Prospects for Using Biomaterials Based on Magnesium Phosphates for Bone Tissue Repair

The global increase in traumatic accidents and aging population has brought bone tissue injury and disease to the forefront of global health concerns. Traditional treatment methods face significant challenges, emphasizing the urgent need for advanced bone tissue repair techniques. The bioelectric phenomenon in natural bones is essential for bone development and fracture healing. Therefore, developing innovative repair strategies that replicate or enhance this electric field is expected to promote bone tissue repair and integration. Developing new electroactive tissue engineering scaffolds based on electromechanical interactions between cells and the extracellular matrix is essential. This article introduces a piezoelectric scaffold, initially fabricated using melt electro-writing, and then coated with a surface piezoelectric coating using electrospraying (ES) technology. The scaffold exhibits suitable stiffness similar to the extracellular matrix, and the piezoelectric coating can provide necessary electrical stimulation under cell traction. Furthermore, ultrasound technology was utilized to effectively replicate the electrical microenvironment of natural bone repair. The synergy of cell traction-induced electrical stimulation and ultrasound-enhanced scaffold piezoelectricity can substantially enhance bone tissue regeneration and repair. This study introduces a novel method for developing electroactive tissue engineering scaffolds, providing a promising solution for non-load-bearing areas’ bone defects via electrical stimulation.Graphical Supplementary InformationThe online version contains supplementary material available at 10.1186/s12951-025-03913-x.

Aptamers represent a distinct category of short nucleotide sequences or peptide molecules characterized by their ability to bind to specific targets with high precision. These molecules are predominantly synthesized through SELEX (Systematic Evolution of Ligands by Exponential Enrichment) technology. Recent findings indicate that aptamers may have significant applications in regenerative medicine, particularly in the domain of tissue repair. In comparison to other bioactive agents, aptamers exhibit superior specificity and affinity, are more readily accessible, and can be chemically modified, thereby presenting a promising avenue for the functionalization of tissue engineering materials in tissue repair applications. This review delineates the properties of aptamers and examines the methodologies and advancements related to aptamer-functionalized hydrogels, nanoparticles, and electrospun materials. It categorizes the four primary functions of aptamers in tissue repair, namely regeneration, delivery systems, anti-inflammatory actions, and pro-coagulation effects. Furthermore, the review explores the utilization of aptamer-functionalized tissue engineering materials in the repair of bone, nerve, and vascular tissues, highlighting the mechanisms by which aptamers facilitate tissue growth and repair through regenerative properties and their role in transporting substances that promote repair. Lastly, the review addresses the future prospects and challenges associated with the application of aptamers in tissue repair, offering novel insights and directions for further research and application in this domain.

The regeneration and repair of bone tissue is a multiphase process that requires a lot of attention, especially if stimulated through scaffold implantation. This review analyzes the process from both a biological and mechanical point of view through the analysis of the porosity and characteristics of the biomaterials that can provide optimal regeneration of bone tissue and functional vascularization that prevents implant failure. Particular attention is paid to the porosity of the new biomaterials and the related physiological effects and the angiogenesis process that the biomaterials themselves can stimulate, analyzing some of the works present in the literature.

Head and neck radiotherapy causes quantitative and qualitative changes in saliva. The objective of this case-control study was to evaluate the salivary biomarkers associated with bone remodeling and tissue repair in patients submitted to radiotherapy for head and neck cancer treatment, compared with non-irradiated individuals. Total unstimulated saliva was collected for ELISA assay analysis of receptor activator for nuclear factor κ B (RANK) and its ligand (RANK-L), osteoprotegerin, matrix metalloproteinase-9/ tissue inhibitor of metalloproteinase-2, vascular endothelial growth factor, and epidermal growth factor. Statistics were performed, and revealed that salivary RANK (p = 0.0304), RANK-L (p = 0.0005), matrix metalloproteinase-9/ tissue inhibitor of metalloproteinase-2 (p = 0.0067), vascular endothelial growth factor (p = 0.0060), and epidermal growth factor (p < 0.0001) were reduced in patients, compared with the control group. Osteoprotegerin did not differ between the groups (p = 0.3765). Salivary biomarkers did not differ according to radiotherapy completion time (p > 0.05). In conclusion, the lower output of the salivary molecules - essential for bone remodeling and tissue repair - may disrupt tissue homeostasis and play a role in the pathogenesis of the radiotherapy-induced deleterious effects in the oral cavity.

Microwave assisted black phosphorus-based core-shell composites with synergistic antibacterial and osteogenic ability for bone tissue repair

Nitric oxide (NO) is endogenously produced free radical that plays important biological roles, such as, the promotion of vasodilation, angiogenesis, tissue repair, wound healing process, antioxidant, antitumoral and antimicrobial actions. Although the regenerative effects of NO in soft tissues have been extensively reported, its role in bone tissue repair has not been completely addressed. Both constitutive and inducible forms of NO synthase (NOS) are expressed in bone-derived cells, and some important cytokines, such as IL-1 and TNF, are potent stimulators of NO production. The effects of NO on bone tissue are dependent on its concentration. NO has dichotomous biological effects, at low concentrations (pico-nano molar range), NO may promote proliferation, differentiation and survival of osteoblasts, whereas at high concentrations (micromolar range) NO may inhibit bone resorption and formation. Therefore, at a certain concentration range, NO can avoid osteoclast-mediated bone resorption and promote osteoblast growth. Due to the potential beneficial effects of NO in bone tissue regeneration, the exogenous administration of NO might find important biomedical applications. As NO is a free radical and a gas, the administration of NO donors/generators has been explored in tissue repair. The delivery of NO to the bone using macromolecular NO releasing scaffolds has been shown to increase osteogenesis with a relevant impact in dental and orthopedist areas. In this sense, this review presents and discusses the recent and important progresses in the effects of NO/NO donors in bone tissue, and highlights the promising approach in the design and use of NO donors allied to biomaterials in the sustained and localized NO release for bone tissue regeneration.

Exosomes are extracellular vesicles secreted by various cell types, which play important roles in physiological processes. In particular, stem cell-derived exosomes have been shown to play crucial functions in intercellular communication during the tissue healing process. This review summarizes the effects of exosomes derived from different stem cell sources on the repair of cutaneous and bone tissue, focusing on the different pathways that could be involved in the regeneration process. The biogenesis, isolation, and content of exosomes have also been discussed. The effectiveness of exosomes is broadly demonstrated for skin and bone regeneration in animal models, supporting the basis for clinical translation of exosomes as a ready-to-use cell-free therapeutic for skin and bone regeneration.

Biomaterials for Regenerative Medicine

Hydrogel-based immunoregulation of macrophages for tissue repair and regeneration

Tissue engineering is a promising and revolutionary strategy to treat patients who suffer the loss or failure of an organ or tissue, with the aim to restore the dysfunctional tissues and enhance life expectancy. Supramolecular adhesive hydrogels are emerging as appealing materials for tissue engineering applications owing to their favorable attributes such as tailorable structure, inherent flexibility, excellent biocompatibility, near-physiological environment, dynamic mechanical strength, and particularly attractive self-adhesiveness. In this review, the key design principles and various supramolecular strategies to construct adhesive hydrogels are comprehensively summarized. Thereafter, the recent research progress regarding their tissue engineering applications, including primarily dermal tissue repair, muscle tissue repair, bone tissue repair, neural tissue repair, vascular tissue repair, oral tissue repair, corneal tissue repair, cardiac tissue repair, fetal membrane repair, hepatic tissue repair, and gastric tissue repair, is systematically highlighted. Finally, the scientific challenges and the remaining opportunities are underlined to show a full picture of the supramolecular adhesive hydrogels. This review is expected to offer comparative views and critical insights to inspire more advanced studies on supramolecular adhesive hydrogels and pave the way for different fields even beyond tissue engineering applications.

Periprosthetic fractures in the area of the femoral component after hip replacement are one of the reasons for performing revision surgery. The treatment is always associated with many complications and therefore does not lose its relevance. The aim of our research was a pathomorphological study of bone tissue repair and reactive changes in the soft tissues around the periprosthetic fracture after arthroplasty. The research results will predict the long-term outcome and stability of the revision endoprosthesis.&#x0D; Materials and methods. The materials for pathomorphological studies were biopsy, (11 periprosthetic fractures in the zone of the femoral component, 5 from the hip joint), fragments of bone tissue from the zone of the periprosthetic fracture, femoral canal, altered connective tissue obtained by repeated interventions in the area of periprosthetic fracture, and revision endoprosthetics. Pathomorphological studies of biopsy specimens of bone fragments and soft tissues were carried out after conventional histological processing with the production of histological sections, 57 m thick, followed by staining with hematoxylin and eosin and according to Van Gieson.&#x0D; Results. Morphological signs of structural disorganization of bone tissue in the fracture zone were revealed after fragments of bone and soft tissues were removed from the fracture zone; various options for repair of bone tissue were investigated, as well as reactive changes up to ischemia from the surrounding soft tissues were observed. Signs of damage to the tubules, lacunae and trabeculae, and with them the intraosseous branches of the supplying artery were noticed. Bone tissue repair in the area of periprosthetic fractures was carried out in various ways: due to activation of osteoblasts, through endesmal osteogenesis (from preexisting fibrous structures), endochondral osteogenesis (from provisional corns), as well as mixed osteogenesis from complexes of bonecartilaginous tissue. Slowing of osteogenesis was the reason for the formation of appositional gluing lines in bone trabeculae, which are considered as a morphological sign of delayed osteogenesis. The absence of multinucleated osteoclasts in the bone tissues we studied is apparently due to the fact that pathological osteolysis with signs of ischemia does not develop in the fracture zone.&#x0D; Conclusion. The results of our histopathological studies indicate that by the time of revision endoprosthetics in the area of femoral fractures, morphological signs of a slowdown in reparative osteogenesis develop with the pathological functional remodeling of bone tissue and microischemia in the bone and, of course, in the surrounding soft tissues.

Quantification of the OCT signal is an important step toward clinical implementation of a diagnostic tool in cartilage imaging. Discrimination of structural cartilage differences in patients with osteoarthritis is critical, yet challenging. This study assesses the variation in the optical attenuation coefficient ( $\mu_{{\rm OCT}}$ ) between healthy cartilage, repair tissue, bone, and layers within repair tissue in a controlled setting. OCT and histology were used to assess goat talus articular surfaces in which central osteochondral defects were created. Exact matches of OCT and histology were selected for research. $\mu_{{\rm OCT}}$ measurements were taken from healthy cartilage, repair tissue, and bone. Measured $\mu_{{\rm OCT}}$ in healthy cartilage was higher compared to both repair tissue and bone tissue. Two possible mechanisms for the difference in attenuation were investigated. We studied morphological parameters in terms of nucleus count, nucleus size, and inter-nucleus distance. Collagen content in healthy cartilage and repair tissue was assessed using polarization microscopy. Quantitative analysis of the nuclei did not demonstrate a difference in nucleus size and nucleus count between healthy cartilage and repair tissue. In healthy cartilage, cells were spaced farther apart and had a lower variation in local nuclear density compared to the repair tissue. Polarization microscopy suggested higher collagen content in the healthy cartilage compared to the repair tissue. $\mu_{{\rm OCT}}$ measurements can distinguish between healthy cartilage, repair tissue, and bone. Results suggest that cartilage OCT attenuation measurements could be of great impact in clinical diagnostics of osteoarthritis.

Quantification of the OCT signal is an important step toward clinical implementation of a diagnostic tool in cartilage imaging. Discrimination of structural cartilage differences in patients with osteoarthritis is critical, yet challenging. This study assesses the variation in the optical attenuation coefficient (μOCT) between healthy cartilage, repair tissue, bone and layers within repair tissue in a controlled setting. OCT and histology was used to assess goat talus articular surfaces in which central osteochondral defects were created. Exact matches of OCT and histology were selected for research. μOCT measurements were taken from healthy cartilage, repair tissue and bone. Measured μOCT in healthy cartilage was higher compared to both repair tissue and bone tissue. Two possible mechanisms for the difference in attenuation were investigated. We studied morphological parameters in terms of nucleus count, nucleus size and inter-nucleus distance. Collagen content in healthy cartilage and repair tissue was assessed using polarization microscopy. Quantitative analysis of the nuclei did not demonstrate a difference in nucleus size and count between healthy cartilage and repair tissue. In healthy cartilage, cells were spaced farther apart and had a lower variation in local nuclear density compared to repair tissue. Polarization microscopy suggested higher collagen content in healthy cartilage compared to repair tissue. μOCT measurements can distinguish between healthy cartilage, repair tissue and bone. Results suggest that cartilage OCT attenuation measurements could be of great impact in clinical diagnostics of osteoarthritis.

Objective To observe the therapeutic effect of treating femoral neck fracture after improved the fixation methods. Methods The bilateral femoral neck fractures model of 18 goats were resulted by operation. The experimental side was fixed using a modified method, and the control side was fixed using the traditional internal fixation techniques. The three-phase radionuclide bone imaging examination was performed 5 times in the pre- and 4,6,8,12 weeks after operation. The femoral head and neck of the goats which were killed in the 4,8,12 weeks after operation were observated by histology. And the treatment effect of femoral neck fractures with modified fixation was evaluated through X-ray examination. Results(1) Blood flow and pool curve showed the blood flow in the artery and the vein of the experimental side was better than that of the control side. Radionuclide bone imaging appear the femoral head blood flow and me-tabolization rate of the experimental side was higher than that of the control side. In the 4th,6thweek after the operation,the bone tissue repaired process was quickly in the experimental side. (2) Histology observation results show that the vascular remodeling and woven bone formation in the experiment side was more rapid than thatof the control side. The clearance of necrosis bone chips in the experiment sidewas accelerated. Conclusion The modified fixation method which in the basis of increasing the stability reduced the intramedullary pressure of femoral neck and protected the residual blood supply, which was conducive to fracture healing, the early reconstruction of femoral head blood supply and promoting bone tissue repair. Key words: Femoral neck fracture; Healing; Femoral head necrosis; Internal fixation; Improvement

SALIVARY BIOMARKERS IN PATIENTS RECEIVING RADIOTHERAPY IN THE HEAD AND NECK REGION