A bone replaceable artificial bone substitute: osteoinduction by combining with bone inducing agent

Comparing the effects of Bone+B® xenograft and InterOss® xenograft bone material on rabbit calvaria bone defect regeneration

BACKGROUND

The bone regeneration therapy is often used in patients with inadequate bone support for implants, particularly following tooth extractions. Xenografts derived from animal tissues are effective bone reconstructive options that resist resorption and pose a low risk of transmitting disease. Therefore, these implants may be a good option for enhancing and stabilizing maxillary sinuses. The purpose of this study was to compare two xenografts, Bone+B® and InterOss®, for the reconstruction of rabbit calvaria defects.

METHODS AND MATERIALS

The study involved seven male New Zealand white rabbits. In the surgical procedure, 21 spots were created on both sides of the midline calvarium by creating three 8-millimeter defects. A control group was used, as well as two treatment groups utilizing Bone+B® Grafts and InterOss® Grafts. After 3 months, the rabbits were euthanized, followed by pathological evaluation. Analysis of these samples focused on bone formation, xenograft remaining material, and inflammation levels, using Adobe Photoshop CS 8.0 and SPSS version 24.

RESULTS

With the application of Bone+B® graft, bone formation ranged from 32% to 45%, with a mean of 37.80% (±5.63), and the remaining material ranged from 28% to 37%, with a mean of 32.60% (±3.65). Using InterOss® grafts, bone formation was 61% to 75%, the mean was 65.83% (±4.75), and the remaining material was 9% to 18%, with a mean of 13.17% (±3.06). The bone formation in the control group ranged from 10% to 25%, with a mean of 17.17% (±6.11). InterOss® had lower inflammation levels than other groups, but the difference was not statistically significant (p > .05).

CONCLUSION

InterOss® bone powder is the best option for maxillofacial surgery and bone reconstruction. This is due to more bone formation, less remaining material, and a lower inflammation level. Compared to the control group, Bone+B® improves healing and bone quality, thus making it an alternative to InterOss®.

Biological Properties and Medical Applications of Carbonate Apatite: A Systematic Review

Bone defects represent an everyday challenge for clinicians who work in the fields of orthopedic surgery, maxillofacial and oral surgery, otorhinolaryngology, and dental implantology. Various bone substitutes have been developed and utilized, according to the needs of bone reconstructive surgery. Carbonate apatite has gained popularity in recent years, due to its excellent tissue behavior and osteoconductive potential. This systematic review aims to evaluate the role of carbonate apatite in bone reconstructive surgery and tissue engineering, analyze its advantages and limitations, and suggest further directions for research and development. The Web of Science, PubMed, and Scopus electronic databases were searched for relevant review articles, published from January 2014 to 21 July 2023. The study was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Eighteen studies were included in the present review. The biological properties and medical applications of carbonate apatite (CO3Ap) are discussed and evaluated. The majority of articles demonstrated that CO3Ap has excellent biocompatibility, resorbability, and osteoconductivity. Furthermore, it resembles bone tissue and causes minimal immunological reactions. Therefore, it may be successfully utilized in various medical applications, such as bone substitution, scaffolding, implant coating, drug delivery, and tissue engineering.

Biocompatibility Assessment of Two Commercial Bone Xenografts by In Vitro and In Vivo Methods

Bone substitutes based on xenografts have been used for a long time in bone regeneration thanks to their inductive capacity for bone tissue regeneration. Some bone-based scaffolds have been modified by adding collagen and other proteins to improve their regenerative capacity and prevent migration and aggregation, especially particles. However, rejection of this graft has been reported due to protein residues caused by poor material preparation. We compared the in vitro and in vivo biological response of two commercial xenografts (InterOss^®, F1 and InterOss^® Collagen, F2) and a commercial porcine collagen membrane (InterCollagen^® Guide, F3) as a rapid degradation control. Fourier Transform Infrared Spectroscopy (FT-IR) analysis evidenced the presence of hydroxyl, orthophosphate, and carbonate groups of the xenografts and amide groups of collagen. Thermogravimetric analysis (TGA) of the xenografts demonstrated their thermal stability and the presence of a few amounts of organic material. The study by differential scanning calorimetry showed the presence of endothermic peaks typical of the dehydration of the xenografts (F1 and F2) and for the collagen membrane (F3), the beginning of structural three-dimensional protein changes. Subsequently, in vitro biocompatibility tests were carried out for the materials with Artemia salina and MTT cell viability with HeLa cells, demonstrating the high biocompatibility of the materials. Finally, in vivo biocompatibility was studied by implanting xenografts in biomodels (Wistar rats) at different periods (30, 60, and 90 days). The F1 xenograft (InterOss) remained remarkably stable throughout the experiment (90 days). F2 (InterOss Collagen) presented a separation of its apatite and collagen components at 60 days and advanced resorption at 90 days of implantation. Finally, the collagen membrane (F3) presented faster resorption since, at 90 days, only some tiny fragments of the material were evident. All the in vivo and in vitro test results demonstrated the biocompatibility of the xenografts, demonstrating the potential of these materials for tissue engineering.

A Comparative Study of Two Bone Graft Substitutes–InterOss® Collagen and OCS-B Collagen®

Bone is a complex hierarchical tissue composed of organic and inorganic materials that provide structure, support, and protection to organs. However, there are some critical size defects that are unable to regenerate on their own and therefore require clinical repair. Bone graft substitutes allow repair by providing a temporary resorbable device. Among the common filler materials that aid in regeneration is hydroxyapatite particles of either animal or human origin which is used to fill or reconstruct periodontal and bony defects in the mouth. However, particulate graft substitutes suffer from localized migration away from the implantation site, necessitating the use of a barrier membrane. In this study, we designed InterOss Collagen, combining bovine hydroxyapatite granules with porcine-skin derived collagen to form a bone filler composite. Physiochemical properties of InterOss Collagen and a commercially available product, OsteoConductive Substitute-Bovine(OCS-B) Collagen, referred to as OCS-B Collagen, were examined. We found two bone graft substitutes to be mostly similar, though InterOss Collagen showed comparatively higher surface area and porosity. We conducted an in vivo study in rabbits to evaluate local tissue responses, percent material resorption and bone formation and showed that the two materials exhibited similar degradation profiles, inflammatory and healing responses following implantation. Based on these results, InterOss Collagen is a promising dental bone grafting material for periodontal and maxillofacial surgeries.

Excellency of Hydroxyapatite Composite Scaffolds for Bone Tissue Engineering

The hydroxyapatite [HAp, Ca10(PO4)6(OH)2] has a variety of applications in bone fillers and replacements due to its excellent bioactivity and osteoconductivity. It comprises the main inorganic component of hard tissues. Among the various approaches, a composite approach using several components like biopolymer, gelatin, collagen, and chitosan in the functionalization of scaffolds with HAp has the prospective to be an engineered biomaterial for bone tissue engineering. HAp composite scaffolds have been developed to obtain a material with different functionalities such as surface reactivity, bioactivity, mechanical strength, and capability of drug or growth factor delivery. Several techniques and processes for the synthesis and fabrication of biocompatible HAp composite scaffolds suitable for bone regeneration are addressed here. Further, this chapter described the excellences of various HAp composite scaffolds used in in vitro and in vivo experiments in bone tissue engineering.

Enhanced osteogenic differentiation of human mesenchymal stem cells on Ti surfaces with electrochemical nanopattern formation

Titanium (Ti) and its alloys are mainly used for dental and orthopedic applications due to their excellent biocompatibility and mechanical properties. However, their intrinsic bioinertness often quotes as a common complaint for biomedical applications. Herein, we produced nanopattern Ti surfaces with 10 nm nanopores in 120 nm dimples by electrochemical nanopattern formation (ENF), and evaluated the osteogenic differentiation of human mesenchymal stem cells (hMSCs) on the nanopattern Ti surfaces. The ENF surfaces were obtained by removing the TiO₂ nanotube (NT) layers prepared by an anodization process. To determine the in vitro effects of the ENF surface, cell proliferation assay, alkaline phosphatase activity assay, alizarin red staining, western blotting, and immunocytochemistry were performed. Atomic force microscopy and scanning electron microscopy analysis show that the ENF surface has an ultrafine surface roughness with highly aligned nanoporous morphology. hMSCs on ENF surfaces exhibit increased proliferation and enhanced osteogenic differentiation as compared to the ordered TiO₂ nanotubular and compact TiO₂ surfaces. Surface modification with the ENF process is a promising technique for fabricating osteointegrative implant materials with a highly bioactive, rigid and purified nano surfaces.

Mesenchymal Stem Cells on Plasma-Deposited Acrylic Acid Coatings: An In Vitro Investigation to Improve Biomaterial Performance in Bone Reconstruction

In this in vitro investigation of a heterogeneous range of bio-functional and modulatory performances of mesenchymal stem cells (MSCs) grown on two plasma-deposited acrylic acid (pdAA) coatings, which differed in chemical characteristics, a view of their potential utility as hybrid scaffolds for bone tissue engineering was obtained. The in vitro behavior of MSCs was compared to that of MG-63 cells, an osteoblast-like cell line that is commonly used to test biocompatibility of materials intended for bone-tissue interface. The coatings exerted a greater stimulus on MSCs and on MG-63 cells in comparison with control cultures. Both studied coatings exhibited satisfactory compatibility and modulatory effects on MSCs, thus they may be suitable for use in 2D or 3D scaffolds for bone tissue reconstruction.

Reduced graphene oxide-coated hydroxyapatite composites stimulate spontaneous osteogenic differentiation of human mesenchymal stem cells

Human mesenchymal stem cells (hMSCs) have great potential as cell sources for bone tissue engineering and regeneration, but the control and induction of their specific differentiation into bone cells remain challenging. Graphene-based nanomaterials are considered attractive candidates for biomedical applications such as scaffolds in tissue engineering, substrates for SC differentiation and components of implantable devices, due to their biocompatible and bioactive properties. Despite the potential biomedical applications of graphene and its derivatives, only limited information is available regarding their osteogenic activity. This study concentrates upon the effects of reduced graphene oxide (rGO)-coated hydroxyapatite (HAp) composites on osteogenic differentiation of hMSCs. The average particle sizes of HAp and rGO were 1270 ± 476 nm and 438 ± 180 nm, respectively. When coated on HAp particulates, rGO synergistically enhanced spontaneous osteogenic differentiation of hMSCs, without hampering their proliferation. This result was confirmed by determining alkaline phosphatase activity and mineralization of calcium and phosphate as early and late stage markers of osteogenic differentiation. It is suggested that rGO-coated HAp composites can be effectively utilized as dental and orthopedic bone fillers since these graphene-based particulate materials have potent effects on stimulating the spontaneous differentiation of MSCs and show superior bioactivity and osteoinductive potential.

Collagen Fabrication for the Cell-based Implants in Regenerative Medicine

Though transplantation of cells, tissue or organ has been regarded as an ideal approach, scarcity of donor is a practical barrier in clinics. Current progresses in cell engineering has opened a new era, providing tools for host-regeneration by implanting manipulated cells in forms of cell therapy, which includes delivery of single cells or multicellular structural support of hybridized cells, as a representative individualized treatment method. This chapter mainly concerns on the cellbased implant made of cells and collagen, the main structural protein in extracellular matrix in mammalian tissue, as it has been regarded as a promising method for manufacturing a biologically mimicked artificial tissues.

Morphological and chemical analysis of bone substitutes by scanning electron microscopy and microanalysis by spectroscopy of dispersion energy

This study evaluated the morphological and chemical composition of the following bone substitutes: cancellous and cortical organic bovine bone with macro and microparticle size ranging from 1.0 to 2.0 mm and 0.25 to 1.0 mm, respectively; inorganic bovine bone with particle size ranging from 0.25 to 1.0 mm; hydroxyapatite with particle size ranging from 0.75 to 1.0 mm; and demineralized freeze-dried bone allograft with particle size ranging from 0.25 to 0.5 mm. The samples were sputter-coated with gold in an ion coater, the morphology was observed and particle size was measured under vacuum by scanning electron microscopy (SEM). The chemical composition was evaluated by spectroscopy of dispersion energy (EDS) microanalysis using samples without coating. SEM analysis provided visual evidence that all examined materials have irregular shape and particle sizes larger than those informed by the manufacturer. EDS microanalysis detected the presence of sodium, calcium and phosphorus that are usual elements of the bone tissue. However, mineral elements were detected in all analyzed particles of organic bovine bone except for macro cancellous organic bovine bone. These results suggest that the examined organic bovine bone cannot be considered as a pure organic material.

Repair of mandible defect with tissue engineering bone in rabbits

BACKGROUND

The aim of the present study was to investigate the effect of tissue engineering bone composed of bone marrow-derived osteoblasts and demineralized bone in repairing mandible defect.

METHODS

Bone marrow-derived osteoblasts of 20 rabbits were cultured and seeded into scaffold of allogeneic demineralized bone to construct tissue engineering bone graft in vitro, which was used to repair the 10 x 5-mm bone defect made in the same rabbit mandible edge. Implant of demineralized bone alone was as the control. Rabbits were killed according to the schedule: five after 2 weeks, five after 4 weeks, five after 8 weeks, five after 12 weeks, and the implants were harvested for gross, radiographic, and histological observation.

RESULTS

New bone formation at the margin region of defect and osteogenesis at the centre were observed in the implant of tissue engineering bone, and the bone formation pattern included osteogenesis, osteoconduction, and osteoinduction. In the implant of demineralized bone alone, the major bone formation pattern was 'creeping substitute'.

CONCLUSIONS

The tissue engineering bone graft constructed by autogenous bone marrow-derived osteoblasts and allogeneic demineralized bone was better than demineralized bone alone in bone formation capability, which might be an ideal graft for bone defect repair.

HA/alginate hybrid composites prepared through bio-inspired nucleation

Poorly crystalline apatite has been directly nucleated on self-assembling alginate chains by neutralization synthesis to obtain a biomimetic artificial bone-like composite. It has been observed that in preparing HA/alginate composites, Ca2+ ions present on the apatitic surface cross-link the alginate chains to produce a material with different morphology and thermal stability, both functions of the HA/alginate weight ratio. In vitro tests were performed on different samples in terms of both the HA/alginate ratio and synthesis temperature. All the samples were cultured for seven days with MG63 osteoblast-like cells and then underwent morphological and biochemical analyses (MTT and ALP tests). Scaffolds showed a different solubility into the culture media, which was related to the temperature of synthesis and to the HA/alginate ratio. All our data confirm the ability of the tested materials to favour cell growth and to maintain their osteoblastic functionality, at least during the examined period.

Ex Vivo Mechanical Evaluation of Carbonate Apatite-Collagen-Grafted Porous Poly-L-lactic Acid Membrane in Rabbit Calvarial Bone

Appropriate mechanical recovery is an important parameter in successful restoration of skeletal defects. Carbonate apatite and type I atelocollagen mixture (CAp) was grafted on a porous poly-L-lactic acid (PLLA) membrane to produce a CAp bilayered PLLA membrane (CAp+PLLA). After implantation, regional mechanical change in the membrane was investigated in rabbit calvarial bone defects. Dynamic viscoelasticity and elastic modulus of the implanted specimen were measured after 2, 4, 8, 12, 16, 26, and 52 weeks. The modulus of the peripheral part was higher than that of the central part of the implanted area, whereas the central part demonstrated a gradual increase. This phenomenon indicates that regeneration initially occurs from the periphery of the calvarial bone. After 26 weeks, stiffness of the central part became similar to that of the periphery in the CAp+PLLA-implanted area. According to this result, measuring viscoelasticity of an implanted biodegradable material would be a useful method to determine degrees of regeneration and replacement of an implanted region.