Bioactive Coatings Loaded with Osteogenic Protein for Metallic Implants

Osteoconductive and osteoinductive coatings represent attractive and tunable strategies towards the enhanced biomechanics and osseointegration of metallic implants, providing accurate local modulation of bone-to-implant interface. Composite materials based on polylactide (PLA) and hydroxyapatite (HAp) are proved beneficial substrates for the modulation of bone cells’ development, being suitable mechanical supports for the repair and regeneration of bone tissue. Moreover, the addition of osteogenic proteins represents the next step towards the fabrication of advanced biomaterials for hard tissue engineering applications, as their regulatory mechanisms beneficially contribute to the new bone formation. In this respect, laser-processed composites, based on PLA, Hap, and bone morphogenetic protein 4(BMP4), are herein proposed as bioactive coatings for metallic implants. The nanostructured coatings proved superior ability to promote the adhesion, viability, and proliferation of osteoprogenitor cells, without affecting their normal development and further sustaining the osteogenic differentiation of the cells. Our results are complementary to previous studies regarding the successful use of chemically BMP-modified biomaterials in orthopedic and orthodontic applications.

Toughening of Bioceramic Composites for Bone Regeneration

Bioceramics are widely considered as elective materials for the regeneration of bone tissue, due to their compositional mimicry with bone inorganic components. However, they are intrinsically brittle, which limits their capability to sustain multiple biomechanical loads, especially in the case of load-bearing bone districts. In the last decades, intense research has been dedicated to combining processes to enhance both the strength and toughness of bioceramics, leading to bioceramic composite scaffolds. This review summarizes the recent approaches to this purpose, particularly those addressed to limiting the propagation of cracks to prevent the sudden mechanical failure of bioceramic composites.

Influence of Human Jaw Periosteal Cells Seeded β-Tricalcium Phosphate Scaffolds on Blood Coagulation

Tissue engineering offers auspicious opportunities in oral and maxillofacial surgery to heal bone defects. For this purpose, the combination of cells with stability-providing scaffolds is required. Jaw periosteal cells (JPCs) are well suited for regenerative therapies, as they are easily accessible and show strong osteogenic potential. In this study, we analyzed the influence of uncoated and polylactic-co-glycolic acid (PLGA)-coated β-tricalcium phosphate (β-TCP) scaffolds on JPC colonization and subsequent osteogenic differentiation. Furthermore, interaction with the human blood was investigated. This study demonstrated that PLGA-coated and uncoated β-TCP scaffolds can be colonized with JPCs and further differentiated into osteogenic cells. On day 15, after cell seeding, JPCs with and without osteogenic differentiation were incubated with fresh human whole blood under dynamic conditions. The activation of coagulation, complement system, inflammation, and blood cells were analyzed using ELISA and scanning electron microscopy (SEM). JPC-seeded scaffolds showed a dense cell layer and osteogenic differentiation capacity on both PLGA-coated and uncoated β-TCP scaffolds. SEM analyses showed no relevant blood cell attachment and ELISA results revealed no significant increase in most of the analyzed cell activation markers (β-thromboglobulin, Sc5B-9, polymorphonuclear (PMN)-elastase). However, a notable increase in thrombin-antithrombin III (TAT) complex levels, as well as fibrin fiber accumulation on JPC-seeded β-TCP scaffolds, was detected compared to the scaffolds without JPCs. Thus, this study demonstrated that besides the scaffold material the cells colonizing the scaffolds can also influence hemostasis, which can influence the regeneration of bone tissue.

Bioactive Calcium Phosphate-Based Composites for Bone Regeneration

Calcium phosphates (CaPs) are widely accepted biomaterials able to promote the regeneration of bone tissue. However, the regeneration of critical-sized bone defects has been considered challenging, and the development of bioceramics exhibiting enhanced bioactivity, bioresorbability and mechanical performance is highly demanded. In this respect, the tuning of their chemical composition, crystal size and morphology have been the matter of intense research in the last decades, including the preparation of composites. The development of effective bioceramic composite scaffolds relies on effective manufacturing techniques able to control the final multi-scale porosity of the devices, relevant to ensure osteointegration and bio-competent mechanical performance. In this context, the present work provides an overview about the reported strategies to develop and optimize bioceramics, while also highlighting future perspectives in the development of bioactive ceramic composites for bone tissue regeneration.

THE RESULTS OF USING A BIOACTIVE GLASS-BASED COATING BY DEPOSITION ON THE CONTACT SURFACE OF PLATES IN BONE FRACTURES ASSOCIATED WITH TUMORS

The article reports on the results of surgical treatment in 20 patients with bone tumors using a coating containing bioactive glass on the contact surface of the fixation plate. As a result of metallic osteosynthesis of the bones, infectious complications were observed in 1 (5%) patient and tumor recurrence was observed in 2 (10%) patients. Limb function after metallic osteosynthesis ranged from 72.3% to 97.4% depending on the location of the lesion focus. The quality of life of the operated patients increased to 75–85 points. Thus, the use of plates with bioactive glassbased material deposited on the contact surface of the plate, in metallic osteosynthesis for pathological bone fracture or at the risk of pathological bone fracture achieves more effective integration of metal plate with bone. Consequently, a better functional stability of the bone is achieved at the fracture site. Morphological examination of bone biopsy samples from the implantation site of the plate and the plate itself with the deposited bioactive glass-based coating revealed active regeneration of bone tissue. This resulted in an increase in the density of the restored bone. According to the results of histological and morphometric examination it can be stated that deposition of a material containing bioactive glass on the contact surface of the metal plate promotes reparative osteogenesis at the site of bone damage and its morphogenesis of the lamellar type.

Features of Bone Regeneration of the Jaws Alveolar Ridge Using Hydroxyapatite-Based Material

Background. Currently, using of osteointegrated titanium implants has become a key component for restoring lost function in various areas of clinical medicine. The actual issue remains preservation or reconstruction of bone tissue for optimal use of titanium implants in traumatology and orthopedics, as well as in maxillofacial surgery. One of the most common grafts are hydroxyapatite-based material with various inclusions, for example, an antibiotic.The aim of the study is to characterize the regeneration of bone tissue of the jaws alveolar ridge using the hydroxyapatite-based material “Collapan-L” in clinical practice.Material and Methods. The study of the material “Collapan-L” (Intermedapatit, Russia) using involved 30 patients with a diagnosis “chronic periodontitis of the tooth”. Patients underwent complex surgical and orthopedic treatment to restore masticatory function. At the first stage, teeth were removed with the “Collapan-L” material used to preserve the alveolus. 4 months after extraction, dental implantation was performed with simultaneous trephine biopsy from the augmentation zone for histomorphometric analysis. At the stage of implant placement and before prosthetics the stability dynamics was measured.Results. The study involved 42 tissue samples obtained at periods from 9 to 32 weeks after removal. The morphological assessment of bone tissue from the implantation zone determined that after 4 months trabeculae from the newly formed bone, including small fragments of biomaterial, were revealed; at the same time, there were signs of biodegradation of the implanted material fragments, there was no inflammatory infiltrate. After 6 months in a significant part of cases the granules of bone material were not found, which indicates a pronounced osseointegration of the material. In its structure, the formed bone tissue differences barely noticeable from the native one, which allows us to conclude that by the time of 24 weeks, the processes of reparative osteogenesis in the alveolus are completed.Conclusion. Histological examination and assessment of changes in the stability showed that using of bone replacement material after tooth extraction can increase the regenerative potential of bone tissue, avoid additional surgical interventions to increase the volume of bone tissue in the area of future implantation, and the formed bone tissue is close in its structure to the native one.

Antibacterial Composite Materials Based on the Combination of Polyhydroxyalkanoates With Selenium and Strontium Co-substituted Hydroxyapatite for Bone Regeneration

Due to the threat posed by the rapid growth in the resistance of microbial species to antibiotics, there is an urgent need to develop novel materials for biomedical applications capable of providing antibacterial properties without the use of such drugs. Bone healing represents one of the applications with the highest risk of postoperative infections, with potential serious complications in case of bacterial contaminations. Therefore, tissue engineering approaches aiming at the regeneration of bone tissue should be based on the use of materials possessing antibacterial properties alongside with biological and functional characteristics. In this study, we investigated the combination of polyhydroxyalkanoates (PHAs) with a novel antimicrobial hydroxyapatite (HA) containing selenium and strontium. Strontium was chosen for its well-known osteoinductive properties, while selenium is an emerging element investigated for its multi-functional activity as an antimicrobial and anticancer agent. Successful incorporation of such ions in the HA structure was obtained. Antibacterial activity against Staphylococcus aureus 6538P and Escherichia coli 8739 was confirmed for co-substituted HA in the powder form. Polymer-matrix composites based on two types of PHAs, P(3HB) and P(3HO-co-3HD-co-3HDD), were prepared by the incorporation of the developed antibacterial HA. An in-depth characterization of the composite materials was conducted to evaluate the effect of the filler on the physicochemical, thermal, and mechanical properties of the films. In vitro antibacterial testing showed that the composite samples induce a high reduction of the number of S. aureus 6538P and E. coli 8739 bacterial cells cultured on the surface of the materials. The films are also capable of releasing active ions which inhibited the growth of both Gram-positive and Gram-negative bacteria.

Main Approaches to the Use of Biomaterials in Oral and Maxillofacial Surgery: A Brief Systematic Review

Introduction: In recent years, procedures with the use of dental implants have increased worldwide, reaching approximately one million dental implants per year. In recent years, a platelet concentrate called FRP (fibrin-rich plasma) has been the subject of clinical studies. Associated with this, the biomaterial Bio-Oss® (Geistlich), as it is biodegradable, biocompatible, non-toxic, and has low immunogenicity, and bio stimulators can act in the regeneration of bone tissue, as it establishes with the cells the appropriate biological niche (favorable microenvironment) for bone growth. Objective: Therefore, the present study aimed to evaluate, through a brief systematic review, the results that involve bone formation for dental implantation, with the use of biomaterials such as fibrin-rich plasma and Bio-Oss®. Methods: The model used for the review was PRISMA. Was used databases such as Scopus, Scielo, Lilacs, Google Scholar, PubMed. Results: Fibrin-rich plasma (FRP) as an autologous biomaterial for use in oral and maxillofacial surgery presents most leukocytes, platelets, and growth factors, forming a fibrin matrix, with three-dimensional architecture. The Bio-Oss® biomaterial (Geistlich), as it is biodegradable, biocompatible, non-toxic, and has low immunogenicity and bio stimulators can act in the regeneration of bone tissue, since it establishes with the adenomatous mesenchymal stem cells the appropriate biological niche for bone growth and, thus, allowing the dental implant to be as effective as possible. Conclusion: The use of FRP associated with Bio-Oss® seems to illustrate high success rates with minimal costs, which may reduce the amount of bone graft needed to fill the sinus cavity, reducing the costs of the procedure.

The effect of Allium cepa extract on the chitosan/PLGA scaffolds bioactivity

Allium cepa extracts (AC) allow the fabrication of a biomaterial that, together with chitosan and PLGA, could be osteoconductive and promote a better and faster regeneration of bone tissue, with biocompatibility and biomineralization properties. In this work, scaffolds were developed by the thermally induced phase separation (TIPS) technique. An in vitro bioactivity analysis was performed using simulated body fluid (SBF). Scanning electron microscopy (SEM), energy dispersion spectroscopy, and infrared spectroscopy were used for the scaffolds characterization. The results showed a structure with a pore size distribution between 50 and 100 μm, which allowed the uniform formation of biological apatite crystals on the surface of the scaffolds. The chitosan/policaprolactone/ Allium cepa scaffold (ChPAC) showed the most promising results with a ratio of P/Ca between 1.6 and 1.7, a value very close to that of hydroxyapatite.

Dynamics of biochemical markers of the connective tissue metabolism in the blood of rats after insertion of steel implants with diamond-like carbon coating into the femur

Objective: It is known that the regeneration of bone tissue after implantation of any structuresdepends on the coating of their surface. Therefore, the research of the influence of steelimplants with diamond-like carbon coating on regeneration of bone tissue in the dynamics afterimplantation is a topical issue. Material and Methods: The study was conducted on 61 male rats,5 of them were intact animals. There were also 2 groups of rats with 28 animals in each group(the 1st group was the control one where implants were without diamond-like carbon coating,the 2nd group was experimental where the implants were without coating). We determined thecontent of glycoproteins, chondroitin sulfates, alkaline phosphatase, total calcium, oxyprolineand osteocalcin in the blood of rats on the 7th, 14th, 30th and 90th days after implantation. Resultsand Discussion: Group 2 rats had a faster osteointegration compared with the group 1 rats, whichwas manifested by the normalization of biochemical markers of bone metabolism (glycoproteins,chondroitinsulfats, oxyproline and osteocalcin) on the 90th day of an experiment. Conclusion:Using steel implants with diamond-like carbon coatings showed that the content of glycoproteinsand chondroitin sulfates increased only on the 7th day; oxyproline and osteocalcin increasedon the 7th, 14th and 30th days after implantation; on the 90th day the rates of these biochemicalmarkers reached the norm, indicating a high efficiency of osteointegration. Bangladesh Journal of Medical Science Vol.20(1) 2021 p.81-85