Bone Scaffolds: An Incorporation of Biomaterials, Cells, and Biofactors

Abstract

Large injuries to bones are still one of the most challenging musculoskeletal problems. Tissue engineering can combine stem cells, scaffold biomaterials, and biofactors to aid in resolving this complication. Therefore, this review aims to provide information on the recent advances made to utilize the potential of biomaterials for making bone scaffolds and the assisted stem cell therapy and use of biofactors for bone tissue engineering. The requirements and different types of biomaterials used for making scaffolds are reviewed. Furthermore, the importance of stem cells and biofactors (growth factors and extracellular vesicles) in bone regeneration and their use in bone scaffolds and the key findings are discussed. Lastly, some of the main obstacles in bone tissue engineering and future trends are highlighted.

Effects of Scaffold Shape on Bone Regeneration: Tiny Shape Differences Affect the Entire System

“…To improve the osteogenesis ability of scaffolds, previous studies mainly focused on the effects of raw material composition, substituted or doped ions, pore characteristics, and incorporation of growth factors, polysaccharides, stem cells, and extracellular vesicles. ,− However, the effects of scaffold shape on bone regeneration remained unclear. To date, the shape of granular scaffolds has not been considered; granular scaffolds are often manufactured by smashing the bulk material, producing irregular-shaped granules.…”

Novel Approaches and Biomaterials for Bone Tissue Engineering: A Focus on Silk Fibroin

“…Four types of living bone cells can be identified: osteoblasts, osteocytes, osteoclasts and bone-lining cells, which together constitute the basic multicellular unit [ 6 ]. Bone extracellular matrix (ECM), a noncellular three-dimensional (3D) structure secreted by cells and made of specific proteins and polysaccharides, represents a complex and dynamic biological environment responsible for the features of the mature bone and involved in many important processes such as the regulation of cell functions, growth factors response, production of new bone by osteoblasts and osteocytes and absorption of bone by osteoclasts [ 7 , 8 ]. An important component of the extracellular matrix (ECM) is represented by hyaluronic acid (HA), which is involved in several signaling pathways that can trigger cell behavior modulation and promote bone formation [ 5 ].…”

“…Globally, bone fractures caused by osteoporosis occur every 20 s in people aged over 50 years, with significant associated healthcare costs and long treatment practices [ 15 ]. Trauma and degenerative diseases such as osteoarthritis, along with tumors, congenital diseases and bone defects larger than the bone-healing capability represent serious issues in health care and a great challenge in modern medicine and reconstructive surgery [ 1 , 2 , 8 ].…”

“…According to their source, a general classification of bone substitutes includes autografts obtained from the patients themselves, xenografts derived from animal sources, and allografts obtained from donors of the same species [ 16 ]. The autologous bone grafts, which are characterized by intrinsic osteoconductive and osteoinductive features, are still considered as the gold standard [ 8 , 10 , 17 ], although some limitations are associated to limited availability sources and damages at donor sites such as morbidity, inflammation, increased risk of infections and even rejection [ 10 , 11 , 18 ]. Allograft collected from other humans, typically cadavers, can also be considered an alternative option, even if donor–recipient infection, disease transmission and host immune responses can represent a risk in this practice.…”

The healing of bone defects by cell-free and stem cell-seeded 3D-printed PLA tissue-engineered scaffolds

“…Although autologous or allogeneic bone transplantation is a common treatment for bone defects, these have some limitations, such as necrosis, infection, pain, and risk of morbidity; therefore, other alternative methods are needed [ 1 – 3 ]. Tissue engineering and regenerative medicine try to use a combination of bioactive materials, growth factors, and cell therapy to repair bone tissue [ 4 – 6 ]. Due to the osteogenic effect, treatment with cells, especially mesenchymal stem cells (MSCs) may be advantageous in treating critical bone defects caused by severe trauma, osteoporosis, aging, and metabolic diseases like diabetes.…”