problem affecting >10 % of the world's populace. Calcium phosphate materials, particularly, bioactive glasses (BG), used as a potential material for hard and soft tissue repair. This study combines nanostructured 45S5 BG with titania (TiO2) and alumina (Al2O3) into a composite via simple sol-gel method. Prepared composites with alginate (Alg) formed a bioactive nanocomposite hydrogel membrane via freezing method. X-ray diffraction revealed formation of two phases such as Na1.8Ca1.1Si6O14 and β-Na2Ca4(PO4)2SiO4 in the silica network. Fourier transformed InfraRed spectroscopy confirmed the network formation and cross-linking between composite and alginate. <2 % hemolysis, optimal in vitro degradation and porosity was systematically evaluated up to 7 days, resulting in increasing membrane bioactivity. Significant cytocompatibility, cell migration and proliferation and a 3-4-fold increase in Collagen (Col) and Vascular Endothelial Growth Factor (VEGF) expression were obtained. Sustained delivery of 80 % Dox in 24 h and effective growth reduction of S. aureus and destruction of biofilm development against E. coli and S. aureus within 24 h. Anatomical fin regeneration, rapid re-epithelialization and wound closure were achieved within 14 days in both zebrafish and in streptozotocin (STZ) induced rat in vivo animal models with optimal blood glucose levels. Hence, the fabricated bioactive membrane can act as effective wound dressing material, for diabetic chronic infectious wounds.

Alginate templated synthesis, characterization and in vitro osteogenic evaluation of strontium-substituted hydroxyapatite

The objective of this study is to explore the potential role of alginate (Alg) in the crystallization of metal-substituted hydroxyapatite, with application in orthopaedic reconstruction. The alginate at different concentrations (0.5 and 1.0 wt%) facilitated in situ mineralization of hydroxyapatite (HA) and strontium-substituted HA (SHA, 10 and 30 mol%). The incorporation of the biopolymer and dopant induced notable changes in HA, including reduced crystal size from 31.0 to 16.4 nm and increased lattice volume from 577.3 to 598.0 Å3. The superior affinity of alginate for Sr2+ than for Ca2+ resulted in higher residual alginate in Alg/SHA (13.0 to 19.0 %) compared to Alg/HA (7.1 to 8.2 %). This residual alginate influenced composite properties: surface charge decreased from -26.5 to -45.7 mV, microhardness increased from 0.33 to 0.54 GPa, and dissolution increased from 0.17 to 0.39 %. The in vitro studies revealed that strontium substitution as well as the organization and crystallographic aspects of apatite regulated osteoblastic cell survival, proliferation, differentiation, and biomineralization. The findings suggest that an alginate concentration of 0.5 wt% is optimal for the crystallization of SHA with 10 mol% substitution, and its resulting composite possesses the ideal biomechanical properties to imitate native bone.

Potential applications of medicinal herbs and phytochemicals in oral and dental health: Status quo and future perspectives

OBJECTIVE

Herbal therapies are utilized to treat a broad diversity of diseases all over the globe. Although no clinical studies have been conducted to demonstrate the antibacterial, antimicrobial, and antiplaque characteristics of these plants, this does not imply that they are ineffectual as periodontal treatments or anti-cariogenic drugs. However, there is a scarcity of research confirming their efficacy and worth.

SUBJECT

Herbs are utilized in dentistry as antimicrobial, antineoplastic, antiseptic, antioxidant, and analgesics agents as well as for the elimination of bad breath. In addition, the application of herbal agents in tissue engineering improved the regeneration of oral and dental tissues. This study reviews the application of medicinal herbs for the treatment of dental and oral diseases in different aspects.

METHODS

This article focuses on current developments in the use of medicinal herbs and phytochemicals in oral and dental health. An extensive literature review was conducted via an Internet database, mostly PubMed. The articles included full-text publications written in English without any restrictions on a date.

CONCLUSION

Plants have been suggested, as an alternate remedy for oral-dental problems, and this vocation needs long-term dependability. More research on herbal medicine potential as pharmaceutical sources and/or therapies is needed.

Biopolymers and Their Application in Bioprinting Processes for Dental Tissue Engineering

Dental tissues are composed of multiple tissues with complex organization, such as dentin, gingiva, periodontal ligament, and alveolar bone. These tissues have different mechanical and biological properties that are essential for their functions. Therefore, dental diseases and injuries pose significant challenges for restorative dentistry, as they require innovative strategies to regenerate damaged or missing dental tissues. Biomimetic bioconstructs that can effectively integrate with native tissues and restore their functionalities are desirable for dental tissue regeneration. However, fabricating such bioconstructs is challenging due to the diversity and complexity of dental tissues. This review provides a comprehensive overview of the recent developments in polymer-based tissue engineering and three-dimensional (3D) printing technologies for dental tissue regeneration. It also discusses the current state-of-the-art, focusing on key techniques, such as polymeric biomaterials and 3D printing with or without cells, used in tissue engineering for dental tissues. Moreover, the final section of this paper identifies the challenges and future directions of this promising research field.

Design and characterization of adipose-derived mesenchymal stem cell loaded alginate/pullulan/hyaluronic acid hydrogel scaffold for wound healing applications

Recently, significant attention has been focused on the progression of skin equivalents to facilitate faster wound healing and thereby skin restoration. The main aim of this study was the design and characterization of a novel polysaccharide-based hydrogel scaffold by using alginate, pullulan, and hyaluronic acid polymers to provide an appropriate microenvironment to deliver Adipose-derived mesenchymal Stem Cells (ASC) in order to promote wound healing in an animal model. Characterization of synthesized hydrogel was done by using a field emission scanning electron microscope (FE-SEM), Fourier Transform-Infrared spectroscopy (FT-IR), and Differential Scanning Calorimetry (DSC). Also, contact angle analysis, the swelling and mechanical tests were performed. As a result of in vitro studies, cells can be attached, alive, and migrate through the prepared hydrogel scaffold. Finally, the therapeutic effect of the cell-seeded hydrogels was tested in the full-thickness animal wound model. Based on obtained results, the hydrogel-ASC treatment improved the healing process and accelerated wound closure.

Dentin extracellular matrix loaded bioactive glass/GelMA support rapid bone mineralization for potential pulp regeneration

The study aims to develop a novel dentin extracellular matrix (dECM) loaded gelatin methacrylate (GelMA)-5 wt% bioactive glass (BG) (Gel-BG) hydrogel for dental pulp regeneration. We investigate the role of dECM content (2.5, 5, and 10 wt%) on the physicochemical characteristics and biological responses of Gel-BG hydrogel in contact with stem cells isolated from human exfoliated deciduous teeth (SHED). Results showed that the compressive strength of Gel-BG/dECM hydrogel significantly enhanced from 18.9 ± 0.5 kPa (at Gel-BG) to 79.8 ± 3.0 kPa after incorporation of 10 wt% dECM. Moreover, we found that in vitro bioactivity of Gel-BG improved and the degradation rate and swelling ratio reduced with increasing dECM content. The hybrid hydrogels also revealed effectual biocompatibility, >138 % cell viability after 7 days of culture; where Gel-BG/5%dECM was most suitable. In addition, the incorporation of 5 wt% dECM within Gel-BG considerably improved alkaline phosphatase (ALP) activity and osteogenic differentiation of SHED cells. Taken together, the novel bioengineered Gel-BG/dECM hydrogels having appropriate bioactivity, degradation rate, osteoconductive and mechanical properties represent the potential applications for clinical practice in the future.

Zinc and Strontium-Substituted Bioactive Glass Nanoparticle/Alginate Composites Scaffold for Bone Regeneration

The global population is growing older and entering an aging society. Aging results in severe tissue disorder and organ dysfunction. Bone-related injuries are particularly significant. The need for alternative bone replacement materials for human implants has grown over the past few decades. Alginate has the potential for use as a cell scaffold for bone tissue engineering due to its high bio-compatibility. To improve the bioactivity of alginate scaffolds, zinc- and strontium-containing sol-gel-derived bioactive glass nanoparticles (Zn-Sr-BGNPs) with sizes ranging from 100 to l40 nm were incorporated. Zn-Sr-BGNPs synthesized through the sol-gel process have a high sur-face-to-volume ratio, homogeneity, and purity, resulting in faster degradation. The therapeutic bivalent ions released from Zn-Sr-BGNPs strengthen the cell scaffold and improve the stimulation of the production and development of bone cells. Zn-Sr-BGNPs with different Zn to Si nominal ratios of 0, 1, and 1.5 were mixed with alginate in this research. The ratio of Zn in Zn-Sr-BGNPs and the ratio of Zn-Sr-BGNPs in scaffolds impact the pore size, swelling, and biological properties of synthesized composite scaffolds. The surface area and pore volume of a 1:1 1Zn-Sr-BGNP:Alg composite scaffold were 22.58 m²/g and 0.055 cm³/g, respectively. The incorporation of Zn-Sr-BGNPs improved the mechanical performance of the scaffolds up to 4.73 ± 0.48 MPa. The swelling rate decreased slightly from 2.12 (pure Alg) to 1.50 (1Zn-Sr-BGNP:Alg (1:1)). The 1Zn-Sr-BGNP:Alg (1:1) composite scaffold promoted bioactivity through apatite layer formation, increased bone cell proliferation via the dissolution products released from the scaffold, enhanced calcium deposition, and facilitated cell attachment. Thus, 1Zn-Sr-BGNP:Alg (1:1) composite scaffold is proposed as a possible artificial bone scaffold in bone tissue regeneration.

Preparation and characterization of a self-crosslinking sodium alginate-bioactive glass sponge

In this research, bioactive glass particles prepared by the reactive flash nanoprecipitation method (RFNP-BG particles) are used to crosslink sodium alginate to prepare biological sponges (SA-BG sponges) by freeze-drying. An experiment for the cross-linking mechanism confirms that the continuous release of Ca²⁺ from RFNP-BG is promoted by the crosslinking reaction and in turn leads to the gelation process of SA. Bioactive glass particles not only provide Ca²⁺ for the crosslinking of sodium alginate, but also enhance the mechanical properties of the SA-BG sponges. The results show that the elastic modulus of the SA-BG sponges increases from 0.026 MPa to 0.641 MPa, and the resistance to external force deformation is greatly improved; the thermal decomposition temperature increases from 105°C to 166°C; compared with a pure SA sponge, the water resistance is significantly improved. In vitro cell experiments show that the SA-BG sponges have a certain adverse effect on cell proliferation, but it is in an acceptable range. qPCR results show that the SA-BG sponges have a certain beneficial effect on promoting osteogenic gene expression. The SA-BG sponges have great application potential in the fields of medicine, hemostasis, and wound closure.

Medical and Dental Applications of Titania Nanoparticles: An Overview

Currently, titanium oxide (TiO₂) nanoparticles are successfully employed in human food, drugs, cosmetics, advanced medicine, and dentistry because of their non-cytotoxic, non-allergic, and bio-compatible nature when used in direct close contact with the human body. These NPs are the most versatile oxides as a result of their acceptable chemical stability, lower cost, strong oxidation properties, high refractive index, and enhanced aesthetics. These NPs are fabricated by conventional (physical and chemical) methods and the latest biological methods (biological, green, and biological derivatives), with their advantages and disadvantages in this epoch. The significance of TiO₂ NPs as a medical material includes drug delivery release, cancer therapy, orthopedic implants, biosensors, instruments, and devices, whereas their significance as a dental biomaterial involves dentifrices, oral antibacterial disinfectants, whitening agents, and adhesives. In addition, TiO₂ NPs play an important role in orthodontics (wires and brackets), endodontics (sealers and obturating materials), maxillofacial surgeries (implants and bone plates), prosthodontics (veneers, crowns, bridges, and acrylic resin dentures), and restorative dentistry (GIC and composites).

Nanofibrous Hydrogel Nanocomposite Based on Strontium-Doped Bioglass Nanofibers for Bone Tissue Engineering Applications

The main aim of the current study is to fabricate an osteocompatible, bioactive, porous, and degradable bone tissue engineering scaffold. For this purpose, bioactive glasses (BGs) were chosen due to their similarity to bone's natural mineral composition, and the effect of replacing Ca ions with Sr on their properties were considered. First, strontium-containing BGs (Sr-BGs) were synthesized using the electrospinning technique and assembled by the sol-gel method, then they were incorporated into the alginate (Alg) matrix. Photographs of the scanning electron microscope (SEM) showed that the BG nanofibers have a diameter of 220 ± 36 nm, which was smaller than the precursor nanofibers (275 ± 66 nm). The scaffolds possess a porous internal microstructure (230-330 nm pore size) with interconnected pores. We demonstrated that the scaffolds could be degraded in the acetate sodium buffer and phosphate-buffered saline. The osteoactivity of the scaffolds was confirmed via visual inspection of the SEM illustrations after seven days of immersing them in the SBF solution. In vitro assessments disclosed that the produced Alg-based composites including Sr-BGs (Alg/Sr-BGs) are blood-compatible and biocompatible. Accumulating evidence shows that Alg/Sr-BG (5%, 10%, and 15%) hydrogels could be a promising scaffold for bone regeneration.

Polymeric Nanotechnologies for the Treatment of Periodontitis: A Chronological Review

Periodontitis is a chronic infectious and inflammatory disease of periodontal tissues estimated to affect 70 - 80 % of all adults. At the same time, periodontium, the site of periodontal pathologies, is an extraordinarily complex plexus of soft and hard tissues, the regeneration of which using even the most advanced forms of tissue engineering continues to be a challenge. Nanotechnologies, meanwhile, have provided exquisite tools for producing biomaterials and pharmaceutical formulations capable of elevating the efficacies of standard pharmacotherapies and surgical approaches to whole new levels. A bibliographic analysis provided here demonstrates a continuously increasing research output of studies on the use of nanotechnologies in the management of periodontal disease, even when they are normalized to the total output of studies on periodontitis. The great majority of biomaterials used to tackle periodontitis, including those that pioneered this interesting field, have been polymeric. In this article, a chronological review of polymeric nanotechnologies for the treatment of periodontitis is provided, focusing on the major conceptual innovations since the late 1990s, when the first nanostructures for the treatment of periodontal diseases were fabricated. In the opening sections, the etiology and pathogenesis of periodontitis and the anatomical and histological characteristics of the periodontium are being described, along with the general clinical manifestations of the disease and the standard means of its therapy. The most prospective chemistries in the design of polymers for these applications are also elaborated. It is concluded that the amount of innovation in this field is on the rise, despite the fact that most studies are focused on the refinement of already established paradigms in tissue engineering rather than on the development of revolutionary new concepts.

Bioactive Glasses in Periodontal Regeneration: Existing Strategies and Future Prospects-A Literature Review

The present review deals with bioactive glasses (BGs), a class of biomaterials renowned for their osteoinductive and osteoconductive capabilities, and thus widely used in tissue engineering, i.e., for the repair and replacement of damaged or missing bone. In particular, the paper deals with applications in periodontal regeneration, with a special focus on in vitro, in vivo and clinical studies. The study reviewed eligible publications, identified on the basis of inclusion/exclusion criteria, over a ranged time of fifteen years (from 1 January 2006 to 31 March 2021). While there are many papers dealing with in vitro tests, only a few have reported in vivo (in animal) research, or even clinical trials. Regardless, BGs seem to be an adequate choice as grafts in periodontal regeneration.

Preparation of the bioglass/chitosan-alginate composite scaffolds with high bioactivity and mechanical properties as bone graft materials

Bioglass/chitosan-alginate (BCA) composite scaffolds with remarkable performance for bone tissue engineering are successfully prepared by freeze-drying method. The influence of the addition amount of sodium alginate (SA) on the microstructure, porosity, pore size, swelling ratio, degradation ratio, mechanical properties and mineralization ability of BCA composite scaffolds is studied and characterized by various techniques of the scanning electron microscopy, X-ray diffraction, infrared absorption spectrometer and so on. The results show that the BCA composite scaffolds have the three-dimensional interconnected network structure with the high porosity of 82%-87% and a suitable average pore size of 140-200 μm. With the increase of SA addition, the porosity and pore size of BCA gradually reduced and the thickness of pore wall increased. The swelling and degradation ratios decreased gradually with the raising SA and increased with the prolongation of soaking time in PBS. The mechanical strength of BCA was also significantly enhanced, and the mineralization ability of bioglass was effectively deployed with the adding SA of BCA. The improved performance of BCA may be attributed to the formed 3D network structure, activated bioavailability and crosslinking ability between chitosan and SA. It indicates that BCA composite scaffolds have potential applications in bone issues engineering.

Velvet antler polypeptide-loaded polyvinyl alcohol-sodium alginate hydrogels promote the differentiation of neural progenitor cells in 3D towards oligodendrocytes in vitro

Three-dimensional (3D) culture of neural progenitor cells (NPCs) in hydrogels represents a powerful means for recapitulating neurodevelopment, disease modelling and drug discovery. However, the differentiation of NPCs to oligodendrocytes in 3D scaffolds remains a great challenge. In this study, polyvinyl alcohol (PVA) - sodium alginate (SA) composite hydrogels intended for NPC culture in 3D were fabricated by ionic crosslinking between SA and calcium ions. It was demonstrated that adding PVA to the composite hydrogels resulted in increases in pore size and swelling rate and decreases in elastic moduli as the PVA proportion was enhanced. In addition, the composite hydrogels were biocompatible with mouse NPCs and improved the proliferation of the encapsulated NPCs compared with SA hydrogels. Moreover, when velvet antler polypeptides (VAPs), which were capable of facilitating the differentiation of NPCs to oligodendrocyte fate in 2D, were loaded into PVA-SA hydrogels, NPCs differentiated into neurons, astrocytes and oligodendrocytes, with the presence of VAPs promoting oligodendrogenesis in a dose-dependant manner. The present composite hydrogels provide a suitable scaffold for the construction of neural tissue engineering and neurological disease modelling.

Biological and bioactivity assessment of dextran nanocomposite hydrogel for bone regeneration

Insufficient biological and bioactive properties of dextran hydrogels limit their applications as promising scaffolds for tissue engineering. We developed nanocomposite dextran hydrogels comprised of bioactive glass (nBGC: 64% SiO2, 31% CaO, 5% P₂O₅) nanoparticles with an average particle size of 77 nm using a chemical crosslinking of dextran chains to form 3D hydrogel networks. In the current study; bioactivity of the obtained nanocomposite hydrogels was evaluated through the formation of apatite crystal structures after the incubation in simulated body fluid (SBF) at various submersion periods and nBGC content. The scanning electron microscopy (SEM) micrographs represented an enhanced hydroxyapatite formation on the cross section of nanocomposite comprising of nBGC content from 2 to 8 (% by wt). Biomineralization results of Dex-8 (% by wt) composite during 7, 14 and 28 days immersion indicated the apatite layer formation and the growth of apatite crystal size on the surface and cross section of the nanocomposite. Moreover, MTT assessments indicated that human osteosarcoma cells (SaOS-2) were able to adhere and spread within the dextran hydrogels reinforced with the bioactive glass nanoparticles. With regard to enhanced bioactivity and biocompatibility, the developed dextran-nBGC hydrogel could be considered as a suitable candidate for bone tissue engineering application.

In Vivo Evaluation of Decellularized Human Tooth Scaffold for Dental Tissue Regeneration

Conventional root canal treatment may result in loss of tooth vitality, which can lead to unfavorable treatment outcomes. Notably, a ceased tooth development of immature permanent teeth with open apices, regeneration of periodontal ligaments (PDL), and pulp is highly expected healing process. For regeneration, the scaffold is one of the critical components that carry biological benefits. Therefore, this study evaluated a decellularized human tooth as a scaffold for the PDL and pulp tissue regeneration. A tooth scaffold was fabricated using an effective decellularization method as reported in previous studies. PDL stem cells (PDLSCs) and dental pulp stem cells (DPSCs) obtained from human permanent teeth were inoculated onto decellularized scaffolds, then cultured to transplant into immunosuppressed mouse. After 9 weeks, PDLSCs and DPSCs that were inoculated onto decellularized tooth scaffolds and cultured in an in vivo demonstrated successful differentiation. In PDLSCs, a regeneration of the cementum/PDL complex could be expected. In DPSCs, the expression of genes related to revascularization and the hard tissue regeneration showed the possibility of pulp regeneration. This study suggested that the potential possible application of decellularized human tooth could be a scaffold in regeneration PDL and pulp tissue along with PDLSCs and DPSCs, respectively, as a novel treatment method.

Hydrogel Composites with Different Dimensional Nanoparticles for Bone Regeneration

The treatment of large segmental bone defects and complex types of fractures caused by trauma, inflammation, or tumor resection is still a challenge in the field of orthopedics. Various natural or synthetic biological materials used in clinical applications cannot fully replicate the structure and performance of raw bone. This highlights how to endow materials with multiple functions and biological properties, which is a problem that needs to be solved in practical applications. Hydrogels with outstanding biocompatibility, for their casting into any shape, size, or form, are suitable for different forms of bone defects. Therefore, they have been used in regenerative medicine more widely. In this review, versatile hydrogels are compounded with nanoparticles of different dimensions, and many desirable features of these materials in bone regeneration are introduced, including drug delivery, cell factor vehicle, cell scaffolds, which have potential in bone regeneration applications. The combination of hydrogels and nanoparticles of different dimensions encourages better filling of bone defect areas and has higher adaptability. This is due to the minimally invasive properties of the material and ability to match irregular defects. These biological characteristics make composite hydrogels with different dimensional nanoparticles become one of the most attractive options for bone regeneration materials.

Biomaterials and osteoradionecrosis of the jaw: Review of the literature according to the SWiM methodology

OBJECTIVES

To systematically present and interpret the current literature on research and treatment perspectives for mandibular osteoradionecrosis (mORN) in the field of biomaterials.

MATERIAL AND METHODS

A systematic review of the literature using the "Synthesis without meta-analysis" (SWiM) methodology was performed on PubMed, Embase and Cochrane, focusing on the implantation of synthetic biomaterials for bone reconstruction in mORN in humans and/or animal models. The primary endpoints were the composition, efficacy on mORN and tolerance of the implanted synthetic biomaterials.

RESULTS

Forty-seven references were obtained and evaluated in full-text by two assessors. Ten (8 in humans and 2 in animal models) met the eligibility criteria and were included for analysis. Materials most often comprised support plates or metal mesh (5 of 10 cases) in combination with grafts or synthetic materials (phosphocalcic ceramics, glutaraldehyde). Other ceramic/polymer composites were also implanted. In half of the selected reports, active compounds (molecules, growth factors, lysates) and/or cells were associated with the reconstruction material. The number of articles referring to implantation of biomaterials for the treatment of mORN was small, and the properties of the implanted biomaterials were generally poorly described, thus limiting a thorough understanding of their role.

CONCLUSION

In preventing the morbidity associated with some reconstructive surgeries, basic research has benefitted from recent advances in tissue engineering and biomaterials to repair limited bone loss.

Applications of nanomaterials in tissue engineering

Recent advancement in nanotechnology has brought prominent benefits in tissue engineering, which has been used to repair or reconstruct damaged tissues or organs and design smart drug delivery systems. With numerous applications of nanomaterials in tissue engineering, it is vital to choose appropriate nanomaterials for different tissue engineering applications because of the tissue heterogeneity. Indeed, the use of nanomaterials in tissue engineering is directly determined by the choice. In this review, we mainly introduced the use of nanomaterials in tissue engineering. First, the basic characteristics, preparation and characterization methods of the types of nanomaterials are introduced briefly, followed by a detailed description of the application and research progress of nanomaterials in tissue engineering and drug delivery. Finally, the existing challenges and prospects for future applications of nanomaterials in tissue engineering are discussed.

Efficient drug delivery vehicles of environmentally benign nano-fibers comprising bioactive glass/chitosan/polyvinyl alcohol composites

Nano-fiber composites have shown promising potential in biomedical and biotechnological applications. Herein, novel nano-fiber composites constituting a blend of polyvinyl alcohol (PVA) and chitosan (CS) along with different weight ratios of nano-bioactive glass (BG) were prepared by electrospinning. Nano-fibers incorporating 10% (by wt.) of BG were uniform, dense and defect-free with a diameter of 20-125 nm. The model osteoporotic drug (Risedronate sodium) was blended with the electrospinning forming solution and the in-vitro drug release was further studied. About 30% of the drug was released after only 30 min and the release pattern was sustained over 96 h. Drug release took place through a two-stage intra-particle diffusion mechanism. BG-incorporated nano-fibers markedly retarded the drug release profile relative to their BG-free counterparts. They also enhanced the drug release efficiency by releasing 93 ± 4% of the drug. The developed nano-fiber composites can be potentially used as drug-delivery vehicles due to their efficiency and sustained drug release capacity.

Lotus-Root-Like Microchanneled Collagen Scaffold

In the human body, there are numerous microtubular tissue structures, such as muscles, vessels, nerves, and tendons. Tissue engineering scaffolds have been regarded as a high-potential candidate for providing such aligned instructive niches to facilitate cell-recruitment and differentiation, and eventually, successful tissue regeneration. Moreover, scaffolds derived from the extracellular matrix (ECM) can provide excellent biocompatibility. However, the fabrication of such microtubular hierarchical scaffolds using ECM has proven to be difficult, and thus, innovative fabrication approaches are required. Herein, we have developed a biofabrication system involving a sequential removal of supporting materials (polycaprolactone (PCL) and poly(vinyl alcohol) (PVA)) to fabricate a uniaxially aligned microtubular collagen scaffold, a lotus-like structure. To generate the unique morphological structures of the scaffold, we manipulated various material-related and processing factors, such as the molecular weight of PVA and the weight fraction of collagen coating. Physical and biological activities of the aligned hierarchical microtubular collagen scaffolds were compared with those of the controls (conventional collagen struts and microtubular collagen scaffolds void of a uniaxial topographical cue). In conclusion, the instructive niche on the aligned hierarchical microtubular collagen structure induced high degrees of myoblast alignment and efficient myogenic differentiation.

Biofabrication and Characterization of Alginate Dialdehyde-Gelatin Microcapsules Incorporating Bioactive Glass for Cell Delivery Application

The effect of the incorporation of 45S5 bioactive glass (BG) microparticles (mean particle size ≈ 2 µm) on the fabrication and physicochemical properties of alginate dialdehyde-gelatin hydrogel capsules is investigated. The addition of BG particles decreases the hydrogel gelation time by ≈79% and 91% for the samples containing 0.1% w/v and 0.5% w/v BG, respectively. Moreover, it results in increasing average diameter of hydrogel capsules produced via a pressure-driven extrusion technique from about 1000 µm for the samples without BG to about 1700 and 1900 µm for the samples containing BG at concentrations of 0.1% w/v and 0.5% w/v, respectively. The presence of BG particles in the capsules decreases the degradation rate and improves the bioactivity of the materials. The viability of MG-63 cells encapsulated in all samples increases during the first 7 d of cultivation and maintains the same level during 21 d of cultivation. The early cell viability in samples containing BG is lower than that in samples without BG. The results show that 45S5 BG can positively regulate the osteogenic activity of cells incorporated in hydrogel capsules. The fabricated composite capsules exhibit promising potential for cell delivery in bone regeneration applications.

Combinatorial effect of nano whitlockite/nano bioglass with FGF-18 in an injectable hydrogel for craniofacial bone regeneration

Comparing the bone regeneration potential of nano whitlockite or nano bioglass in combination with FGF-18, loaded in an injectable, shear-thinning chitin/PLGA hydrogel for craniofacial bone regeneration.

A Review of Bioactive Glass/Natural Polymer Composites: State of the Art

Collagen, gelatin, silk fibroin, hyaluronic acid, chitosan, alginate, and cellulose are biocompatible and non-cytotoxic, being attractive natural polymers for medical devices for both soft and hard tissues. However, such natural polymers have low bioactivity and poor mechanical properties, which limit their applications. To tackle these drawbacks, collagen, gelatin, silk fibroin, hyaluronic acid, chitosan, alginate, and cellulose can be combined with bioactive glass (BG) nanoparticles and microparticles to produce composites. The incorporation of BGs improves the mechanical properties of the final system as well as its bioactivity and regenerative potential. Indeed, several studies have demonstrated that polymer/BG composites may improve angiogenesis, neo-vascularization, cells adhesion, and proliferation. This review presents the state of the art and future perspectives of collagen, gelatin, silk fibroin, hyaluronic acid, chitosan, alginate, and cellulose matrices combined with BG particles to develop composites such as scaffolds, injectable fillers, membranes, hydrogels, and coatings. Emphasis is devoted to the biological potentialities of these hybrid systems, which look rather promising toward a wide spectrum of applications.

Effect of zirconia-mullite incorporated biphasic calcium phosphate/biopolymer composite scaffolds for bone tissue engineering

New bioactive scaffolds with improved mechanical properties, biocompatibility and providing structural support for bone tissue are being developed for use in the treatment of bone defects. In this study, we have synthesized bioactive scaffolds consisting of biphasic calcium phosphate (BCP) and zirconia-Mullite (2ZrO₂·[3Al₂O₃ ·2 SiO₂] (ZAS)) (BCPZAS) combined with polymers matrix of polycaprolactone (PCL)-alginate (Alg)-chitosan (Chi) (Chi/Alg-PCL) (BCPZAS@Chi/Alg-PCL). The composite material scaffolds were prepared by a blending technique. The microstructure, mechanical, bioactivity and in vitro biological properties with different ratios of BCP to ZAS of 1:0, 3:1, 1:1, 1:3 and 0:1 wt% in polymer matrix were analyzed. Microstructure analysis showed a successful incorporation of the BCPZAS particles with an even distribution of them within the polymer matrix. The mechanical properties were found to gradually decrease with increasing the ratio of ZAS particles in the scaffolds. The highest compressive strength was 42.96 ± 1.01MPa for the 3:1 wt% BCP to ZAS mixing. Bioactivity test, the BCPZAS@Chi/Alg-PCL composite could induce apatite formation in simulate body fluid (SBF). In-vitro experiment using UMR-106 osteoblast-like cells on BCPZAS@Chi/Alg-PCL composite scaffold showed that there is cell attachment to the scaffolds with proliferation. These experimental results demonstrate that the BCPZAS@Chi/Alg-PCL composite especially for the BCP:ZAS at 3:1 wt% could be utilized as a scaffold for bone tissue engineering applications.

Effect of bioglass nanoparticles on the properties and bioactivity of poly(lactic acid) films

Bioglass nanoparticles (n-BGs, 54SiO₂ :40CaO:6P₂ O₅ mol %) with about 27 nm diameter were synthesized by the sol-gel method and incorporated into a poly(lactic acid) (PLA) matrix by the melting process in order to obtain nanocomposites with filler contents of 5, 10, and 25 wt %. Our results showed that during the cooling scan, the crystallization temperature (T_c ) of the PLA/n-BG nanocomposites decreased 13°C as compared to neat PLA. The presence of nanoparticles also decreased the thermal stability of the PLA matrix, as nanocomposites presented up to about 20°C lower degradation temperatures in a nitrogen atmosphere. The presence of n-BG increased the stiffness of the polymer matrix, and for instance the composite with 25 wt % of filler presented about 52.6% higher Young's modulus than neat PLA. n-BG incorporation into PLA increased also the hydrolytic degradation of the polymer over time. When the PLA composites were immersed in simulated body fluid, an apatite layer was formed on their surface, as verified by Fourier transform infrared, X-Ray Diffraction (XRD), and scanning electron microscopy-EDS, showing that the presence of n-BG induced bioactivity on the PLA matrix. Moreover, the viability of cervical uterine adenocarcinoma cells was higher on PLA/n-BG nanocomposite with 25 wt % of filler. The presence of n-BG barely gave an antibacterial effect on the polymer matrix, despite the well-known biocidal properties of these nanoparticles. Our results show that the presence of n-BGs is a proper route for improving the bioactivity of PLA with potential application in tissue engineering.

Freeze-gelled alginate/gelatin scaffolds for wound healing applications: An in vitro, in vivo study

In this study, fabrication of a three-dimensional porous scaffold was performed using freeze gelation method. Recently, fabrication of scaffolds using polymer blends has become common for many tissue engineering applications due to their unique tunable properties. In this work, we fabricated alginate-gelatin porous hydrogels for wound healing application using a new method based on some modifications to the freeze-gelation method. Alginate and gelatin were mixed in three different ratios and the resulting solutions underwent freeze gelation to obtain 3D porous matrices. We analyzed the samples using different characterization tests. The scanning electron microscopy (SEM) results indicated that the freeze gelation method was successful in obtaining porous morphologies for all the fabricated alginate-gelatin samples as previously was seen in single-polymer fabrication using this method. The alginate to gelatin ratio affected swelling, biodegradation, cell culture and mechanical properties of the matrices. The scaffold with the lowest content of gelatin had the highest swelling ratio while biodegradation and cell proliferation and viability were increased with the gelatin content. Regarding the mechanical properties, as the gelatin content increased, the scaffold became more ductile and showed higher tensile strength. The in-vivo results also showed the biocompatibility of the blend scaffold and its positive role in wound healing process in rats. The low-cost procedure used in this study to fabricate the porous alginate-gelatin scaffolds can be adapted and modified to suit different tissue engineering applications.

Effect of nanoscale bioactive glass with radial spherical particles on osteogenic differentiation of rat bone marrow mesenchymal stem cells

To validate the feasibility of two types of bioactive glass that contains spherical and radical spherical nano-sized particles in promoting bone repair, we hypothesize that radical spherical nano-sized particles have higher bone repair effectiveness than spherical one due to the physicochemical properties. We rigorously compared the physicochemical properties and bioactivities of these two types of bioactive glass. Specifically, we measured the size, surface morphology, concentration of ionic-dissolution products, bioactivity, and biological effects of two groups of bioactive glass on rat bone marrow mesenchymal stem cells (rBMSCs) and evaluate their effect on proliferation and osteogenic differentiation of rBMSCs in vitro. We observed that spherical nano-bioactive glass (SNBG) was spherical with smooth boundary, while the radial spherical nano-bioactive glass (RSNBG) had radial pore on the surface of particle boundary. When the two materials were immersed in simulated body fluid for 24 h, RSNBG produced more and denser hydroxyapatite carbonate than SNBG. The concentration of Ca and Si ions in RSNBG 24 h extract is higher than that of SNBG, while the concentration of P ions is lower. Proliferation, alkaline phosphatase (ALP) activity, intracellular Ca ion concentrations defined as the number of mineralized nodules produced, and the expression of osteogenic genes were significantly higher in rBMSCs co-cultured with 50 µg/mL RSNBG than SNBG. Overall, these results validated our hypothesis that RSNBG can provide better benefit than SNBG for inducing proliferation and osteogenic differentiation in rBMSCs, in turn suggested the feasibility of this RSNBG in further studies and utilization toward the ends of improved bone repair effectiveness.

In vitro comparison of 3D printed polylactic acid/hydroxyapatite and polylactic acid/bioglass composite scaffolds: Insights into materials for bone regeneration

3D printing of polylactic acid (PLA) and hydroxyapatite (HA) or bioglass (BG) bioceramics composites is the most promising technique for artificial bone construction. However, HA and BG have different chemical composition as well as different bone regeneration inducing mechanisms. Thus, it is important to compare differentiation processes induced by 3D printed PLA + HA and PLA + BG scaffolds in order to evaluate the strongest osteoconductive and osteoinductive properties possessing bioceramics. In this study, we analysed porous PLA + HA (10%) and PLA + BG (10%) composites' effect on rat's dental pulp stem cells fate in vitro. Obtained results indicated, that PLA + BG scaffolds lead to weaker cell adhesion and proliferation than PLA + HA. Nevertheless, osteoinductive and other biofriendly properties were more pronounced by PLA + BG composites. Overall, the results showed a strong advantage of bioceramic BG against HA, thus, 3D printed PLA + BG composite scaffolds could be a perspective component for patient-specific, cheaper and faster artificial bone tissue production.