Stiffness-tuned and ROS-sensitive hydrogel incorporating complement C5a receptor antagonist modulates antibacterial activity of macrophages for periodontitis treatment

Microenvironment-sensitive hydrogels as promising drug delivery systems for co-encapsulating microbial homeostasis probiotics and anti-inflammatory drugs to treat periodontitis

Developing and utilizing effective local antimicrobial agents can help treat periodontitis while minimizing the risks associated with systemic antibiotic use. Recent studies have shown that the mucosal adhesion properties of hydrogels can play a potential role in the treatment of periodontitis. The hydrogel can improve the contact and retention time of drugs in the periodontal pocket. Through the adhesion of mucosa, it interacts with the mucin coating surface of epithelium and teeth to form a specific interface force. The hydrogel exhibits strong mucosal adhesion (adhesion strength: 5-6 N/cm2) and prolonged retention in periodontal pockets (≥6 h), enabling sustained drug release through dynamic sol-gel transitions triggered by pH and reactive oxygen species (ROS). This design overcomes the limitations of poor mechanical stability in conventional formulations. The dynamic balance of oral microbiota plays an important role in maintaining oral health. Probiotics, by colonizing the oral cavity, transform the infected site from an environment rich in inflammatory cytokines to a more benign environment, inhibit harmful pathogenic microorganisms, and contribute to overall health. Microenvironment sensitive hydrogels can perform dynamic sol gel transformation in situ, and can accurately control drug release when exposed to various stimuli (such as temperature change, light, pH change, reactive oxygen species, etc.). Oral probiotics and anti-inflammatory drugs are encapsulated in hydrogels to inhibit the proliferation and adhesion of oral pathogens by planting in the mouth and producing metabolites, effectively preventing and treating oral diseases.

AMY-101 as complement C3 inhibitor for periodontitis therapy: mechanisms, efficacy, and clinical translation

Periodontitis is a chronic inflammatory disease characterized by gingival inflammation, alveolar bone resorption, and periodontal tissue destruction. Complement activation, particularly through the C3 component, plays a critical role in the inflammatory processes underlying periodontitis. AMY-101, a selective inhibitor of complement C3, has demonstrated significant potential in modulating complement activity and mitigating periodontal inflammation. This study comprehensively evaluates AMY-101's effects through in vitro, preclinical, and clinical studies. Mechanistic investigations revealed that AMY-101 effectively suppresses pro-inflammatory cytokines and matrix metalloproteinases (MMPs), reducing tissue destruction. Preclinical models confirmed AMY-101's ability to improve clinical parameters such as probing pocket depth, attachment loss, and bone preservation. Moreover, clinical trials demonstrated AMY-101's safety and efficacy in reducing gingival inflammation and bleeding without serious adverse events. These findings highlight AMY-101's therapeutic potential for periodontitis and broader applicability in other complement-driven inflammatory diseases.

pH-responsive molybdenum disulphide composite nanomaterials for skin wound healing using "ROS leveraging" synergistic immunomodulation

With the increasing prevalence of drug-resistant bacterial infections, wound bacterial infections have evolved into an escalating medical problem that poses a threat to the individual health as well as global public health. Traditional drug therapy not only suffers from a single treatment method, low drug utilisation and limited therapeutic effect, but long-term antibiotic abuse has significantly increased bacterial resistance. It is imperative to develop an antibiotic-free biomaterial with antibacterial and anti-inflammatory properties. The current use of photothermal therapy (PTT) and photodynamic therapy (PDT) relies on the generation of massive reactive oxygen species (ROS), which inevitably aggravates the inflammatory response. Herein, we developed AuAg bimetallic nanoparticles based on PDA modification and prepared a novel MoS2-based composite nanomaterials (AuAg@PDA-MoS2 NPs) with multiple mechanisms of antibacterial and anti-inflammatory potentials through the adhesion of PDA. In the early phase, PDT and PTT generated a large amount of ROS for rapid sterilisation. While in the later stage, MoS2 mimicked the peroxidase activity to leverage the ROS, balancing the generation of ROS in the infected environment to achieve the long-term anti-inflammatory. In vitro experiments showed that the killing efficiency of AuAg@PDA-MoS2 NPs was nearly 99 % under the irradiation of 808 nm near-infrared light for 10 min, which demonstrated excellent antibacterial activity. In vivo experiments showed that 808 nm NIR-assisted AuAg@PDA-MoS2 NPs to effectively inhibit infection, alleviated the inflammation, and accelerated the wound healing process. Therefore, AuAg@PDA-MoS2 NPs as a novel biomaterial could achieve programmed antimicrobial and anti-inflammatory effects, which has a promising potential for future application in the treatment of infected wounds.

Injection of ROS-Responsive Hydrogel Loaded with IL-1β-targeted nanobody for ameliorating myocardial infarction

The cardiac microenvironment profoundly restricts the efficacy of myocardial regeneration tactics for the treatment of myocardial infarction (MI). A prospective approach for MI therapeutics encompasses the combined strategy of scavenging reactive oxygen species (ROS) to alleviate oxidative stress injury and facilitating macrophage polarization towards the regenerative M2 phenotype. In this investigation, we fabricated a ROS-sensitive hydrogel engineered to deliver our previously engineered IL-1β-VHH for myocardial restoration. In mouse and rat models of myocardial infarction, the therapeutic gel was injected into the pericardial cavity, effectively disseminated over the heart surface, forming an in situ epicardial patch. The IL-1β-VHH released from the hydrogel exhibited penetrative potential into the myocardium. Our results imply that this infarct-targeting gel can adhere to the damaged cardiac tissue and augment the quantity of anti-IL-1β antibodies. Moreover, the anti-IL-1β hydrogel safeguards cardiomyocytes from apoptosis by neutralizing IL-1β and inducing M2-type polarization within the myocardial infarction regions, thereby facilitating therapeutic cardiac repair. Our results emphasize the effectiveness of this synergistic comprehensive treatment modality in the management of MI and showcase its considerable potential for promoting recovery in infarcted hearts.

A multimodal defect-rich nanoreactor triggers sono-piezoelectric tandem catalysis and iron metabolism disruption for implant infections

Tracking and eradicating drug-resistant bacteria are critical for combating implant-associated infections, yet effective antibacterial therapies remain elusive. Herein, we propose an oxygen vacancy-rich (BiFe)0.9(BaTi)0.1O3-x nanoreactor as a piezoelectric sonosensitizer by spatiotemporal ultrasound-driven sono- and chemodynamic tandem catalysis to amplify antibacterial efficacy. The piezoelectric charge carriers under a built-in electric field synchronize the reaction of O2 and H2O, efficiently generating H2O2. The electron-rich oxygen vacancies modulate the local electronic structure of an Fe site. It facilitates reactive oxygen species generation by piezoelectric electrons and accelerates valence state cycles of Fe(III)/Fe(II) to achieve the sustained maintenance of hydroxyl radicals via H2O2/Fe(II)-catalyzed chemodynamic reactions, which lead to bacterial membrane damage. Transcriptomics analysis revealed that intracellular Fe overload induced by excessive Fe(II)-mediated dysregulation of the two-component system disrupts bacterial metabolism, triggering bacterial ferroptosis-like death. Thus, the porous titanium scaffold, engineered with a piezoelectric nanoreactor, demonstrates superior antibacterial efficacy under ultrasound and facilitates osteogenesis via piezoelectric immunomodulation-activated therapy.

Injectable hydrogels with ROS-triggered drug release enable the co-delivery of antibacterial agent and anti-inflammatory nanoparticle for periodontitis treatment

Periodontitis, a chronic inflammatory disease caused by bacteria, is characterized by localized reactive oxygen species (ROS) accumulation, leading to an inflammatory response, which in turn leads to the destruction of periodontal supporting tissues. Therefore, antibacterial, scavenging ROS, reducing the inflammatory response, regulating periodontal microenvironment, and alleviating alveolar bone resorption are effective methods to treat periodontitis. In this study, we developed a ROS-responsive injectable hydrogel by modifying hyaluronic acid with 3-amino phenylboronic acid (PBA) and reacting it with poly(vinyl alcohol) (PVA) to form a borate bond. In addition, the ROS-responsive hydrogel encapsulated the antibacterial agent minocycline hydrochloride (MH) and Fe-Quercetin anti-inflammatory nanoparticles (Fe-Que NPs) for on-demand drug release in response to the periodontitis microenvironment. This hydrogel (HP-PVA@MH/Fe-Que) exhibited highly effective antibacterial properties. Moreover, by modulating the Nrf2/NF-κB pathway, it effectively eliminated ROS and promoted macrophage polarization to the M2 phenotype, reducing inflammation and enhancing the osteogenic differentiation potential of human periodontal ligament stem cells (hPDLSCs) in the periodontal microenvironment. Animal studies showed that HP-PVA@MH/Fe-Que significantly reduced alveolar bone loss and enhanced osteogenic factor expression by killing bacteria and inhibiting inflammation. Thus, HP-PVA@MH/Fe-Que hydrogel had efficient antibacterial, ROS-scavenging, anti-inflammatory, and alveolar bone resorption-alleviation abilities, showing excellent application potential for periodontitis healing.

Microenvironment-Responsive Hydrogels Comprising Engineering Zeolitic Imidazolate Framework-8-Anchored Parathyroid Hormone-Related Peptide-1 for Osteoarthritis Therapy

Intra-articular drug injections are effective for osteoarthritis (OA), but challenges such as the complex microenvironment and rapid drug diffusion require frequent injections. Herein, we propose a biofunctional hydrogel-based strategy for prolonged drug delivery and microenvironment remodeling. We propose a strategy to functionalize zeolitic imidazolate framework-8 with tannic acid (TA-ZIF), anchor PTH-related peptide-1 (PTHrP-1) within this framework (TA-ZIF@P1) and incorporate a phenylboronic acid-modified gelatin-based hydrogel (GP hydrogel) drug delivery system (GP@TA-ZIF@P1, GPTP hydrogel) with responsive release properties that respond to the pathological microenvironments of OA. The GPTP hydrogel facilitated controlled, sustained release of PTHrP-1 via dynamic boronic esters, with in vitro and in vivo studies showing continuous release for over 28 days. It not only promotes chondrocyte proliferation but also exhibits significant cytoprotective effects under hyperactive ROS and IL-1β-induced conditions. Notably, transcriptome sequencing confirms that the GPTP hydrogel facilitates both chondrocyte proliferation and chondrogenesis under inflammatory conditions by deactivating Wnt/β-Catenin signaling pathways and enhancing the PI3K/AKT signaling pathway. Additionally, the GPTP hydrogel delays the catabolic metabolism of cartilage explants from mice in inflammatory environments. In a surgical model of mouse OA, we show that the intra-articular injection of GPTP hydrogels reduced periarticular bone remodeling and promoted the production of glycosaminoglycans while offering chondroprotection against cartilage degeneration. To sum up, this pioneering research on PTHrP-1 as a treatment for OA, combined with the GPTP hydrogel system, offers valuable insights and a paradigm for the controlled and sustained release of PTHrP-1, representing a significant advancement in OA treatment strategies.

Polymer-based antimicrobial strategies for periodontitis

Periodontitis is a chronic inflammatory condition driven by plaque-associated microorganisms, where uncontrolled bacterial invasion and proliferation impair host immune responses, leading to localized periodontal tissue inflammation and bone destruction. Conventional periodontal therapies face challenges, including incomplete microbial clearance and the rise of antibiotic resistance, limiting their precision and effectiveness in managing periodontitis. Recently, nanotherapies based on polymeric materials have introduced advanced approaches to periodontal antimicrobial therapy through diverse antimicrobial mechanisms. This review explored specific mechanisms, emphasizing the design of polymer-based agents that employ individual or synergistic antimicrobial actions, and evaluated the innovations and limitations of current strategies while forecasting future trends in antimicrobial development for periodontitis.

Sono-Catalytic Tooth Whitening and Oral Health Enhancement with Oxygen Vacancies-Enriched Mesoporous TiO2 Nanospheres: A Nondestructive Approach for Daily Tooth Care

Tooth discoloration and the breeding of oral microorganisms pose threats to both one's aesthetic appearance and oral health. Clinical whitening agents based on H2O2 with high concentrations are effective in tooth whitening and bacterial elimination but may also cause enamel demineralization, gingival irritation, or cytotoxicity, necessitating professional supervision. Herein, leveraging sono-catalysis effects, a nondestructive and convenient tooth whitening strategy was developed, utilizing oxygen vacancies (OVs)-enriched mesoporous TiO2 nanospheres. The introduction of OVs leads to TiO2 bandgap narrowing, boosting the generation of reactive oxygen species (ROS) by TiO2 under ultrasound treatment. Additionally, through the chemocatalysis effect, the ROS yield can be further augmented by employing OVs-enriched TiO2 in conjunction with an extremely low concentration of H2O2 (1%) during ultrasound treatment. Hence, under ultrasound treatment simulating daily tooth brushing using an electronic toothbrush, the combination of OVs-enriched TiO2 and 1% H2O2 proves to be effective in whitening teeth stained by tea, coffee, and mix juice. Furthermore, the combination of OVs-enriched TiO2 and 1% H2O2 demonstrates potent bacterial-killing and biofilm-eradicating effects under ultrasound treatment within an extremely short duration (5 min). Additionally, given the mesoporous structure, curcumin, serving as an anti-inflammatory agent, can be efficiently loaded into OVs-enriched TiO2 and then controllably released through ultrasound treatment. The curcumin-loaded TiO2 facilitates the transition of macrophages to the anti-inflammatory M2 phenotype, potentially alleviating oral inflammation induced by bacterial infection without showing any biotoxicity. The OVs-enriched TiO2 based sono-catalysis tooth whitening procedure provides the convenience of whitening teeth during daily brushing without requiring professional supervision.

ROS-Responsive Injectable Hydrogel Loaded with SLC7A11-modRNA Inhibits Ferroptosis and Mitigates Intervertebral Disc Degeneration in Rats

Intervertebral disc degeneration (IVDD) is the primary cause of low back pain, with oxidative stress being a recognized factor that causes its development. Presently, low back pain imposes a significant global economic burden. However, the effectiveness of treatments for IVDD remains extremely limited. Therefore, this study aims to explore innovative and effective IVDD treatments by focusing on oxidative stress as a starting point. In this study, an injectable reactive oxygen species-responsive hydrogel (PVA-tsPBA@SLC7A11 modRNA) is developed, designed to achieve rapid loading and selective release of chemically synthesized modified mRNA (modRNA). SLC7A11 modRNA is specifically used to upregulate the expression of the ferroptosis marker SLC7A11. The local injection of PVA-tsPBA@SLC7A11 modRNA into the degenerated intervertebral disc (IVD) results in the cleavage of PVA-tsPBA, leading to the release of enclosed SLC7A11 modRNA. The extent of SLC7A11 modRNA release is directly proportional to the severity of IVDD, ultimately ameliorating IVDD by inhibiting ferroptosis in nucleus pulposus cells (NPCs). This study proposes an innovative system of PVA-tsPBA hydrogel-encapsulated modRNA, representing a potential novel treatment strategy for patients with early-stage IVDD.

Nanomaterial-integrated injectable hydrogels for craniofacial bone reconstruction

The complex anatomy and biology of craniofacial bones pose difficulties in their effective and precise reconstruction. Injectable hydrogels (IHs) with water-swollen networks are emerging as a shape-adaptive alternative for noninvasively rebuilding craniofacial bones. The advent of versatile nanomaterials (NMs) customizes IHs with strengthened mechanical properties and therapeutically favorable performance, presenting excellent contenders over traditional substitutes. Structurally, NM-reinforced IHs are energy dissipative and covalently crosslinked, providing the mechanics necessary to support craniofacial structures and physiological functions. Biofunctionally, incorporating unique NMs into IH expands a plethora of biological activities, including immunomodulatory, osteogenic, angiogenic, and antibacterial effects, further favoring controllable dynamic tissue regeneration. Mechanistically, NM-engineered IHs optimize the physical traits to direct cell responses, regulate intracellular signaling pathways, and control the release of biomolecules, collectively bestowing structure-induced features and multifunctionality. By encompassing state-of-the-art advances in NM-integrated IHs, this review offers a foundation for future clinical translation of craniofacial bone reconstruction.

Harnessing the potential of hydrogels for advanced therapeutic applications: current achievements and future directions

The applications of hydrogels have expanded significantly due to their versatile, highly tunable properties and breakthroughs in biomaterial technologies. In this review, we cover the major achievements and the potential of hydrogels in therapeutic applications, focusing primarily on two areas: emerging cell-based therapies and promising non-cell therapeutic modalities. Within the context of cell therapy, we discuss the capacity of hydrogels to overcome the existing translational challenges faced by mainstream cell therapy paradigms, provide a detailed discussion on the advantages and principal design considerations of hydrogels for boosting the efficacy of cell therapy, as well as list specific examples of their applications in different disease scenarios. We then explore the potential of hydrogels in drug delivery, physical intervention therapies, and other non-cell therapeutic areas (e.g., bioadhesives, artificial tissues, and biosensors), emphasizing their utility beyond mere delivery vehicles. Additionally, we complement our discussion on the latest progress and challenges in the clinical application of hydrogels and outline future research directions, particularly in terms of integration with advanced biomanufacturing technologies. This review aims to present a comprehensive view and critical insights into the design and selection of hydrogels for both cell therapy and non-cell therapies, tailored to meet the therapeutic requirements of diverse diseases and situations.

Recent advances in injectable hydrogel therapies for periodontitis

Periodontitis is an immune-inflammatory disease caused by dental plaque, and deteriorates the periodontal ligament, causes alveolar bone loss, and may lead to tooth loss. To treat periodontitis, antibacterial and anti-inflammation approaches are required to reduce bone loss. Thus, appropriate drug administration methods are significant. Due to their "syringeability", biocompatibility, and convenience, injectable hydrogels and associated methods have been extensively studied and used for periodontitis therapy. Such hydrogels are made from natural and synthetic polymer materials using physical and/or chemical cross-linking approaches. Interestingly, some injectable hydrogels are stimuli-responsive hydrogels, which respond to the local microenvironment and form hydrogels that release drugs. Therefore, as injectable hydrogels are different and highly varied, we systematically reviewed the periodontal treatment field from three perspectives: raw material sources, cross-linking methods, and stimuli-responsive methods. We then discussed current challenges and opportunities for the translation of hydrogels to clinic, which may guide further injectable hydrogel designs for periodontitis.

The potential application of complement inhibitors-loaded nanosystem for autoimmune diseases via regulation immune balance

The complement is an important arm of the innate immune system, once activated, the complement system rapidly generates large quantities of protein fragments that are potent mediators of inflammation. Recent studies have shown that over-activated complement is the main proinflammatory system of autoimmune diseases (ADs). In addition, activated complements interact with autoantibodies, immune cells exacerbate inflammation, further worsening ADs. With the increasing threat of ADs to human health, complement-based immunotherapy has attracted wide attention. Nevertheless, efficient and targeted delivery of complement inhibitors remains a significant challenge owing to their inherent poor targeting, degradability, and low bioavailability. Nanosystems offer innovative solutions to surmount these obstacles and amplify the potency of complement inhibitors. This prime aim to present the current knowledge of complement in ADs, analyse the function of complement in the pathogenesis and treatment of ADs, we underscore the current situation of nanosystems assisting complement inhibitors in the treatment of ADs. Considering technological, physiological, and clinical validation challenges, we critically appraise the challenges for successfully translating the findings of preclinical studies of these nanosystem assisted-complement inhibitors into the clinic, and future perspectives were also summarised. (The graphical abstract is by BioRender.).

Stimuli‐Responsive Hydrogels for Antibacterial Applications

Hydrogels have emerged as promising candidates for biomedical applications, especially in the field of antibacterial therapeutics, due to their unique structural properties, highly tunable physicochemical properties, and excellent biocompatibility. The integration of stimuli-responsive functions into antibacterial hydrogels holds the potential to enhance their antibacterial properties and therapeutic efficacy, dynamically responding to different external or internal stimuli, such as pH, temperature, enzymes, and light. Therefore, this review describes the applications of hydrogel dressings responsive to different stimuli in antibacterial therapy. The collaborative interaction between stimuli-responsive hydrogels and antibacterial materials is discussed. This synergistic approach, in contrast to conventional antibacterial materials, not only amplifies the antibacterial effect but also alleviates adverse side effects and diminishes the incidence of multiple infections and drug resistance. The review provides a comprehensive overview of the current challenges and outlines future research directions for stimuli-responsive antibacterial hydrogels. It underscores the imperative for ongoing interdisciplinary research aimed at unraveling the mechanisms of wound healing. This understanding is crucial for optimizing the design and implementation of stimuli-responsive antibacterial hydrogels. Ultimately, this review aims to offer scientific guidance for the development and practical clinical application of stimuli-responsive antibacterial hydrogel dressings.

Wet environment-induced adhesion and softening of coenzyme-based polymer elastic patch for treating periodontitis

Periodontitis, a common chronic inflammatory disease caused by pathogenic bacteria, can be treated with diverse biomaterials by loading drugs, cytokines or proteins. However, these biomaterials often show unsatisfactory therapeutic efficiency due to their poor adhesion, short residence time in the wet and dynamic oral cavity and emerging drug resistance. Here we report a wet-responsive methacrylated gelatin (GelMA)-stabilized co-enzyme polymer poly(α-lipoic acid) (PolyLA)-based elastic patch with water-induced adhesion and softening features. In PolyLA-GelMA, the multiple covalent and hydrogen-bonding crosslinking between PolyLA and GelMA prevent PolyLA depolymerization and slow down the dissociation of PolyLA in water, allowing durable adhesion to oral periodontal tissue and continuous release of LA-based bioactive small molecule in periodontitis wound without resorting external drugs. Compared with the undifferentiated adhesion behavior of traditional adhesives, this wet-responsive patch demonstrates a favorable periodontal pocket insertion ability due to its non-adhesion and rigidity in dry environment. In vitro studies reveal that PolyLA-GelMA patch exhibits satisfactory wet tissue adhesion, antibacterial, blood compatibility and ROS scavenging abilities. In the model of rat periodontitis, the PolyLA-GelMA patch inhibits alveolar bone resorption and accelerates the periodontitis healing by regulating the inflammatory microenvironment. This biomacromolecule-stabilized coenzyme polymer patch provides a new option to promote periodontitis treatment.

Molecular Engineering of Electrosprayed Hydrogel Microspheres to Achieve Synergistic Anti-Tumor Chemo-Immunotherapy with ACEA Cargo

Molecular engineering of drug delivering platforms to provide collaborative biological effects with loaded drugs is of great medical significance. Herein, cannabinoid receptor 1 (CB1)- and reactive oxygen species (ROS)-targeting electrosprayed microspheres (MSs) are fabricated by loading with the CB1 agonist arachidonoyl 2'-chloroethylamide (ACEA) and producing ROS in a photoresponsive manner. The synergistic anti-tumor effects of ACEA and ROS released from the MSs are assessed. ACEA inhibits epidermal growth factor receptor signaling and altered tumor microenvironment (TME) by activating CB1 to induce tumor cell death. The MSs are composed of glycidyl methacrylate-conjugated xanthan gum (XGMA) and Fe3+, which form dual molecular networks based on a Fe3+-(COO-)3 network and a C═C addition reaction network. Interestingly, the Fe3+-(COO-)3 network can be disassembled instantly under the conditions of lactate sodium and ultraviolet exposure, and the disassembly is accompanied by massive ROS production, which directly injures tumor cells. Meanwhile, the transition of dual networks to a single network boosts the ACEA release. Together, the activities of the ACEA and MSs promote immunogenic tumor cell death and create a tumor-suppressive TME by increasing M1-like tumor-associated macrophages and CD8+ T cells. In summation, this study demonstrates strong prospects of improving anti-tumor effects of drug delivering platforms through molecular design.

Emerging roles of hydrogel in promoting periodontal tissue regeneration and repairing bone defect

Periodontal disease is the most common type of oral disease. Periodontal bone defect is the clinical outcome of advanced periodontal disease, which seriously affects the quality of life of patients. Promoting periodontal tissue regeneration and repairing periodontal bone defects is the ultimate treatment goal for periodontal disease, but the means and methods are very limited. Hydrogels are a class of highly hydrophilic polymer networks, and their good biocompatibility has made them a popular research material in the field of oral medicine in recent years. This paper reviews the current mainstream types and characteristics of hydrogels, and summarizes the relevant basic research on hydrogels in promoting periodontal tissue regeneration and bone defect repair in recent years. The possible mechanisms of action and efficacy evaluation are discussed in depth, and the application prospects are also discussed.

Achieving Clearance of Drug-Resistant Bacterial Infection and Rapid Cutaneous Wound Regeneration Using an ROS-Balancing-Engineered Heterojunction

Intractable infected microenvironments caused by drug-resistant bacteria stalls the normal course of wound healing. Sono-piezodynamic therapy (SPT) is harnessed to combat pathogenic bacteria, but the superabundant reactive oxygen species (ROS) generated during SPT inevitably provoke severe inflammatory response, hindering tissue regeneration. Consequently, an intelligent nanocatalytic membrane composed of poly(lactic-co-glycolic acid) (PLGA) and black phosphorus /V2C MXene bio-heterojunctions (2D2-bioHJs) is devised. Under ultrasonication, 2D2-bioHJs effectively eliminate drug-resistant bacteria by disrupting metabolism and electron transport chain (ETC). When ultrasonication ceases, they enable the elimination of SPT-generated ROS. The 2D2-bioHJs act as a "lever" that effectively achieves a balance between ROS generation and annihilation, delivering both antibacterial and anti-inflammatory properties to the engineered membrane. More importantly, in vivo assays corroborate that the nanocatalytic membranes transform the stalled chronic wound environment into a regenerative one by eradicating the bacterial population, dampening the NF-κB inflammatory pathway and promoting angiogenesis. As envisaged, this work demonstrates a novel tactic to arm membranes with programmed antibacterial and anti-inflammatory effects to remedy refractory infected wounds from drug-fast bacteria.

Injectable Nanocomposite Hydrogels with Strong Antibacterial, Osteoinductive, and ROS-Scavenging Capabilities for Periodontitis Treatment

Injectable antibacterial and osteoinductive hydrogels have received considerable attention for promoting bone regeneration owing to their versatile functionalities. However, a current hydrogel with antibacterial, osteoinductive, and antioxidant properties by a facile method for periodontitis treatment is still missing. To overcome this issue, we designed an injectable hydrogel system (GPM) composed of gelatin, Ti3C2Tx MXene nanosheets, and poly-l-lysine using a simple enzymatic cross-linking technique. Physicochemical characterization demonstrated that the GPM hydrogel matrix exhibited excellent stability, moderate tissue adhesion ability, and good mechanical behavior. The GPM hydrogels significantly inhibited the growth of Porphyromonas gingivalis, scavenged reactive oxygen species, attenuated inflammatory responses, and enhanced bone tissue regeneration. Intriguingly, the arrangement of the junctional epithelium, alveolar bone volume, and alveolar bone height in the GPM-treated periodontal disease group recovered to that of the healthy group. Therefore, our injectable hydrogel system with versatile functions may serve as an excellent tissue scaffold for the treatment of periodontitis.

Copper ion/gallic acid MOFs-laden adhesive pomelo peel sponge effectively treats biofilm-infected skin wounds and improves healing quality

Bacterial infection and scar formation remain primary challenges in wound healing. To address these issues, we developed a decellularized pomelo peel (DPP) functionalized with an adhesive PVA-TSPBA hydrogel and antibacterial gallic acid/copper MOFs. The hybrid wound dressing demonstrates favorable biocompatibility. It does not impede the proliferation of fibroblasts or immune cells and can stimulate fibroblast migration, endothelial angiogenesis, and M2 macrophage polarization. Additionally, the dressing can scavenge reactive oxygen species (ROS) and provide antioxidant effects. Furthermore, DPP + MOF@Gel effectively inhibits the viability of S. aureus and E. coli in vitro and in vivo. The histological observations revealed enhanced granulation tissue formation, re-epithelialization, and angiogenesis in the DPP + MOF@Gel group compared to other groups. The local immune response also shifted from a pro-inflammatory to a pro-regenerative status with DPP + MOF@Gel treatment. The skin incision stitching experiment further exhibits DPP + MOF@Gel could reduce scar formation during wound healing. Taken together, the hybrid DPP + MOF@Gel holds great promise for treating bacteria-infected skin wounds and inhibiting scar formation during wound healing.

Cleavage and Noncleavage Chemistry in Reactive Oxygen Species (ROS)-Responsive Materials for Smart Drug Delivery

The design and development of advanced drug delivery systems targeting reactive oxygen species (ROS) have gained significant interest in recent years for treating various diseases, including cancer, psychiatric diseases, cardiovascular diseases, neurological diseases, metabolic diseases, and chronic inflammations. Integrating specific chemical bonds capable of effectively responding to ROS and triggering drug release into the delivery system is crucial. In this Review, we discuss commonly used conjugation linkers (chemical bonds) and categorize them into two groups: cleavable linkers and noncleavable linkers. Our goal is to clarify their unique drug release mechanisms from a chemical perspective and provide practical organic synthesis approaches for their efficient production. We showcase numerous significant examples to demonstrate their synthesis routes and diverse applications. Ultimately, we strive to present a comprehensive overview of cleavage and noncleavage chemistry, offering insights into the development of smart drug delivery systems that respond to ROS.

Catechol-Modified and MnO2-Nanozyme-Reinforced Hydrogel with Improved Antioxidant and Antibacterial Capacity for Periodontitis Treatment

Periodontitis is an inflammatory disease characterized by tooth loss and alveolar bone resorption. Bacteria are the original cause of periodontitis, and excess reactive oxygen species (ROS) encourage and intensify inflammation. In this study, a mussel-inspired and MnO2 NPs-reinforced adhesive hydrogel capable of alleviating periodontitis with improved antibacterial and antioxidant abilities was developed. The hydrogel was created by combining polyvinyl alcohol (PVA), 3,4-dihydroxy-d-phenylalanine (DOPA), and MnO2 nanoparticles (NPs) (named PDMO hydrogel). The hydrogel was demonstrated to be able to scavenge various free radicals (including total ROS─O2•- and OH•) and relieve the hypoxia in an inflammatory microenvironment by scavenging excess ROS and generating O2 due to its superoxide dismutase (SOD)/catalase (CAT)-like activity. Besides, under 808 nm near-infrared (NIR) light, the photothermal performance of the PDMO hydrogel displayed favorable antibacterial and antibiofilm effects toward Escherichia coli, Staphylococcus aureus, and Porphyromonas gingivalis (up to nearly 100% antibacterial rate). Furthermore, the PDMO hydrogel exhibited favorable therapeutic efficacy in alleviating gingivitis in Sprague-Dawley rats, even comparable to or better than the commercial PERIO. In addition, in the periodontitis models, the PDMO2 group showed the height of the residual alveolar bone and the smallest shadow area of low density among other groups, indicating the positive role of the PDMO2 hydrogel in bone regeneration. Finally, the biosafety of the PDMO hydrogel was comprehensively investigated, and the hydrogel was demonstrated to have good biocompatibility. Therefore, the developed PDMO hydrogel provided an effective solution to resolve biofilm recolonization and oxidative stress in periodontitis and could be a superior candidate for local drug delivery system in the clinical management of periodontitis with great potential for future clinical translation.

[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.

Treatment of Periodontal Infections, the Possible Role of Hydrogels as Antibiotic Drug-Delivery Systems

With the advancement of biomedical research into antimicrobial treatments for various diseases, the source and delivery of antibiotics have attracted attention. In periodontal diseases, antibiotics are integral in positive treatment outcomes; however, the use of antibiotics is with caution as the potential for the emergence of resistant strains is of concern. Over the years, conventional routes of drug administration have been proven to be effective for the treatment of PD, yet the problem of antibiotic resistance to conventional therapies continues to remain a setback in future treatments. Hydrogels fabricated from natural and synthetic polymers have been extensively applied in biomedical sciences for the delivery of potent biological compounds. These polymeric materials either have intrinsic antibacterial properties or serve as good carriers for the delivery of antibacterial agents. The biocompatibility, low toxicity and biodegradability of some hydrogels have favoured their consideration as prospective carriers for antibacterial drug delivery in PD. This article reviews PD and its antibiotic treatment options, the role of bacteria in PD and the potential of hydrogels as antibacterial agents and for antibiotic drug delivery in PD. Finally, potential challenges and future directions of hydrogels for use in PD treatment and diagnosis are also highlighted.