Investigation of background, novelty and recent advance of iron (II,III) oxide- loaded on 3D polymer based scaffolds as regenerative implant for bone tissue engineering: A review

Alginate/bacterial cellulose/GelMA scaffolds with aligned nanopatterns and hollow channel networks for vascularized bone repair

Designed macropores and nanopatterned surfaces are important architectural cues in three-dimensional (3D) scaffolds for promoting vascularization and bone regeneration. However, the fabrication of 3D scaffolds with both controlled nanopatterned surfaces and designed macropores remains a challenge, especially for hydrogel-based scaffolds. Herein, alginate (Alg)/bacterial cellulose (BC)/ Gelatin Methacryloyl (GelMA) composite scaffold with fully interconnected Hollow Channel Networks And An Aligned Nanopatterned Surface (HCAS) is fabricated using 3D printing, surface crosslinking, and prestretching/drying-induced orientation. The highly aligned nanofibrous structures significantly enhance the mechanical properties, as well as the structural stability of the hydrogel scaffold. In vitro experiments prove that the HCAS scaffold exhibits apparently enhanced angiogenic and osteogenic properties compared to the control groups since the aligned nanopatterns and hollow channels can activate the cyclic AMP-dependent Ras-related protein 1 (cAMP-RAP1) and mitogen-activated protein kinase (MAPK) pathways, respectively, and jointly promote the downstream phosphoinositide 3-kinase/hypoxia-inducible factor-1 (PI3K/HIF-1) pathway. In vivo experiments also show that HCAS scaffold significantly promotes vascularization and bone regeneration, further verifying the joint effect of the aligned nanopatterned surface and fully interconnected hollow channels in promoting vascularization and osteogenesis. Thus, the HCAS scaffold demonstrates that a cell- and growth factor-free approach can also promote satisfactory vascularization and bone regeneration, simply by creating nanopatterned surfaces and designed hollow channels within hydrogel scaffolds.

Mesenchymal stem cell-derived extracellular vesicles: A promising therapeutic strategy in diabetic osteoporosis

Diabetic osteoporosis (DOP) is a serious complication of diabetes mellitus. It is urgent to explore efficient clinical treatment strategies for DOP. It has been found that mesenchymal stem cell-derived extracellular vesicles (MSC-EVs), as an emerging cell-free therapy, show great potential in DOP treatment. MSC-EVs can effectively promote bone formation, inhibit bone resorption, and modulate the inflammatory microenvironment by delivering cargoes of microRNAs, long non-coding RNAs, and proteins to target cells, thereby ameliorating bone loss in DOP. However, there are limited reports on the treatment of DOP with MSC-EVs. To evoke more attention to this potential strategy, this article summarised the extant literature on MSC-EVs for DOP to provide new directions for further research and to promote the application of MSC-EVs in the clinical management of DOP.

Effects of Nanomaterials on Synthesis and Degradation of the Extracellular Matrix

Extracellular matrix (ECM) remodeling is accompanied by the continuous synthesis and degradation of the ECM components. This dynamic process plays an important role in guiding cell adhesion, migration, proliferation, and differentiation, as well as in tissue development, body repair, and maintenance of homeostasis. Nanomaterials, due to their photoelectric and catalytic properties and special structure, have garnered much attention in biomedical fields for use in processes such as tissue engineering and disease treatment. Nanomaterials can reshape the cell microenvironment by changing the synthesis and degradation of ECM-related proteins, thereby indirectly changing the behavior of the surrounding cells. This review focuses on the regulatory role of nanomaterials in the process of cell synthesis of different ECM-related proteins and extracellular protease. We discuss influencing factors and possible related mechanisms of nanomaterials in ECM remodeling, which may provide different insights into the design and development of nanomaterials for the treatment of ECM disorder-related diseases.