Critical bone defects present significant clinical challenges due to their debilitating nature and associated costs. Tissue engineering offers a promising solution, employing biomaterials like porous chitosan (CH) and xanthan gum (XG) membranes as scaffolds for tissue regeneration. Electrical stimulation (ES) and laser (L) therapy, known for osteogenic and anti-inflammatory effects, respectively, may synergistically enhance bone healing when combined with these membranes. This study evaluated CH/XG membranes and their association with ES and L for the treatment of critical bone defects (25 mm2) created in 80 male Wistar rats. The animals were divided into four groups: untreated, CH/XG, CH/XG + ES, and CH/XG + L, assessed at days 30 and 90. Histomorphometric and real-time PCR analyses revealed greater tissue and blood vessel formation in the CH/XG, CH/XG + ES, and CH/XG + L groups compared to the untreated group. At day 30, reduced Runx-2 and Osx expression in the treated groups suggested an initial high inflammatory response. The CH/XG group showed pronounced inflammation (elevated Il-1β and pro-inflammatory markers) alongside an anti-inflammatory response. Conversely, compared with the CH/XG-only group, the CH/XG + ES and CH/XG + L groups generally showed lower expression of the evaluated pro-inflammatory markers after 30 days, together with treatment- and time-dependent changes in anti-inflammatory markers. Although inflammation limited the initial effectiveness of CH/XG membranes, significant positive impacts were observed after 90 days. Combining membranes to cover bone defects and adjunctive therapies, as demonstrated in this study, emerges as a beneficial approach for enhancing bone repair outcomes. Adding osteoconductive or osteoinductive fillers may bring further healing improvements.
Graphene-based nanomaterials (GBNs), such as graphene oxide and reduced graphene oxide, have been considered as promising functional materials for bone tissue engineering due largely to their intrinsic biological functions and great drug delivery capacity. As bioactive materials, GBNs possess antibacterial activity, photothermal effect, and the ability to regulate immune microenvironment and osteogenesis-related signaling pathways such as Wnt/β-catenin, MAPK, and BMP/Smad. As drug delivery systems, the large surface area and multiple functionalization sites allow GBNs to have great potential in loading and delivering various active agents, such as drugs, genes, and growth factors. Based on these properties, GBNs prevent infections, facilitate stem cell adhesion, proliferation, and osteogenic differentiation, and ultimately promote bone regeneration. In the past few years, reports regarding the applications of GBNs in bone tissue engineering have been well documented, but the clinical translation is still limited. Herein, on the basis of the two major roles of GBNs (bioactive agents and drug delivery systems), we aim to provide a comprehensive understanding of the multiple functions and mechanisms of GBNs in promoting bone tissue regeneration. The progress and challenges in clinical translation are also discussed.
Effective nose-to-brain delivery is limited by the mucus-mucosal barrier, which severely hinders drug transport after nasal administration. Although nanostructured lipid carriers (NLCs) offer promising solutions by improving their retention duration in the mucosal layer or promoting mucosal permeation and intracellular uptake, the nanoparticle-mucus interactions, epithelial uptake, and mechanisms supporting transcellular transport in the nasal cavity remain poorly learned. This study was developed to assess the interactions between mucin and NLCs, the absorption and transport capabilities of Cannabidiol (CBD) nanostructured lipid carriers (CBD-NLCs) in rat nasal mucosal epithelial (RNME) cells. Molecular docking (MD) was used to evaluate the interactions between the human mucin protein MUC5AC (hMUC5AC) and some main components of CBD-NLCs. In vitro experiments were conducted to assess the mucus penetration of CBD-NLCs. Cellular uptake, localization, and transport mechanisms of coumarin-6-labeled NLCs (C6-NLCs) in RNME cells were examined by confocal laser scanning microscopy, endocytosis inhibition assays, and transcellular transport assays. Our results show that there were no interactions between the main components of NLCs and hMUC5AC according to MD simulations. In vitro experiments, NLCs promoted mucus penetration and had little interaction with mucin. Cellular studies confirmed cytoplasmic (non-nuclear) localization of C6-NLCs in RNME cells, and transport assays showed that the clathrin-mediated endocytic route was a predominant pathway for their internalization. When across the RNME cell monolayer, NLCs had a great benefit on CBD transportation across monolayers of RNME cells. Our results clarify the mechanism by which NLCs enhance mucosal penetration and facilitate cellular trafficking in RNME cells. Their little interaction with mucin, combined with efficient cellular uptake and transcellular transport, supports the potential of NLCs as a promising nanoplatform for nose-to-brain drug delivery.
Oxidative stress is a critical barrier to effective bone regeneration, often impairing cellular function and osteogenic differentiation. In this study, we report the novel development of a multifunctional chitosan/collagen (CS/Coll) hydrogel integrated with praseodymium-doped mesoporous bioactive glass nanoparticles (Pr-MBGNs) engineered for the first time to simultaneously scavenge reactive oxygen species (ROS) and promote osteogenesis. The antioxidant potential of the Pr-MBGNs-loaded hydrogels was confirmed through hydrogen peroxide (H2O2) scavenging assays, demonstrating over 98% H2O2 reduction at optimal concentrations with significant reduction in intracellular ROS production. Under oxidative stress conditions, the hydrogels significantly restored rMSC viability, enhanced cell adhesion, and supported sustained proliferation. Mechanically, the incorporation of Pr-MBGNs modulated hydrogel crosslink density and stiffness, which favor improved cell-material interactions. Osteogenic assays showed a significant upregulation of key osteogenic markers (RUNX2, OCN, and OSX) and increase in matrix mineralization over 28 days. These outcomes are attributed to the synergistic effect of antioxidant protection and sustained release of bioactive ions from the Pr-MBGNs, which reprogrammed the redox environment and enhanced the osteoinductive microenvironment. Collectively, this study presents a first-of-its-kind nanoengineered hydrogel system that integrates ROS scavenging and osteogenic stimulation, offering a promising biomimetic strategy for bone tissue engineering in oxidative stress-related pathological conditions.
Type I collagen (Col-I) is widely used in biomaterials and cell biology, yet the glycosignature of commercial Col-I preparations remains poorly characterized. Here, we established an integrated lectin-based workflow to profile the glycan landscape of commercially sourced bovine pepsin-soluble Col-I as supplied for biomaterial use. Using a panel of 15 biotinylated and fluorescent lectins, we combined qualitative fluorescence staining, quantitative enzyme-linked lectin sorbent assay (ELLSA), and lectin-probed western blotting to compare three production batches. The batches shared common mannose- and galactose-reactive signals but displayed marked heterogeneity in low-abundance fucosylated and sialylated epitopes. Haptenic sugar inhibition and targeted digestion with α(1,6)-fucosidase and α(2,3)-neuraminidase confirmed lectin specificity and showed that some lectin-reactive motifs were partially masked in native films. In light of the known restriction of classical Type I collagen glycosylation to galactosyl- and glucosylgalactosyl-hydroxylysine, together with physicochemical evidence consistent with residual non-collagenous components, the complex fucosylated and sialylated signals detected here most likely arise predominantly from co-purified collagen-associated extracellular-matrix glycoproteins rather than from the collagen α-chains alone. Functionally, all Col-I-coated surfaces strongly promoted MDA-MB-231 cell adhesion, while glycosidase treatment produced batch-dependent visual trends in wound-closure kinetics without significant differences at matched time points. Overall, this work identifies a hidden source of batch variability in commercial collagen biomaterials and positions lectin profiling as an accessible quality-control tool for characterizing the full glycoprotein composition of collagen raw materials.
This study explores the development and characterization of polymeric nanoparticles encapsulating Brazilian red propolis extract (BRPE) for application in ovarian (OVCAR-3) and breast (MDA-MB-231) cancers. The nanoparticles (NCBRPE), produced by nanoprecipitation, were evaluated for size, polydispersity index (PdI), zeta potential, and encapsulation efficiency (EE). Stability assessments over 365 days confirmed preserved physicochemical properties. Release kinetics, evaluated using a dialysis membrane assay and UPLC-MS, revealed that vestitol and formononetin followed the Peppas-Korsmeyer model, while biochanin A followed Higuchi kinetics, indicating diffusion-controlled mechanisms. Flow cytometry and confocal microscopy showed lower uptake of NCBRPE compared to free BRPE, though uptake was significantly higher in OVCAR-3 cells, suggesting receptor-mediated internalization. Cell cycle analysis revealed that NCBRPE, but not BRPE, induced a shift from G1 to S phase, potentially impairing cell proliferation. Migration assays demonstrated significant inhibition of OVCAR-3 cell migration by both BRPE and NCBRPE. Acute toxicity evaluation in Galleria mellonella confirmed the safety of NCBRPE, with over 80% survival at doses up to 50 mg/kg. These results demonstrate that nanoencapsulation enhances the stability, release control, and therapeutic activity of BRPE, supporting its potential as a multifunctional nanoplatform for treating female cancers, particularly ovarian carcinoma.
The therapeutic effectiveness of superficial tumors is currently limited by the operational difficulty of traditional surgery. Localized target delivery of nanomedicine provides a promising solution for superior antitumor effect in superficial tumors, but its delivery efficiency can be greatly hampered by the dense tumor stroma. Compared with external modulation against the tumor extracellular matrix by physical methods, internal regulation of the tumor microenvironment via enzyme enables more direct degradation of the tumor extracellular matrix and robust antitumor efficacy. Herein, we report a dual-enzyme delivery nanoplatform to impart a cascade catalytic reaction for potent chemodynamic therapy with enhanced penetration depth in the superficial tumor. In response to the tumor microenvironment, the glucose oxidase/papain complex loaded in MnO2 nanoparticles could be rapidly released to trigger cascade chemodynamic therapy and grant deeper penetration of therapeutic effect in the superficial tumor. The collective actions of papain's protease and peroxidase-like activity allowed significant tumor penetration and reactive oxygen species production cascaded with glucose oxidase, holding great promise as a potential strategy to improve the efficacy of superficial tumor treatment.
Biomaterials for orthopedic and dental implantation are designed to promote the timely resolution of inflammation and new bone formation while limiting the deposition of fibrotic tissue, which can cause implant failure. During the immune response to implantation, T cells at the peri-implant interface release cytokines that modulate innate immune cell response, mesenchymal stem cell (MSC) recruitment and proliferation, and new bone formation. However, T cells contribute to fibrosis in tissues such as the heart, lungs, liver, kidneys, and skin. This study aimed to determine how T cells contribute to peri-implant fibrosis using two biomaterials with differing inflammatory responses: pure titanium (Ti) and polyetheretherketone (PEEK). Following implantation of these materials in mice, we found greater recruitment of pro-inflammatory macrophages, CD4+ T cells, and CD8+ T cells in response to PEEK implants than to Ti implants. Likewise, macrophages cultured on PEEK surfaces demonstrated higher gene expression and protein secretion of pro-inflammatory factors (IL-6, IL-17A, TNF-α, and TGF-β1) than on Ti, an effect robustly enhanced when cells were cocultured with T cells. Finally, MSCs cultured with the conditioned media from macrophage-T cell co-cultures on PEEK had high expression of pro-fibrotic genes. Our findings demonstrate that biomaterial properties directly contribute to MSC differentiation toward myofibroblasts through the activation and crosstalk of macrophages and T cells, suggesting that these cells play a significant role in the fibrotic encapsulation of biomaterials.
A major challenge for cell and tissue transplantation is providing a sustaining environment for newly transplanted cells and tissues. They require a temporary oxygen source since newly transplanted cells and tissues are not yet connected to the recipient's vascular system. Here we report on core-sheath fiber membranes formed using the coaxial electrospinning process that contain calcium peroxide (CPO) embedded in the fiber core to provide a source of oxygen by diffusion from the fibers over a period of multiple days. Embedding the enzyme catalase in the fiber sheath as a catalyst is found to significantly reduce the production of cytotoxic hydrogen peroxide (H2O2) by ~59% and to increase the overall amount of oxygen released up to ~28% after 4 days of release. CPO-containing PCL/PVP-PEO core-sheath fiber membranes produced enhanced cell viability of > 90% at Day 5 for metabolically active pancreatic beta cell spheroids in a hypoxic environment, while non-CPO control cases resulted in no surviving cells at Day 5. Preliminary investigations with the incorporation of lysozyme as a model protein in the fiber core for eventual growth factor incorporation have yielded promising sustained release of lysozyme up to 10 days.
Severe wound healing impairment risks persistent tissue damage and even necrosis. Cell-free exosome therapy demonstrates significant potential in wound healing due to its high efficacy and micro-volume characteristics. However, its clinical-scale translation faces challenges including low yield, limited sources, functional monotony, and low bioavailability. We developed a lentiviral co-engineering strategy introducing exosome secretion-related genes into macrophage and fibroblast cell lines, achieving stable, high-yield (twofold increase) exosome production. Co-engineered extracellular vesicles (EVs) demonstrated enhanced cellular uptake and synergistically upregulated pro-angiogenic (HIF-1α, VEGF-A) and anti-inflammatory (IL-4, IL-10) factors. In a cell model and murine full-thickness wound model, the combination of EVs from both sources potently accelerated healing, promoting re-epithelialization and collagen deposition while orchestrating an anti-inflammatory response via TNF-α/IL-1β downregulation and IL-10 upregulation. In summary, co-cultured EVs not only exhibit high yield and purity but also demonstrate potent pro-angiogenic, anti-inflammatory, and antioxidant effects, effectively promoting wound healing, epithelial tissue regeneration, and collagen deposition. This study proposes an innovative and highly efficient method for synergistically regulating the production of EVs from cellular systems, providing promising research resources for their application in wound healing and medical esthetics. It also offers crucial insights for investigating the underlying mechanisms.
Biomaterials are indispensable to modern healthcare, yet their development remains hindered by traditional trial-and-error approaches that are costly, time-intensive, and inefficient. Artificial intelligence (AI) offers a powerful alternative, but most existing reviews treat AI merely as a computational tool for property prediction rather than as a systemic driver of innovation across the entire biomaterials' lifecycle. This review bridges that gap by providing a holistic, end-to-end perspective that integrates AI-driven design, intelligent manufacturing, and clinical translation into a unified framework. We systematically examine how AI-powered predictive modeling and structure-function optimization are reshaping the discovery of polymers, proteins, drug carriers, and tissue scaffolds, while also driving breakthroughs in 3D bioprinting, laser processing, composite manufacturing, and genetically programmed bio-fabrication. Recognizing that computational promise does not automatically translate into clinical reality, we critically evaluate persistent barriers such as data scarcity, poor data quality, the interpretability-accuracy trade-off, and regulatory uncertainties, and discuss strategies to overcome them through Explainable AI and rigorous validation protocols. Looking forward, we explore the convergence of AI with quantum computing and CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats) gene editing, which together could enable a new generation of multifunctional, responsive biomaterials. By synthesizing advances across the full lifecycle and offering a structured framework for selecting AI methodologies tailored to specific biomaterials challenges, this review aims to serve as both a comprehensive resource and a strategic roadmap for translating computational innovation into tangible clinical impact.
Current treatment modalities for head and neck cancer often leave patients with severe morbidities including difficulty swallowing, breathing, and speaking. Novel therapeutics are needed which induce suppress tumors, provide more precise surgical resection, and minimize damage to the complex surrounding tissue. In this study, plasmonic gold-silver-gold core-shell-shell (CSS) nanoparticles were functionalized with miR-20a-5p via a thermo-responsive furan-based Diels-Alder linker. The delivery of microRNA (miRNA) mimics allows for the post-transcriptional regulation of gene expression across numerous signaling pathways simultaneously. The CSS morphology and composition of the nanoparticles resulted in plasmonic maximum at 849 nm, within the near-infrared range. Upon photo-activation with an 850 nm LED, the linker underwent a retrograde Diels-Alder reaction releasing the miRNA mimic. In vitro results showed that 50 nM miR-20a-5p delivered with the CSS nanoparticles and photo-activated led to a 60% reduction in cancer cell survival. A combination of bioinformatic and gene expression analysis revealed that multiple gene targets of miR-20a-5p within the apoptosis signaling pathway were knocked down. Murine xenograft models emphasized spatiotemporal control of therapeutic release through photo-activation at 850 nm. Furthermore, FaDu cell tumor volume decreased ~95% within 48 h of a singular dose of 100 picomoles of miR-20a-5p from the CSS nanoparticles. Both in vitro and in vivo results exhibit the promise of the CSS nanoparticle system for miRNA mimic delivery. With responsivity in the near-infrared range, head and neck cancer applications are ideal for this system.
Most cancer patients are at high risk of thrombotic complications. However, tumor therapy combined with thrombosis treatment is a challenge due to the discrepancy in the microenvironment between tumors and thrombosis. In this study, a nano polymer-conjugate with tumor targeting and thrombolysis was developed. The nano polymer-conjugate is formed by a cross-linking agent containing imine bonds to cross-link anti-thrombosis drug nattokinase (NK) with a second-generation dendrimer (G2) in the outer layer (NK-G2), and magnetic silica is introduced during the cross-linking. Then, a dual drug loading system (NK-G2)n/FA-Dox is obtained by loading anti-tumor drug doxorubicin (Dox) modified with folic acid (FA). FA and the magnetic silica enable the nano polymer-conjugate to accumulate at the tumor sites. Most importantly, the nano polymer-conjugate shows weak acid responsiveness, allowing it to dissociate in the tumor microenvironment and release two drugs without entering cancer cells. This addresses the problem of the discrepancy in the microenvironment between tumors and thrombosis. This dual-drug loaded nano polymer-conjugate exhibits excellent potential in the combined treatment of tumor and the thrombotic complications.
Sepsis-associated acute kidney injury (SA-AKI) is a common and life-threatening complication of sepsis, whose high incidence and mortality severely impair patient prognosis. Existing anti-AKI drugs exhibit limited efficacy due to their inability to efficiently target injured kidneys. Although kidney-targeted nanocarrier delivery systems show potential, exogenous nanoparticles are rapidly cleared by the immune system, resulting in a short blood circulatory half-life and unsatisfactory targeting efficiency. Recombinant apolipoprotein H (rAPOH) exhibits anti-apoptotic and anti-inflammatory activities, holding promise for SA-AKI treatment; however, its efficacy is constrained by insufficient targeting capability and rapid in vivo metabolic clearance. In this study, we constructed a biomimetic delivery system (KMA@rAPOH) consisting of A@rAPOH nanoparticles coated with kidney-targeting peptide-functionalized renal tubular epithelial cell membranes to realize targeted rAPOH delivery for SA-AKI therapy. The nanocarrier demonstrated satisfactory encapsulation efficiency, high drug loading capacity, and favorable controlled release, along with excellent long-term stability in DMEM and deionized water. In vitro, KMA@rAPOH was efficiently internalized by renal tubular epithelial cells and exerted significant anti-apoptotic and anti-inflammatory effects. In a mouse model of SA-AKI, KMA@rAPOH markedly alleviated renal pathological damage and inhibited cell apoptosis. Additionally, it reduced the proportion of CD11c+F4/80+ pro-inflammatory macrophages in the renal CD45+CD11b+ population. Mechanistically, KMA@rAPOH was found to reduce TLR4 levels and inhibit NF-κB p65 phosphorylation, accompanied by decreased secretion of pro-inflammatory cytokines including TNF-α, IL-1β, and IL-6. These observations indicate that the TLR4/NF-κB cascade may partially mediate the renoprotective activity of KMA@rAPOH, and this biomimetic nanoplatform represents a promising targeted delivery strategy for the treatment of renal inflammatory disorders.
Currently, there is a lack of effective methods to repair annulus fibrosus (AF) defects in clinical practice. Therefore, exploring strategies to promote AF regeneration is of significant importance for delaying intervertebral disc degeneration. In recent years, tissue engineering technology has become a hotspot in the field of AF repair, offering promising treatments for intervertebral disc degenerative diseases. Studies have shown that surface structural characteristics, such as the fiber orientation of scaffold materials, play a crucial role in regulating the differentiation of cells adhering to the scaffold surface. Here we used electrospinning technology to prepare aligned and random decellularized annulus fibrosus matrix (DAFM)/poly(ether carbonate urethane)urea (PECUU) blended fibrous scaffolds. Rat AF stem cells (AFSCs) cultured on the aligned DAFM/PECUU blended fibrous scaffolds exhibited an aligned distribution, and the secreted AF-associated extracellular matrix components, including Collagen type I, Collagen type II, and Aggrecan, were also aligned. In contrast, AFSCs on the random DAFM/PECUU blended fibrous scaffolds exhibited an irregular distribution, and the secreted AF-associated extracellular matrix components were also irregularly distributed. Moreover, AFSCs on the aligned DAFM/PECUU blended fibrous scaffolds expressed higher levels of Col-I and Aggrecan than those on the random DAFM/PECUU blended fibrous scaffold. Both aligned and random DAFM/PECUU blended fibrous scaffolds degraded slowly in vivo. Magnetic resonance imaging, hematoxylin and eosin staining, Safranin O-fast green staining, and immunohistochemical staining demonstrated that both aligned and random DAFM/PECUU blended fibrous scaffolds effectively repaired AF defects in rats in vivo. However, the aligned DAFM/PECUU blended fibrous scaffolds exhibited superior repair capability.
Approaches to the structural design of tissue engineered heart valves (TEHVs) have varied broadly, ranging from material choice to microstructural and macro-scale functional characteristics. Not only will each variable on this extensive list impact functional and restorative potential after implantation, but most of these variables also have dynamic, cross-talking effects. While there has been a great deal of discussion in the field on this topic, there has only been a limited amount of evidence generated that systematically isolated specific design features and validated them in vivo. In order to reduce this knowledge gap, two groups of stented polymer tissue engineered pulmonary valve (TEPV) scaffolds were fabricated with similar structural characteristics, differing only in their initial thickness values, and implanted in an ovine pulmonary valve replacement model for 30 or 90 days. In vivo functional performance was measured by echocardiography, and histological analysis was performed on each scaffold explant. No differences were evident in valve regurgitation or neotissue formation between valve scaffolds of either thickness group or study duration. This may be due in part to broad variability between animals of the same group and even leaflets of the same valve. These results suggest that, with the condition of limited cell infiltration, modulation of leaflet thickness alone may be insufficient to address early remodeling in TEPVs, and reemphasize the complexity of designing TEHVs according to the myriad of interrelated structural variables that have direct and indirect impacts on tissue engineering viability, coupled with further variability associated with in vivo experiments.
All current clinical treatments for peripheral nerve injury (PNI), including end-to-end suturing, allografts, non-surgical management, and autografts, suffer from inherent limitations that prevent adequate functional recovery. To address this challenge, we fabricated anisotropic polycaprolactone (PCL) mesh scaffolds via near-field direct-writing (NFDW) 3D printing for neural tissue engineering. To endow the scaffolds with electroactivity, a layer-by-layer (LbL) self-assembly technique was employed to coat polyethylenimine/graphene oxide (PEI/GO), followed by in situ reduction to form conductive reduced graphene oxide/PCL (RGO/PCL) composite scaffolds. Systematic characterization demonstrated that scaffolds coated with 10 LbL cycles achieved an optimal balance, maintaining a favorable topological structure while exhibiting significantly enhanced electrical conductivity, mechanical properties, and hydrophilicity. Biological evaluations confirmed the excellent biocompatibility of the composite scaffolds, which effectively promoted the adhesion, spreading, and neural differentiation of PC12-L cells. Notably, scaffolds with 10 and 15 coating cycles upregulated β-tubulin III expression and facilitated the formation of axon-like structures. Furthermore, the composite scaffold was successfully fashioned into a nerve conduit, highlighting its potential for peripheral nerve repair. This work offers a promising strategy for constructing electroactive, biomimetic scaffolds to enhance neural regeneration.
This study presents a novel approach to enhance the early-stage osseointegration of orthopedic implants through surface engineering. Lithium (Li), strontium (Sr), and silver (Ag)-doped hydroxyapatite (HA) were coated on Ti6Al4V substrates using RF induction based plasma spray coating and loaded with polydopamine (PD) and Cissus quadrangularis extract (CQE). The engineered coating integrates bioactive metal ions, drug-loaded polymer layers, and plant-derived osteogenic compounds to accelerate bone healing. Co-culture with mesenchymal stem cells and monocytes demonstrates that Li-Sr-Ag-doped HA upregulated key osteogenic markers, including alkaline phosphatase and bone gamma-carboxyglutamic acid-containing protein, while also modulating osteoclastic activity. An in vivo rat distal femur study demonstrated enhanced osteoid formation with the addition of CQE, promoting mineralized bone formation. We demonstrate that induction plasma spray can be used to design and manufacture doped HA coated implant with PD and CQE, thereby accelerating early stage osseointegration and providing a scalable, clinically translatable solution to enhance the performance of cementless orthopedic and dental implants.
Magnesium-based biomaterials show great potential in bone regeneration due to their inherent biocompatibility, osteogenic activity, and ability to modulate the immune microenvironment. However, their rapid degradation rate remains a critical barrier to clinical translation. To address these challenges, we developed a magnesium hydride-gelatin methacryloyl (MgH2-GelMA) composite with sustained release of hydrogen gas and magnesium ions, featuring a bone-mimetic organic-inorganic hybrid network. First, magnesium hydride microcrystals were coated with an inorganic silica layer to mitigate degradation; subsequently, the coated particles were embedded within an organic GelMA hydrogel matrix. The composite achieves controlled co-release of magnesium ions (Mg2+) and hydrogen gas (H2). The released Mg2+ directly stimulates the differentiation of bone marrow mesenchymal stem cells (BMSCs) into osteoblasts, accelerating osteogenesis. Concurrently, Mg2+ and H2 synergistically induce polarization of bone marrow-derived macrophages (BMDMs) toward an anti-inflammatory phenotype. During the active inflammatory phase, this polarization modulates the immune microenvironment and establishes a pro-regenerative local niche. This study not only elucidates a novel ion-gas synergistic mechanism but also provides innovative insights and theoretical foundations for advancing artificial bone materials from passive biomimetic replacement to active regenerative modulation.
To address alveolar bone defects and the limitations of conventional grafts, tissue-engineered scaffolds have emerged as a promising alternative. Carboxymethyl chitosan (CMC) is a biocompatible and biodegradable polysaccharide with potential for bone regeneration; however, its brittleness and poor mechanical strength restrict its application. Here, we developed CMC-reduced graphene oxide (rGO) composite scaffolds with rGO concentrations of 0%, 0.5%, 1%, and 2% to overcome these drawbacks. The scaffolds were systematically characterized for their morphological, crystallographic, spectroscopic, and biomechanical properties, as well as their in vitro cytocompatibility and in vivo osteogenic performance. The incorporation of rGO enhanced structural homogeneity, optimized pore architecture, and significantly improved mechanical strength in a concentration-dependent manner, with tensile strength increasing from 1.64 to 8.13 MPa and elastic modulus from 1.14 to 25.05 MPa. In vitro, when MC3T3-E1 cells were grown in osteogenic medium, scaffolds loaded with 0.5%-1% rGO led to better cell survival and higher ALP activity-both pointing to stronger osteogenic differentiation. The 2% rGO scaffolds, however, turned out to be toxic to cells. Structural analyses confirmed the preservation of CMC crystallinity and revealed hydrogen bonding between rGO and CMC, elucidating the reinforcement mechanism. In a rat cranial defect model, the 1% rGO scaffold group demonstrated superior new bone formation, mineralization, and trabecular maturation. These findings underscore the dual function of rGO in simultaneously improving the mechanical integrity and osteogenic capacity of CMC-based scaffolds, with 0.5%-1% rGO identified as the optimal concentration window for bone tissue engineering applications.
