Bioactive glass-collagen/poly (glycolic acid) scaffold nanoparticles exhibit improved biological properties and enhance osteogenic lineage differentiation of mesenchymal stem cells

Additively manufactured porous scaffolds by design for treatment of bone defects

There has been increasing attention to produce porous scaffolds that mimic human bone properties for enhancement of tissue ingrowth, regeneration, and integration. Additive manufacturing (AM) technologies, i.e., three dimensional (3D) printing, have played a substantial role in engineering porous scaffolds for clinical applications owing to their high level of design and fabrication flexibility. To this end, this review article attempts to provide a detailed overview on the main design considerations of porous scaffolds such as permeability, adhesion, vascularisation, and interfacial features and their interplay to affect bone regeneration and osseointegration. Physiology of bone regeneration was initially explained that was followed by analysing the impacts of porosity, pore size, permeability and surface chemistry of porous scaffolds on bone regeneration in defects. Importantly, major 3D printing methods employed for fabrication of porous bone substitutes were also discussed. Advancements of MA technologies have allowed for the production of bone scaffolds with complex geometries in polymers, composites and metals with well-tailored architectural, mechanical, and mass transport features. In this way, a particular attention was devoted to reviewing 3D printed scaffolds with triply periodic minimal surface (TPMS) geometries that mimic the hierarchical structure of human bones. In overall, this review enlighten a design pathway to produce patient-specific 3D-printed bone substitutions with high regeneration and osseointegration capacity for repairing large bone defects.

Advancements in scaffold for treating ligament injuries; in vitro evaluation

Tendon/ligament (T/L) injuries are a worldwide health problem that affects millions of people annually. Due to the characteristics of tendons, the natural rehabilitation of their injuries is a very complex and lengthy process. Surgical treatment of a T/L injury frequently necessitates using autologous or allogeneic grafts or synthetic materials. Nonetheless, these alternatives have limitations in terms of mechanical properties and histocompatibility, and they do not permit the restoration of the original biological function of the tissue, which can negatively impact the patient's quality of life. It is crucial to find biological materials that possess the necessary properties for the successful surgical treatment of tissues and organs. In recent years, the in vitro regeneration of tissues and organs from stem cells has emerged as a promising approach for preparing autologous tissue and organs, and cell culture scaffolds play a critical role in this process. However, the biological traits and serviceability of different materials used for cell culture scaffolds vary significantly, which can impact the properties of the cultured tissues. Therefore, this review aims to analyze the differences in the biological properties and suitability of various materials based on scaffold characteristics such as cell compatibility, degradability, textile technologies, fiber arrangement, pore size, and porosity. This comprehensive analysis provides valuable insights to aid in the selection of appropriate scaffolds for in vitro tissue and organ culture.

Neuro-bone tissue engineering: emerging mechanisms, potential strategies, and current challenges

The skeleton is a highly innervated organ in which nerve fibers interact with various skeletal cells. Peripheral nerve endings release neurogenic factors and sense skeletal signals, which mediate bone metabolism and skeletal pain. In recent years, bone tissue engineering has increasingly focused on the effects of the nervous system on bone regeneration. Simultaneous regeneration of bone and nerves through the use of materials or by the enhancement of endogenous neurogenic repair signals has been proven to promote functional bone regeneration. Additionally, emerging information on the mechanisms of skeletal interoception and the central nervous system regulation of bone homeostasis provide an opportunity for advancing biomaterials. However, comprehensive reviews of this topic are lacking. Therefore, this review provides an overview of the relationship between nerves and bone regeneration, focusing on tissue engineering applications. We discuss novel regulatory mechanisms and explore innovative approaches based on nerve-bone interactions for bone regeneration. Finally, the challenges and future prospects of this field are briefly discussed.

Physicochemical properties and cell proliferation and adhesive bioactivity of collagen-hyaluronate composite gradient membrane

Membrane materials were widely used in guided tissue regeneration (GTR) to prevent fibroblast invasion and form a confined area for preferentially growing of osteoblast. A novel collagen-hyaluronate composite gradient membrane was prepared by Tilapia (Oreochromis mossambicus) skin collagen and sodium hyaluronate for potential GTR applications and their bioactivities were investigated by cellular viability. SEM results indicated the membrane showed a dense outer and a porous inner surface for effectively guiding the growth of bone tissue. Physicochemical and biosafety experiments showed the tensile strength of membrane was 466.57 ± 44.31 KPa and contact angle was 74.11°, and the membrane showed perfect biocompatibility and cytocompatibility as well, which met the requirements of GTR material. Cell morphology revealed that the membrane could facilitate the adherence and proliferation of fibroblast and osteoblast. The results of qRT-PCR and ELISA demonstrated that the membrane could effectively activate TGF-β/Smad pathway in fibroblast, and promote the expressions of TGF-β1, FN1 and VEGF. Remarkably, RUNX2 was stimulated in BMP2 pathway by the membrane to regulate osteoblast differentiation. In summary, the collagen-hyaluronate composite gradient membrane not only fulfills the prerequisites for use as a GTR material but also demonstrates substantial potential for practical applications in the field.

Human Ovarian Follicular Fluid Mesenchymal Stem Cells Express Osteogenic Markers When Cultured on Bioglass 58S-Coated Titanium Scaffolds

Recent studies have reported that stem cells (human follicular fluid mesenchymal stem cells or hFF-MSCs) are present in ovarian follicular fluid (hFF) and that they have a proliferative and differentiative potential which is similar to that of MSCs derived from other adult tissue. These mesenchymal stem cells, isolated from human follicular fluid waste matter discarded after retrieval of oocytes during the IVF process, constitute another, as yet unutilized, source of stem cell materials. There has been little work on the compatibility of these hFF-MSCs with scaffolds useful for bone tissue engineering applications and the aim of this study was to evaluate the osteogenic capacity of hFF-MSCs seeded on bioglass 58S-coated titanium and to provide an assessment of their suitability for bone tissue engineering purposes. Following a chemical and morphological characterization with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), cell viability, morphology and expression of specific osteogenic markers were examined after 7 and 21 days of culture. The hFF-MSCs seeded on bioglass and cultured with osteogenic factors, when compared with those seeded on tissue culture plate or on uncoated titanium, exhibited enhanced cell viability and osteogenic differentiation, as reflected by increased calcium deposition and increased ALP activity with expression and production of bone-related proteins. Taken together, these results demonstrate that MSCs from human follicular fluid waste materials can be easily cultured in titanium scaffolds coated with bioglass, having osteoinductive properties. This process has significant potential for regenerative medicine applications and indicates that hFF-MSCs may be a valid alternative to hBM-MSC cells in experimental models in bone tissue engineering.

Scaphoid Bone Nonunions: Clinical and Functional Outcomes of Collagen/PGA Scaffolds and Cell-Based Therapy

In this study, the procedure for treating the nonunion complication of scaphoid fractures using collagen/poly glycolic acid (CPGA) scaffolds with bone marrow mesenchymal stem cell (BM-MSC) therapy was adopted and compared with the commonly employed autologous bone tissue graft. With conducting a two-armed clinical trial, 10 patients with scaphoid nonunions were enrolled in this investigation. Patients were randomly assigned to two groups treated with (1) CPGA + cell therapy and (2) autologous iliac crest bone graft standard therapy. Treatment outcomes were evaluated three months after surgery, measuring the grip and pinch strengths and wrist range of motion, with two questionnaires: Patient-Rated Wrist Evaluation (PRWE) and Quick form of Disabilities of the Arm, Shoulder, and Hand (QDASH). We have also assessed the union rate using clinical and radiologic healing criteria one and three months post-operatively. Restorative effects of CPGA + cell therapy were similar to those of the autologous bone graft standard therapy, except for the grip strength (P = 0.048) and QDASH score (P = 0.044) changes, which were higher in the CPGA + cell therapy group. Three months following the surgery, radiographic images and computed tomography (CT) scans also demonstrated that the scaphoid union rate in the test group was comparable to that of scaphoids treated with the standard autograft method. Our findings demonstrate that the CPGA + cell therapy is a potential alternative for bone grafting in the treatment of bone nonunions.

Bioglass/collagen scaffolds combined with bone marrow stromal cells on bone healing in an experimental model in cranial defects in rats

This study aimed to develop bone regenerative therapeutic strategies, based on the addition of bone marrow stromal cells (BMSC) on bioglass/collagen (BG/COL) scaffolds. For this purpose, an in vivo study was conducted using tissue response of the BG/COL scaffolds combined with BMSC in a critical-size defects. Wistar rats were submitted to the surgical procedure to perform the cranial critical size bone defects and distributed in four groups (20 animals per group): Control Group (CG) (rats submitted to the cranial bone defect surgery without treatment), Bioglass Group (BG) (rats treated with BG), BG/COL Group (rats treated with BG/COL) and Bioglass/Collagen and BMSC Group (BG/COL/BMSC) (rats treated with BG/COL scaffolds enriched with BMSCs). Animals were euthanized 15 and 30 days after surgery. Scanning electron microscopy, histopathological and immunohistochemistry analysis were used. SEM analysis demonstrated that porous scaffolds were obtained, and Col fibers were successfully impregnated to BG matrices. The implantation of the BMSC on BG/COL based scaffolds was effective in stimulating newly bone formation and produced an increased immunoexpression of markers related to the bone repair. These results highlight the potential of BG/COL scaffolds and BMSCs to be used as a therapeutic approach for bone regeneration.