Aim: RADA16-PLGA composite scaffolds constructed with simultaneous loading of BMSCs and TGF-β3 and explored their ability for chondrogenic differentiation in vitro.Methods: The performance of the composite scaffolds is assessed by rheometer assay, electron microscopic structural observation and ELISA release assay. The biosafety of the composite scaffolds is assessed by cytocompatibility assay and cell migration ability. The chondrogenic differentiation ability of composite scaffolds is evaluated by Alisin blue staining, PCR and immunofluorescence staining.Results: The composite scaffold has a good ECM-like structure, the ability to control the release of TGF-β3 and good biocompatibility. More importantly, the composite scaffolds can induce the differentiation of BMSCs to chondrocytes.Conclusion: Composite scaffolds are expected to enhance the endogenous NP repair process.
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BACKGROUND: The integration of stem cells, signaling molecules, and biomaterial scaffolds is fundamental for the successful engineering of functional bone tissue. Currently, the development of composite scaffolds has emerged as an attractive approach to meet the criteria of ideal scaffolds utilized in bone tissue engineering (BTE) for facilitating bone regeneration in bone defects. Recently, the incorporation of polycaprolactone (PCL) with hydroxyapatite (HA) has been developed as one of the suitable substitutes for BTE applications owing to their promising osteogenic properties. In this study, a three-dimensional (3D) scaffold composed of PCL integrated with HA (PCL/HA) was prepared and assessed for its ability to support osteogenesis in vitro. Furthermore, this scaffold was evaluated explicitly for its efficacy in promoting the proliferation and osteogenic differentiation of canine bone marrow-derived mesenchymal stem cells (cBM-MSCs) to fill the knowledge gap regarding the use of composite scaffolds for BTE in the veterinary orthopedics field.
RESULTS: Our findings indicate that the PCL/HA scaffolds substantially supported the proliferation of cBM-MSCs. Notably, the group subjected to osteogenic induction exhibited a markedly upregulated expression of the osteogenic gene osterix (OSX) compared to the control group. Additionally, the construction of 3D scaffold constructs with differentiated cells and an extracellular matrix (ECM) was successfully imaged using scanning electron microscopy. Elemental analysis using a scanning electron microscope coupled with energy-dispersive X-ray spectroscopy confirmed that these constructs possessed the mineral content of bone-like compositions, particularly the presence of calcium and phosphorus.
CONCLUSIONS: This research highlights the synergistic potential of PCL/HA scaffolds in concert with cBM-MSCs, presenting a multidisciplinary approach to scaffold fabrication that effectively regulates cell proliferation and osteogenic differentiation. Future in vivo studies focusing on the repair and regeneration of bone defects are warranted to further explore the regenerative capacity of these constructs, with the ultimate goal of assessing their potential in veterinary clinical applications.

Chitosan chemical functionalization is a powerful tool to provide novel materials for additive manufacturing strategies. The main aim of this study was the employment of computer-aided wet spinning (CAWS) for the first time to design and fabricate carboxymethyl chitosan (CMCS) scaffolds. For this purpose, the synthesis of a chitosan derivative with a high degree of O-substitution (1.07) and water soluble in a large pH range allowed the fabrication of scaffolds with a 3D interconnected porous structure. In particular, the developed scaffolds were composed of CMCS fibers with a small diameter (< 60 μm) and a hollow structure due to a fast non solvent-induced coagulation. Zn2+ ionotropic crosslinking endowed the CMCS scaffolds with stability in aqueous solutions, pH-sensitive water uptake capability, and antimicrobial activity against Escherichia coli and Staphylococcus aureus. In addition, post-printing functionalization through collagen grafting resulted in a decreased stiffness (1.6 ± 0.3 kPa) and a higher elongation at break (101 ± 9 %) of CMCS scaffolds, as well as in their improved ability to support in vitro fibroblast viability and wound healing process. The obtained results encourage therefore further investigation of the developed scaffolds as antimicrobial wound dressing hydrogels for skin regeneration.

The development of synthetic bone substitutes that equal or exceed the efficacy of autologous graft remains challenging. In this study, a rat calvarial defect model was used as a reference to investigate the influence of composition and architecture of 3D-printed cement, with or without bioactives, on tissue regeneration. Printable cement pastes were formulated by combining hyaluronic acid and cement precursors. Cementitious scaffolds were printed with 3 different patterns. After 7 weeks of implantation with or without bone marrow, multiparametric qualitative and quantitative assessments were performed using µCT, SEM, and histology. None of the set-up strategies was as efficient as autologous cancellous bone graft to repair calvarial defects. Nonetheless, the presence of scaffold improved the skull vault closure, particularly when the scaffold was soaked in total bone marrow before implantation. No significant effect of scaffold macro-architecture was observed on tissue mineralization. Magnesium phosphate-based scaffolds (MgP) seemed to induce higher bone formation than their calcium-phosphate-based counterparts. They also displayed a quicker biodegradation and sparse remaining material was found after 7 weeks of implantation. Although further improvements are required to reach clinical settings, this study demonstrated the potential of organo-mineral cements for bone regeneration and highlighted the peculiar properties of MgP-based cements.

A common malignant bone neoplasm in teenagers is Osteosarcoma. Chemotherapy, surgical therapy, and radiation therapy together comprise the usual clinical course of treatment for Osteosarcoma. While Osteosarcoma and other bone tumors are typically treated surgically, however, surgical resection frequently fails to completely eradicate tumors, and in turn becomes the primary reason for postoperative recurrence and metastasis, ultimately leading to a high rate of mortality. Patients still require radiation and/or chemotherapy after surgery to stop the spread of the tumor and its metastases, and both treatments have an adverse influence on the body\'s organ systems. In the postoperative management of osteosarcoma, bone scaffolds can load cargos (growth factors or drugs) and function as drug delivery systems (DDSs). This review describes the different kinds of bone scaffolds that are currently available and highlights key studies that use scaffolds as DDSs for the treatment of osteosarcomas. The discussion also includes difficulties and perspectives regarding the use of scaffold-based DDSs. The study may serve as a source for outlining efficient and secure postoperative osteosarcoma treatment plans.

To assess the efficacy of a novel 3D biomimetic hydrogel scaffold with immunomodulatory properties in promoting fracture healing. Immunomodulatory scaffolds were used in cell experiments, osteotomy mice treatment, and single-cell transcriptomic sequencing. In vitro, fluorescence tracing examined macrophage mitochondrial transfer and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Scaffold efficacy was assessed through alkaline phosphatase (ALP), Alizarin Red S (ARS) staining, and in vivo experiments. The scaffold demonstrated excellent biocompatibility and antioxidant-immune regulation. Single-cell sequencing revealed a shift in macrophage distribution towards the M2 phenotype. In vitro experiments showed that macrophage mitochondria promoted BMSCs\' osteogenic differentiation. In vivo experiments confirmed accelerated fracture healing. The GAD/Ag-pIO scaffold enhances osteogenic differentiation and fracture healing through immunomodulation and promotion of macrophage mitochondrial transfer.

The peripheral nervous system consists of ganglia, nerve trunks, plexuses, and nerve endings, that transmit afferent and efferent information. Regeneration after a peripheral nerve damage is sluggish and imperfect. Peripheral nerve injury frequently causes partial or complete loss of motor and sensory function, physical impairment, and neuropathic pain, all of which have a negative impact on patients\' quality of life. Because the mechanism of peripheral nerve injury and healing is still unclear, the therapeutic efficacy is limited. As peripheral nerve injury research has processed, an increasing number of studies have revealed that biological scaffolds work in tandem with progenitor cells to repair peripheral nerve injury. Here, we fabricated collagen chitosan nerve conduit bioscaffolds together with collagen and then filled neuroepithelial stem cells (NESCs). Scanning electron microscopy showed that the NESCs grew well on the scaffold surface. Compared to the control group, the NESCs group contained more cells with bigger diameters and myelinated structures around the axons. Our findings indicated that a combination of chitosan-collagen bioscaffold and neural stem cell transplantation can facilitate the functional restoration of peripheral nerve tissue, with promising future applications and research implications.

In order to properly satisfy biomedical constraints for cardiovascular applications, additively manufactured NiTi scaffolds required further process and metallurgical engineering. Additively manufactured NiTi materials for cardiovascular use will have to undergo surface finishing in order to minimize negative surface interactions within the artery. In this study, we sought to understand biocompatibility from chemically etched additively manufactured NiTi scaffolds by laser powder bed fusion (LPBF). Although two distinct oxide films were created in the surface etching process (labeled CP-A and CP-B), no qualitative changes in microroughness were seen between the two conditions. CP-A possessed significantly less Ni at the surface (0.19 at. %) than the CP-B group (3.30 at. %), via x-ray photoelectron spectroscopy, alongside a concomitant shift in the O1 s peak presentation alluding to a greater formation of a Ni based oxide in the CP-B group. Our live dead staining revealed significant toxicity and reduced cellular attachment for the CP-B group, in addition to inducing more cell lysis (20.9 ± 5.1%), which was significantly increased when compared to CP-A (P < 0.01). Future practices of manufacturing NiTi scaffolds using LPBF should focus on producing surface films that are not only smooth, but free of cytotoxic Ni based oxides.

Chemical crosslinking is a method widely used to enhance the mechanical strength of biopolymer-based scaffolds. Polysaccharides are natural and biodegradable carbohydrate polymers that can act as crosslinking agents to promote the formation of scaffolds. Compared to synthetic crosslinking agents, Polysaccharide-based crosslinking agents have better biocompatibility for cell adhesion and growth. Traditional Chinese medicine has special therapeutic effects on various diseases and is rich in various bioactive ingredients. Among them, polysaccharides have immune regulatory, antioxidant, and anti-inflammation effects, which allow them to not only act as crosslinking agents but endow the scaffold with greater bioactivity. This article focuses on the latest developments of polysaccharide-based crosslinking agents for biomedical scaffolds, including hyaluronic acid, chondroitin sulfate, dextran, alginate, cellulose, gum polysaccharides, and traditional Chinese medicine polysaccharides. Also, we provide a summary and prospects on the research of polysaccharide-based crosslinking agents.

The interconnected structures in a 3D scaffold allows the movement of cells and nutrients. Therefore, this study aimed to investigate the in-vivo bioactivity of 3D-printed β-tricalcium phosphate (β-TCP) and hydroxyapatite (HAP) scaffolds that replicate biological bone. This study included 24-week-old male New Zealand white rabbits. A cylindrical bone defect with a diameter of 4.5 mm and a depth of 8 mm was created in the lateral aspect of the distal femur. A 3D-printed scaffold was implanted in the right femur (experimental side), whereas the left femur was kept free of implantation (control side). Micro-CT analysis and histological observations of the bone defect site were conducted at 4, 8, and 12 weeks postoperatively to track the bone repair progress. No evidence of new bone tissue formation was found in the medullary cavity of the bone defect on the control side. In contrast, on the experimental side, the 3D scaffold demonstrated sufficient bioactivity, leading to the growth of new bone tissue. Over time, new bone tissue gradually extended from the periphery toward the center, a phenomenon evident in both micro-CT images and biopsy staining. In the current study, we observed that the cells involved in bone metabolism adhered, spread, and proliferated on our newly designed 3D-printed scaffold with a bone microstructure. Therefore, it is suggested that this scaffold has sufficient bioactivity to induce new bone formation and could be expected to be a more useful artificial bone than the existing version.