Bone Tissue Formation Research Articles

Formation of bone tissue apatite on starch-based nanofiber-capped nanohydroxyapatite and reduced graphene oxide: a preliminary study.

In the present study, blends of polyvinyl alcohol (PVA), starch (SH), nanohydroxyapatite (Nano-HA), and reduced graphene oxide (r-GO) were used to fabricate an electrospun nano scaffold (ENS), via electrospinning for their potential application in oral and maxillofacial bone soft and hard tissue regeneration. The scaffold was characterized for its physicochemical and mechanical properties. An invitro study was carried out using human osteoblast MG-63 bone cells. Surface characterization, particularly the analysis of calcium content, was performed before and after immersion in the simulated body fluid (SBF). Additionally, the impact of surface treatment on antimicrobial activity was investigated. The results demonstrated that the tensile strength (18.12 ± 0.14MPa), elongation at break (19.23 ± 0.11%), and flexing index (20.15 ± 0.13%) of the ENS were outstanding, indicating promising performance. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assays demonstrated the biocompatible nature of the ENS. The bioactivity test result of ENS showed excellent deposition of bone apatite crystals. The ENS exhibited antimicrobial properties against E. coli (3.41 ± 0.03mm) and S. aureus (3.12 ± 0.08mm). The ENS, possessing the desired properties, has the potential to be tested in large animals for oral and maxillofacial bone and soft tissue regeneration after obtaining the necessary approvals. The developed ENS offers a promising solution for bone tissue regeneration in the oral and maxillofacial region.

Incorporation of Cerium Oxide Nanoparticles into the Micro-arc Oxidation Layer Promotes Bone Formation and Achieves Structural Integrity in Magnesium Orthopedic Implants

Biodegradable metals offer significant advantages by reducing the need for additional surgeries following bone fixation. These materials, with their optimal mechanical and degradable properties, also mitigate stress-shielding effects while promoting biological processes essential for healing. This study investigated the in vitro and in vivo biocompatibility of ZK60 magnesium alloy coated with a micro-arc oxidative layer incorporated with cerium oxide nanoparticles in orthopedic implants. The results demonstrated that the magnesium substrate undergoes gradual degradation, effectively eliminating long-term inflammation during bone formation. The micro-arc oxidative coating forms a dense ceramic layer, acting as a protective barrier that reduces corrosion rates and enhances the biocompatibility of the magnesium substrate. The incorporation of cerium oxide nanoparticles improves the tribological properties of the coating, refining degradation patterns and improving osteogenic characteristics. Furthermore, cerium oxide nanoparticles enhance bone reconstruction by facilitating appropriate interconnections between newly formed bone and native bone tissue. Consequently, cerium oxide nanoparticles contribute to favorable biosafety outcomes and exceptional bone remodeling capabilities by supporting bone healing and sustaining a prolonged degradation process, ultimately achieving dynamic equilibrium in bone tissue formation. Statement of SignificanceThis study comprehensively examined the incorporation of ceria nanoparticles into biodegradable magnesium through a micro-arc oxidative process for use in orthopedic implants. This study conducted a comprehensive analysis involving material characterization, biodegradability testing, in vitro osteogenesis assays, and in vivo implantation, highlighting the potential benefits of the distinctive properties of ceria nanoparticles. This research emphasizes the ability of ceria nanoparticles to enhance the biodegradability of magnesium and facilitate remarkable bone regeneration, suggesting promising advantages for additive materials in orthopedic implants.

Highly porous sildenafil loaded polylactic acid/polyvinylpyrrolidone based 3D printed scaffold containing forsterite nanoparticles for craniofacial reconstruction

Tissue engineering has emerged as a promising substitute for traditional tissue repair methods. Nowadays, advancements in 3D printing technology have enabled the fabrication of customized scaffolds to support tissue regeneration. In the present study, a polylactic acid-polyvinylpyrrolidone 3D-printed scaffold containing 10 % forsterite was fabricated. Subsequently, lyophilized fucoidan microstructures loaded with sildenafil were filled the channels of this 3D-printed scaffold. The fabricated scaffold loaded with sildenafil was thoroughly characterized, revealing that 97.46 % of the loaded sildenafil was released in a sustained manner over 28 days. Furthermore, the biocompatibility of MG63 was evaluated through cell viability and adhesion tests. The findings indicated a direct and favorable influence on cell behavior. Based on the chicken chorioallantoic membrane assay, the fabricated scaffold significantly increases angiogenesis due to the sustained release of sildenafil. Moreover, in-vivo studies conducted on a rat model demonstrated that the 3D-printed scaffold was able to stimulate and accelerate the repair of calvarial defects within 8 weeks, and the amount of new bone tissue formation was significantly higher than that of other experimental groups. Based on the comprehensive in-vitro and in-vivo assessments, the scaffold with a macro- and microporous structure combined with the ability to release sildenafil is suggested as a potential candidate for repairing bone tissue, especially in the context of skull defects.

Stem cell-homing biomimetic hydrogel promotes the repair of osteoporotic bone defects through osteogenic and angiogenic coupling.

Osteoporotic bone defects refer to the disruption of bone structural integrity in patients with osteoporosis and pose a substantial challenge to orthopedic surgeons. In this study, we developed a biomimetic hydrogel to improve the osteogenic microenvironment and promote stem cell homing. This hydrogel served as a container for S-nitrosoglutathione and Ca2+, promoting the release of bioactive nitric oxide (NO) from bone marrow mesenchymal stem cells (BMSCs) and human vascular endothelial cells and activating the NO/cyclic guanosine monophosphate signaling pathway. These changes promote osteogenic and angiogenic couplings. The hydrogel simultaneously recruited BMSCs by conjugating the stem cell homing peptide SKPPGTSS. Using a rat distal femoral defect model, it was demonstrated that this hydrogel can effectively increase the formation of bone tissue and new blood vessels and has immune-regulating functions. We envision that this hydrogel may be a minimally invasive yet highly effective strategy for expediting the healing of osteoporotic bone defects.

Mechanical Properties of 3D Printed PLA Scaffolds for Bone Regeneration

Abstract The growing interest in biodegradable scaffolds for bone regeneration created a need to investigate new materials suitable for scaffold formation. Poly(lactic acid) (PLA) is a polymer commonly used in biomedical engineering, e.g. in tissue engineering as a biodegradable material. However, the mechanical behavior of PLA along its degradation time is still not explored well. For this reason, the mechanical properties of PLA scaffolds affected by incubation in physiological medium needs to be investigated to show the potential of PLA to be used as a material for biodegradable scaffold formation. The purpose of this research is to determine the mechanical properties of PLA scaffolds before and after incubation, and to apply constitutive material models for further behavior prediction. Two sets of PLA scaffolds were printed by the 3D printer “Prusa i3 MK3S” and sterilized by ultraviolet light and ethanol solution. The first set of specimens was incubated in DMEM (Dulbecco’s Modified Eagle Medium) for 60, 120, and 180 days maintaining 36.5 °C temperature. The mechanical properties of the scaffolds were determined after performing the compression test in the “Mecmesin MultiTest 2.5-i” testing stand with a force applied at two different speed modes. The obtained data was curve fitted with the hyperelastic material models for a model suitability study. The second set of specimens was incubated in PBS (Phosphate Buffered Saline) for 20 weeks and used in a polymer degradation study. The obtained results show that the mechanical properties of PLA scaffolds do not decrease during incubation in physiological medium for a predicted new bone tissue formation period, though hydrolysis starts at the very beginning and increases with time. PLA as a material seems to be suitable for the use in bone tissue engineering as it allows to form biocompatible and biodegradable scaffolds with high mechanical strength, required for effective tissue formation.

Regulation of Osteogenic Differentiation of hBMSCs by the Overlay Angles of Bone Lamellae-like Matrices.

Oriented fibers in bone lamellae are recognized for their contribution to the anisotropic mechanical performance of the cortical bone. While increasing evidence highlights that such oriented fibers also exhibit osteogenic induction to preosteoblasts, little is known about the effect of the overlay angle between lamellae on the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). In this study, bone lamellae-like fibrous matrices composed of aligned core-shell [core: polycaprolactone (PCL)/type I collagen (Col I) + shell: Col I] nanofibers were seeded with human BMSCs (hBMSCs) and then laid over on each other layer-by-layer (L-b-L) at selected angles (0 or 45°) to form three-dimensional (3D) constructs. Upon culture for 7 and 14 days, osteogenic differentiation of hBMSCs and mineralization within the lamellae assembly (LA) were characterized by real-time PCR, Western blot, immunofluorescent staining for osteogenic markers, and alizarin red staining for calcium deposition. Compared to those of random nanofibers (LA-RF) or aligned fibers with the overlay angle of 45° (LA-AF-45), the LA of aligned fibers at a 0° overlay angle (LA-AF-0) exhibited a noticeably higher osteogenic differentiation of hBMSCs, i.e., elevated gene expression of OPN, OCN, and RUNX2 and protein levels of ALP and RUNX2, while promoting mineral deposition as indicated by alizarin red staining and mechanical testing. Further analyses of hBMSCs within LA-AF-0 revealed an increase in both total and phosphorylated integrin β1, which subsequently increased total focal adhesion kinase (FAK), phosphorylated FAK (p-FAK), and phosphorylated extracellular signal kinase ERK1/2 (p-ERK1/2). Inhibition of integrin β1 and ERK1/2 activity effectively reduced the LA-AF-0-induced upregulation of p-FAK and osteogenic markers (OPN, OCN, and RUNX2), confirming the involvement of integrin β1-FAK-ERK1/2 signaling. Altogether, the overlay angle of aligned core-shell nanofiber membranes regulates the osteogenic differentiation of hBMSCs via integrin β1-FAK-ERK1/2 signaling, unveiling the effects of anisotropic fibers on bone tissue formation.

Mechanisms and significance of spontaneous platelet aggregation in pathology

Platelets are unique blood elements that, in addition to blood coagulation, modulate the processes of fibrinolysis, inflammation, physiological regeneration, repair, angiogenesis, bone tissue formation, formation of the mother-placenta-fetus system, etc. Of particular interest is the phenomenon of spontaneous platelet aggregation in vivo under various physiological and pathological conditions, which is associated with expanded capabilities for assessing the risks of thrombotic events. A separate aspect of this problem is associated with the study of the mechanisms and biological role of reversible platelet aggregation. To date, the significance of this phenomenon under normal and pathological conditions remains not entirely clear. This review is devoted to the phenomenon of spontaneous reversible platelet aggregation, the modern understanding of its mechanisms, approaches to its diagnosis and its association with various pathological conditions.

BIOCHEMICAL PARAMETERS OF THE BLOOD OF RATS OF DIFFERENT AGES AFTER FILLING THE METAPHYSEAL DEFECT OF THE FEMUR WITH ALLOGENEIC BONE IMPLANTS WITH LOCAL ADMINISTRATION OF BLOOD PLASMA ENRICHED WITH PLATELETS

A promising method of regenerative medicine is the saturation of allografts with platelet-rich plasma (PRP). Objective. To evaluate the course of metabolic processes after filling a hole defect in the distal metaphysis of the femur with allogeneic bone implants in conditions of additional local administration of allogeneic PRP. Methods. In the model of a hole defect in white rats with the filling of the defect with an allograft, as well as with additional local stimulation of PRP on the 7th day; on the 3rd and 7th days and on the 1st, 3rd and 7th days in blood serum, the content of glycoproteins (GP), chondroitin sulfates (CST), total protein (TP), calcium (Ca), activity alkaline phosphatase (AlP) and acid phosphatase (AcP). The results. 14 day. In the 3-month rats, under one stimulation, an increase in TP and Ca, a decrease in AcP was observed, with two stimulations there was a 1.11 times smaller GP, 1.13 times larger TP and 1.43 times Ca compared to those in rats without stimulation. During three stimulations, the GP was 1.24 times lower than that in animals without stimulation. In the 12-month rats in comparison with the data of rats without stimulation, 1.15 times higher GP, Ca, AlP activity, and 1.44 times more AcP were noted. 28 days of the 3-month rats for one injection exceeded the data of animals without stimulation by 1.34 times for GP, and were inferior to them by 1.31 times for AcP. In the 12-month rats, compared to these animals without stimulation, with three injections, a 1.19 times greater TP was noted. 90 d. In the 3-month rats for one injection showed 1.24 times less CST with 1.28 times lower AlP compared to data from rats without stimulation. 12-month rats exceeded the data of the group without stimulation by 1.43 times for AlP. Conclusions. In rats with an alloimplant (especially at 12 months), an increase in connective tissue formation markers and a decrease in LF activity were observed. Filling the defect with an alloimplant led to an increase in inflammation indicators and an increase in markers of bone tissue formation.

Comparative histomorphological assessment of the osteoinductive capacity of a nanofibrillated cellulose-based composite and autologous blood clot.

The present study aimed to evaluate and compare the effect of nanofibrillated cellulose (NFC)-based composite with dicalcium phosphate dihydrate and an autologous blood clot (ABC) on the formation of new bone tissue in vivo by histological and histomorphometric assessment. A total of 72 rats with created femoral defects (2 mm) were used. The rats were divided into three groups: (1) with filling of the defect with an ABC, (2) NFC-1-with filling of both the cortical plate and intramedullary space in the defect area, and (3) NFC-2-with filling of only the intramedullary space in the defect area. Histological and histomorphometric analysis was performed to assess the healing of the bone defect after 14, 30 and 60 days. Complete closure of the cortical plate defect was detected in the NFC-2 group on Day 30 (p < 0.0001). Moreover, in both NFC groups on the 30th and 60th days, ongoing osteogenesis was observed, characterized by a large volume of newly formed circular pattern bone tissue in the intramedullary space. This study demonstrated that the NFC-based composite, which is located below the level of the cortical plate, tamponing only the intramedullary space (NFC-2), improves bone tissue repair at the site of a bone defect of the cortical plate and has the potential of prolonged osteoinductivity. Not applicable.

Multilayer Gelatin-Supported BMP-9 Coating Promotes Osteointegration and Neo-Bone Formation at the n-CDHA/PAA Composite Biomaterial-Bone Interface.

The development of biomaterials capable of accelerating bone wound repair is a critical focus in bone tissue engineering. This study aims to evaluate the osteointegration and bone regeneration potential of a novel multilayer gelatin-supported Bone Morphogenetic Protein 9 (BMP-9) coated nano-calcium-deficient hydroxyapatite/poly-amino acid (n-CDHA/PAA) composite biomaterials, focusing on the material-bone interface, and putting forward a new direction for the research on the interface between the coating material and bone. The BMP-9 recombinant adenovirus (Adenovirus (Ad)-BMP-9/Bone Marrow Mesenchymal Stem Cells (BMSc)) was produced by transfecting BMSc and supported using gelatin (Ad-BMP-9/BMSc/Gelatin (GT). Multilayer Ad-BMP-9/BMSc/GT coated nano-calcium deficient hydroxyapatite/polyamino acid (n-CDHA/PAA) composite biomaterials were then prepared and co-cultured with MG63 cells for 10 days, with biocompatibility assessed through microscopy, Cell Counting Kit-8 (CCK-8), and alkaline phosphatase (ALP) assays. Subsequently, multilayer Ad-BMP-9/BMSc/GT coated n-CDHA/PAA composite biomaterial screws were fabricated, and the adhesion of the coating to the substrate was observed using scanning electron microscopy (SEM). In vivo studies were conducted using a New Zealand White rabbit intercondylar femoral fracture model. The experimental group was fixed with screws featuring multilayer Ad-BMP-9/BMSc/GT coatings, while the control groups used medical metal screws and n-CDHA/PAA composite biomaterial screws. Fracture healing was monitored at 1, 4, 12, and 24 weeks, respectively, using X-ray observation, Micro-CT imaging, and SEM. Integration at the material-bone interface and the condition of neo-tissue were assessed through these imaging techniques. The Ad-BMP-9/GT coating significantly enhanced MG63 cell adhesion, proliferation, and differentiation, while increasing BMP-9 expression in vitro. In vivo studies using a rabbit femoral fracture model confirmed the biocompatibility and osteointegration potential of the multilayer Ad-BMP-9/BMSc/GT coated n-CDHA/PAA composite biomaterial screws. Compared to control groups (medical metal screws and n-CDHA/PAA composite biomaterial screws), this material demonstrated faster fracture healing, stronger osteointegration, and facilitated new bone tissue formation with increased calcium deposition at the material-bone interface. The multilayer GT-supported BMP-9 coated n-CDHA/PAA composite biomaterials have demonstrated favorable osteogenic cell interface performance, both in vitro and in vivo. This study provides a foundation for developing innovative bone repair materials, holding promise for significant advancements in clinical applications.

The Effect of Vitamins and Minerals on Dental Implants: A Review

Aims: The focus of this review study was to examine and analyze the impact of vitamins and minerals on dental implants. Methods and Material: In order to obtain information on the effects of vitamins and minerals on dental implants, a group of existing articles was thoroughly examined for their findings. This examination process involved the selection of specific articles that met the necessary criteria to be included in the analysis, which were then subjected to an extensive review process. The duration of this review process was over a time span of 11 years, starting from the year 2011 and concluding in the year 2022. Results: A total of 23 articles were included in the study, consisting of 9 clinical studies, 6 animal studies, 1 laboratory study, and 7 reviews. Clinical studies were limited due to uncertain results regarding the impact of vitamins and minerals on DIT, with most focusing on vitamin D levels rather than other nutrients. Conclusions: It has been concluded that vitamins and minerals play an important role in forming bone tissue. The lack of these essential elements may result in several diseases, such as diabetes mellitus and osteoporosis. It is therefore recommended to increase the levels of vitamins and minerals in patients before undergoing dental implant treatment (DIT), even though the quality of the patient's bone can also impact the success of the implant. Consequently, the patient's diet should be modified, and essential supplements and vitamins should be administered to ensure optimal implant success.

Three-dimensional printed calcium phosphate scaffolds emulate bone microstructure to promote bone regrowth and repair

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.Graphical

Evaluation of the effect of osteosynthesis wires on the structural reorganization of metaepiphyseal cartilage (an experimental and morphological study)

Introduction Premature arrest of bone growth is the most common complication of bone fractures at the growth plate level.The purpose of the work was to evaluate the structural reorganization of metaepiphyseal cartilage following its direct injury with metal and biodegradable wires in an experiment.Materials and methods The metaepiphyseal cartilage of the distal femur of 18 lambs of both sexes was studied. The age of the animals at the beginning of the study was (43.92 ± 0.8) days, by 60 and 120 days (102.63 ± 0.82) and (161.1 ± 0.9) days, respectively. The animals underwent transphyseal insertion of wires/ pins: series 1 — Kirschner wires, series 2 — titanium wires, series 3 — poly-L-lactic acid pins. The duration of the experiment was 60 and 120 days. Clinical and radiographic studies were carried out. Histomorphometry was performed using an AxioScope.A1 microscope and Zenblue software (CarlZeissMicroImagingGmbH, Germany).Results Reactive changes in the growth plate at the interface with the wire were manifested by proliferation of chondrocytes in the zone of proliferating cartilage and in the reserve zone; the minimally expressed changes were noted in series 2, the most pronounced were in series 1. By the end of the experiment, at the interface with the wire in series 1, blood vessels penetrated into the metaepiphyseal cartilage; in series 3 the amount of the fibrous component was increased, which indicates further formation of “bone bridges” and “fibrous bridges,” respectively. In undamaged areas of the growth plate in all series, the zonal structure was preserved. By the end of the experiment, increased values of the thickness of the metaepiphyseal cartilage were noted (1.2 times higher than the control), differences between series were a tendency; in series 2 and 3 the ratio of metaepiphyseal cartilage zones was comparable to the control; in series 1 the proportion of the proliferating cartilage zone was increased by 4 %.Discussion The main problem with growth plate injuries is the formation of bone tissue or fibrosis, which affects the growing process. Currently, the question of choosing a treatment tactic for growth plate injury depending on the size of the “bone bridges” is debatable. Relevant are future comparative studies of the regeneration of metaepiphyseal cartilage defects after the use of fixators made from different materials.Conclusion Histomorphometric characteristics of the growth zone reliably showed that the insertion of wires, regardless of their material, was not accompanied by inhibition of the bone-forming function of the distal metaepiphyseal cartilage of the femur.

Effect of Scaffold Geometrical Structure on Macrophage Polarization during Bone Regeneration Using Honeycomb Tricalcium Phosphate.

The polarization balance of M1/M2 macrophages with different functions is important in osteogenesis and bone repair processes. In a previous study, we succeeded in developing honeycomb tricalcium phosphate (TCP), which is a cylindrical scaffold with a honeycomb arrangement of straight pores, and we demonstrated that TCP with 300 and 500 μm pore diameters (300TCP and 500TCP) induced bone formation within the pores. However, the details of the influence of macrophage polarization on bone formation using engineered biomaterials, especially with respect to the geometric structure of the artificial biomaterials, are unknown. In this study, we examined whether differences in bone tissue formation due to differences in TCP geometry were due to the polarity of the assembling macrophages. Immunohistochemistry for IBA-1, iNOS, and CD163 single staining was performed. The 300TCP showed a marked infiltration of iNOS-positive cells, which are thought to be M1 macrophages, during the osteogenesis process, while no involvement of CD163-positive cells, which are thought to be M2 macrophages, was observed in the TCP pores. In addition, 500TCP showed a clustering of iNOS-positive cells and CD163-positive cells at 2 weeks, suggesting the involvement of M2 macrophages in the formation of bone tissue in the TCP pores. In conclusion, we demonstrated for the first time that the geometrical structure of the artificial biomaterial, i.e., the pore size of honeycomb TCP, affects the polarization of M1/2 macrophages and bone tissue formation in TCP pores.

Tissue scaffolds mimicking hierarchical bone morphology as biomaterials for oral maxillofacial surgery with augmentation: structure, properties, and performance evaluation for in vitro testing

In this study, tissue scaffolds mimicking hierarchical morphology are constructed and proposed for bone augmentation. The scaffolds are fabricated using lyophilization, before coating them with collagen (Col). Subsequently, the Col-coated scaffolds undergo a second lyophilization, followed by silk fibroin (SF) coating, and a third lyophilization. Thereafter, the scaffolds are divided into six groups with varying ratios of Col to SF: Col/SF = 7:3, 5:5, 3:7, 10:0, and 0:10, with an SF scaffold serving as the control group. The scaffold morphology is examined using a scanning electron microscope, while molecular and structural formations are characterized by Fourier transform infrared spectrometer and differential scanning calorimeter, respectively. Physical and mechanical properties including swelling and compression are tested. Biological functions are assessed throughin vitroosteoblast cell culturing. Biomarkers indicative of bone formation-cell viability and proliferation, alkaline phosphatase activity, and calcium content-are analyzed. Results demonstrate that scaffolds coated with Col and SF exhibit sub-porous formations within the main pore. The molecular formation reveals interactions between the hydrophilic groups of Col and SF. The scaffold structure contains bound water and SF formation gets disrupted by Col. Physical and mechanical properties are influenced by the Col/SF ratio and morphology due to coating. The biological functions of scaffolds with Col and SF coating show enhanced potential for promoting bone tissue formation, particularly the Col/SF (7:3) ratio, which is most suitable for bone augmentation in small defect areas.

Production of platelet-rich plasma (PRP)-enriched scaffolds for bone tissue regeneration with 3D printing technology

Bone disorders signify diverse abnormalities in the structure, development, and functions of bone tissue in the human body, with a significant correlation to ageing, insufficient physical activity, and escalating obesity. Recent advancements in bone tissue engineering aim to enhance bone tissue formation through the use of biomaterials, growth factors, and cells. The present study focuses on the fabrication and characterisation of scaffolds with a composition of gelatin (GEL) / sodium alginate (SA) / hydroxyapatite (HA) / platelet-rich plasma (PRP) using the 3D printing process. The inclusion of PRP, derived from blood, is of particular interest due to its potential to enhance bone regeneration through various growth factors. Scanning electron microscope (SEM) analysis revealed average pore sizes ranging from 481.50 ± 7.65 to 623.96 ± 11.54 µm. SEM images also showed that scaffold surfaces became smooth as the concentration of PRP increased. The mechanical test results demonstrated that as the PRP increased, the compressive strength decreased. When the swelling and degradation behaviours of scaffolds were examined, it was observed that GEL/SA/HA/3PRP scaffolds exhibited approximately 200 % swelling capability until the 4th day. GEL/SA/HA scaffolds showed a degradation behaviour about 70 % higher compared to other groups. A controlled release profile of PRP was maintained up to the 144th, 216th, and 240th hours from the scaffolds. According to the highest correlation coefficients (R2) in the release kinetics of scaffolds, GEL/SA/HA/0.5PRP and GEL/SA/HA/1PRP scaffolds were explained by the first-order model. In contrast, the GEL/SA/HA/3PRP scaffold was described using the Korsmeyer–Peppas model. The MTT analysis conducted with osteoblast cells showed that scaffolds did not demonstrate any toxic effects and facilitated cell adhesion by inducing the formation of extensions. These findings underscore the potential of PRP-incorporated GEL/SA/HA composites as a promising approach for bone tissue engineering, offering significant advancements in the treatment of bone disorders. This could lead to more effective treatments for bone disorders and injuries, reducing the need for more invasive procedures and improving patient recovery times.

GO/Cu Nanosheet-Integrated Hydrogel Platform as a Bioactive and Biocompatible Scaffold for Enhanced Calvarial Bone Regeneration.

The treatment of craniofacial bone defects caused by trauma, tumors, and infectious and degenerative diseases is a significant issue in current clinical practice. Following the rapid development of bone tissue engineering (BTE) in the last decade, bioactive scaffolds coupled with multifunctional properties are in high demand with regard to effective therapy for bone defects. Herein, an innovative bone scaffold consisting of GO/Cu nanoderivatives and GelMA-based organic-inorganic hybrids was reported for repairing full-thickness calvarial bone defect. In this study, motivated by the versatile biological functions of nanomaterials and synthetic hydrogels, copper nanoparticle (CuNP)-decorated graphene oxide (GO) nanosheets (GO/Cu) were combined with methacrylated gelatin (GelMA)-based organic-inorganic hybrids to construct porous bone scaffolds that mimic the extracellular matrix (ECM) of bone tissues by photocrosslinking. The material characterizations, in vitro cytocompatibility, macrophage polarization and osteogenesis of the biohybrid hydrogel scaffolds were investigated, and two different animal models (BALB/c mice and SD rats) were established to further confirm the in vivo neovascularization, macrophage recruitment, biocompatibility, biosafety and bone regenerative potential. We found that GO/Cu-functionalized GelMA/β-TCP hydrogel scaffolds exhibited evidently promoted osteogenic activities, M2 type macrophage polarization, increased secretion of anti-inflammatory factors and excellent cytocompatibility, with favorable surface characteristics and sustainable release of Cu2+. Additionally, improved neovascularization, macrophage recruitment and tissue integration were found in mice implanted with the bioactive hydrogels. More importantly, the observations of microCT reconstruction and histological analysis in a calvarial bone defect model in rats treated with GO/Cu-incorporated hydrogel scaffolds demonstrated significantly increased bone morphometric values and newly formed bone tissues, indicating accelerated bone healing. Taken together, this BTE-based bone repair strategy provides a promising and feasible method for constructing multifunctional GO/Cu nanocomposite-incorporated biohybrid hydrogel scaffolds with facilitated osteogenesis, angiogenesis and immunoregulation in one system, with the optimization of material properties and biosafety, it thereby demonstrates great application potential for correcting craniofacial bone defects in future clinical scenarios.

In Situ Printing of Polylactic Acid/Nanoceramic Filaments for the Repair of Bone Defects Using a Portable 3D Device.

In situ 3D printing is attractive for the direct repair of bone defects in underdeveloped countries and in emergency situations. So far, the lack of an interesting method to produce filament using FDA-approved biopolymers and nanoceramics combined with a portable strategy limits the use of in situ 3D printing. Herein, we investigated the osseointegration of new nanocomposite filaments based on polylactic acid (PLA), laponite (Lap), and hydroxyapatite (Hap) printed directly at the site of the bone defect in rats using a portable 3D printer. The filaments were produced using a single-screw extruder (L/D = 26), without the addition of solvents that can promote the toxicity of the materials. In vitro performance was evaluated in the cell differentiation process with mesenchymal stem cells (MSC) by an alkaline phosphatase activity test and visualization of mineralization nodules; a cell viability test and total protein dosage were performed to evaluate cytotoxicity. For the in vivo analysis, the PLA/Lap composite filaments with a diameter of 1.75 mm were printed directly into bone defects of Wistar rats using a commercially available portable 3D printer. Based on the in vitro and in vivo results, the in situ 3D printing technique followed by rapid cooling proved to be promising for bone tissue engineering. The absence of fibrous encapsulation and inflammatory processes became a good indicator of effectiveness in terms of biocompatibility parameters and bone tissue formation, and the use of the portable 3D printer showed a significant advantage in the application of this material by in situ printing.

Evaluation of the elemental composition and radiological density of bone tissue when replacing a metaphyseal defect with bioceramic phosphate-silicate granules (experimental study)

Background: It is known that bioceramic implants containing various calcium or silicon compounds in isolation demonstrate osteoconductive effect in the replacement of post-traumatic bone defects. The combined use of these elements in single material should potentiate the organotypic filling of the bone cavity by creating favorable ion microenvironment and staged biodegradation. AIM: To identify the correlation of radiological indicators of the density of newly formed bone tissue and content of micro- and macronutrients in a bone defect when it is replaced by bioceramics with various mass ratio of calcium phosphate and silicate. MATERIALS AND METHODS: The study was performed on male rabbits of the “white giant” breed, which, after receiving a standardized delimited metaphysical bone defect, implants with variable ratio of calcium phosphate and calcium silicate (in proportions of 40/60, 50/50 and 60/40 wt. %) were used to replace it. The results were evaluated using multispiral computed tomography and scanning electron microscopy energy dispersive analysis with detection by the method of correlation analysis of possible connections between the obtained data. RESULTS: Quantitative indicators of calcium and phosphorus content in bone regenerate in all groups increased mainly in the period from 30 to 60 days, and silicon content, reaching maximum amounts by the 30th day of the experiment, subsequently decreased monotonously, which showed participation of this element in the starting regenerative processes, and its decrease served as a marker of organotypic restructuring. In the elemental analysis of newly formed bone tissue during implantation of bioceramics containing phosphate and calcium silicate in the proportion of 60/40 wt. %. The highest amounts of calcium, phosphorus and silicon and the highest density of newly formed bone tissue were noted, which had direct correlation, and this pattern was observed both in the early stages (30 days) and throughout the experimental study. CONCLUSION: Analyzing the data obtained, it can be concluded that it is advisable to study the features of the course of reparative osteogenesis depending on the ionic environment, as well as the high potential of using synthetic bioceramics in general and the prospects of using implants on the basis of phosphate-silicate composites for bone defects replacement.

Recent Progress in the Research on RNA-Binding Proteins in Bone Development and Diseases.

RNA-binding proteins (RBPs), which regulate gene expression through post-transcriptional modifications of RNAs, play a role in diverse biological processes that include bone cell development and bone tissue formation. RBP dysregulation may result in aberrant bone homeostasis and contribute to various bone diseases. The function of RBPs in bone physiology and pathophysiology and the underlying molecular mechanisms have been extensively studied in recent years. This article provides a review of such studies, highlighting the potential of RBPs as pivotal targets for therapeutic intervention.