Azithromycin-loaded chitosan films: a multifunctional platform for oral tissue regeneration.

The increasing incidence of osteoporotic vertebral compression fractures (OVCFs) necessitates the development of effective treatment strategies. Polymethylmethacrylate (PMMA) bone cement, which is widely used, lacks adequate antimicrobial properties and poses the risk of postoperative infections. Molybdenum disulfide (MoS₂) nanosheets, which are known for their antimicrobial and osteogenic potential, offer a novel approach. We synthesized PMMA-MoS₂ nanocomposites by incorporating MoS₂ nanosheets into PMMA bone cement. The mechanical properties of the composites were evaluated using tensile tests. Additionally, finite element analysis was conducted to simulate the stress distribution in the spine after vertebroplasty. Osteoblast viability, differentiation, and maturation were assessed using the CCK-8 assay, alkaline phosphatase (ALP) staining, and alizarin red S (ARS) staining. The antimicrobial activity was tested against Escherichia coli. PMMA-MoS₂ nanocomposites significantly increased elastic modulus from 2100.1 ± 29.7 to 2706.1 ± 14.7MPa (P < 0.05) and tensile strength from 45.2 ± 2.1 to 56.9 ± 1.5MPa at 5% MoS₂. Finite element models showed no significant alterations in stress distribution patterns on the adjacent vertebral surfaces, indicating mechanical stability. As assessed by CCK-8 assays, the presence of MoS₂ led to a marked increase in osteoblast proliferation, with cell viability consistently exceeding 100% at all time points. ALP staining demonstrated a concentration-dependent enhancement in osteoblast differentiation, with the PMMA + 5%MoS₂ composite showing the highest ALP activity. Moreover, the ARS-stained area expanded as the MoS₂ concentration increased, indicating a pronounced increase in the formation of mineralized nodules. Antimicrobial testing confirmed that the PMMA-MoS₂ composites substantially reduced Escherichia coli counts, with the PMMA + 5%MoS₂ composite exhibiting the most potent effect. This study demonstrates that PMMA-MoS₂ nanocomposites offer improved mechanical, osteogenic, and antimicrobial properties, presenting a promising material for orthopedic applications.

Metallic implants frequently face three critical challenges that compromise long-term clinical performance: (i) limited biofunctionality that delays osteointegration, (ii) corrosion processes that deteriorate the implant surface and release harmful ions, and (iii) bacterial biofilm formation, which increases the risk of persistent infection. This study explores multilayer [YSZ/HAp-Ag]n coatings engineered to overcome these issues by enhancing osteoblastic response, improving surface stability, and providing antimicrobial potential. Multilayer coatings with different bilayer numbers (n=1, 10, 30, 50, 70) were deposited on titanium substrates using magnetron sputtering. Structural and surface characterization included morphology, roughness, wettability, and stiffness. MC3T3-E1 osteoblastic cells were cultured on the coatings to evaluate adhesion, viability (MTT), and differentiation through alkaline phosphatase (ALP) activity at 7 and 14 days. Crater-like surface textures, roughness above 220nm, and higher hydrophilicity promoted enhanced cell spreading, greater confluence, and decreased circularity, indicative of strong anchorage. All coatings exhibited >70% cell viability, confirming non-cytotoxic behavior. Rougher and more hydrophilic surfaces outperformed uncoated titanium. Stiffer coatings produced a significant increase in ALP activity at day 7, suggesting accelerated early osteogenic differentiation, followed by a decrease at day 14 consistent with cellular maturation. Among all configurations, the 30-bilayer coating (n30) offered the most balanced structural and mechanical properties, resulting in the highest biological performance. Multilayer [YSZ/HAp-Ag]n coatings effectively stimulate osteoblastic adhesion, viability, and early differentiation while addressing key limitations of metallic implants. Their tunable architecture-especially the n30 configuration-represents a promising strategy to enhance implant integration and long-term functional performance.

Ginger extract release from 3D printed calcium phosphate scaffolds for bone regeneration.

Objectives: In dental implantology, the priorities in scientific research are to identify solutions that guarantee a beneficial biomaterial-tissue interaction, both in terms of implant biointegration and protection against infections. The experimental approach consisted of chemical deposition of silver (Ag), silver and hydroxyapatite (HAP) on a TiZr metallic support. The aim of the research is to study the influence of hydroxyapatite on the possible adverse effects produced by silver in antibacterial coatings. Methods: The characterization of the coating was performed by scanning electron microscopy (SEM) and EDS spectroscopy, XRD diffraction and FT-IR infrared analysis. In vitro cell viability and adhesion testing was performed by quantitative (MTT) and qualitative fluorescence-based assays on samples (without deposition and with chemical deposition), in the presence of human fetal osteoblasts (hFOB cell line) after 8 days of incubation. Results: The findings of the study indicate an increase in cell viability by combining silver with hydroxyapatite. Preliminary data indicated a cell viability of 20% when the metal support is coated exclusively with silver and 60% in the presence of hydroxyapatite in the silver coating. Conclusions: The experimental study offers insights into the potential cytotoxic effects of silver in antibacterial coatings. Co-deposition with hydroxyapatite improved osteoblast viability compared to surfaces coated with silver alone, indicating that it may have a beneficial effect in Ag-based surface functionalization. The underlying mechanism (e.g., modulation of silver species/ion release) was not directly quantified in this work and should be addressed in future studies.

This study aimed to evaluate the in vitro biocompatibility, physicochemical characteristics, and in vivo biological performance of the composite scaffold (hydroxyapatite [HA]-collagen-S. littoralis-polyvinyl alcohol [PVA]).In vitro assays were conducted on 7F2 preosteoblast cells to assess osteoblast viability and proliferation. Scanning electron microscopy (SEM) was then used to determine the optimal concentration identified by these assays. The composite scaffold was also characterized using Fourier transform infrared (FT-IR) spectroscopy, SEM, and X-ray diffraction (XRD). In vivo evaluation was performed using a Sprague-Dawley rat calvarial defect model, with a control group without a scaffold and a treatment group receiving the composite scaffold, at 3, 7, 14, 21, and 28 days to assess osteoblast counts and histological features associated with later stages of bone healing.In vitro results demonstrated a progressive increase in 7F2 viability and proliferation up to 72 hours, with the optimal concentration at 1,500 ppm. These findings were consistent with SEM observations. FT-IR confirmed the presence of characteristic functional groups with molecular interactions among components. SEM showed a porous structure with good interconnectivity that supported cell adhesion. XRD indicated the presence of crystalline HA and amorphous organic phases, supporting mechanical stability and biocompatibility. Histological analysis showed earlier osteoblast recruitment in the composite scaffold group, peaking at day 7, followed by reduced osteoblast numbers at day 28, suggesting progression toward later stages of bone healing. In contrast, the control group exhibited a delayed osteoblast peak at day 14 and persistent fibrous tissue. In vivo statistical analysis demonstrated significantly higher osteoblast counts in the scaffold group than in controls (p < 0.05 at days 3, 7, 14, and 21), indicating an enhanced early osteogenic response.The composite scaffold (HA-collagen-S. littoralis-PVA) demonstrated structural properties, biocompatibility, and biological performance that support osteoconduction and osteogenesis, highlighting its potential as an innovative biomaterial for bone regeneration in dental, oral, and maxillofacial tissue engineering.

The objective of this in vitro study was to examine the impact of metformin (MET) at different concentrations (0.1, 1, 10, 50, and 100 mM) on rat primary osteoblasts, as the results obtained so far are inconsistent. Osteoblast apoptosis, viability, alkaline phosphatase (ALPL) activity, production of osteoblast-specific biomarkers, including ALPL, osteocalcin (BGLAP), type I collagen alpha 1 (COL1A1), integrin-binding sialoprotein (IBSP), bone morphogenetic protein 2 (BMP2), runt-related transcription factor 2 (RUNX2), vascular endothelial growth factor (VEGF), tumor necrosis factor ligand superfamily member 11 (TNFSF11 or RANKL), as well as calcium/collagen deposition were assessed. Our results revealed that a dose of 100 mM was cytotoxic to osteoblasts and resulted in a complete loss of their viability. Therefore, this concentration was excluded from further analyses. In general, MET exhibited a dose-dependent impact on multiple osteoblast-specific functional biomarkers, with beneficial effects noted on ALPL activity (at 0.1 and 1 mM) as well as on the levels of ALPL (0.1 and 1 mM), BGLAP (at 0.1-50 mM), IBSP (at 0.1-50 mM), BMP2 (at 0.1, 10 and 50 mM), VEGF (at 0.1 and 1 mM), and RANKL (at 0.1 mM). Calcium/collagen deposition at concentrations of 0.1 and 1 mM reached the same level as control cells, higher doses (10 and 50 mM) dramatically reduced cell viability after 21 days and the aforementioned parameters could not be evaluated. It can be concluded that MET at concentrations up to 1 mM can promote osteoblast viability, osteogenic differentiation, angiogenic signaling, and reduce osteoclastogenesis. Key words Metformin " Osteoblasts " Bone health " In vitro.

IntroductionPolyetheretherketone (PEEK) is a promising orthopedic implant material due to its bone-mimetic mechanical properties; however, its bioinert surface and susceptibility to bacterial colonization limit its clinical efficacy. Strategies to enhance osteointegration while providing antibacterial functionality are urgently needed.MethodsGraphene oxide (GO) was functionalized with polyethylene glycol (PEG) and complexed with a plasmid encoding bone morphogenetic protein-2 (pBMP-2) to form a GO-PEG/pBMP-2 complex. This complex was coated onto sulfonated PEEK (SPEEK) via freeze-drying, yielding SPEEK-(GO-PEG/pBMP-2) composites. The materials were systematically compared with pristine PEEK, SPEEK, and SPEEK-GO-PEG controls. Surface chemistry, morphology, hydrophilicity, gene loading efficiency, and coating uniformity were characterized. In vitro assessments included cell adhesion, proliferation, viability, alkaline phosphatase (ALP) activity, mineralized matrix deposition, osteogenic gene expression, and antibacterial activity against Staphylococcus aureus and Escherichia coli.ResultsSuccessful PEGylation of GO and efficient pBMP-2 loading were confirmed, with uniform coating and significantly improved hydrophilicity on SPEEK-(GO-PEG/pBMP-2). This composite markedly enhanced osteoblast adhesion, proliferation, and viability, along with elevated ALP activity, increased mineralized nodule formation, and upregulated expression of key osteogenic genes (e.g., Runx2, OPN, OCN). Both GO-containing coatings—SPEEK-GO-PEG and SPEEK-(GO-PEG/pBMP-2)—exhibited strong antibacterial effects against both Gram-positive and Gram-negative bacteria, with no significant difference attributable to BMP-2 loading.ConclusionThe SPEEK-(GO-PEG/pBMP-2) platform simultaneously promotes osteogenesis through localized BMP-2 gene delivery and provides robust antibacterial protection via GO. This dual-functional design addresses two major limitations of PEEK implants, offering a promising strategy for next-generation orthopedic biomaterials.

Electrodeposited biodegradable Zn-Fe alloy foams: Synergistic control of degradation kinetics and biomechanical properties for cranial bone implants.

Bone cancer and especially osteosarcoma is one disease that has proven to be a challenging therapeutic area because of poor prognosis, systemic drug toxicity, and limited response to conventional therapy. As an alternative method of treatment delivery, the localized drug delivery systems have come up promising with controlled release, lesser side effects and better therapeutic results. Hydroxyapatite (HAp), which is a calcium phosphate mineral that occurs naturally and demonstrates high biocompatibility as well as osteoconductivity, has attracted a lot of interest in bone tissue engineering and specific drug delivery. Nevertheless, there are inherent shortcomings of it such as brittle and low drug loading capacity (typically 2–10 wt%), which demand functionalization strategies. Coatings with polymers (PEG, chitosan, PLGA), inorganic ions (Zn, Ag, Sr), and carbon-based nanomaterials (graphene, CNTs) have been demonstrated to increase mechanical strength, drug encapsulation and release kinetics (enhancing loading efficiency up to 60–85 % and prolonging release over 7–30 days). Nanocomposites constructed by HAp through co-precipitation, sol-gel, and hydrothermal techniques have been shown to deliver anticancer agents including doxorubicin, cisplatin and methotrexate with control. Additional targeting techniques such as ligand-mediated delivery, pH/enzyme-responsive release, and bone-seeking agents such as bisphosphonates further enhance targeting. The results of preclinical in vitro and in vivo studies suggest encouraging cytotoxicity against cancer cells, biocompatibility (osteoblast viability often >90 %), and sustained drug delivery, but challenges to translational scalability, reproducibility and clinical validation exist. Smart stimuli-responsive carriers, theranostic integration and individualized medicine strategy should be investigated in the future, with functionalized HAp nanocomposites being the advanced option in the next generation of localized bone cancer therapy platforms.

Biodegradable zinc (Zn) alloys are promising candidates for bone implants due to their suitable degradation rate and inherent bioactivity. However, current Zn alloys require enhancement of their mechanical properties and biological functions through alloying and thermomechanical processing. Herein, we report the outstanding mechanical properties, corrosion, biocompatibility, and biofunctionalities of hot-rolled (HR) and hot-extruded (HE) Zn-4Ag-0.4Sr (ZAS) alloy in comparison with those of Zn-4Ag (ZA) for biodegradable orthopedic fixation. The HE ZAS sample exhibited the optimal balance of mechanical properties, including ultimate tensile strength of 318.0 MPa, tensile and compressive yield strengths of 257.3 MPa and 343.3 MPa, respectively, elongation at break of 22.3%, and Vickers and Brinell hardness values of 116.7 HV and 105.7 HB, respectively, satisfying the mechanical requirements for bone-implant applications. Nanoindentation identified the SrZn13 phase as a key reinforcement. The HE ZAS alloy exhibited the highest electrochemical corrosion rate of 614 μm/y and the highest degradation rate of 39.7 μm/y after 30 days of immersion, as well as the best biotribological performance in Hanks' solution, among all ZA and ZAS samples. Biologically, extracts of the HE ZAS alloy enhanced osteoblast viability, promoted angiogenesis in HUVECs, and stimulated osteogenic differentiation and mineralization in hBMSCs. Furthermore, the HE ZAS alloy displayed higher antibacterial efficacy against S. aureus in both in vitro and in vivo models while maintaining high biosafety. These results collectively indicate that the HE ZAS alloy is a promising candidate for next-generation biodegradable orthopedic-fixation devices, offering a notable balance of mechanical integrity, controllable degradation, and multifunctional bioactivity. STATEMENT OF SIGNIFICANCE: This work reports the notable mechanical performance, controlled corrosion, enhanced biotribological behavior, and multifunctional bioactivity of the hot-extruded Zn-4Ag-0.4Sr (HE ZAS) alloy for biodegradable orthopedic fixation devices. The HE ZAS alloy exhibits an optimal strength-ductility balance, with an ultimate tensile strength of 318.0 MPa, tensile yield strength of 257.3 MPa, and 22.3% elongation, satisfying the mechanical requirements for bone implants. The alloy also demonstrates the highest electrochemical corrosion rate (614 μm/y), degradation rate (39.7 μm/y), and biotribological performance among the tested alloys. Biologically, the alloy enhances osteoblast viability, stimulates angiogenesis and osteogenic differentiation, and exhibits effective antibacterial activity against Staphylococcus aureus both in vitro and in vivo, while maintaining complete biosafety.

Interface-engineered 3D-printed PCEC/collagen composite scaffold for large bone defect repair under static and mechanical stimulation.

The work is devoted to research on the influence of β-cyclodextrin/eugenol complex (CP-EU) on the properties of methacrylic bone cement. Eugenol (4-allyl-2-methoxyphenol) is an essential oil that exhibits antimicrobial properties against pathogenic bacteria, and these properties are desirable in bone cements. This may allow the replacement of antibiotics currently used in bone cements. However, since eugenol causes a decrease in the polymerization rate, it was decided to modify it with sulfobutylether-β-cyclodextrin (Captisol). The use of CP-EU complex in the amount of 0.5 wt% (calculated on EU amount) eliminated this unfavorable effect of eugenol on the polymerization process and influenced its release from bone cement. Properties of modified bone cements were examined, including doughing time, maximum temperature (Tmax), setting temperature (Tset), setting time (tset), compressive strength, and antibacterial properties. The CP-EU complex does not affect the maximum curing temperature of bone cement, which remained within the clinically acceptable range (58.7°C-69.8°C), and all formulations meet ISO 5833:2002 standards. Importantly, it causes an increase in compressive strength of up to 33.5% and Young's modulus of up to 454.1%, demonstrating a beneficial enhancement in the mechanical performance of the tested materials. The release of eugenol was very high, ranging from 84.5% to 86.9%. Furthermore, antibacterial studies show that the tested materials, the CP-EU complex and modified bone cements, have antibacterial properties for Escherichia coli strains. The cell viability in the presence of the CP-EU complex was 39.9% after 72 h of incubation. Cytotoxicity assays conducted on osteoblasts demonstrated that free eugenol induces both acute and persistent cytotoxic effects, whereas its complexation with Captisol restores biocompatibility and enhances osteoblast viability. Consequently, Captisol serves as an effective carrier for modulating eugenol release and improving the biological performance of modified acrylic cements. In summary, the modified bone cements meet all standard requirements and are characterized by good mechanical properties, high eugenol release, and antibacterial properties. Thus, the incorporation of eugenol into β-cyclodextrin allowed obtaining a CP-EU complex for bone cement modification, exhibiting the desired properties.

This article is being retracted from Bioscience Reports at the request of the Editor-in-Chief and the Editorial Board. This follows the receipt of a notification from a reader, alerting the Editorial Board to irregularities in the flow cytometry graphs, some of which suggest that the graphs could have been hand-drawn. The authors were contacted regarding the concerns and the retraction but have not yet responded or provided requested raw data. Given the extent of the issues raised, the Editorial Board stand by the decision to retract the article.

To elucidate the role of interleukin-33 (IL-33) in glucocorticoid-induced osteonecrosis of the femoral head (ONFH) in mice, with particular emphasis on its effects on bone remodeling, inflammatory regulation, and fibrosis. In vivo: Fifteen 9-week-old male C57BL/6J wild-type mice were randomly divided into a normal control group, an ONFH group, and an intervention group, with 5 mice in each group. A glucocorticoid-induced ONFH model was established in the ONFH group and intervention group using a combined administration of lipopolysaccharide and methylprednisolone. The intervention group received intraperitoneal injection of IL-33 for 4 consecutive days during the early stage of model establishment; the normal control group received saline injection at the same time points. General conditions of mice were observed during the experiment. Endogenous IL-33 and transmembrane ST2 (ST2 ligand, ST2L) expression in the femoral head was assessed via immunofluorescence, quantitative PCR (qPCR), and Western blot. Bone necrosis and fibrosis were evaluated using HE and Masson staining. Immunohistochemistry was performed to detect osteogenic markers [osteocalcin (OCN), osteopontin (OPN), Runt-related transcription factor 2 (Runx2)] and osteoclastic marker (receptor activator of nuclear factor-κB ligand, RANKL), while serum cytokine levels [tumor necrosis factor (TNF-α), IL-6, IL-1β, IL-4, IL-10] were quantified by ELISA. In vitro: Murine osteoblasts were divided into control group (DMEM+PBS), IL-33 group (DMEM+10 ng/mL IL-33), and IL-33+ST2L group (DMEM+10 ng/mL IL-33+1 μg/mL ST2L antibody). After corresponding treatment, cell proliferation was detected by EdU incorporation assay. Additional osteoblasts were subjected to osteogenic induction culture, and mineralization, and the expression of osteogenesis-related genes (Runx2, collagen type Ⅰ, OCN, and OPN) were assessed by using alkaline phosphatase (ALP) staining, Alizarin red staining, and qPCR, respectively. In vivo: All animals survived until the completion of the experiment. Mice in the intervention group and ONFH group showed restricted mobility. Compared with the normal control group, the expressions of IL-33 and ST2L significantly upregulated at both mRNA and protein levels ( P<0.05). Exogenous IL-33 administration exacerbated, rather than ameliorated, trabecular destruction and fibrosis, with the intervention group showing significantly increased fibrosis area percentage and empty lacunae rate compared with the other two groups ( P<0.05). Furthermore, IL-33 treatment further suppressed the expressions of osteogenic markers (Runx2, OCN, OPN) while significantly enhancing the expression of the osteoclastic marker (RANKL) ( P<0.05). ELISA results showed that compared with the ONFH group, serum levels of pro-inflammatory cytokines (IL-4, IL-6, IL-1β) were significantly lower in the intervention group ( P<0.05). In vitro: Compared with control group, IL-33 significantly impaired osteoblast proliferation and differentiation, as evidenced by reduced cell proliferation rate, decreased ALP activity, and reduced calcium nodule formation ( P<0.05). The expression of osteogenesis-related genes was also suppressed, with significant differences between groups ( P<0.05). ST2L blockade effectively reversed these IL-33-mediated suppressive effects, leading to significant recovery of osteoblast proliferation and differentiation ( P<0.05). Notably, the mRNA expression levels of collagen typeⅠand OCN were restored to normal ( P>0.05). IL-33 exacerbates ONFH by impairing osteoblast viability and function and inhibiting bone regeneration. Targeting the IL-33/ST2L signaling axis may represent a promising novel therapeutic strategy for ONFH.

Diabetes-induced osteoporosis significantly elevates the risk of fracture-related disability and mortality. Developing effective therapeutic strategies for diabetic-related bone defects has become a pressing concern in both clinical and research domains. This study innovatively constructs a near-infrared light-responsive (NIR) intelligent hydrogel system (carboxymethyl chitosan/gelatin/black phosphorus@bFGF, CG/BPb), utilizing carboxymethyl chitosan and gelatin as the matrix while integrating polydopamine (PDA)-functionalized black phosphorus nanosheets (BP@PDA) as a controlled-release carrier for basic fibroblast growth factor (bFGF). The CG/BPb hydrogel demonstrated remarkable mechanical strength (up to 25kPa compressive stress at 55% strain) and antioxidant capacity, scavenging 81.1% of ROS and 83.3% of hydroxyl radicals. Under NIR irradiation (1W/cm², 5min), the hydrogel achieved a stable photothermal temperature of 42 ± 1°C, enabling controlled release of bFGF (60% cumulative release within 20min at pH 6.5) and phosphate ions. In vitro, assessments revealed that the hydrogel enhanced osteoblast viability by 85% in scratch assays and upregulated osteogenic genes (ALP, Runx2, and OCN). Additionally, it also promoted M2 macrophage polarization (increased CD206, decreased iNOS) and suppressed osteoclast activity via NFATc1 and MAPK pathways. In vivo, in a diabetic rat calvarial defect model, the CG/BPb + NIR group showed significant bone regeneration, with increases in bone volume fraction (BV/TV) and bone mineral density (BMD), alongside enhanced vascularization (elevated CD31/CD34/α-SMA expression). This innovative strategy, grounded in material design and synergistic biological functions, not only provides a new solution for the treatment of diabetic bone defects but also promotes technological progress in the field of bone tissue engineering, with substantial academic value and practical applications.

Steroid-induced osteonecrosis of the femoral head (SONFH) is a severe bone disease associated with long-term glucocorticoid use, characterized by impaired bone metabolism and vascular insufficiency. Bilobalide (BB), a natural sesquiterpene from Ginkgo biloba, exhibits anti-apoptotic, antioxidant, and pro-angiogenic properties, yet its role in SONFH remains unclear. We integrated network pharmacology and molecular docking to predict the targets and pathways of BB in SONFH. Key targets were validated using molecular docking software. For in vivo experiments, a rat SONFH model was established using methylprednisolone (MPS), and BB was administered orally. Micro-CT, H&E staining, TUNEL assay, and immunohistochemistry were employed to evaluate bone microstructure, apoptosis, and the expression of osteogenic and angiogenic markers. Immunofluorescence was used to assess HIF-1α expression in rat femoral head tissues. For in vitro experiments, MC3T3-E1 osteoblasts were treated with dexamethasone(DEX) and BB. Cell viability was detected using the CCK-8 assay, and the protein levels of the HIF-1α and ERK pathways were examined by Western blot. Network pharmacology identified 94 common targets between BB and SONFH, with enrichment in HIF-1 and ERK signaling pathways. Molecular docking confirmed strong binding affinities between BB and core targets. In MPS-induced rats, BB treatment significantly improved bone mineral density, trabecular microstructure, and reduced osteocyte apoptosis. BB also upregulated HIF-1α, Runx2, OCN, CD31, and VEGF expression, indicating enhanced osteogenesis and angiogenesis. In vitro, BB rescued dexamethasone-induced suppression of osteoblast viability and upregulated the ERK/HIF-1α pathway. Bilobalide attenuates SONFH progression by activating the ERK/HIF-1α signaling pathway, promoting osteogenesis and angiogenesis, and reducing osteocyte apoptosis. These findings highlight BB as a promising candidate for SONFH prevention and support the utility of network pharmacology in mechanistic natural product research.

Osteoporosis (OP) is a metabolic bone disease characterized by impaired bone formation and excessive resorption. Ferroptosis has been implicated in osteoblast dysfunction. Adipose-derived stem cell exosomes (ADSC-exos) have emerged as promising regenerative therapies. This study investigated whether ADSC-exos alleviate ferroptosis and promote osteogenic differentiation by modulating the miR-215-5p/USP1/PTEN/AKT/GSK3β/NRF2 pathway. Human ADSC-exos were evaluated using transmission electron microscopy, nanoparticle tracking analysis, and western blot. Ferroptosis was induced in MG63 cells using ferric ammonium citrate (FAC). Cell viability, lipid peroxidation, and osteogenic differentiation were evaluated using the CCK-8 assay, C11-BODIPY staining, malondialdehyde quantification, ALP staining, and Alizarin Red S staining. The effects of ADSC-exos on PTEN ubiquitination and AKT/GSK3β/NRF2 pathway activation were assessed using western blot, RT-qPCR, and immunoprecipitation. ADSC-exos significantly improved osteoblast viability, reduced lipid peroxidation, and enhanced osteogenic differentiation in FAC-treated MG63 cells. Dual-luciferase reporter assay identified miR-215-5p as a key exosomal cargo that targets USP1. Mechanistically, ADSC-exos downregulated USP1, leading to PTEN ubiquitination and degradation, thereby activating the AKT/GSK3β/NRF2 signaling pathway. USP1 overexpression reversed the protective effects of ADSC-exos, confirming that miR-215-5p-mediated USP1 inhibition plays a crucial role in regulating ferroptosis and osteogenic differentiation. In conclusion, ADSC-exos diminish ferroptosis and enhance osteogenic differentiation by delivering miR-215-5p, which inhibits USP1, promotes PTEN ubiquitination, and activates the AKT/GSK3β/NRF2 pathway. These findings provide new insights into the mechanisms by which ADSC-exos promote bone repair and highlight their potential as an innovative treatment for OP.

Polyethylene glycol (PEG), a polymer widely employed in biomaterials for its biocompatibility and protein-repellent properties, is conventionally deemed bioinert. However, its interactions with extracellular components such as carbon dioxide (CO 2 ), may critically influence cellular responses. The effect of PEG on cellular viability has not been properly investigated. This study investigates how PEG (2000 g/mol) at varying molar concentrations (0.5, 1.0, and 1.5 µmol/mL) alters the viability and morphology of osteoblasts and gingival fibroblasts in Dulbecco’s Modified Eagle’s Medium (DMEM), and DMEM supplemented with HEPES as a comparative buffering system. Resazurin assays, crystal violet staining, and pH measurements revealed that PEG concentration elevated medium pH, and enhanced cell viability. Notably, osteoblasts in standard DMEM exhibited the highest viability increase, 215%, 196%, and 168%, respectively, while in HEPES-buffered DMEM showed attenuated responses compared to controls ( N = 5, p &lt; 0.05). Although alkaline conditions enhanced cellular viability, concurrent morphological alterations, including membrane blebbing and cellular rounding, were observed contingent upon PEG concentration and HEPES presence. These findings underscore the capacity of PEG to modulate extracellular pH, impacting cellular behavior. Such effects challenge the perception of PEG as a passive biomaterial and highlight microenvironmental dynamics as a critical variable in biomaterial design. Thus, optimizing PEG concentration is vital to balancing biocompatibility and cell viability in tissue engineering.

Osteomyelitis (OM) is caused by the entry of septic cells into bone tissue. Due to systemic antibiotic side effects and drug resistance, local administration is a strategy for treating OM. In this study, a biodegradable, injectable thermosensitive hydrogel containing vancomycin hydrochloride (VA) was developed to reduce drug resistance and prolong the therapeutic efficacy of Staphylococcus aureus by sustained topical delivery of VA. VA was loaded into an injectable butyl glycidyl ether-modified methylcellulose hydrogel (MC-BGE), and VA-loaded MC-BGE hydrogel (VA@MC-BGE) was obtained. The gelation time of VA@MC-BGE at 37°C was approximately 10 min. Invitro, the hydrogel released ~40% of its VA payload within the first 4 days, followed by a sustained release that reached 91.0% cumulative release by Day 28. During this period, mass-loss measurements showed ~67% degradation of the hydrogel. The invitro study showed that the VA@MC-BGE had stronger antimicrobial activity against S. aureus for at least 7 days and could reduce the cytotoxicity of VA with high osteoblast viability (> 85%) over 72 h. VA@MC-BGE inhibited S. aureus infection and improved inflammation and oxidative stress in osteoblasts. The invivo study showed that the hydrogel was able to degrade gradually invivo and that only a small amount of hydrogel remained at 28 days. The hydrogel was also not significantly toxic to major organs. In an OM rat model, injecting the VA@MC-BGE into the site of tibial infection in rats further reduced bone infection and improved bone regeneration compared to free VA. In conclusion, insitu thermosensitive MC-BGE hydrogels encapsulating VA have slow-release properties and good biocompatibility, which are promising for the treatment of OM.