Effects of protein-coated nanofibers on conformation of gingival fibroblast spheroids: potential utility for connective tissue regeneration

Surface Modification Progress for PLGA-Based Cell Scaffolds

Poly(lactic-glycolic acid) (PLGA) is a biocompatible bio-scaffold material, but its own hydrophobic and electrically neutral surface limits its application as a cell scaffold. Polymer materials, mimics ECM materials, and organic material have often been used as coating materials for PLGA cell scaffolds to improve the poor cell adhesion of PLGA and enhance tissue adaptation. These coating materials can be modified on the PLGA surface via simple physical or chemical methods, and coating multiple materials can simultaneously confer different functions to the PLGA scaffold; not only does this ensure stronger cell adhesion but it also modulates cell behavior and function. This approach to coating could facilitate the production of more PLGA-based cell scaffolds. This review focuses on the PLGA surface-modified materials, methods, and applications, and will provide guidance for PLGA surface modification.

Nanomaterials for Periodontal Tissue Regeneration: Progress, Challenges and Future Perspectives

Bioactive nanomaterials are increasingly being applied in oral health research. Specifically, they have shown great potential for periodontal tissue regeneration and have substantially improved oral health in translational and clinical applications. However, their limitations and side effects still need to be explored and elucidated. This article aims to review the recent advancements in nanomaterials applied for periodontal tissue regeneration and to discuss future research directions in this field, especially focusing on research using nanomaterials to improve oral health. The biomimetic and physiochemical properties of nanomaterials such as metals and polymer composites are described in detail, including their effects on the regeneration of alveolar bone, periodontal ligament, cementum and gingiva. Finally, the biomedical safety issues of their application as regenerative materials are updated, with a discussion about their complications and future perspectives. Although the applications of bioactive nanomaterials in the oral cavity are still at an initial stage, and pose numerous challenges, recent research suggests that they are a promising alternative in periodontal tissue regeneration.

Bilayer scaffold from PLGA/fibrin electrospun membrane and fibrin hydrogel layer supports wound healingin vivo

Hybrid scaffolds from natural and synthetic polymers have been widely used due to the complementary nature of their physical and biological properties. The aim of the present study, therefore, has been to analyzein vivoa bilayer scaffold of poly(lactide-co-glycolide)/fibrin electrospun membrane and fibrin hydrogel layer on a rat skin model. Fibroblasts were cultivated in the fibrin hydrogel layer and keratinocytes on the electrospun membrane to generate a skin substitute. The scaffolds without and with cells were tested in a full-thickness wound model in Wistar Kyoto rats. The histological results demonstrated that the scaffolds induced granulation tissue growth, collagen deposition and epithelial tissue remodeling. The wound-healing markers showed no difference in scaffolds when compared with the positive control. Activities of antioxidant enzymes were decreased concerning the positive and negative control. The findings suggest that the scaffolds contributed to the granulation tissue formation and the early collagen deposition, maintaining an anti-inflammatory microenvironment.

Poly(Caprolactone)-Aligned Nanofibers Associated with Fibronectin-loaded Collagen Hydrogel as a Potent Bioactive Scaffold for Cell-Free Regenerative Endodontics

AIM

Guided tissue regeneration has been considered a promising strategy to replace conventional endodontic therapy of teeth with incomplete root formation. Therefore, the objective of this study was to develop a tubular scaffold (TB-SC) with poly (caprolactone)-aligned nanofibers associated with a fibronectin-loaded collagen hydrogel and assess the pulp regeneration potential mediated by human apical papilla cells (hAPCs) using an in vitro model of teeth with incomplete root formation.

METHODOLOGY

Aligned nanofiber strips based on 10% poly(caprolactone) (PCL) were synthesized with the electrospinning technique to produce the TB-SCs. These were submitted to different treatments, according to the following groups: TB-SC (negative control): TB-SC without treatment; TB-SC+FN (positive control): TB-SC coated with 10 μg/mL of fibronectin; TB-SC+H: TB-SC associated with collagen hydrogel; TB-SC+HFN: TB-SC associated with fibronectin-loaded collagen hydrogel. Then, the biomaterials were inserted into cylindrical devices to mimic the regenerative therapy of teeth with incomplete root formation. The hAPCs were seeded on the upper surface of the TB-SCs associated or not with any treatment, and cell migration/proliferation and the gene expression of markers related to pulp regeneration (ITGA5, ITGAV, COL1A1, and COL1A3) were evaluated. The data were submitted to ANOVA/Tukey's tests (α=5 %).

RESULTS

Higher values of cell migration/proliferation and gene expression of all markers tested were observed in groups TB-SC+FN, TB-SC+H, and TB-SC+HFN compared with the TB-SC group (p<0.05). The hAPCs in the TB-SC+HFN group showed the highest values of cell proliferation and gene expression of COL1A1 and COL3A1 (p<0.05), as well as superior cell migration results to groups TB-SC and TB-SC+H (p<0.05).

CONCLUSION

Aligned nanofiber scaffolds associated with the fibronectin-loaded collagen hydrogel enhanced the migration and proliferation of hAPCs, and gene expression of pulp regeneration markers. Therefore, the use of these biomaterials may be considered an interesting strategy for regenerative pulp therapy of teeth with incomplete root formation.

Porphyromonas gingivalis lipopolysaccharide and gingival fibroblast augment MMP-9 expression of monocytic U937 cells through cyclophilin A

BACKGROUND

Intercellular cross-talking was suggested in matrix metalloproteinase (MMP)-9 expression with unknown mechanisms. Studies showed cyclophilin A (CypA) playing an important role in regulating MMP-9 expression in varied diseases. The aim of the study was to examine the CyPA on the MMP-9 augmentation in monocytic U937 cells after Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS) treatment and human gingival fibroblast (hGF) co-culture.

METHODS

In independent culture or co-culture of hGF and U937 cell, quantitative real-time polymerase chain reaction (qPCR) and zymography were selected to examine the mRNA and protein activity of MMP-9, respectively. The CyPA expression was determined by qPCR.

RESULTS

LPS could enhance MMP-9 mRNA expression and enzyme activity in U937 cell. However, the enhancements were not observed in hGF. Similarly, LPS enhanced CyPA mRNA in U937, but not in hGF. After co-cultured with hGF, however, MMP-9 and CyPA in U937 increased regardless of the presence/absence of LPS. In U937 cells, the extra-supplied CyPA increased MMP-9 mRNA and enzyme activity, whereas the CyPA inhibitor, cyclosporine A, suppressed the LPS- and co-culture-enhanced MMP-9. Moreover, the inhibitors for MAP kinase, including PD98059 (ERK) and SP600125 (JNK), suppressed the CyPA-enhanced MMP-9 in U937.

CONCLUSION

Through the CyPA pathway, the LPS and the hGF could augment the MMP-9 expression in the U937 cells.

Influence of bio-aging on corrosion behavior of different implant materials

BACKGROUND

Dental implants and abutments are exposed to challenging oral environment. Corrosion of these materials can affect the overall performance of titanium implants.

PURPOSE

To investigate the effects of biofilm-induced bio-aging on corrosion behavior of different implant materials surface.

MATERIALS AND METHODS

Commercial polished titanium (Polish), sand-blasted, large grit, acid-etched surface treated titanium (SLA), microarc oxidation (MAO), and hydroxyapatite (HA) coated titanium were bio-aged with saliva biofilm for 30 days. Titanium surfaces topography, chemical composition, roughness, and water contact angle changes were evaluated. In addition, human gingival fibroblasts (HGFs) adhesion, Streptococcus sanguinis (S. sanguinis) biofilm formation were determined.

RESULTS

Surface topography, roughness, and chemical composition have no significant changes for all groups after bio-aging (P > .05). Water contact angle of bio-aged SLA was greatly increased (P < .05). While other groups showed no sign of change (P > .05). Adhesion and proliferation of HGFs on the bio-aged SLA titanium surfaces were decreased (P < .05), but increased on bio-aged Polish and HA titanium (P < .05). S. sanguinis biofilm viability was promoted with bio-aging in HA group (P < .05).

CONCLUSIONS

Biological characteristics of Polish, SLA, and HA titanium surfaces were influenced by bio-aging. While MAO group was relatively resistant to saliva biofilm bio-aging.

Engineering principles for guiding spheroid function in the regeneration of bone, cartilage, and skin

There is a critical need for strategies that effectively enhance cell viability and post-implantation performance in order to advance cell-based therapies. Spheroids, which are dense cellular aggregates, overcome many current limitations with transplanting individual cells. Compared to individual cells, the aggregation of cells into spheroids results in increased cell viability, together with enhanced proangiogenic, anti-inflammatory, and tissue-forming potential. Furthermore, the transplantation of cells using engineered materials enables localized delivery to the target site while providing an opportunity to guide cell fate in situ, resulting in improved therapeutic outcomes compared to systemic or localized injection. Despite promising early results achieved by freely injecting spheroids into damaged tissues, growing evidence demonstrates the advantages of entrapping spheroids within a biomaterial prior to implantation. This review will highlight the basic characteristics and qualities of spheroids, describe the underlying principles for how biomaterials influence spheroid behavior, with an emphasis on hydrogels, and provide examples of synergistic approaches using spheroids and biomaterials for tissue engineering applications.