Journal of Functional Biomaterials最新文献

Tissue engineering approaches for cartilage tissue regeneration are expanding to include the complex features of the tissue, such as the biological and mechanical gradients. Many of these approaches are, however, based on the use of multiple biomaterials or concentrations, and crosslinking methods that make it difficult to integrate and control the properties of the resulting scaffolds. In this study, a 3D bioprinted scaffold with a stiffness gradient was fabricated by using a single biomaterial type and concentration combined with a directional ionic crosslinking method. The scaffolds revealed a gradient in stiffness from 39.8 ± 6.6 kPa at the top to 60.6 ± 10.9 kPa at the bottom of the scaffolds. Live/dead analysis of human chondrocytes embedded in the scaffolds showed no negative effects of the stiffness gradient on cell viability over 28 days. The induced stiffness gradient led to a gradient in cell density and sulfated glycosaminoglycan deposition in the bioprinted tissue constructs with enhanced values in the softer top region of the scaffolds as compared to the stiffer bottom part. This study showed a novel method to generate scaffolds with stiffness gradients from a single biomaterial and indicates that such scaffolds could be used to spatially regulate the behavior of chondrocytes and the associated deposition of the cartilage matrix.

The overactivation of endosomal Toll-like receptor (TLR) in macrophages plays an important role in the pathogenesis of acute lung injury (ALI). There is currently still a lack of nano-formulated and macrophage-targeted endosomal TLR inhibitors that have been approved for clinical uses. We previously discovered that the elevation of endosomal pH using nanodevices provides a promising strategy to specifically inhibit endosomal TLRs in macrophages. The weakly basic drug hydroxychloroquine (HCQ) has been reported for its capability to accumulate in endolysosomes and modulate the acidity in these compartments. To enhance its macrophage-targeting ability and the therapeutic efficacy in vivo, herein we formulated HCQ into a nanoform using liposomes, named HCQ-L. We found that HCQ-L was less cytotoxic and more effective in inhibiting endosomal TLRs (including TLR3, TLR4, TLR 7/8) than the molecular HCQ. Subsequently, a hexapeptide, Pep12, was inserted onto the surface of HCQ-L to form HCQ-L-P12. Interestingly, Pep12 modification significantly improved the stability of liposomes in aqueous solution for at least 2 years; while having enhanced inhibitory effects on TLR7/8 signaling, HCQ-L-P12 displayed similar effects on inhibiting the TLR4 pathway and down-stream pro-inflammatory cytokine production when compared with HCQ-L. Furthermore, both HCQ nanoformulations potently elevated the endosomal pH. In vivo evaluation showed that HCQ-L-P12 and HCQ-L (but not molecular HCQ) were able to alleviate lung inflammation and injuries by decreasing inflammatory cell infiltration upon intratracheal instillation in a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. This research provides a new strategy to fabricate lipid-based nanocarriers for targeted delivery of endosomal pH modulators to treat ALI and other acute and chronic inflammatory disorders.

The objective of this study was to investigate the effect of surface disinfectant solutions against COVID-19 on the surface roughness, gloss, and color of removable denture materials. Fifty rectangular metallic specimens made of Co-Cr alloy and fifty disk-shaped specimens made of PMMA were prepared according to the manufacturers' instructions. Fifty maxillary right central incisors were also included in the study. The above-mentioned specimens were equally divided into five groups (n = 10). Four disinfectant solutions were tested (0.1 wt% NaOCl, 0.5 wt% H₂O₂, 78 wt% ethanol, and 1 wt% Povidone Iodine), and freshly distilled water was used as the control. To simulate clinical practice, each specimen was immersed in the disinfectant solution 15 times. All specimens were marked, and surface roughness, gloss, and color were measured before and after immersion. All roughness parameters (Sa, Sq, Sz, Sc, and Sv) and gloss values before and after immersion were statistically compared. ΔE*ab values were statistically compared with perception and acceptability thresholds according to ISO/TR 28642. No significant differences were identified for surface roughness parameters for all groups tested. All materials demonstrated a significant increase in gloss after aging regime, while only the metallic specimens illustrated ΔE*ab values higher than the acceptability threshold after disinfection with H₂O₂. None of the surface properties deteriorated after exposure to tested disinfectants, and thus, all of them can be effectively implemented in everyday practice.

Background/Objectives: This study aimed to evaluate the mechanical properties, particularly the fracture load, modulus of elasticity, and fracture patterns, of four-unit posterior tooth-supported fixed dental prostheses (FDPs) fabricated from various computer-aided design/computer-aided manufacturing (CAD-CAM) materials. Understanding the mechanical behavior of these materials is crucial for optimizing prosthesis performance in high-load-bearing posterior regions. Methods: A total of 68 standardized FDP frameworks were fabricated, each consisting of two abutments (first premolar and second molar) and two pontics (second premolar and first molar). The specimens were divided into four groups (n = 17): polyetheretherketone (PEEK), polyetherketoneketone (PEKK), 3Y zirconia (control 1), and 4Y zirconia (control 2). All samples underwent three-point bending tests using a universal testing machine with a crosshead speed of 0.5 mm/min. Fracture patterns were assessed visually and documented. Fractured specimens were examined using scanning electron microscopy (SEM). Data were analyzed using the SPSS v20. Normality was assessed with the Shapiro-Wilk test. The fracture loads were compared using the Kruskal-Wallis test with Bonferroni correction, and the modulus of elasticity was analyzed via a one-way ANOVA with Dunnett's T3 post hoc test. A significance level of α = 0.05 was applied. Results: Significant differences were observed among the groups. The 3Y zirconia demonstrated the highest fracture load (2275 ± 511.03 N), followed by the 4Y zirconia (1034.28 ± 221.55 N), PEEK (883.21 ± 172.24 N), and PEKK (402.01 ± 127.98 N). PEEK showed ductile fracture behavior, while PEKK exhibited brittle failure. Both zirconia groups demonstrated brittle fracture patterns. Conclusions: PEEK and 4Y zirconia presented comparable fracture loads, but with differing fracture behaviors-ductile in PEEK and brittle in 4Y zirconia. The 3Y zirconia offered the highest fracture load, but with limited flexibility. PEKK showed the lowest mechanical performance. These findings highlight the importance of material selection for FDPs in posterior load-bearing areas, considering both fracture load and failure mode.

Tissue responses to zirconia-coated implants treated with molecular precursor method were evaluated. The zirconia film was characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). Cylindrical titanium (ZrO₂/Ti) specimens were sandblasted, acid-etched, and coated with zirconia using the molecular precursor method. Control specimens were sandblasted and acid-etched only (SLA/Ti). After maxillary first molar extraction, four ZrO₂/Ti and four SLA/Ti implants were placed in the alveolar bone of the rats, and tissue responses were observed after 3 weeks. Surface analysis using SEM and AFM showed zirconia was present on ZrO₂/Ti surface, with coating not affecting surface morphology compared to SLA/Ti. EDX, XPS, and XRD measurements confirmed the ZrO₂ coating on the roughened Ti. The amount of new bone was greater in ZrO₂/Ti (77.0 ± 7.2%) than in SLA/Ti (59.7 ± 5.8%) (p = 0.807). Collagen fibers oriented perpendicular to implant surface were observed more frequently in ZrO₂/Ti (67.3 ± 9.5%) than in SLA/Ti (18.8 ± 10.01%) (p < 0.001). The area of perpendicular collagen fibers was significantly larger in ZrO₂/Ti (53.1 ± 13.4%) than in SLA/Ti (16.8 ± 2.6%) (p = 0.002). Zirconia-coated implants maintained surface morphology and improved bone formation and fiber orientation in the gingiva compared to conventional titanium implants in short-term animal experiments.

Implantable scaffolds are increasingly recognized as transformative tools in regenerative medicine, offering the potential to prevent or mitigate tissue degeneration. Osteoarthritis is a widespread degenerative joint disease that often progresses from early focal lesions to severe joint damage, creating substantial clinical and socioeconomic burdens. Preventive strategies for early-stage lesions remain limited. This study reports the design and development of a functional polymeric scaffold intended to support early tissue regeneration and potentially prevent lesion progression. The scaffold consists of an electrospun poly (ε-caprolactone) nanofibrous membrane enriched with glycosaminoglycans, including hyaluronic acid and chondroitin sulfate, to mimic essential features of the cartilage extracellular matrix and provide a supportive microenvironment. Complete structural, physicochemical, and mechanical characterization was performed to assess the scaffold architecture, stability, hydration properties, and suitability for tissue environments. In vitro investigations were conducted to evaluate cytocompatibility and the interaction of the scaffold with relevant cell types. The scaffold is designed as a potential future preventive strategy to support cartilage integrity and limit disease progression. This approach represents a promising strategy to preserve joint integrity and function, addressing a critical unmet clinical need and enabling translation toward clinical application.

Calcium silicate-based cement is commonly used for bone repair and regeneration. Current research focuses on developing innovative antibacterial materials with radiopacity, which is essential for ensuring successful clinical outcomes in procedures like vertebroplasty and endodontic treatments. Strontium (Sr) has emerged as a powerful additive, stimulating bone formation and inhibiting bone resorption. In this study, we evaluated the impact of varying levels of Sr-5, 10, and 20 mol% (designated as CSSr5, CSSr10, and CSSr20) on critical attributes of bone cement, including radiopacity, setting time, in vitro bioactivity, antibacterial efficacy, and osteogenic activity. The findings indicated that as the Sr content increased, the setting time and radiopacity of the cement increased. Remarkably, the cement formulations containing over 10 mol% Sr achieved radiopacity values surpassing the 3 mm aluminum threshold mandated by ISO 6876:2001 standards. Furthermore, incorporating Sr significantly improved MG63 cell attachment, proliferation, differentiation, and mineralization, while also boosting antibacterial properties in a dose-dependent manner. After 48 h of inoculation with E. coli or S. aureus, the CSSr10 and CSSr20 cements showed a bacteriostatic ratio exceeding 1.7 or 2 times that of the control without Sr. In conclusion, the CSSr10 cement could be a promising bone filler, exhibiting favorable setting time, radiopacity, antibacterial ability, and osteogenic activity.

This study aimed to evaluate the effect of popular beverages, coffee, matcha, and protein isolate, on the microhardness and color stability of feldspar glass ceramic (VB) and nano-ceramic hybrid composite (GD) CAD/CAM materials. Three hundred specimens were prepared and divided into control and immersion groups (water, coffee, matcha, protein). Vicker's microhardness (HN) was recorded for the control group and post-immersion groups, while color changes were measured before and after immersion. Microhardness values (HN) and color change (ΔE00) were statistically analyzed using the Kruskal-Wallis test followed by Dunn's post hoc test (p < 0.05). Results: The HN values of all VB and GD immersion subgroups were significantly lower than those of the control groups (p < 0.001). The VB water immersion group had a significantly lower HN than the protein and matcha immersion groups. The GD immersion groups showed no significant difference in HN between them (p > 0.05). VB had a significantly lower ΔE00 (>3.5) and higher HN (790.8 ± 123.62 kgf/mm²) than GD (175.22 ± 28.95 kgf/mm²) (p < 0.001). Coffee caused the greatest ΔE00 in both VB and GD, whereas protein caused the lowest ΔE00 in GD. Conclusion: The study revealed that the feldspar glass ceramic CAD/CAM material had higher microhardness and color stability than the nano-ceramic hybrid composite. Immersion reduces the microhardness and color stability of CAD/CAM ceramics. Matcha and protein have less impact on glass ceramic microhardness, with protein causing less discoloration in nano-ceramic hybrid composites than other immersion media.

The literature consistently identifies Zeolitic Imidazolate Framework-8 (ZIF-8) as an excellent material for on-demand drug delivery. Its appeal results from its superior loading capacity, inherent stability within physiological environments, and the ability to fine-tune its drug release kinetics. In this work, we investigated the encapsulation of snail slime extracted from Cornu aspersum mucus into ZIF-8. PXRD, SEM microscopy, ATR-FTIR spectroscopy, and fluorescence microscopy were used for a detailed characterization of the nanoparticles. The antibacterial potential of the ZIF-8-based biocomposite was assayed in vitro against Staphylococcus epidermidis. Overall, the results indicate that encapsulating the snail slime within ZIF-8 enhances its antibacterial activity, yielding a potent antimicrobial material.

In clinical practice, the selection of dental material is a crucial factor for the final success of the treatment, regarding mechanical properties and biocompatibility. Our study aimed to evaluate the cytotoxicity of a PMMA dental resin used for denture base fabrication and to investigate whether autophagy might be involved in the response of the exposed cells. In vitro tests, such as assessments of cell viability and metabolism, nitric oxide (NO), lactate dehydrogenase (LDH), and autophagy, were conducted. The results showed that exposure to PMMA-based material decreased cell viability by 35% after 24 h and 36% after 48 h. NO levels increased by 10% after 24 h and 2% after 48 h. LDH levels increased by 8% after 24 h and 31% after 48 h. Within the limits of this present study, our results suggest a significant activation of autophagy in the exposed fibroblasts, possibly as a survival mechanism, based on the viability and cell metabolic activity results.