One-Step Preparation of an AgNP-nHA@RGO Three-Dimensional Porous Scaffold and Its Application in Infected Bone Defect Treatment

Structure-optimized and microenvironment-inspired nanocomposite biomaterials in bone tissue engineering

Critical-sized bone defects represent a significant clinical challenge due to their inability to undergo spontaneous regeneration, necessitating graft interventions for effective treatment. The development of tissue-engineered scaffolds and regenerative medicine has made bone tissue engineering a highly viable treatment for bone defects. The physical and biological properties of nanocomposite biomaterials, which have optimized structures and the ability to simulate the regenerative microenvironment of bone, are promising for application in the field of tissue engineering. These biomaterials offer distinct advantages over traditional materials by facilitating cellular adhesion and proliferation, maintaining excellent osteoconductivity and biocompatibility, enabling precise control of degradation rates, and enhancing mechanical properties. Importantly, they can simulate the natural structure of bone tissue, including the specific microenvironment, which is crucial for promoting the repair and regeneration of bone defects. This manuscript provides a comprehensive review of the recent research developments and applications of structure-optimized and microenvironment-inspired nanocomposite biomaterials in bone tissue engineering. This review focuses on the properties and advantages these materials offer for bone repair and tissue regeneration, summarizing the latest progress in the application of nanocomposite biomaterials for bone tissue engineering and highlighting the challenges and future perspectives in the field. Through this analysis, the paper aims to underscore the promising potential of nanocomposite biomaterials in bone tissue engineering, contributing to the informed design and strategic planning of next-generation biomaterials for regenerative medicine.

Development and application of hydroxyapatite-based scaffolds for bone tissue regeneration: A systematic literature review

Hydroxyapatite [HA, Ca10(PO4)6(OH)2], with its robust biocompatibility and bioactivity, has found extensive utility in bone grafting, replacement therapies, and supplemental medical materials. HA is highly regarded for its osteoconductive properties because it boasts hydrophilicity, nontoxicity, non-allergenicity, and non-mutagenicity. Nevertheless, HA's intrinsic mechanical weakness has spurred efforts to enhance its properties. This enhancement is achieved through ion incorporation, with elements such as magnesium, zinc, lithium, strontium, boron, and others being integrated into the HA structure. In the domain of orthopedics, HA-based scaffolds have emerged as a solution for addressing prevalent issues like bone deformities and defects stemming from congenital anomalies, injuries, trauma, infections, or tumors. The fabrication of three-dimensional scaffolds (3D scaffolds) has enabled advancements in bone regeneration and replacement, with a focus on practical applications such as repairing calvarial, skull, and femoral defects. In vitro and in vivo assessments have substantiated the effectiveness of 3D scaffolds for bone defect repair, regeneration, and tissue engineering. Beyond bone-related applications, scaffolds demonstrate versatility in enhancing cartilage healing and serving as bioimplants. The wide array of scaffold applications underscores their ongoing potential for further development in the realm of medical science.

Preparation and Properties of GO/ZnO/nHAp Composite Microsphere Bone Regeneration Material

The purpose of this study is to explore the possibility of using graphene-zinc oxide-hydroxyapatite (GO/ZnO/nHAp) composite microspheres as bone regeneration materials by making use of the complementary advantages of nanocomposites, so as to provide reference for the clinical application of preventing and solving bacterial infection after implantation of synthetic materials. Firstly, GO/ZnO composites and hydroxyapatite nanoparticles were synthesized using the hydrothermal method, and then GO/ZnO/nHAp composite microspheres were prepared via high-temperature sintering. The graphene-zinc oxide-calcium phosphate composite microspheres were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), energy dispersion spectroscopy (EDS), water contact angle measurement, degradation and pH determination, and differential thermal analysis (DiamondTG/DTA). The biocompatibility, osteogenic activity, and antibacterial activity of GO/ZnO/nHAp composite microspheres were further studied. The results of the cell experiment and antibacterial experiment showed that 0.5% and 1% GO-ZnO-nHAp composite microspheres not only had good biocompatibility and osteogenic ability but also inhibited Escherichia coli and Staphylococcus aureus by more than 45% and 70%. Therefore, GO/ZnO/nHAp composite microspheres have good physical and chemical properties and show good osteogenic induction and antibacterial activity, and this material has the possibility of being used as a bone regeneration material.

Choosing the right animal model for osteomyelitis research: Considerations and challenges

Osteomyelitis is a debilitating bone disorder characterized by an inflammatory process involving the bone marrow, bone cortex, periosteum, and surrounding soft tissue, which can ultimately result in bone destruction. The etiology of osteomyelitis can be infectious, caused by various microorganisms, or noninfectious, such as chronic nonbacterial osteomyelitis (CNO) and chronic recurrent multifocal osteomyelitis (CRMO). Researchers have turned to animal models to study the pathophysiology of osteomyelitis. However, selecting an appropriate animal model that accurately recapitulates the human pathology of osteomyelitis while controlling for multiple variables that influence different clinical presentations remains a significant challenge. In this review, we present an overview of various animal models used in osteomyelitis research, including rodent, rabbit, avian/chicken, porcine, minipig, canine, sheep, and goat models. We discuss the characteristics of each animal model and the corresponding clinical scenarios that can provide a basic rationale for experimental selection. This review highlights the importance of selecting an appropriate animal model for osteomyelitis research to improve the accuracy of the results and facilitate the development of novel treatment and management strategies.

Silver-Containing Biomaterials for Biomedical Hard Tissue Implants

Bacterial infection caused by biomaterials is a very serious problem in the clinical treatment of implants. The emergence of antibiotic resistance has prompted other antibacterial agents to replace traditional antibiotics. Silver is rapidly developing as an antibacterial candidate material to inhibit bone infections due to its significant advantages such as high antibacterial timeliness, high antibacterial efficiency, and less susceptibility to bacterial resistance. However, silver has strong cytotoxicity, which can cause inflammatory reactions and oxidative stress, thereby destroying tissue regeneration, making the application of silver-containing biomaterials extremely challenging. In this paper, the application of silver in biomaterials is reviewed, focusing on the following three issues: 1) how to ensure the excellent antibacterial properties of silver, and not easy to cause bacterial resistance; 2) how to choose the appropriate method to combine silver with biomaterials; 3) how to make silver-containing biomaterials in hard tissue implants have further research. Following a brief introduction, the discussion focuses on the application of silver-containing biomaterials, with an emphasis on the effects of silver on the physicochemical properties, structural properties, and biological properties of biomaterials. Finally, the review concludes with the authors' perspectives on the challenges and future directions of silver in commercialization and in-depth research.

A scoping review of graphene-based biomaterials for in vivo bone tissue engineering

The growing demand for more efficient materials for medical applications brought together two previously distinct fields: medicine and engineering. Regenerative medicine has evolved with the engineering contributions to improve materials and devices for medical use. In this regard, graphene is one of the most promising materials for bone tissue engineering and its potential for bone repair has been studied by several research groups. The aim of this study is to conduct a scoping review including articles published in the last 12 years (from 2010 to 2022) that have used graphene and its derivatives (graphene oxide and reduced graphene) in preclinical studies for bone tissue regeneration, searching in PubMed/MEDLINE, Embase, Web of Science, Cochrane Central, and clinicaltrials.gov (to confirm no study has started with clinical trial). Boolean searches were performed using the defined key words "bone" and "graphene", and manuscript abstracts were uploaded to Rayyan, a web-tool for systematic and scoping reviews. This scoping review was conducted based on Joanna Briggs Institute Manual for Scoping Reviews and the report follows the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses - Extension for Scoping Reviews (PRISMA-ScR) statement. After the search protocol and application of the inclusion criteria, 77 studies were selected and evaluated by five blinded researchers. Most of the selected studies used composite materials associated with graphene and its derivatives to natural and synthetic polymers, bioglass, and others. Although a variety of graphene materials were analyzed in these studies, they all concluded that graphene, its derivatives, and its composites improve bone repair processes by increasing osteoconductivity, osteoinductivity, new bone formation, and angiogenesis. Thus, this systematic review opens up new opportunities for the development of novel strategies for bone tissue engineering with graphene.

Fabrication, bacteriostasis and osteointegration properties researches of the additively-manufactured porous tantalum scaffolds loading vancomycin

Infected bone defects (IBDs) remains a challenging problem for orthopedists. Clinically, routine management for IBDs has two stages: debridement and systematic antibiotics administration to control infection, and secondary grafting to repair bone defects. Whereas the efficacy is not satisfactory, because the overuse of antibiotics may lead to systemic toxicity, and the emergence of drug-resistant bacteria, as well as the secondary surgery would cause additional trauma and economic burden to the patients. Therefore, it is imperative to develop a novel scaffold for one-stage repair of IBDs. In this study, vancomycin (Van) was encapsulated into poly(lactic co-glycolic acid) (PLGA) microspheres through the double emulsion method, which were then loaded into the additively-manufactured porous tantalum (AM-Ta) through gelatin methacryloyl (GelMA) hydrogel to produce the composite Ta/GelMA hydrogel (Gel)/PLGA/vancomycin(Van) scaffolds for repairing IBDs. Physiochemical characterization of the newly-developed scaffold indicated that the releasing duration of Van was over 2 weeks. Biological experiments indicated good biocompatibility of the composite scaffold, as well as bacteriostasis and osteointegration properties, which showed great potential for clinical application. The construction of this novel scaffold would provide new sight into the development of orthopaedic implants, shedding a novel light on the treatment of IBDs.

The Antibacterial Effect, Biocompatibility, and Osteogenesis of Vancomycin-Nanodiamond Composite Scaffold for Infected Bone Defects

Purpose

The repair and treatment of infected bone defects (IBD) is a common challenge faced by orthopedic clinics, medical materials science, and tissue engineering.

Methods

Based on the treatment requirements of IBD, we utilized multidisciplinary knowledge from clinical medicine, medical materials science, and tissue engineering to construct a high-efficiency vancomycin sustained-release system with nanodiamond (ND) and prepare a composite scaffold. Its effect on IBD treatment was assessed from materials, cytology, bacteriology, and zoology perspectives.

Results

The results demonstrated that the Van-ND-45S5 scaffold exhibited an excellent antibacterial effect, biocompatibility, and osteogenesis in vitro. Moreover, an efficient animal model of IBD was established, and a Van-ND-45S5 scaffold was implanted into the IBD. Radiographic and histological analyses and bone repair-related protein expression, confirmed that the Van-ND-45S5 scaffold had good biocompatibility and osteogenic and anti-infective activities in vivo.

Conclusion

Collectively, our findings support that the Van-ND-45S5 scaffold is a promising new material and approach for treating IBD with good antibacterial effects, biocompatibility, and osteogenesis.

Biodegradable Bone Implants as a New Hope to Reduce Device-Associated Infections-A Systematic Review

Bone fractures often require fixation devices that frequently need to be surgically removed. These temporary implants and procedures leave the patient more prone to developing medical device-associated infections, and osteomyelitis associated with trauma is a challenging complication for orthopedists. In recent years, biodegradable materials have gained great importance as temporary medical implant devices, avoiding removal surgery. The purpose of this systematic review was to revise the literature regarding the use of biodegradable bone implants in fracture healing and its impact on the reduction of implant-associated infections. The systematic review followed the PRISMA guidelines and was conducted by searching published studies regarding the in vivo use of biodegradable bone fixation implants and its antibacterial activity. From a total of 667 references, 23 studies were included based on inclusion and exclusion criteria. Biodegradable orthopedic implants of Mg-Cu, Mg-Zn, and Zn-Ag have shown antibacterial activity, especially in reducing infection burden by MRSA strains in vivo osteomyelitis models. Their ability to prevent and tackle implant-associated infections and to gradually degrade inside the body reduces the need for a second surgery for implant removal, with expectable gains regarding patients’ comfort. Further in vivo studies are mandatory to evaluate the efficiency of these antibacterial biodegradable materials.

Treatment methods toward improving the anti-infection ability of poly(etheretherketone) implants for medical applications

Due to its favorable chemical stability, biocompatibility, and mechanical properties, Poly(etheretherketone) (PEEK) is a promising material for repairing bone and dental hard tissue defects. However, there are critical disadvantages: PEEK is biologically and chemically inert, which influences osseointegration of implants and bonding strength of prostheses, and its mechanical properties still cannot meet the requirements for some medical applications. Furthermore, bacterial infections and inflammatory reactions often accompany bone defects caused by trauma or inflammation or teeth loss caused by periodontitis. Previous studies mainly focused on enhancing PEEK's bioactivity and mechanical performance, but PEEK also lacks effective anti-infection ability. Thus, it is necessary to improve its anti-infection ability, and this is considered in this paper from two aspects. The first is to inhibit the attachment and growth of bacteria on the material, and the second is to endow the material with immunoregulatory ability, which means mobilizing the host immune system to protect tissue from inflammation. In this review, we analyze and discuss the existing treatment methods to improve the antibacterial and immunomodulatory abilities of PEEK addressing their limitations, relevant future challenges, and required research efforts.

Is Silver the New Gold? A Systematic Review of the Preclinical Evidence of Its Use in Bone Substitutes as Antiseptic

Antibiotic-laden bone substitutes represent a viable option in the treatment of bone and joint infections with bone defects. In particular, the addition of silver ions or silver nanoparticles to bone substitutes to achieve local antiseptic activity could represent a further contribution, also helping to prevent bacterial resistance to antibiotics. An in-depth search of the main scientific databases was performed regarding the use of silver compounds for bone substitution. The available evidence is still limited to the preclinical level: 22 laboratory studies, 2 animal models, and 3 studies, with both in vitro and in vivo analysis, were found on the topic. Numerous biomaterials have been evaluated. In vitro studies confirmed that silver in bone substitutes retains the antibacterial activity already demonstrated in coatings materials. Cytotoxicity was generally found to be low and only related to silver concentrations higher than those sufficient to achieve antibacterial activity. Instead, there are only a few in vivo studies, which appear to confirm antibacterial efficacy, although there is insufficient evidence on the pharmacokinetics and safety profile of the compounds investigated. In conclusion, research on bone substitutes doped with silver is in its early stages, but the preliminary findings seem promising.

Biocompatible Materials in Otorhinolaryngology and Their Antibacterial Properties

For decades, biomaterials have been commonly used in medicine for the replacement of human body tissue, precise drug-delivery systems, or as parts of medical devices that are essential for some treatment methods. Due to rapid progress in the field of new materials, updates on the state of knowledge about biomaterials are frequently needed. This article describes the clinical application of different types of biomaterials in the field of otorhinolaryngology, i.e., head and neck surgery, focusing on their antimicrobial properties. The variety of their applications includes cochlear implants, middle ear prostheses, voice prostheses, materials for osteosynthesis, and nasal packing after nasal/paranasal sinuses surgery. Ceramics, such as as hydroxyapatite, zirconia, or metals and metal alloys, still have applications in the head and neck region. Tissue engineering scaffolds and drug-eluting materials, such as polymers and polymer-based composites, are becoming more common. The restoration of life tissue and the ability to prevent microbial colonization should be taken into consideration when designing the materials to be used for implant production. The authors of this paper have reviewed publications available in PubMed from the last five years about the recent progress in this topic but also establish the state of knowledge of the most common application of biomaterials over the last few decades.

Development of Graphene-Based Materials in Bone Tissue Engineaering

Bone regeneration-related graphene-based materials (bGBMs) are increasingly attracting attention in tissue engineering due to their special physical and chemical properties. The purpose of this review is to quantitatively analyze mass academic literature in the field of bGBMs through scientometrics software CiteSpace, to demonstrate the rules and trends of bGBMs, thus to analyze and summarize the mechanisms behind the rules, and to provide clues for future research. First, the research status, hotspots, and frontiers of bGBMs are analyzed in an intuitively and vividly visualized way. Next, the extracted important subjects such as fabrication techniques, cytotoxicity, biodegradability, and osteoinductivity of bGBMs are presented, and the different mechanisms, in turn, are also discussed. Finally, photothermal therapy, which is considered an emerging area of application of bGBMs, is also presented. Based on this approach, this work finds that different studies report differing opinions on the biological properties of bGBMS due to the lack of consistency of GBMs preparation. Therefore, it is necessary to establish more standards in fabrication, characterization, and testing for bGBMs to further promote scientific progress and clinical translation.

An injectable gellan gum-based hydrogel that inhibits Staphylococcus aureus for infected bone defect repair

The treatment of infected bone defects in complex anatomical structures, such as oral and maxillofacial structures, remains an intractable clinical challenge. Therefore, advanced biomaterials that have excellent anti-infection activity and allow convenient delivery are needed. We fabricated an innovative injectable gellan gum (GG)-based hydrogel loaded with nanohydroxyapatite particles and chlorhexidine (nHA/CHX). The hydrogel has a porous morphology, suitable swelling ratio, and good biocompatibility. It exerts strong antibacterial activity against Staphylococcus aureus growth and biofilm formation in vitro. We successfully established an infected calvarial defect rat model. Bacterial colony numbers were significantly lower in tissues surrounding the bone in rats of the GG/nHA/CHX group after debride surgery and hydrogel implantation in the defect regions than in rats of the blank group. Rats in the GG/nHA/CHX group exhibited significantly increased new bone formation compared to those in the blank group at 4 and 8 weeks. These findings indicate that gellan gum-based hydrogel with nHA/CHX can accelerate the repair of infected bone defects.

Osteoinductive and antimicrobial mechanisms of graphene-based materials for enhancing bone tissue engineering

Graphene-based materials (GMs) have great application prospects in bone tissue engineering due to their osteoinductive ability and antimicrobial activity. GMs induce osteogenic differentiation through several mechanisms and pathways in bone tissue engineering. First of all, the surface and high hardness of the porous folds of graphene or graphene oxide (GO) can generate mechanical stimulation to initiate a cascade of reactions that promote osteogenic differentiation without any chemical inducers. In addition, change of the extracellular matrix (ECM), regulation of macrophage polarization, the oncostatin M (OSM) signaling pathway, the MAPK signaling pathway, the BMP signaling pathway, the Wnt/β-catenin signaling pathway, and other pathways are involved in GMs' regulation of osteogenesis. In bone tissue engineering, GMs prevent the formation of microbial biofilms mainly through preventing microbial adhesion and killing them. The former is mainly achieved by reducing surface free energy (SFE) and increasing hydrophobicity. The latter mainly includes oxidative stress and photothermal/photodynamic effects. Graphene and its derivatives (GDs) are mainly combined with bioactive ceramic materials, metal materials and macromolecular polymers to play an antimicrobial effect in bone tissue engineering. Concentration, number of layers, and type of GDs often affect the antimicrobial activity of GMs. In this paper, we reviewed relevant osteoinductive and antimicrobial mechanisms of GMs and their applications in bone tissue engineering.

A review of biomimetic scaffolds for bone regeneration: Toward a cell-free strategy

In clinical terms, bone grafting currently involves the application of autogenous, allogeneic, or xenogeneic bone grafts, as well as natural or artificially synthesized materials, such as polymers, bioceramics, and other composites. Many of these are associated with limitations. The ideal scaffold for bone tissue engineering should provide mechanical support while promoting osteogenesis, osteoconduction, and even osteoinduction. There are various structural complications and engineering difficulties to be considered. Here, we describe the biomimetic possibilities of the modification of natural or synthetic materials through physical and chemical design to facilitate bone tissue repair. This review summarizes recent progresses in the strategies for constructing biomimetic scaffolds, including ion-functionalized scaffolds, decellularized extracellular matrix scaffolds, and micro- and nano-scale biomimetic scaffold structures, as well as reactive scaffolds induced by physical factors, and other acellular scaffolds. The fabrication techniques for these scaffolds, along with current strategies in clinical bone repair, are described. The developments in each category are discussed in terms of the connection between the scaffold materials and tissue repair, as well as the interactions with endogenous cells. As the advances in bone tissue engineering move toward application in the clinical setting, the demonstration of the therapeutic efficacy of these novel scaffold designs is critical.