Development of Cerium Oxide-Laden GelMA/PCL Scaffolds for Periodontal Tissue Engineering.

This study investigated gelatin methacryloyl (GelMA) and polycaprolactone (PCL) blend scaffolds incorporating cerium oxide (CeO) nanoparticles at concentrations of 0%, 5%, and 10% w/w via electrospinning for periodontal tissue engineering. The impact of photocrosslinking on these scaffolds was evaluated by comparing crosslinked (C) and non-crosslinked (NC) versions. Methods included Fourier transform infrared spectroscopy (FTIR) for chemical analysis, scanning electron microscopy (SEM) for fiber morphology/diameters, and assessments of swelling capacity, degradation profile, and biomechanical properties. Biological evaluations with alveolar bone-derived mesenchymal stem cells (aBMSCs) and human gingival fibroblasts (HGFs) encompassed tests for cell viability, mineralized nodule deposition (MND), and collagen production (CP). Statistical analysis was performed using Kruskal-Wallis or ANOVA/post-hoc tests (α = 5%). Results indicate that C scaffolds had larger fiber diameters (~250 nm) compared with NC scaffolds (~150 nm). NC scaffolds exhibited higher swelling capacities than C scaffolds, while both types demonstrated significant mass loss (~50%) after 60 days (p < 0.05). C scaffolds containing CeO showed increased Young's modulus and tensile strength than NC scaffolds. Cells cultured on C scaffolds with 10% CeO exhibited significantly higher metabolic activity (>400%, p < 0.05) after 7 days among all groups. Furthermore, CeO-containing scaffolds promoted enhanced MND by aBMSCs (>120%, p < 0.05) and increased CP in 5% CeO scaffolds for both variants (>180%, p < 0.05). These findings underscore the promising biomechanical properties, biodegradability, cytocompatibility, and enhanced tissue regenerative potential of CeO-loaded GelMA/PCL scaffolds for periodontal applications.

Antimicrobial Silk Fibroin Methacrylated Scaffolds for Regenerative Endodontics.

INTRODUCTION: Recognizing the necessity of novel disinfection strategies for improved bacterial control to ultimately favor tissue regeneration, this study developed and characterized antibiotics-laden silk fibroin methacrylated (SilkMA) scaffolds for regenerative endodontics. METHODS: SilkMA-based solutions (10% w/v) containing Clindamycin (CLI) or Tinidazole (TIN) (0 - control; 5, 10, or 15% w/w) or the combination of both drugs (BiMix CLI/TIN 10%) were electrospun and photocrosslinked. Morphology and composition were assessed using scanning electron microscopy and Fourier-transform infrared spectroscopy. Additionally, swelling and degradation profiles were also determined. Cytotoxicity was evaluated in stem cells from apical papilla. Antibacterial efficacy was tested using direct and indirect contact assays against Aggregatibacter actinomycetemcomitans/Aa, Actinomyces naeslundii/An, Enterococcus faecalis/Ef, and Fusobacterium nucleatum/Fn. E. faecalis biofilm inhibition on dentin discs was specifically evaluated for BiMix-laden scaffolds. Data were statistically analyzed with a significance level of 5%. RESULTS: Scanning electron microscopy revealed that all scaffolds had similar characteristics, including fiber morphology and bead absence. Fourier-transform infrared spectroscopy showed the incorporation of CLI and TIN into the fibers and in BiMix scaffolds. Antibiotic-laden scaffolds exhibited lower swelling capacity than the control and were degraded entirely after 45 days. Scaffolds laden with CLI, TIN, or BiMix throughout all time points did not reduce stem cells from apical papilla's viability. CLI-laden scaffolds inhibited the growth of Aa, An, and Ef, while TIN-laden scaffolds inhibited Fn growth. BiMix-laden scaffolds significantly inhibited Aa, An, Ef, and Fn in direct contact, and their aliquots inhibited An and Fn through indirect contact, with additional biofilm inhibition against Ef. CONCLUSIONS: BiMix-laden SilkMA scaffolds are cytocompatible and exhibit antimicrobial effects against endodontic pathogens, indicating their therapeutic potential as a drug delivery system for regenerative endodontics.

Anti-inflammatory potential of casein enzymatic hydrolysate/gelatin methacryloyl scaffolds for vital pulp therapy.

OBJECTIVES: To synthesize casein enzymatic hydrolysate (CEH)-laden gelatin methacryloyl (GelMA) fibrous scaffolds and evaluate the cytocompatibility and anti-inflammatory effects on dental pulp stem cells (DPSCs). MATERIALS AND METHODS: GelMA fibrous scaffolds with 10%, 20%, and 30% CEH (w/w) and without CEH (control) were obtained via electrospinning. Chemo-morphological, degradation, and mechanical analyses were conducted to evaluate the morphology and composition of the fibers, mass loss, and mechanical properties, respectively. Adhesion/spreading and viability of DPSCs seeded on the scaffolds were also assessed. The anti-inflammatory potential on DPSCs was tested after the chronic challenge of cells with lipopolysaccharides (LPS), followed by treatment with extracts obtained after immersing the scaffolds in α-MEM. The synthesis of the pro-inflammatory cytokines IL-6, IL-1α, and TNF-α was measured by ELISA. Data were analyzed by ANOVA/post-hoc tests (α = 5%). RESULTS: CEH-laden electrospun fibers had a larger diameter than pure GelMA (p ≤ 0.036). GelMA scaffolds laden with 20% and 30% CEH had a greater mass loss. Tensile strength was reduced for the 10% CEH fibers (p = 0.0052), whereas no difference was observed for the 20% and 30% fibers (p ≥ 0.6736) compared to the control. Young's modulus decreased with CEH (p < 0.0001). Elongation at break increased for the 20% and 30% CEH scaffolds (p ≤ 0.0038). Over time, DPSCs viability increased across all groups, indicating cytocompatibility, with CEH-laden scaffolds exhibiting greater cell viability after seven days (p ≤ 0.0166). Also, 10% CEH-GelMA scaffolds decreased the IL-6, IL-1α, and TNF-α synthesis (p ≤ 0.035). CONCLUSION: CEH-laden GelMA scaffolds facilitated both adhesion and proliferation of DPSCs, and 10% CEH provided anti-inflammatory potential after chronic LPS challenge. CLINICAL RELEVANCE: CEH incorporated in GelMA fibrous scaffolds demonstrated the potential to be used as a cytocompatible and anti-inflammatory biomaterial for vital pulp therapy.

Sol-gel-derived calcium silicate cement incorporating collagen and mesoporous bioglass nanoparticles for dental pulp therapy.

OBJECTIVE: Calcium silicate cements (CSCs) are often used in endodontics despite some limitations related to their physical properties and antibacterial efficacy. This study aimed to develop and demonstrate the viability of a series of CSCs that were produced by sol-gel method and further modified with mesoporous bioactive glass nanoparticles (MBGNs) and collagen, for endodontic therapy. METHODS: Calcium silicate (CS) particles and MBGNs were synthesized by the sol-gel method, and their elemental, molecular, and physical microstructure was characterized. Three CSCs were developed by mixing the CS with distilled water (CS+H2O), 10 mg/mL collagen solution (CS+colH2O), and MBGNs (10 %) (CSmbgn+colH2O). The mixing (MT) and setting (ST) times of the CSCs were determined, while the setting reaction was monitored in real-time. Antibacterial efficacy against Enterococcus faecalis (E. faecalis) and regenerative potential on dental pulp stem cells (DPSCs) were also analyzed. RESULTS: The CS+H2O displayed a ST comparable to commercial products, while CSmbgn+colH2O achieved the longest MT of 68 s and the shortest ST of 8 min. All the experimental CSCs inhibited the growth of E. faecalis. Additionally, compared to the control group, CSCs supported cell proliferation and spreading and mineralized matrix production, regardless of their composition. SIGNIFICANCE: Tested CSCs presented potential as candidates for pulp therapy procedures. Future research should investigate the pulp regeneration mechanisms alongside rigorous antibacterial evaluations, preferably with multi-organism biofilms, executed over extended periods.

Bifunctional naringenin-laden gelatin methacryloyl scaffolds with osteogenic and anti-inflammatory properties.

OBJECTIVE: To fabricate and characterize an innovative gelatin methacryloyl/GelMA electrospun scaffold containing the citrus flavonoid naringenin/NA with osteogenic and anti-inflammatory properties. METHODS: GelMA scaffolds (15 % w/v) containing 0/Control, 5, 10, or 20 % of NA w/w were obtained via electrospinning. The chemical composition, fiber morphology/diameter, swelling/degradation profile, and NA release were investigated. Cytotoxicity, cell proliferation, adhesion and spreading, total protein/TP production, alkaline phosphatase/ALP activity, osteogenic genes expression (OCN, OPN, RUNX2), and mineralized nodules deposition/MND with human alveolar bone-derived mesenchymal stem cells (aBMSCs) seeded on the scaffolds were assessed. Moreover, aBMSCs seeded on the scaffolds and stimulated with tumor necrosis factor-alpha/TNF-α were submitted to collagen, nitric oxide/NO, interleukin/IL-1α, and IL-6 production assessment. Data were analyzed using ANOVA and t-student/post-hoc tests (α = 5 %). RESULTS: NA-laden scaffolds presented increased fiber diameter, lower swelling capacity, and faster degradation profile over 28 days (p < 0.05). NA release was detected over time. Cell adhesion and spreading, and TP production were similar between GelMA and GelMA+NA5 % scaffolds, while cell proliferation, ALP activity, OCN/OPN/RUNX2 gene expression, and MND were higher for GelMA+NA5 % scaffolds (p < 0.05). Cells seeded on control scaffolds and TNF-α-stimulated presented higher levels of NO, IL-1α/IL-6, and lower levels of collagen (p < 0.05). In contrast, cells seeded on GelMA+NA5 % scaffolds showed downregulation of inflammatory markers and higher collagen synthesis (p < 0.05). SIGNIFICANCE: GelMA+NA5 % scaffold was cytocompatible, stimulated aBMSCs proliferation and differentiation, and downregulated inflammatory mediators' synthesis, suggesting its therapeutic effect as a multi-target bifunctional scaffold with osteogenic and anti-inflammatory properties for bone tissue engineering.

Biodegradable electrospun poly(L-lactide-co-ε-caprolactone)/polyethylene glycol/bioactive glass composite scaffold for bone tissue engineering.

The field of tissue engineering has witnessed significant advancements in recent years, driven by the pursuit of innovative solutions to address the challenges of bone regeneration. In this study, we developed an electrospun composite scaffold for bone tissue engineering. The composite scaffold is made of a blend of poly(L-lactide-co-ε-caprolactone) (PLCL) and polyethylene glycol (PEG), with the incorporation of calcined and lyophilized silicate-chlorinated bioactive glass (BG) particles. Our investigation involved a comprehensive characterization of the scaffold's physical, chemical, and mechanical properties, alongside an evaluation of its biological efficacy employing alveolar bone-derived mesenchymal stem cells. The incorporation of PEG and BG resulted in elevated swelling ratios, consequently enhancing hydrophilicity. Thermal gravimetric analysis confirmed the efficient incorporation of BG, with the scaffolds demonstrating thermal stability up to 250°C. Mechanical testing revealed enhanced tensile strength and Young's modulus in the presence of BG; however, the elongation at break decreased. Cell viability assays demonstrated improved cytocompatibility, especially in the PLCL/PEG+BG group. Alizarin red staining indicated enhanced osteoinductive potential, and fluorescence analysis confirmed increased cell adhesion in the PLCL/PEG+BG group. Our findings suggest that the PLCL/PEG/BG composite scaffold holds promise as an advanced biomaterial for bone tissue engineering.

Influence of Bisphosphonates on the Behavior of Osteoblasts Seeded Onto Titanium Discs.

Among other factors, types of bisphosphonates and treatment regimens seem to be strongly associated with the success or failure of installation of osseointegrated implants. This study investigated the influence of two bisphosphonates, sodium alendronate (SA) and zoledronic acid (ZA), on the metabolism of osteoblasts. Human osteoblasts (Saos-2) were seeded onto machined or acid-treated titanium discs previously placed on 24-well plates in complete culture medium. After 24 h, cells were exposed to bisphosphonates at 0.5, 1 or 5 µM for 24 h, 48 h or 7 days. The effects of SA and ZA on osteoblasts were assessed based on the adhesion of these cells to the titanium surfaces by direct fluorescence, cell viability, total protein and collagen synthesis. Alkaline phosphatase activity and mineral nodule deposition by these cells were also evaluated. Data were evaluated by ANOVA and Tukey tests (α=0.05). Decreased adhesion of cells to the titanium discs was observed when exposed to both bisphosphonates; however, this lack of cell adhesion was more evident for ZA-treated cells. In addition, the exposure of osteoblasts to ZA decreased the viability, ALP activity and mineral nodule deposition, which may be related to poor osseointegration after implant installation.

Influence of bisphosphonates on the behavior of osteoblasts seeded onto titanium discs

Abstract Among other factors, types of bisphosphonates and treatment regimens seem to be strongly associated with the success or failure of installation of osseointegrated implants. This study investigated the influence of two bisphosphonates, sodium alendronate (SA) and zoledronic acid (ZA), on the metabolism of osteoblasts. Human osteoblasts (Saos-2) were seeded onto machined or acid-treated titanium discs previously placed on 24-well plates in complete culture medium. After 24 h, cells were exposed to bisphosphonates at 0.5, 1 or 5 µM for 24 h, 48 h or 7 days. The effects of SA and ZA on osteoblasts were assessed based on the adhesion of these cells to the titanium surfaces by direct fluorescence, cell viability, total protein and collagen synthesis. Alkaline phosphatase activity and mineral nodule deposition by these cells were also evaluated. Data were evaluated by ANOVA and Tukey tests (α=0.05). Decreased adhesion of cells to the titanium discs was observed when exposed to both bisphosphonates; however, this lack of cell adhesion was more evident for ZA-treated cells. In addition, the exposure of osteoblasts to ZA decreased the viability, ALP activity and mineral nodule deposition, which may be related to poor osseointegration after implant installation.

Resumo Entre outros fatores, os tipos de bisfosfonatos bem como os regimes de tratamento parecem estar diretamente associados com o sucesso ou falhas na instalação de implantes osseointegrados. Este estudo avaliou a influência de dois bisfosfonatos, o alendronato de sódio (AS) e o ácido zoledrônico (AZ), no metabolismo de osteoblastos. Osteoblastos humanos (Saos-2) foram cultivados sobre discos de titânio polidos ou submetidos a tratamento ácido superficial, previamente alocados em placas de 24 compartimentos, utilizando meio de cultura completo. Após 24 horas, as células foram expostas aos bisfosfonatos, nas concentrações de 0,5, 1 ou 5 µM, por 24 h, 48 h, ou 7 dias. Os efeitos do AZ e AZ sobre os osteoblastos foram determinados considerando a adesão destas células às superfícies de titânio, por meio de fluorescência direta, a viabilidade celular, produção de proteína total e síntese de colágeno. A atividade de fosfatase alcalina e a deposição de nódulos mineralizados também foram avaliadas. Os dados foram analisados por meio do teste ANOVA complementado por Tukey (α = 0.05). Menor adesão dos osteoblastos foi observada quando estas células foram expostas a ambos os bisfosfonatos, porém, esta falha na adesão foi mais evidente para as células tratadas com AZ. Além disso, a exposição dos osteoblastos ao AZ também resultou em diminuição da viabilidade, atividade de ALP e deposição de nódulos mineralizados, o que pode estar relacionado a uma pobre osseointegração após a instalação do implante.

Influence of bisphosphonates on the adherence and metabolism of epithelial cells and gingival fibroblasts to titanium surfaces.

OBJECTIVES: To evaluate the effects of sodium alendronate (SA) and zoledronic acid (ZA), on the adhesion and metabolism of epithelial cells and gingival fibroblasts to titanium surfaces considering cell functions related to an effective mucosal barrier around the implant. MATERIALS AND METHODS: Cells were seeded onto titanium discs and incubated for 24 h. Then, serum-free DMEM containing selected bisphosphonates (0, 0.5, 1, or 5 µM) was added for 24 and 48 h. Factors related to the achievement of an effective mechanical and immunological barrier-cell adhesion, viability, collagen epidermal growth factor, and immunoglobulin synthesis-were evaluated. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests as well as by ANOVA and Tukey's tests, (α = 0.05). RESULTS: The presence of bisphosphonates culminated in lower cell adhesion to the titanium discs, particularly for SA at 5 µM (40%) and ZA at all concentrations (from 30 to 50%, according to increased concentrations). Reduced cell viability occurred after exposing these cells to ZA (40%); however, only 5 µM SA-treated cells had decreased viability (30%). Reduced synthesis of growth factors and collagen was observed when cells were reated with ZA (20 and 40%, respectively), while about 70% of IgG synthesis was enhanced. CONCLUSION: Bisphosphonates negatively affected the adhesion and metabolism of oral mucosal cells, and this effect was related to the type of bisphosphonate as well as to concentration and period of treatment. CLINICAL RELEVANCE: The negative effects of bisphosphonates on oral mucosal cells can hamper the formation of an effective biological seal in osseointegrated implants.

Proliferation, migration, and expression of oral-mucosal-healing-related genes by oral fibroblasts receiving low-level laser therapy after inflammatory cytokines challenge.

BACKGROUND AND OBJECTIVES: Increased expression of inflammatory cytokines in the oral cavity has been related to the etiopathogenesis of oral mucositis and to delayed oral mucosal repair. Low-level laser therapy (LLLT) stimulates proliferation and migration of gingival fibroblasts, but the effects of specific inflammatory cytokines on oral mucosal cells and the modulation of these effects by LLLT have not been fully investigated. Therefore, this study investigated the effects of LLLT on oral fibroblasts after being challenged by oral-mucositis-related inflammatory cytokines. METHODS: Human gingival fibroblasts were seeded in plain culture medium (DMEM) containing 10% fetal bovine serum (FBS) for 24 hours. Then, cells were kept in contact with inflammatory cytokines (TNF-α, IL-1ß, IL-6, and IL-8) in serum-free DMEM for 24 hours. After this period, cells were subjected to LLLT with a diode laser device (LaserTABLE, InGaAsP, 780 nm, 25 mW) delivering energy doses from 0.5 to 3 J/cm2 . Irradiation was repeated for 3 consecutive days. Twenty-four hours after the last irradiation, cell migration (wound-healing and transwell migration assays), cell proliferation (BrdU), gene expression of COL-I and growth factors (real-time PCR), and synthesis of COL-I (Sirius Red assay) and VEGF (ELISA) were assessed. Data were subjected to two-way ANOVA and Tukey's tests or Kruskall-Walis and Mann-Whitney tests (P < 0.05). RESULTS: The inflammatory cytokines decreased the migration capacity of gingival fibroblasts. However, a statistically significant difference was observed only for IL-6, detected by transwell assay, where 30% less cells migrated through the pores (P < 0.05) and IL-8, with an increased wound area (116%; P < 0.05), detected by the wound healing method. Cell proliferation was not affected by contact with cytokines, while growth factors and COL-I expression (approximately 80%; P < 0.05), as well as VEGF synthesis (approximately 20%; P < 0.05), were decreased after contact to all tested cytokines. The opposite was seen for total collagen synthesis. LLLT promoted an acceleration of fibroblast migration (30%; P < 0.05) and proliferation (112%; P < 0.05) when delivering 0.5 J/cm2 to the cells previously in contact with the inflammatory cytokines. Gene expression of VEGF (approximately 30%; P < 0.05), and EGF (17%; P < 0.05), was stimulated by LLLT after contact with TNF-α and IL-6. CONCLUSION: LLLT can counteract the negative effects of high concentrations of inflammatory cytokines, especially IL-6 and IL-8 on gingival fibroblast functions directly related to the wound-healing process. Lasers Surg. Med. 48:1006-1014, 2016. © 2016 Wiley Periodicals, Inc.