An injectable and thermosensitive hydrogel: Promoting periodontal regeneration by controlled-release of aspirin and erythropoietin

Advances in hydrogels for the treatment of periodontitis

Periodontitis is the second most prevalent oral disease and can cause serious harm to human health. Hydrogels are excellent biomaterials that can be used for periodontitis as drug delivery platforms to achieve inflammation control through high drug delivery efficiency and sustained drug release and as tissue scaffolds to achieve tissue remodelling through encapsulated cell wrapping and effective mass transfer. In this review, we summarize the latest advances in the treatment of periodontitis with hydrogels. The pathogenic mechanisms of periodontitis are introduced first, followed by the recent progress of hydrogels in controlling inflammation and tissue reconstruction, in which the specific performance of hydrogels is discussed in detail. Finally, the challenges and limitations of hydrogels for clinical applications in periodontitis are discussed and possible directions for development are proposed. This review aims to provide a reference for the design and fabrication of hydrogels for the treatment of periodontitis.

Research Progress on Nanomaterials for Tissue Engineering in Oral Diseases

Due to their superior antibacterial properties, biocompatibility and high conductivity, nanomaterials have shown a broad prospect in the biomedical field and have been widely used in the prevention and treatment of oral diseases. Also due to their small particle sizes and biodegradability, nanomaterials can provide solutions for tissue engineering, especially for oral tissue rehabilitation and regeneration. At present, research on nanomaterials in the field of dentistry focuses on the biological effects of various types of nanomaterials on different oral diseases and tissue engineering applications. In the current review, we have summarized the biological effects of nanoparticles on oral diseases, their potential action mechanisms and influencing factors. We have focused on the opportunities and challenges to various nanomaterial therapy strategies, with specific emphasis on overcoming the challenges through the development of biocompatible and smart nanomaterials. This review will provide references for potential clinical applications of novel nanomaterials in the field of oral medicine for the prevention, diagnosis and treatment of oral diseases.

An injectable MB/BG@LG sustained release lipid gel with antibacterial and osteogenic properties for efficient treatment of chronic periodontitis in rats

Periodontitis is a chronic inflammatory disease characterized by the colonization of pathogenic microorganisms and the loss of periodontal supporting tissue. However, the existing local drug delivery system for periodontitis has some problems including subpar antibacterial impact, easy loss, and unsatisfactory periodontal regeneration. In this study, a multi-functional and sustained release drug delivery system (MB/BG@LG) was developed by encapsulating methylene blue (MB) and bioactive glass (BG) into the lipid gel (LG) precursor by Macrosol technology. The properties of MB/BG@LG were characterized using a scanning electron microscope, a dynamic shear rotation rheometer, and a release curve. The results showed that MB/BG@LG could not only sustained release for 16 days, but also quickly fill the irregular bone defect caused by periodontitis through in situ hydration. Under 660 ​nm light irradiation, methylene blue-produced reactive oxygen species (ROS) can reduce local inflammatory response by inhibiting bacterial growth. In addition, in vitro and vivo experiments have shown that MB/BG@LG can effectively promote periodontal tissue regeneration by reducing inflammatory response, promoting cell proliferation and osteogenic differentiation. In summary, MB/BG@LG exhibited excellent adhesion properties, self-assembly properties, and superior drug release control capabilities, which improved the clinical feasibility of its application in complex oral environments.

Alleviate Periodontitis and Its Comorbidity Hypertension using a Nanoparticle-Embedded Functional Hydrogel System

Periodontitis and hypertension often occur as comorbidities, which need to be treated at the same time. To resolve this issue, a controlled-release composite hydrogel approach is proposed with dual antibacterial and anti-inflammatory activities as a resolution to achieve the goal of co-treatment of comorbidities. Specifically, chitosan (CS) with inherent antibacterial properties is cross-linked with antimicrobial peptide (AMP)-modified polyethylene glycol (PEG) to form a dual antibacterial hydrogel (CS-PA). Subsequently, curcumin loaded into biodegradable nanoparticles (CNP) are embedded in the hydrogel exhibiting high encapsulation efficiency and sustained release to achieve long-term anti-inflammatory activities. In a mouse model of periodontitis complicated with hypertension, CS-PA/CNP is applied to gingival sulcus and produced an optimal therapeutic effect on periodontitis and hypertension simultaneously. The therapeutic mechanisms are deeply studied and indicated that CS-PA/CNP exerted excellent immunoregulatory effects by suppressing the accumulation of lymphocytes and myeloid cells and enhanced the antioxidant capacity and thus the anti-inflammatory capacity of macrophages through the glutathione metabolism pathway. In conclusion, CS-PA/CNP has demonstrated its superior therapeutic effects and potential clinical translational value in the co-treatment of periodontitis and hypertension, and also serves as a drug delivery platform to provide combinatorial therapeutic options for periodontitis with complicated pathogenesis.

[Latest Findings on Hydrogel Drug Delivery Systems in the Treatment of Periodontitis]

Hydrogel drug delivery systems possess unique structures and properties and hence can be injected and retained in the periodontal pocket for slow and controlled release of medications with antibacterial, anti-inflammatory, and periodontal tissue regeneration-promotional effects. Due to their safety, practicability, and effectiveness, they show great potential in the treatment of periodontitis. In this paper, we gave an overview of hydrogel drug delivery systems in the treatment of periodontitis, summing up the classification and forms of the drugs delivered and the strengths and weaknesses of common types of hydrogel matrixes. In addition, we discussed properties required for hydrogel drug delivery systems applicable in the treatment of periodontitis, including a certain level of viscosity, suitable degradation cycle, and temperature sensitivity. Finally, we summarized the stimulus responsiveness types of hydrogel drug delivery systems applicable in the treatment of periodontitis, including pH-responsiveness, enzyme-responsiveness, reactive oxygen species-responsiveness, light-responsiveness, and sugar-responsiveness. In the future, researchers should make further investigation into the clinical efficacy of hydrogel drug delivery systems and promote their translation into clinical applications. Additionally, hydrogel drug delivery systems carrying biologic drugs could be further investigated to promote advancement in the field of periodontal tissue regeneration. Furthermore, the response sources, realization strategies, and safe preparation methods of smart hydrogel drug delivery systems should also be further clarified and explored to achieve drug delivery of better efficiency and safety. In addition to drug delivery, hydrogel matrixes with medicinal values also show great promises.

Injectable antibacterial Ag-HA/ GelMA hydrogel for bone tissue engineering

Background: Fracture or bone defect caused by accidental trauma or disease is a growing medical problem that threats to human health.Currently, most orthopedic implant materials must be removed via follow-up surgery, which requires a lengthy recovery period and may result in bacterial infection. Building bone tissue engineering scaffolds with hydrogel as a an efficient therapeutic strategy has outstanding bionic efficiency.By combining some bionic inorganic particles and hydrogels to imitate the organic-inorganic characteristics of natural bone extracellular matrix, developing injectable multifunctional hydrogels with bone tissue repair effects and also displaying excellent antibacterial activity possesses attractive advantages in the field of minimally invasive therapy in clinical. Methods: In the present work, a multifunctional injectable hydrogel formed by photocrosslinking was developed by introducing hydroxyapatite (HA) microspheres to Gelatin Methacryloyl (GelMA) hydrogel. Results: The composite hydrogels exhibited good adhesion and bending resistance properties due to the existence of HA. In addition, when the concentration of GelMA is 10% and the concentration of HA microspheres is 3%, HA/GelMA hydrogel system displayed increased microstructure stability, lower swelling rate, increased viscosity, and improved mechanical properties. Furthermore, the Ag-HA/GelMA demonstrated good antibacterial activity against Staphylococcus aureus and Escherichia coli, which could signifificantly lower the risk of bacterial infection following implantation. According to cell experiment, the Ag-HA/GelMA hydrogel is capable of cytocompatibility and has low toxicity to MC3T3 cell. Conclusion: Therefore, the new photothermal injectable antibacterial hydrogel materials proposed in this study will provide a promising clinical bone repair strategy and is expected to as a minimally invasive treatment biomaterial in bone repair fields.

Functional hydrogels for the repair and regeneration of tissue defects

Tissue defects can be accompanied by functional impairments that affect the health and quality of life of patients. Hydrogels are three-dimensional (3D) hydrophilic polymer networks that can be used as bionic functional tissues to fill or repair damaged tissue as a promising therapeutic strategy in the field of tissue engineering and regenerative medicine. This paper summarises and discusses four outstanding advantages of hydrogels and their applications and advances in the repair and regeneration of tissue defects. First, hydrogels have physicochemical properties similar to the extracellular matrix of natural tissues, providing a good microenvironment for cell proliferation, migration and differentiation. Second, hydrogels have excellent shape adaptation and tissue adhesion properties, allowing them to be applied to a wide range of irregularly shaped tissue defects and to adhere well to the defect for sustained and efficient repair function. Third, the hydrogel is an intelligent delivery system capable of releasing therapeutic agents on demand. Hydrogels are capable of delivering therapeutic reagents and releasing therapeutic substances with temporal and spatial precision depending on the site and state of the defect. Fourth, hydrogels are self-healing and can maintain their integrity when damaged. We then describe the application and research progress of functional hydrogels in the repair and regeneration of defects in bone, cartilage, skin, muscle and nerve tissues. Finally, we discuss the challenges faced by hydrogels in the field of tissue regeneration and provide an outlook on their future trends.

TRAF-STOP alleviates osteoclastogenesis in periodontitis

The enhanced osteoclastogenesis contributes to alveolar bone resorption in periodontitis, which increases the risk of tooth loss. To reduce bone destruction, the inhibition of osteoclast development is proposed as a feasible treatment. CD40L-CD40-TRAF6 signal transduction plays a crucial role in inflammation, but how it regulates osteoclast activity in periodontitis has not been elucidated. In this study, we showed the potential role of CD40L-CD40-TRAF6 signaling in periodontitis. CD40L obviously promoted osteoclast formation and bone resorption capacity in vitro. Mechanistically, we found that osteoclastogenesis was enhanced by the overexpression of NFATc1 and NF-κB activation. Importantly, osteoclast activity was effectively suppressed by TRAF-STOP, a small molecular inhibitor of TRAF6. Furthermore, local injection of TRAF-STOP-loaded injectable PLGA-PEG-PLGA hydrogel could alleviate ligation-induced periodontitis in vivo. Taken together, TRAF-STOP shows promising clinical efficacy in periodontitis through alleviating osteoclastogenesis.

Chitosan-Based Smart Biomaterials for Biomedical Applications: Progress and Perspectives

Over the past decade, smart and functional biomaterials have escalated as one of the most rapidly emerging fields in the life sciences because the performance of biomaterials could be improved by careful consideration of their interaction and response with the living systems. Thus, chitosan could play a crucial role in this frontier field because it possesses many beneficial properties, especially in the biomedical field such as excellent biodegradability, hemostatic properties, antibacterial activity, antioxidant properties, biocompatibility, and low toxicity. Furthermore, chitosan is a smart and versatile biopolymer due to its polycationic nature with reactive functional groups that allow the polymer to form many interesting structures or to be modified in various ways to suit the targeted applications. In this review, we provide an up-to-date development of the versatile structures of chitosan-based smart biomaterials such as nanoparticles, hydrogels, nanofibers, and films, as well as their application in the biomedical field. This review also highlights several strategies to enhance biomaterial performance for fast growing fields in biomedical applications such as drug delivery systems, bone scaffolds, wound healing, and dentistry.

Hydrogels for Oral Tissue Engineering: Challenges and Opportunities

Oral health is crucial to daily life, yet many people worldwide suffer from oral diseases. With the development of oral tissue engineering, there is a growing demand for dental biomaterials. Addressing oral diseases often requires a two-fold approach: fighting bacterial infections and promoting tissue growth. Hydrogels are promising tissue engineering biomaterials that show great potential for oral tissue regeneration and drug delivery. In this review, we present a classification of hydrogels commonly used in dental research, including natural and synthetic hydrogels. Furthermore, recent applications of these hydrogels in endodontic restorations, periodontal tissues, mandibular and oral soft tissue restorations, and related clinical studies are also discussed, including various antimicrobial and tissue growth promotion strategies used in the dental applications of hydrogels. While hydrogels have been increasingly studied in oral tissue engineering, there are still some challenges that need to be addressed for satisfactory clinical outcomes. This paper summarizes the current issues in the abovementioned application areas and discusses possible future developments.

New Challenges and Prospective Applications of Three-Dimensional Bioactive Polymeric Hydrogels in Oral and Craniofacial Tissue Engineering: A Narrative Review

Regenerative medicine, and dentistry offers enormous potential for enhancing treatment results and has been fueled by bioengineering breakthroughs over the previous few decades. Bioengineered tissues and constructing functional structures capable of healing, maintaining, and regenerating damaged tissues and organs have had a broad influence on medicine and dentistry. Approaches for combining bioinspired materials, cells, and therapeutic chemicals are critical in stimulating tissue regeneration or as medicinal systems. Because of its capacity to maintain an unique 3D form, offer physical stability for the cells in produced tissues, and replicate the native tissues, hydrogels have been utilized as one of the most frequent tissue engineering scaffolds during the last twenty years. Hydrogels' high water content can provide an excellent conditions for cell viability as well as an architecture that mimics real tissues, bone, and cartilage. Hydrogels have been used to enable cell immobilization and growth factor application. This paper summarizes the features, structure, synthesis and production methods, uses, new challenges, and future prospects of bioactive polymeric hydrogels in dental and osseous tissue engineering of clinical, exploring, systematical and scientific applications.

AZ63/Ti/Zr Nanocomposite for Bone-Related Biomedical Applications

Considering the unique properties of magnesium and its alloy, it has a vast demand in biomedical applications, particularly the implant material in tissue engineering due to its biodegradability. But the fixing spares must hold such implants till the end of the biodegradation of implant material. The composite technology will offer the added benefits of altering the material properties to match the requirements of the desired applications. Hence, this experimental investigation is aimed at developing a composite material for manufacturing fixing spares like a screw for implants in biomedical applications. The matrix of AZ63 magnesium alloy is reinforced with nanoparticles of zirconium (Zr) and titanium (Ti) through the stir casting-type synthesis method. The samples were prepared with equal contributions of zirconium (Zr) and titanium (Ti) nanoparticles in the total reinforcement percentage (3%, 6%, 9%, and 12%). The corrosive and tribological studies were done. In the corrosive study, the process parameters like NaCl concentration, pH value, and exposure time were varied at three levels. In the wear study, the applied Load, speed of sliding, and the distance of the slide were considered at four levels. Taguchi analysis was employed in this investigation to optimize the reinforcement and independent factors to minimize the wear and corrosive losses. The minimum wear rate was achieved in the 12% reinforced sample with the input factor levels of 60 N of load on the pin, 1 m/s of disc speed at a sliding distance was 1500 m, and the 12% reinforce samples also recorded a minimum corrosive rate of 0.0076 mm/year at the operating environment of 5% NaCl-concentrated solution with the pH value of 9 for 24 hrs of exposure. The prediction model was developed based on the experimental results.

Hydrogel Drug Delivery Systems for Bone Regeneration

With the in-depth understanding of bone regeneration mechanisms and the development of bone tissue engineering, a variety of scaffold carrier materials with desirable physicochemical properties and biological functions have recently emerged in the field of bone regeneration. Hydrogels are being increasingly used in the field of bone regeneration and tissue engineering because of their biocompatibility, unique swelling properties, and relative ease of fabrication. Hydrogel drug delivery systems comprise cells, cytokines, an extracellular matrix, and small molecule nucleotides, which have different properties depending on their chemical or physical cross-linking. Additionally, hydrogels can be designed for different types of drug delivery for specific applications. In this paper, we summarize recent research in the field of bone regeneration using hydrogels as delivery carriers, detail the application of hydrogels in bone defect diseases and their mechanisms, and discuss future research directions of hydrogel drug delivery systems in bone tissue engineering.

Local Delivery and Controlled Release Drugs Systems: A New Approach for the Clinical Treatment of Periodontitis Therapy

Periodontitis is an inflammatory disease of the gums characterized by the degeneration of periodontal ligaments, the formation of periodontal pockets, and the resorption of the alveolar bone, which results in the destruction of the teeth's supporting structure. Periodontitis is caused by the growth of diverse microflora (particularly anaerobes) in the pockets, releasing toxins and enzymes and stimulating the immune system. Various approaches, both local and systemic, have been used to treat periodontitis effectively. Successful treatment depends on reducing bacterial biofilm, bleeding on probing (BOP), and reducing or eliminating pockets. Currently, the use of local drug delivery systems (LDDSs) as an adjunctive therapy to scaling and root planing (SRP) in periodontitis is a promising strategy, resulting in greater efficacy and fewer adverse effects by controlling drug release. Selecting an appropriate bioactive agent and route of administration is the cornerstone of a successful periodontitis treatment plan. In this context, this review focuses on applications of LDDSs with varying properties in treating periodontitis with or without systemic diseases to identify current challenges and future research directions.

Microstructural and micromechanical modeling of gum-gelatin-based soft tissue engineering scaffolds

Oral and dental diseases, including periodontal disease, are among the most common conditions in the field of dentistry. The best treatment for this complication is the use of different polymers and multi-component biological tissue prepared through the freeze-drying technique. In this study, biocompatible and biodegradable polymers, namely polyvinyl alcohol (PVA) and gelatin (GN), were used for this purpose, along with Arabian gum-hydroxyapatite (HA) for its antibacterial properties. Arabian gum, with weight percentages of 0, 2, 4, and 6 wt%, was added to the polyvinyl alcohol-gelatin composition at -55 °C for 28 h in the freezer and 48 h at -45 °C under a pressure of 0.01 mbar. The resulting porous biological tissue, with four different ratios, was tested for mechanical and biological analysis in a physiological solution. Then, the samples were analyzed using a scanning electron microscope (SEM) and X-ray diffraction (XRD) technique to study the morphology and structure of the compounds before and after placement in biological solutions. Additionally, a wettability and antibacterial test were performed on the nanocomposite specimen. The SEM observations revealed that this method can create a porous structure with a porosity of about 30-50 μm with a spherical and circular architecture, which was further improved by the addition of gum, reducing the percentage of porosity and improving the tissue's tensile strength and elastic modulus. The porosity changes showed a decrease from 72 % to 60 %, and the tensile strength increased from 53.5 KPa to 76 KPa, resulting in an elastic modulus of 510 KPa to 800 KPa. The addition of gum also reduced the rate of destruction of the biological tissue, making it more suitable for soft tissue applications. The obtained results of the pH test showed that the concentration changes were neutral. The contact angle of water droplets was measured to determine hydrophilicity, indicating an improvement in hydrophilicity after the addition of gum. The results showed that the use of PVA and gelatin, due to their ductility and suitable mechanical properties, along with Arabian gum-HA, could accelerate the healing process of dental periodontal problems.

Smart stimuli-responsive hydrogels for drug delivery in periodontitis treatment

Periodontitis is a chronic inflammatory disease initiated by pathogenic biofilms and host immunity that damages tooth-supporting tissues, including the gingiva, periodontal ligament and alveolar bone. The physiological functions of the oral cavity, such as saliva secretion and chewing, greatly reduce the residence of therapeutic drugs in the area of a periodontal lesion. In addition, complex and diverse pathogenic mechanisms make effectively treating periodontitis difficult. Therefore, designing advanced local drug delivery systems and rational therapeutic strategies are the basis for successful periodontitis treatment. Hydrogels have attracted considerable interest in the field of periodontitis treatment due to their biocompatibility, biodegradability and convenient administration to the periodontal pocket. In recent years, the focus of hydrogel research has shifted to smart stimuli-responsive hydrogels, which can undergo flexible sol-gel transitions in situ and control drug release in response to stimulation by temperature, light, pH, ROS, glucose, or enzymes. In this review, we systematically introduce the development and rational design of emerging smart stimuli-responsive hydrogels for periodontitis treatment. We also discuss the state-of-the-art therapeutic strategies of smart hydrogels based on the pathogenesis of periodontitis. Additionally, the challenges and future research directions of smart hydrogels for periodontitis treatment are discussed from the perspective of developing efficient hydrogel delivery systems and potential clinical applications.

Quality by design driven development and evaluation of thermosensitive hydrogel loaded with IgY and LL37-SLNs to combat experimental periodontitis

Egg yolk immunoglobulin (IgY) and LL37, potent antibacterial substances, can fight against periodontitis. This work aimed to develop a locally injectable hydrogel for potential co-delivery of special IgY and LL37-loaded solid lipid nanoparticles (LL37-SLNs) to synergistically inhibit the proliferation of oral pathogens, thus relieving periodontal inflammation and redness. The formulation of thermosensitive hydrogel loaded with IgY and LL37-SLNs was developed by adopting the Quality by Design approach. Then the formulations were optimized by two-factor three-level full factorial design by Design-Expert software. Finally, the optimized formulation was characterized and estimated in vitro and in vivo. In vitro release and antibacterial activity studies have revealed that the optimized formulation was homogeneous and can be released slowly, with sustainably antibacterial power. And the physical and chemical composition analysis and morphological observations further confirmed the sustained-release capability. On the other hand, in vivo studies proved that the optimized formulation significantly decreased gingival redness, bleeding, and plaque formation, avoided excessive resorption of alveolar bone, and reduced the levels of inflammatory factor in periodontitis rats. In conclusion, the optimized thermosensitive hydrogel loaded with IgY and LL37-SLNs may be a promising local sustained-release preparation for the effective treatment of periodontal diseases.

Clindamycin phosphate and bone morphogenetic protein-7 loaded combined nanoparticle-graft and nanoparticle-film formulations for alveolar bone regeneration - An in vitro and in vivo evaluation

Commonly utilized techniques for healing alveolar bone destruction such as the use of growth factors, suffering from short half-life, application difficulties, and the ability to achieve bioactivity only in the presence of high doses of growth factor. The sustained release of growth factors through a scaffold-based delivery system offers a promising and innovative tool in dentistry. Furthermore, it is suggested to guide the host response by using antimicrobials together with growth factors to prevent recovery and achieve ideal regeneration. Herein, the aim was to prepare and an in vitro - in vivo evaluation of bone morphogenetic protein 7 (BMP-7) and clindamycin phosphate (CDP) loaded polymeric nanoparticles, and their loading into the alginate-chitosan polyelectrolyte complex film or alloplastic graft to accelerate hard tissue regeneration. PLGA nanoparticles containing CDP and BMP-7, separately or together, were prepared using the double emulsion solvent evaporation technique. Through in vitro assays, it was revealed that spherical particles were homogeneously distributed in the combination formulations, and sustained release could be achieved for >12 weeks with all formulations. Also, results from the micro-CT and histopathological analyses indicated that CDP and BMP-7 loaded nanoparticle-film formulations were more effective in treatment than the nanoparticle loaded grafts.

Role of Berberine Thermosensitive Hydrogel in Periodontitis via PI3K/AKT Pathway In Vitro

Periodontitis is a long-term inflammatory illness and a leading contributor to tooth loss in humans. Due to the influence of the anatomic parameters of teeth, such as root bifurcation lesions and the depth of the periodontal pocket, basic periodontal treatment on its own often does not completely obliterate flora microorganisms. As a consequence, topical medication has become a significant supplement in the treatment of chronic periodontitis. Berberine (BBR) has various pharmacological effects, such as hypoglycemic, antitumor, antiarrhythmic, anti-inflammatory, etc. The target of our project is to develop a safe and non-toxic carrier that can effectively release berberine, which can significantly reduce periodontal tissue inflammation, and to investigate whether berberine thermosensitive hydrogel can exert anti-inflammatory and osteogenic effects by modulating phosphatifylinositol-3-kinase/Protein Kinase B (PI3K/AKT) signaling pathway. Consequently, firstly berberine temperature-sensitive hydrogel was prepared, and its characterizations showed that the mixed solution gelated within 3 min under 37 °C with a hole diameter of 10-130 µm, and the accumulation of berberine release amounted to 89.99% at 21 days. CCK-8 and live-dead cell staining results indicated that this hydrogel was not biotoxic, and it is also presumed that the optimum concentration of berberine is 5 µM, which was selected for subsequent experiments. Real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB)results demonstrated that inflammatory factors, as well as protein levels, were significantly reduced in the berberine-loaded hydrogel group, and LY294002 (PI3K inhibitor) could enhance this effect (p < 0.05). In the berberine-loaded hydrogel group, osteogenesis-related factor levels and protein profiles were visibly increased, along with an increase in alkaline phosphatase expression, which was inhibited by LY294002 (p < 0.05). Therefore, berberine thermosensitive hydrogel may be an effective treatment for periodontitis, and it may exert anti-inflammatory and osteogenic effects through the PI3K/AKT signaling pathway.

Research Advances on Hydrogel-Based Materials for Tissue Regeneration and Remineralization in Tooth

Tissue regeneration and remineralization in teeth is a long-term and complex biological process, including the regeneration of pulp and periodontal tissue, and re-mineralization of dentin, cementum and enamel. Suitable materials are needed to provide cell scaffolds, drug carriers or mineralization in this environment. These materials need to regulate the unique odontogenesis process. Hydrogel-based materials are considered good scaffolds for pulp and periodontal tissue repair in the field of tissue engineering due to their inherent biocompatibility and biodegradability, slow release of drugs, simulation of extracellular matrix, and the ability to provide a mineralized template. The excellent properties of hydrogels make them particularly attractive in the research of tissue regeneration and remineralization in teeth. This paper introduces the latest progress of hydrogel-based materials in pulp and periodontal tissue regeneration and hard tissue mineralization and puts forward prospects for their future application. Overall, this review reveals the application of hydrogel-based materials in tissue regeneration and remineralization in teeth.

The role of non-steroidal anti-inflammatory drugs as adjuncts to periodontal treatment and in periodontal regeneration

Periodontitis is the sixth most prevalent chronic disease globally and places significant burdens on societies and economies worldwide. Behavioral modification, risk factor control, coupled with cause-related therapy have been the "gold standard" treatment for managing periodontitis. Given that host inflammatory and immunological responses play critical roles in the pathogenesis of periodontitis and impact treatment responses, several adjunctive strategies aimed at modulating host responses and improving the results of periodontal therapy and maintenance have been proposed. Of the many pharmacological host modulators, we focused on non-steroidal anti-inflammatory drugs (NSAIDs), due to their long history and extensive use in relieving inflammation and pain and reducing platelet aggregation. NSAIDs have been routinely indicated for treating rheumatic fever and osteoarthritis and utilized for the prevention of cardiovascular events. Although several efforts have been made to incorporate NSAIDs into the treatment of periodontitis, their effects on periodontal health remain poorly characterized, and concerns over the risk-benefit ratio were also raised. Moreover, there is emerging evidence highlighting the potential of NSAIDs, especially aspirin, for use in periodontal regeneration. This review summarizes and discusses the use of NSAIDs in various aspects of periodontal therapy and regeneration, demonstrating that the benefits of NSAIDs as adjuncts to conventional periodontal therapy remain controversial. More recent evidence suggests a promising role for NSAIDs in periodontal tissue engineering and regeneration.

Fabrication of an exosome-loaded thermosensitive chitin-based hydrogel for dental pulp regeneration

Injective thermosensitive hydrogels are considered promising scaffolds to trigger dental pulp regeneration in devitalized human teeth. In this study, we developed a hydroxypropyl chitin (HPCH)/chitin whisker (CW) thermosensitive hydrogel with enhanced mechanical properties and biological activities. Exosomes can serve as biomimetic tools for tissue engineering, but the rapid clearance of unconjugated exosomes in vivo limits their therapeutic effects. To address this challenge, exosomes were isolated from human pulp stem cells (hDPSCs) and directly embedded into the HPCH/CW pre-gel to form an exosome-loaded hydrogel (HPCH/CW/Exo). The exosome-loaded thermosensitive hydrogel can be easily injected into an irregular endodontic space and gelated in situ. In vitro cell experiments proved that the delivery of exosomes significantly improved the ability of hydrogels to promote odontogenesis and angiogenesis. Meanwhile, in vivo animal experiments revealed the formation of new dental pulp-like tissues in an implanted tooth root model. Therefore, the proposed hydrogel provides a great potential alternative to traditional root canal therapy in dental clinics.

Applications of Hydrogels in Drug Delivery for Oral and Maxillofacial Diseases

Oral and maxillofacial diseases have an important impact on local function, facial appearance, and general health. As a multifunctional platform, hydrogels are widely used in the biomedical field due to their excellent physicochemical properties. In recent years, a large number of studies have been conducted to adapt hydrogels to the complex oral and maxillofacial environment by modulating their pore size, swelling, degradability, stimulus-response properties, etc. Meanwhile, many studies have attempted to use hydrogels as drug delivery carriers to load drugs, cytokines, and stem cells for antibacterial, anticancer, and tissue regeneration applications in oral and maxillofacial regions. This paper reviews the application and research progress of hydrogel-based drug delivery systems in the treatment of oral and maxillofacial diseases such as caries, endodontic diseases, periodontal diseases, maxillofacial bone diseases, mucosal diseases, oral cancer, etc. The characteristics and applications of hydrogels and drug-delivery systems employed for the treatment of different diseases are discussed in order to provide a reference for further research on hydrogel drug-delivery systems in the future.

Thermosensitive smart hydrogel of PEITC ameliorates the therapeutic efficacy in rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune condition that accompanies chronic inflammation of joints with limited therapeutic options. Phenethyl isothiocyanate (PEITC), a bioactive phytochemical, exerts its chemopreventive, anti-oxidant, and anti-inflammatory activity via the Nrf-2 pathway. However, limited water solubility, short half-life, and instability are reasons for the low bioavailability of PEITC that hampers clinical application. From studies in healthy rats, the performance of PEITC-loaded chitosan/pluronic F-127 smart hydrogel (PH) as a thermosensitive injectable demonstrated adequate thermosensitivity (gel formation), injectability (ease of administration), biocompatibility (with prolonged contact), pharmacokinetics (sustained drug release), and biosafety (nontoxic to major organs). In the adjuvant-induced arthritis (AIA) rat model, PEITC-hydrogel (PH50) injected into the knee joint lowered RA-related symptoms significantly (paw edema and arthritis score). Further, a marked reduction in bone erosion and inflammation-specific biomarkers was observed. Finally, this study demonstrates a smart injectable hydrogel optimally loaded with PEITC which is safe, biocompatible and exhibits significant therapeutic efficacy in RA conditions.

Inhibitory effect of polysaccharides extracted from Changbai Mountain Ganoderma lucidum on periodontal inflammation

As the main bioactive substance of Ganoderma lucidum, Ganoderma lucidum polysaccharide (GLP) has anti-inflammatory, antibacterial, and other biological activities. Studies have shown that GLP can regulate the expression of multiple inflammatory cytokines in different inflammatory models and diseases as part of the anti-infection immune response. We extracted crude Changbai Mountain Ganoderma lucidum polysaccharides (CGLPs), analyzed their physical and chemical properties, and then applied them to the periodontitis model to verify whether they have an inhibitory effect on mouse periodontitis. CGLP was determined to be a heteropolysaccharide with dextran as the main component. Its molecular weight was 17.40 kDa. In vivo experiments in mice showed that CGLP can inhibit the alveolar bone loss and reduced inflammation caused of periodontitis by regulating the expression of the inflammatory factors IL-1β, TNF-α, and IL-10 in a concentration-dependent manner.

Osteogenic and anti-inflammatory effect of the multifunctional bionic hydrogel scaffold loaded with aspirin and nano-hydroxyapatite

Although tissue engineering offered new approaches to repair bone defects, it remains a great challenge to create a bone-friendly microenvironment and rebuild bone tissue rapidly by a scaffold with a bionic structure. In this study, a multifunctional structurally optimized hydrogel scaffold was designed by integrating polyvinyl alcohol (PVA), gelatin (Gel), and sodium alginate (SA) with aspirin (ASA) and nano-hydroxyapatite (nHAP). The fabrication procedure is through a dual-crosslinking process. The chemical constitution, crystal structure, microstructure, porosity, mechanical strength, swelling and degradation property, and drug-release behavior of the hydrogel scaffold were analyzed. Multi-hydrogen bonds, electrostatic interactions, and strong "egg-shell" structure contributed to the multi-network microstructure, bone tissue-matched properties, and desirable drug-release function of the hydrogel scaffold. The excellent performance in improving cell viability, promoting cell osteogenic differentiation, and regulating the inflammatory microenvironment of the prepared hydrogel scaffold was verified using mouse pre-osteoblasts (MC3T3-E1) cells. And the synergistic osteogenic and anti-inflammatory functions of aspirin and nano-hydroxyapatite were also verified. This study provided valuable insights into the design, fabrication, and biological potential of multifunctional bone tissue engineering materials with the premise of constructing a bone-friendly microenvironment.

Preparation and Synergistic Effect of Biomimetic Poly(lactic acid)/Graphene Oxide Composite Scaffolds Loaded with Dual Drugs

To promote the bone repair ability of drug-loaded scaffolds, poly(lactic acid) (PLA)/graphene oxide (GO)/Salvianolic acid B (Sal-B)/aspirin (ASA) dual drug-loaded biomimetic composite scaffolds were prepared. The results showed that the addition of these two drugs delayed the gel formation of the composite system, but a biomimetic nanofiber structure could still be obtained by extending the gel time. The addition of Sal-B increased the hydrophilicity of the scaffold, while an increase in ASA reduced the porosity. Dual drug-loaded scaffolds had good haemocompatibility and synergically promoted the proliferation of MC3T3-E1 cells and enhanced alkaline phosphatase activity. Sustained-release experiments of the two drugs showed that the presence of ASA slowed the cumulative release of Sal-B, while Sal-B promoted the release of ASA. Kinetic modeling showed that the release of both drugs conforms to the Korsmeyer-Peppas model, but Sal-B conforms to the Fick diffusion mechanism and ASA follows Fick diffusion and carrier swelling/dissolution.

Multifunctional Mesoporous Silica Nanoparticles Reinforced Silk Fibroin Composite with Antibacterial and Osteogenic Effects for Infectious Bone Rehabilitation

BACKGROUND

Existing implant materials cannot meet the essential multifunctional requirements of repairing infected bone defects, such as antibacterial and osteogenesis abilities. A promising strategy to develop a versatile biomimicry composite of the natural bone structure may be accomplished by combining a multifunctional nanoparticle with an organic scaffold.

METHODS

In this study, a quaternary ammonium silane-modified mesoporous silica containing nano silver (Ag@QHMS) was successfully synthesized and further combined with silk fibroin (SF) to fabricate the multifunctional nano-reinforced scaffold (SF-Ag@QHMS) using the freeze-drying method. Furthermore, the antibacterial and osteogenic effects of this composite were evaluated in vitro and in vivo.

RESULTS

SF-Ag@QHMS inherited a three-dimensional porous structure (porosity rate: 91.90 ± 0.62%) and better mechanical characteristics (2.11 ± 0.06 kPa) than that of the SF scaffold (porosity rate: 91.62 ± 1.65%; mechanic strength: 2.02 ± 0.01 kPa). Simultaneously, the introduction of versatile nanoparticles has provided the composite with additional antibacterial ability against Porphyromonas gingivalis, which can be maintained for 15 days. Furthermore, the expression of osteogenic-associated factors was up-regulated due to the silver ions eluting from the composite scaffold. The in vivo micro-CT and histological results indicated that the new bone formation was not only localized around the border of the defect but also arose more in the center with the support of the composite.

CONCLUSION

The multifunctional silver-loaded mesoporous silica enhanced the mechanical strength of the composite while also ensuring greater and sustained antibacterial and osteogenic properties, allowing the SF-Ag@QHMS composite to be used to repair infected bone defects.

An antibacterial chitosan-based hydrogel as a potential degradable bio-scaffold for alveolar ridge preservation

Post-extraction, preventing the absorption of alveolar ridge to retain the supporting construction for implanted teeth is still a challenge. Herein, we developed modified chitosan (CS)-based hydrogel using N-hydroxysuccinimide-terminated 4-arm poly (ethylene glycol) (4-arm-PEG-NHS) as the crosslinking agent, after introducing it to the polyhexamethyleneguanidine hydrochloride (PHMB) solution, CS/PEG/PHMB hydrogel with the enhanced antibacterial properties was obtained. The CS/PEG hydrogel and CS/PEG/PHMB hydrogel prepared here showed excellent mechanical strength and their compressive strength could reach 440 kPa and 450 kPa, respectively. The composite hydrogel was designed to be directional porous, low cytotoxic, pH-sensitive, and degradable. The weight of the hydrogel was reduced by ∼30% after 28 days of incubation, and it swelled significantly in the acidic condition while it did not swell in the neutral and weakly alkaline environments, indicating an excellent biodegradability in the inflammation site. In vitro antibacterial experiments showed that the bacteriostatic rate of the CS/PEG/PHMB hydrogel against S. aureus was above 90%, which could effectively inhibit the spread of the bacteria and inflammation in the alveolar ridge. Additionally, the hybrid hydrogels demonstrated good biocompatibility with the NIH 3T3 fibroblast cells. Overall, the CS/PEG/PHMB hydrogel is a promising biological scaffold for maintaining the alveolar ridge and subsequently improving the success rate of the dental implant.

A Biomimetic Smart Nanoplatform as “Inflammation Scavenger” for Regenerative Therapy of Periodontal Tissue

Introduction

The functional reconstruction of periodontal tissue defects remains a clinical challenge due to excessive and prolonged host response to various endogenous and exogenous pro-inflammatory stimuli. Thus, a biomimetic nanoplatform with the capability of modulating inflammatory response in a microenvironment-responsive manner is attractive for regenerative therapy of periodontal tissue.

Methods

Herein, a facile and green design of engineered bone graft materials was developed by integrating a biomimetic apatite nanocomposite with a smart-release coating, which could realize inflammatory modulation by “on-demand” delivery of the anti-inflammatory agent through a pH-sensing mechanism.

Results

In vitro and in vivo experiments demonstrated that this biocompatible nanoplatform could facilitate the clearance of reactive oxygen species in human periodontal ligament stem cells under inflammatory conditions via inhibiting the production of endogenous proinflammatory mediators, in turn contributing to the enhanced healing efficacy of periodontal tissue. Moreover, this system exhibited effective antimicrobial activity against common pathogenic bacteria in the oral cavity, which is beneficial for the elimination of exogenous pro-inflammatory factors from bacterial infection during healing of periodontal tissue.

Conclusion

The proposed strategy provides a versatile apatite nanocomposite as a promising “inflammation scavenger” and propels the development of intelligent bone graft materials for periodontal and orthopedic applications.

Aspirin/PLGA coated 3D-printed Ti-6Al-4V alloy modulate macrophage polarization to enhance osteoblast differentiation and osseointegration

Although titanium (Ti) and Ti-based alloy have been widely used as dental and orthopedic implant materials, its bioinertness hindered the rapid osseointegration. Therefore, it is recommended to acquire ideal topographic and chemical characteristics through surface modification methods. 3D printing is a delicate manufacture technique which possesses superior controllability and reproducibility. While aspirin serve as a well-established non-steroidal anti-inflammatory agent. Recently, the importance of immune system in regulating bone dynamics has attracted increasing attention. We herein superimposed the aspirin/poly (lactic-co-glycolic acid) (ASP/PLGA) coating on the 3D-printed Ti-6Al-4V surface with uniform micro-structure to establish the Ti64-M-ASP/PLGA substrate. Scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS) and contact angle test confirmed the successful fabrication of the Ti64-M-ASP/PLGA substrate, with increased wettability and sustained release pattern of ASP. Compared with the Ti64 base material, the Ti64-M-ASP/PLGA substrate showed enhanced M2 and depressed M1 genes and proteins expressions in macrophages. The novel Ti64-M-ASP/PLGA substrate also displayed enhanced osteoblast proliferation, adhesion, extracellular mineralization ability and osteogenic gene expressions when cultured with macrophage conditioned medium in vitro. Furthermore, rat femora implantation model was used for in vivo evaluation. After 4 weeks of implantation, push out test, micro-computed tomography (micro-CT) and histological analyses all confirmed the superior osseointegration capabilities of the Ti64-M-ASP/PLGA implant than the other groups. Our study revealed the synergistic role played by 3D-printed micro topography and immunoregulatory drug aspirin in promoting osteogenesis in vitro and accelerating osseointegration in vivo, thus providing a promising method for better modifying the implant surface. Graphical abstract.

Advances of Hydrogel Therapy in Periodontal Regeneration-A Materials Perspective Review

Hydrogel, a functional polymer material, has emerged as a promising technology for therapies for periodontal diseases. It has the potential to mimic the extracellular matrix and provide suitable attachment sites and growth environments for periodontal cells, with high biocompatibility, water retention, and slow release. In this paper, we have summarized the main components of hydrogel in periodontal tissue regeneration and have discussed the primary construction strategies of hydrogels as a reference for future work. Hydrogels provide an ideal microenvironment for cells and play a significant role in periodontal tissue engineering. The development of intelligent and multifunctional hydrogels for periodontal tissue regeneration is essential for future research.

Nanomaterials based on thermosensitive polymer in biomedical field

The progress of nanotechnology enables us to make use of the special properties of materials on the nanoscale and open up many new fields of biomedical research. Among them, thermosensitive nanomaterials stand out in many biomedical fields because of their “intelligent” behavior in response to temperature changes. However, this article mainly reviews the research progress of thermosensitive nanomaterials, which are popular in biomedical applications in recent years. Here, we simply classify the thermally responsive nanomaterials according to the types of polymers, focusing on the mechanisms of action and their advantages and potential. Finally, we deeply investigate the applications of thermosensitive nanomaterials in drug delivery, tissue engineering, sensing analysis, cell culture, 3D printing, and other fields and probe the current challenges and future development prospects of thermosensitive nanomaterials.

Injectable and Self-Invigorating Hydrogel Applications in Dentistry and Periodontal Regeneration: A Literature Review

Hydrogels are thought of as unique polymers utilized to build new materials, and two key factors that impact their features are their hydrophilicity and the degree of cross-linking of the polymer chains. An injectable hydrogel is based on the hypothesis that certain biomaterials can be injected into the body as a liquid and progressively solidify there. The scientific research community was intrigued and interested by its discovery. The hydrophilic polymers that are used to make hydrogels can typically be split into two groups: natural polymers derived from tissues or other sources of natural materials, and synthetic polymers produced by combining principles from organic chemistry and molecular engineering. A variety of organic and synthetic biomaterials, such as chitosan, collagen or gelatin, alginate, hyaluronic acid, heparin, chondroitin sulfate, polyethylene glycol, and polyvinyl alcohol, are used to generate injectable hydrogels. A promising biomaterial for the therapeutic injection of cells and bioactive chemicals for tissue regeneration in both dentistry and medicine, injectable hydrogels have recently attracted attention. Since injectable scaffolds can be implanted with less invasive surgery, their application is seen as a viable strategy in the regeneration of craniofacial tissue. Treatment for periodontitis that effectively promotes periodontal regeneration involves injecting a hydrogel that contains medications with simultaneous anti-inflammatory and tissue-regenerating capabilities. The advantages of injectable hydrogel for tissue engineering are enhanced by the capability of three-dimensional encapsulation. A material's injectability can be attributed to a variety of mechanisms. The hydrogels work well to reduce inflammation and promote periodontal tissue regeneration.

A Self-Supplying H2O2 Modified Nanozyme-Loaded Hydrogel for Root Canal Biofilm Eradication

The success of root canal therapy depends mainly on the complete elimination of the root canal bacterial biofilm. The validity and biocompatibility of root canal disinfectant materials are imperative for the success of root canal treatment. However, the insufficiency of the currently available root canal disinfectant materials highlights that more advanced materials are still needed. In this study, a nanozyme-loaded hydrogel (Fe3O4-CaO2-Hydrogel) was modified and analyzed as a root canal disinfectant material. Fe3O4-CaO2-Hydrogel was fabricated and examined for its release profile, biocompatibility, and antibacterial activity against E. faecalis and S. sanguis biofilms in vitro. Furthermore, its efficiency in eliminating the root canal bacterial biofilm removal in SD rat teeth was also evaluated. The results in vitro showed that Fe3O4-CaO2-Hydrogel could release reactive oxygen species (ROS). Moreover, it showed good biocompatibility, disrupting bacterial cell membranes, and inhibiting exopolysaccharide production (p < 0.0001). In addition, in vivo results showed that Fe3O4-CaO2-Hydrogel strongly scavenged on root canal biofilm infection and prevented further inflammation expansion (p < 0.05). Altogether, suggesting that Fe3O4-CaO2-Hydrogel can be used as a new effective biocompatible root canal disinfectant material. Our research provides a broad prospect for clinical root canal disinfection, even extended to other refractory infections in deep sites.

Long-acting formulation strategies for protein and peptide delivery in the treatment of PSED

The invigoration of protein and peptides in serious eye disease includes age-related macular degeneration, choroidal neovascularization, retinal neovascularization, and diabetic retinopathy. The transportation of macromolecules like aptamers, recombinant proteins, and monoclonal antibodies to the posterior segment of the eye is challenging due to their high molecular weight, rapid degradation, and low solubility. Moreover, it requires frequent administration for prolonged therapy. The long-acting novel formulation strategies are helpful to overcome these issues and provide superior therapy. It avoids frequent administration, improves stability, high retention time, and avoids burst release. This review briefly enlightens posterior segments of eye diseases with their diagnosis techniques and treatments. This article mainly focuses on recent advanced approaches like intravitreal implants and injectables, electrospun injectables, 3D printed drug-loaded implants, nanostructure thin-film polymer devices encapsulated cell technology-based intravitreal implants, injectable and depots, microneedles, PDS with ranibizumab, polymer nanoparticles, inorganic nanoparticles, hydrogels and microparticles for delivering macromolecules in the eye for intended therapy. Furthermore, novel techniques like aptamer, small Interference RNA, and stem cell therapy were also discussed. It is predicted that these systems will make revolutionary changes in treating posterior segment eye diseases in future.

Chitosan-Based Scaffolds for Facilitated Endogenous Bone Re-Generation

Facilitated endogenous tissue engineering, as a facile and effective strategy, is emerging for use in bone tissue regeneration. However, the development of bioactive scaffolds with excellent osteo-inductivity to recruit endogenous stem cells homing and differentiation towards lesion areas remains an urgent problem. Chitosan (CS), with versatile qualities including good biocompatibility, biodegradability, and tunable physicochemical and biological properties is undergoing vigorously development in the field of bone repair. Based on this, the review focus on recent advances in chitosan-based scaffolds for facilitated endogenous bone regeneration. Initially, we introduced and compared the facilitated endogenous tissue engineering with traditional tissue engineering. Subsequently, the various CS-based bone repair scaffolds and their fabrication methods were briefly explored. Furthermore, the functional design of CS-based scaffolds in bone endogenous regeneration including biomolecular loading, inorganic nanomaterials hybridization, and physical stimulation was highlighted and discussed. Finally, the major challenges and further research directions of CS-based scaffolds were also elaborated. We hope that this review will provide valuable reference for further bone repair research in the future.

Drug-Loaded Chitosan Scaffolds for Periodontal Tissue Regeneration

Chitosan is a natural anionic polysaccharide with a changeable architecture and an abundance of functional groups; in addition, it can be converted into various shapes and sizes, making it appropriate for a variety of applications. This article examined and summarized current developments in chitosan-based materials, with a focus on the modification of chitosan, and presented an abundance of information about the fabrication and use of chitosan-derived products in periodontal regeneration. Numerous preparation and modification techniques for enhancing chitosan performance, as well as the uses of chitosan and its metabolites, were reviewed critically and discussed in depth in this study. Chitosan-based products may be formed into different shapes and sizes, considering fibers, nanostructures, gels, membranes, and hydrogels. Various drug-loaded chitosan devices were discussed regarding periodontal regeneration.

Locally Applied Repositioned Hormones for Oral Bone and Periodontal Tissue Engineering: A Narrative Review

Bone and periodontium are tissues that have a unique capacity to repair from harm. However, replacing or regrowing missing tissues is not always effective, and it becomes more difficult as the defect grows larger. Because of aging and the increased prevalence of debilitating disorders such as diabetes, there is a considerable increase in demand for orthopedic and periodontal surgical operations, and successful techniques for tissue regeneration are still required. Even with significant limitations, such as quantity and the need for a donor area, autogenous bone grafts remain the best solution. Topical administration methods integrate osteoconductive biomaterial and osteoinductive chemicals as hormones as alternative options. This is a promising method for removing the need for autogenous bone transplantation. Furthermore, despite enormous investigation, there is currently no single approach that can reproduce all the physiologic activities of autogenous bone transplants. The localized bioengineering technique uses biomaterials to administer different hormones to capitalize on the host’s regeneration capacity and capability, as well as resemble intrinsic therapy. The current study adds to the comprehension of the principle of hormone redirection and its local administration in both bone and periodontal tissue engineering.

Development of Cationic Cellulose-Modified Bentonite-Alginate Nanocomposite Gels for Sustained Release of Alachlor

The nanocomposite gel prepared from nanoclay and natural polysaccharides showed a good sustained-release property. Herein, a cationic cellulose-modified bentonite-alginate nanocomposite gel was prepared and used to enhance the sustained release of alachlor. The underlying effect and mechanism of the structure of modified bentonite-alginate nanocomposite gels on the release behavior of alachlor were explored by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and thermogravimetric (TG) analysis. The results showed that the release of alachlor from the nanocomposite gels was dominated by Fickian diffusion and closely related to the adsorption capacity and permeability of the matrix. The cationic cellulose intercalated into the interlayer space of bentonite through an ion exchange reaction, which significantly enhanced the hydrophobicity of bentonite and its interaction with alachlor. The stacking aggregation of bentonite nanoplatelets and permeability of the gel network were decreased through the electrostatic interaction between cationic cellulose and alginate molecular chains, thus remarkably enhancing the sustained-release property of the nanocomposite gel. The release kinetics revealed that the release rate of alachlor from the nanocomposite gel first decreased and then increased as the content of bentonite and modified bentonite gradually increased. Also, the best sustained-release property of the nanocomposite gel was obtained at bentonite and modified bentonite additions of about 10%, under which the release time of 50% alachlor (T ₅₀) from bentonite-alginate and modified bentonite-alginate nanocomposite gels was 4.4 and 5.6 times longer than the release time from pure alginate gels, respectively.

Physically Cross-Linked DNA Hydrogel-Based Sustained Cytokine Delivery for In Situ Diabetic Alveolar Bone Rebuilding

The development of a biodegradable and shape-adaptable bioscaffold that can enhance local cytokine retention and bioactivity is essential for the application of immunotherapy in periodontal diseases. Here, we report a biodegradable, anti-inflammatory, and osteogenic ILGel that uses a physically cross-linked DNA hydrogel as a soft bioscaffold for the long-term sustained release of cytokine interleukin-10 (IL-10) to accelerate diabetic alveolar bone rebuilding. Porous microstructures of ILGel favored the encapsulation of IL-10 and maintained IL-10 bioactivity for at least 7 days. ILGel can be gradually degraded or hydrolyzed under physiological conditions, avoiding the potential undesired side effects on dental tissues. Long-term sustained release of bioactive IL-10 from ILGel not only promoted M2 macrophage polarization and attenuated periodontal inflammation but also triggered osteogenesis of mesenchymal stem cells (MSCs), leading to accelerated alveolar bone formation and healing of alveolar bone defects under diabetic conditions in vivo. ILGel treatment significantly accelerated the defect healing rate of diabetic alveolar injury up to 93.42 ± 4.6% on day 21 post treatment compared to that of free IL-10 treatment (63.30 ± 7.39%), with improved trabecular architectures. Our findings imply the potential application of the DNA hydrogel as the bioscaffold for cytokine-based immunotherapy in diabetic alveolar bone injury and other periodontal diseases.

A sustained-release Trametinib bio-multifunction hydrogel inhibits orthodontically induced inflammatory root resorption

Orthodontic tooth movement (OTM) is a bone reconstruction process. In most cases, OTM could induce root resorption as a common side effect, called orthodontically induced inflammatory root resorption (OIIRR). OIIRR affects tooth health and interferes with the stability of orthodontic treatment. Osteoclasts, which perform bone resorption in OTM, attack cementum, causing OIIRR. Many signaling pathways are involved in the maturation and differentiation of osteoclasts, among which the ERK1/2 is one of the important pathways. In this experiment, we added Trametinib (Tra), a specific inhibitor of ERK1/2, to catechol-modified chitosan (CHI-C) and oxidized dextran (ODex) to form a CCOD-Trametinib composite hydrogel (CCOD-Tra) to prevent OIIRR. CCOD-Tra exhibited good biocompatibility, injectability, strong adhesion, good hemostatic function and sustained release of Tra. We performed local injection of CCOD-Tra into the periodontal tissues of rats. CCOD-Tra firmly adhered to the periodontal tissues and then released Tra to establish a good biological environment and maintain a drug concentration at a high level around the roots for a long time. H&E, TRAP, immunochemistry staining and micro-CT indicated that CCOD-Tra had a good effect in terms of preventing OIIRR. Cell experiments showed that CCOD-Tra reduced the expression of TRAP, MMP-9 and C-FOS in osteoclast cells through the ERK1/2 signaling pathway to inhibit the differentiation and maturation of osteoclasts. Based on the above results, we concluded that CCOD-Tra had the ability to prevent OIIRR, the high adhesion and injectability of CCOD may provide better therapeutic ideas for clinical prevention of OIIRR.

Biomaterials and biotechnology for periodontal tissue regeneration: Recent advances and perspectives

Periodontal tissues are organized in a complex three-dimensional (3D) architecture, including the alveolar bone, cementum, and a highly aligned periodontal ligament (PDL). Regeneration is difficult due to the complex structure of these tissues. Currently, materials are developing rapidly, among which synthetic polymers and hydrogels have extensive applications. Moreover, techniques have made a spurt of progress. By applying guided tissue regeneration (GTR) to hydrogels and cell sheets and using 3D printing, a scaffold with an elaborate biomimetic structure can be constructed to guide the orientation of fibers. The incorporation of cells and biotic factors improves regeneration. Nevertheless, the current studies lack long-term effect tracking, clinical research, and in-depth mechanistic research. In summary, periodontal tissue engineering still has considerable room for development. The development of materials and techniques and an in-depth study of the mechanism will provide an impetus for periodontal regeneration.