Antibacterial Activity and Cytocompatibility of Bone Cement Enriched with Antibiotic, Nanosilver, and Nanocopper for Bone Regeneration

Preparation and characterizations of antibacterial poly(methyl methacrylate) bone cement via copolymerization with a quaternary ammonium monomer of dimethylaminotriclosan methacrylate

Poly (methyl methacrylate) (PMMA) bone cement relies on the loaded antibiotic to realize the antibacterial purpose. But the exothermic behavior during setting often makes temperature-sensitive antibiotics inactivated. It is necessary to develop new material candidates to replace antibiotics. In this study, a new quaternary ammonium methacrylate (QAM) monomer called dimethylaminetriclosan methacrylate (DMATCM) was designed by the quaternization between 2-(Dimethylamino)ethyl methacrylate and triclosan, then employed as the modifier to explore the feasibility of equipping bone cement with antibacterial activity, and to investigate the variations on the physical and biological performances brought by the substitution ratio of DMATCM to MMA. Results showed that DMATCM opened its C=C bonding to participate in the MMA polymerization, and the quaternary ammonium group helped it to perform broad-spectrum antibacterial property against both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. With an increased substitution ratio of DMATCM to MMA, the glass transition temperatures, the maximum exothermic temperatures, and the contact angles of bone cements declined, but the residual monomer contents, the fluid uptakes, and the setting times under Vical indentation increased. Long-term soaking made almost no changes to the weight loss and the mechanical properties of DMATCM-modified cements with lower substitution ratios of 0∼20%, and the activation rather enhanced the strengths of uncured AMBC-4 and AMBC-5 samples. Owing to more DMATCM exposed on the cement surface, the inhibition ring diameter produced by modified cement was improved to a maximum of 28.09 mm, and MC3T3-E1 cells performed the cell viabilities all beyond 70% and healthy adhesion after 72 h co-culturing. Taking all measured properties and ISO standards into account, the antibacterial bone cement under the ratio of 10% performed better, besides its good bactericidal effect, the other properties satisfied the requirements for clinical application.

Effect of using nano-particles of magnesium oxide and titanium dioxide to enhance physical and mechanical properties of hip joint bone cement

In this work, the effect of adding Magnesium Oxide (MgO) and Titanium Dioxide (TiO2) nanoparticles to enhance the properties of the bone cement used for hip prosthesis fixation. Related to previous work on enhanced bone cement properties utilizing MgO and TiO2, samples of composite bone cement were made using three different ratios (0.5%:1%, 1.5%:1.5%, and 1%:0.5%) w/w of MgO and TiO2 to determine the optimal enhancement ratio. Hardness, compression, and bending tests were calculated to check the mechanical properties of pure and composite bone cement. The surface structure was studied using Fourier transform infrared spectroscopy (FTIR) and Field emission scanning electron microscopy (FE-SEM). Setting temperature, porosity, and degradation were calculated for each specimen ratio to check values matched with the standard range of bone cement. The results demonstrate a slight decrease in porosity up to 2.2% and degradation up to 0.17% with NP-containing composites, as well as acceptable variations in FTIR and setting temperature. The compression strength increased by 2.8% and hardness strength increased by 1.89% on adding 0.5%w/w of MgO and 1.5%w/w TiO2 NPs. Bending strength increases by 0.35% on adding 1.5% w/w of MgO and 0.5% w/w TiO2 NPs, however, SEM scan shows remarkable improvement for surface structure.

A Toolbox of Bone Consolidation for the Interventional Radiologist

Bone consolidation is increasingly used in the treatment of both benign and malignant bone conditions. Percutaneous vertebroplasty, for example, has been shown to be useful in vertebral compression fractures in the VAPOUR trial which showed its superiority to placebo for pain reduction in the treatment of acute vertebral compressive fractures. Further tools have since been developed, such as kyphoplasty, spinal implants, and even developments in bone cements itself in attempt to improve outcome, such as chemotherapy-loaded cement or cement replacements such as radio-opaque silicon polymer. More importantly, bone fixation and its combination with cement have been increasingly performed to improve outcome. Interventional radiologists must first know the tools available, before they can best plan for their patients. This review article will focus on the tool box available for the modern interventional radiologist.

Research progress and future prospects of antimicrobial modified polyetheretherketone (PEEK) for the treatment of bone infections

Infection of the bone is a difficult problem in orthopedic diseases. The key and basis of the treatment of bone infection is the effective control of local infection, as well as the elimination of infection focus and dead cavities. The most commonly used approach utilized for the prevention and management of bone infection is the application of antibiotic bone cement. However, the incorporation of antibiotics into the cement matrix has been found to considerably compromise the mechanical characteristics of bone cement. Moreover, some investigations have indicated that the antibiotic release rate of antibiotic bone cement is relatively low. Polyetheretherketone (PEEK) and its composites have been considered to perfectly address the challenges above, according to its favorable biomechanical characteristics and diverse surface functionalizations. This article provides a comprehensive overview of the recent advancements in the antimicrobial modification of PEEK composites in the field of antibacterial therapy of bone infection. Furthermore, the potential application of PEEK-modified materials in clinical treatment was discussed and predicted.

Study on injectable silver-incorporated calcium phosphate composite with enhanced antibacterial and biomechanical properties for fighting bone cement-associated infections

Although commonly used in orthopedic surgery, bone cements often face a high risk of post-operative infection. Developing bone cement with antibacterial capability is an effective path for eliminating implant-associated infections. Herein, the potential of silver ions (Ag⁺) and silver nanoparticles (AgNPs) in modifying CPC for long-term antibacterial property was investigated. Ag⁺ ions or AgNPs of various concentrations were incorporated in starch-modified calcium phosphate bone cement (CPB) to obtain Ag⁺-containing (Ag⁺@CPB) and AgNPs-containing (AgNP@CPB) bone cements. The results showed that all silver-containing CPBs had setting times of about 25-40 min, compressive strengths of greater than 22 MPa, high cytocompatibility but inhibitory effect on Staphylococcus aureus growth. After soaking for 1 week, the mechanical properties and the cytocompatibility of all cements revealed no significant changes, but only CPB with a relatively high content of Ag⁺ (H-Ag⁺@CPB) maintained good antibacterial capability over the tested time period. In addition, all the cements showed high injectability and interdigitating capability in cancellous bone and demonstrated augmentation effect on the cannulated pedicle screws fixation in the Sawbones model. In summary, the sustainable antibacterial capability and enhanced biomechanical properties demonstrated that Ag⁺ ions were more suitable for the fabrication of antibacterial CPC compared to AgNPs. Also, the H-Ag⁺@CPB, with good injectability, high cytocompatibility, good interdigitating and biomechanical property in cancellous bone, and sustainable antibacterial effects, bears great potential for the treatments of bone infections or implant-associated infections.

Silver Nanoparticles Enhance the Antibacterial Effect of Antibiotic-Loaded Bone Cement

Purpose The goal of this study was to determine the antibacterial activity of bone cement in polymethyl methacrylate (PMMA) structures with varying amounts of silver nanoparticles (AgNPs) included. Additionally, we aimed to evaluate whether AgNPs affect the biomechanical properties of PMMA cement in our study. Materials and methods Between April 2020 and June 2020, we conducted a series of experiments to demonstrate the antibacterial characteristics by adding silver nanoparticles to PMMA bone cement. PMMA bone cement (Cemex, Tecres Company, Verona, Italy) was used as the base material. Seven different samples were prepared in order to evaluate the amount and presence of AgNPs. Cement samples containing AgNPs and teicoplanin at different concentrations and empty cement (control, without teicoplanin and AgNPs) were placed on Petri plates. The agar diffusion method was used to determine the antibacterial effect (Kirby-Bauer). Results Kirby-Bauer assays demonstrated that AgNPs added to bone cement increased the antimicrobial activity compared to antibiotic-free or only teicoplanin-loaded cement. It was observed that increasing the AgNPs ratio further increased the antimicrobial activity. Conclusion AgNPs in various combinations enhance antimicrobial activity synergistically while maintaining the mechanical strength of bone cement. Increasing the amount of AgNPs results in a significant increase in antimicrobial activity.

Nano-embedded medical devices and delivery systems in interventional radiology

Nanomaterials research has significantly accelerated the development of the field of vascular and interventional radiology. The incorporation of nanoparticles with unique and functional properties into medical devices and delivery systems has paved the way for the creation of novel diagnostic and therapeutic procedures for various clinical disorders. In this review, we discuss the advancements in the field of interventional radiology and the role of nanotechnology in maximizing the benefits and mitigating the disadvantages of interventional radiology theranostic procedures. Several nanomaterials have been studied to improve the efficacy of interventional radiology interventions, reduce the complications associated with medical devices, improve the accuracy and efficiency of drug delivery systems, and develop innovative imaging modalities. Here, we summarize the recent progress in the development of medical devices and delivery systems that link nanotechnology in vascular and interventional radiology. This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices Diagnostic Tools > In Vivo Nanodiagnostics and Imaging Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease.

Effect of the Antimicrobial Agents Peppermint Essential Oil and Silver Nanoparticles on Bone Cement Properties

The main problems directly linked with the use of PMMA bone cements in orthopedic surgery are the improper mechanical bond between cement and bone and the absence of antimicrobial properties. Recently, more research has been devoted to new bone cement with antimicrobial properties using mainly antibiotics or other innovative materials with antimicrobial properties. In this paper, we developed modified PMMA bone cement with antimicrobial properties proposing some experimental antimicrobial agents consisting of silver nanoparticles incorporated in ceramic glass and hydroxyapatite impregnated with peppermint oil. The impact of the addition of antimicrobial agents on the structure, mechanical properties, and biocompatibility of new PMMA bone cements was quantified. It has been shown that the addition of antimicrobial agents improves the flexural strength of the traditional PMMA bone cement, while the yield strength values show a decrease, most likely because this agent acts as a discontinuity inside the material rather than as a reinforcing agent. In the case of all samples, the addition of antimicrobial agents had no significant influence on the thermal stability. The new PMMA bone cement showed good biocompatibility and the possibility of osteoblast proliferation (MTT test) along with a low level of cytotoxicity (LDH test).

A PMMA bone cement with improved antibacterial function and flexural strength

A novel non-leaching antibacterial bone cement has been developed and evaluated. An antibacterial furanone derivative was synthesized and covalently coated onto the surface of alumina filler particles, followed by mixing into a conventional poly(methyl methacrylate) bone cement. Flexural strength and bacterial viability were used to evaluate the modified cements. Effects of coated antibacterial moiety content, coated alumina filler particle size and loading were investigated. Results showed that almost all the modified cements showed higher flexural strength (up to 10%), flexural modulus (up to 18%), and antibacterial activity (up to 67% to S. aureus and up to 84% to E. coli), as compared to original poly(methyl methacrylate) cement. Increasing antibacterial moiety and filler loading significantly enhanced antibacterial activity. On the other hand, increasing coated filler particle size decreased antibacterial activity. Increasing antibacterial moiety content and particle size did not significantly affect flexural strength and modulus. Increasing filler loading did not significantly affect flexural modulus but reduced flexural strength. Antibacterial agent leaching tests showed that it seems no leachable antibacterial component from the modified experimental cement to the surrounding environment. Within the limitations of this study, the modified poly(methyl methacrylate) bone cement may potentially be developed into a clinically useful bone cement for reducing in-surgical and post-surgical infection.

Antibiotic-free antimicrobial poly (methyl methacrylate) bone cements: A state-of-the-art review

Prosthetic joint infection (PJI) is the most serious complication following total joint arthroplasty, this being because it is associated with, among other things, high morbidity and low quality of life, is difficult to prevent, and is very challenging to treat/manage. The many shortcomings of antibiotic-loaded poly (methyl methacrylate) (PMMA) bone cement (ALBC) as an agent for preventing and treating/ managing PJI are well-known. One is that microorganisms responsible for most PJI cases, such as methicillin-resistant S. aureus, have developed or are developing resistance to gentamicin sulfate, which is the antibiotic in the vast majority of approved ALBC brands. This has led to many research efforts to develop cements that do not contain gentamicin (or, for that matter, any antibiotic) but demonstrate excellent antimicrobial efficacy. There is a sizeable body of literature on these so-called “antibiotic-free antimicrobial” PMMA bone cements (AFAMBCs). The present work is a comprehensive and critical review of this body. In addition to summaries of key trends in results of characterization studies of AFAMBCs, the attractive features and shortcomings of the literature are highlighted. Shortcomings provide motivation for future work, with some ideas being formulation of a new generation of AFAMBCs by, example, adding a nanostructured material and/or an extract from a natural product to the powder and/or liquid of the basis cement, respectively.

Current Knowledge on Biomaterials for Orthopedic Applications Modified to Reduce Bacterial Adhesive Ability

A significant challenge in orthopedics is the design of biomaterial devices that are able to perform biological functions by substituting or repairing various tissues and controlling bone repair when required. This review presents an overview of the current state of our recent research into biomaterial modifications to reduce bacterial adhesive ability, compared with previous reviews and excellent research papers, but it is not intended to be exhaustive. In particular, we investigated biomaterials for replacement, such as metallic materials (titanium and titanium alloys) and polymers (ultra-high-molecular-weight polyethylene), and biomaterials for regeneration, such as poly(ε-caprolactone) and calcium phosphates as composites. Biomaterials have been designed, developed, and characterized to define surface/bulk features; they have also been subjected to bacterial adhesion assays to verify their potential capability to counteract infections. The addition of metal ions (e.g., silver), natural antimicrobial compounds (e.g., essential oils), or antioxidant agents (e.g., vitamin E) to different biomaterials conferred strong antibacterial properties and anti-adhesive features, improving their capability to counteract prosthetic joint infections and biofilm formation, which are important issues in orthopedic surgery. The complexity of biological materials is still far from being reached by materials science through the development of sophisticated biomaterials. However, close interdisciplinary work by materials scientists, engineers, microbiologists, chemists, physicists, and orthopedic surgeons is indeed necessary to modify the structures of biomaterials in order to achieve implant integration and tissue regeneration while avoiding microbial contamination.

Evaluation of the Effect of Selected Physiological Fluid Contaminants on the Mechanical Properties of Selected Medium-Viscosity PMMA Bone Cements

Revision surgeries several years after the implantation of the prosthesis are unfavorable from the patient’s point of view as they expose him to additional discomfort, to risk of complications and are expensive. One of the factors responsible for the aseptic loosening of the prosthesis is the gradual degradation of the cement material as a result of working under considerable loads, in an aggressive environment of the human body. Contaminants present in the surgical field may significantly affect the durability of the bone cement and, consequently, of the entire bone-cement-prosthesis system. The paper presents the results of an analysis of selected mechanical properties of two medium-viscosity bone cements DePuy CMW3 Gentamicin and Heraeus Palamed, for the samples contaminated with saline and blood in the range of 1–10%. The results obtained for compressive strength and modulus of elasticity were subjected to statistical analysis, which estimated the nature of changes in these parameters depending on the amount and type of contamination and their statistical significance.

Influence of Different Nanometals Implemented in PMMA Bone Cement on Biological and Mechanical Properties

Cemented arthroplasty is a common process to fix prostheses when a patient becomes older and his/her bone quality deteriorates. The applied cements are biocompatible, can transfer loads, and dampen vibrations, but do not provide antibacterial protection. The present work is aimed at the development of cement with antibacterial effectivity achieved with the implementation of nanoparticles of different metals. The powders of Ag, Cu with particles size in a range of 10–30 nm (Cu10) and 70–100 nm (Cu70), AgCu, and Ni were added to PMMA cement. Their influence on compression strength, wettability, and antibacterial properties of cement was assessed. The surface topography of samples was examined with biological and scanning electron microscopy. The mechanical properties were determined by compression tests. A contact angle was observed with a goniometer. The biological tests included an assessment of cytotoxicity (XTT test on human cells Saos-2 line) and bacteria viability exposure (6 months). The cements with Ag and Cu nanopowders were free of bacteria. For AgCu and Ni nanoparticles, the bacterial solution became denser over time and, after 6 months, the bacteria clustered into conglomerates, creating a biofilm. All metal powders in their native form in direct contact reduce the number of eukaryotic cells. Cell viability is the least limited by Ag and Cu particles of smaller size. All samples demonstrated hydrophobic nature in the wettability test. The mechanical strength was not significantly affected by the additions of metal powders. The nanometal particles incorporated in PMMA-based bone cement can introduce long-term resistance against bacteria, not resulting in any serious deterioration of compression strength.

Advances in Copper-Based Biomaterials With Antibacterial and Osteogenic Properties for Bone Tissue Engineering

Treating bone defects coupled with pathogen infections poses a formidable challenge to clinical medicine. Thus, there is an urgent need to develop orthopedic implants that provide excellent antibacterial and osteogenic properties. Of the various types, copper-based biomaterials capable of both regenerating bone and fighting infections are an effective therapeutic strategy for bone tissue engineering and therefore have attracted significant research interest. This review examines the advantages of copper-based biomaterials for biological functions and introduces these materials’ antibacterial mechanisms. We summarize current knowledge about the application of copper-based biomaterials with antimicrobial and osteogenic properties in the prevention and treatment of bone infection and discuss their potential uses in the field of orthopedics. By examining both broad and in-depth research, this review functions as a practical guide to developing copper-based biomaterials and offers directions for possible future work.

Hyaluronic Acid-Silver Nanocomposites and Their Biomedical Applications: A Review

For the last years scientific community has witnessed a rapid development of novel types of biomaterials, which properties made them applicable in numerous fields of medicine. Although nanosilver, well-known for its antimicrobial, anti-angiogenic, anti-inflammatory and anticancer activities, as well as hyaluronic acid, a natural polysaccharide playing a vital role in the modulation of tissue repair, signal transduction, angiogenesis, cell motility and cancer metastasis, are both thoroughly described in the literature, their complexes are still a novel topic. In this review we introduce the most recent research about the synthesis, properties, and potential applications of HA-nanosilver composites. We also make an attempt to explain the variety of mechanisms involved in their action. Finally, we present biocompatible and biodegradable complexes with bactericidal activity and low cytotoxicity, which properties suggest their suitability for the prophylaxis and therapy of chronic wounds, as well as analgetic therapies, anticancer strategies and the detection of chemical substances and malignant cells. Cited studies reveal that the usage of hyaluronic acid-silver nanocomposites appears to be efficient and safe in clinical practice.

Intrinsically radiopaque biomaterial assortments: a short review on the physical principles, X-ray imageability, and state-of-the-art developments

X-ray attenuation ability, otherwise known as radiopacity of a material, could be indisputably tagged as the central and decisive parameter that produces contrast in an X-ray image. Radiopaque biomaterials are vital in the healthcare sector that helps clinicians to track them unambiguously during pre and post interventional radiological procedures. Medical imaging is one of the most powerful resources in the diagnostic sector that aids improved treatment outcomes for patients. Intrinsically radiopaque biomaterials enable themselves for visual targeting/positioning as well as to monitor their fate and further provide the radiologists with critical insights about the surgical site. Moreover, the emergence of advanced real-time imaging modalities is a boon to the contemporary healthcare systems that allow to perform minimally invasive surgical procedures and thereby reduce the healthcare costs and minimize patient trauma. X-ray based imaging is one such technologically upgraded diagnostic tool with many variants like digital X-ray, computed tomography, digital subtraction angiography, and fluoroscopy. In light of these facts, this review is aimed to briefly consolidate the physical principles of X-ray attenuation by a radiopaque material, measurement of radiopacity, classification of radiopaque biomaterials, and their recent advanced applications.

Current approaches for the exploration of antimicrobial activities of nanoparticles

Infectious diseases of bacterial and viral origins contribute to substantial mortality worldwide. Collaborative efforts have been underway between academia and the industry to develop technologies for a more effective treatment for such diseases. Due to their utility in various industrial applications, nanoparticles (NPs) offer promising potential as antimicrobial agents against bacterial and viral infections. NPs have been established to possess potent antimicrobial activities against various types of pathogens due to their unique characteristics and cell-damaging ability through several mechanisms. The recently accepted antimicrobial mechanisms possessed by NPs include metal ion release, oxidative stress induction, and non-oxidative mechanisms. Another merit of NPs lies in the low likelihood of the development of microbial tolerance towards NPs, given the multiple simultaneous mechanisms of action against the pathogens targeting numerous gene mutations in these pathogens. Moreover, NPs provide a fascinating opportunity to curb microbial growth before infections: this outstanding feature has led to their utilization as active antimicrobial agents in different industrial applications, e.g. the coating of medical devices, incorporation in food packaging, promoting wound healing and encapsulation with other potential materials for wastewater treatment. This review discusses the progress and achievements in the antimicrobial applications of NPs, factors contributing to their actions, mechanisms underlying their efficiency, and risks of their applications, including the antimicrobial action of metal nanoclusters (NCs). The review concludes with a discussion of the restrictions on present studies and future prospects of nanotechnology-based NPs development.

Effect of Gold Nanoparticles and Silicon on the Bioactivity and Antibacterial Properties of Hydroxyapatite/Chitosan/Tricalcium Phosphate-Based Biomicroconcretes

Bioactive, chemically bonded bone substitutes with antibacterial properties are highly recommended for medical applications. In this study, biomicroconcretes, composed of silicon modified (Si-αTCP) or non-modified α-tricalcium phosphate (αTCP), as well as hybrid hydroxyapatite/chitosan granules non-modified and modified with gold nanoparticles (AuNPs), were designed. The developed biomicroconcretes were supposed to combine the dual functions of antibacterial activity and bone defect repair. The chemical and phase composition, microstructure, setting times, mechanical strength, and in vitro bioactive potential of the composites were examined. Furthermore, on the basis of the American Association of Textile Chemists and Colorists test (AATCC 100), adapted for chemically bonded materials, the antibacterial activity of the biomicroconcretes against S. epidermidis, E. coli, and S. aureus was evaluated. All biomicroconcretes were surgically handy and revealed good adhesion between the hybrid granules and calcium phosphate-based matrix. Furthermore, they possessed acceptable setting times and mechanical properties. It has been stated that materials containing AuNPs set faster and possess a slightly higher compressive strength (3.4 ± 0.7 MPa). The modification of αTCP with silicon led to a favorable decrease of the final setting time to 10 min. Furthermore, it has been shown that materials modified with AuNPs and silicon possessed an enhanced bioactivity. The antibacterial properties of all of the developed biomicroconcretes against the tested bacterial strains due to the presence of both chitosan and Au were confirmed. The material modified simultaneously with AuNPs and silicon seems to be the most promising candidate for further biological studies.

The Combined Use of Gentamicin and Silver Nitrate in Bone Cement for a Synergistic and Extended Antibiotic Action against Gram-Positive and Gram-Negative Bacteria

Using bone cement as a carrier, gentamicin was for years the default drug to locally treat orthopedic infections but has lost favor due to increasing bacterial resistance to this drug. The objective of this study was to investigate the effect of combining gentamicin with silver nitrate in bone cement against S. aureus and P. aeruginosa. Antibacterial effects (CFU counts) of gentamicin and silver were initially studied followed by studies using subtherapeutic concentrations of each in combination. The release rates from cement were measured over 10 days and day 7 release samples were saved and analyzed for antibiotic activity. A strong synergistic effect of combining silver with gentamicin was found using both dissolved drugs and using day 7 bone cement release media for both Gram-positive and Gram-negative bacteria. The cement studies were extended to vancomycin and tobramycin, which are also used in bone cement, and similar synergistic effects were found for day 7 release media with P. aeruginosa but not S. aureus. These studies conclude that the combined use of low loadings of gentamicin and silver nitrate in bone cement may offer an economical and much improved synergistic method of providing anti-infective orthopedic treatments in the clinic.

Nanosilver-loaded PMMA bone cement doped with different bioactive glasses - evaluation of cytocompatibility, antibacterial activity, and mechanical properties

Nanosilver-loaded PMMA bone cement (BC-AgNp) is a novel cement developed as a replacement for conventional cements. Despite its favorable properties and antibacterial activity, BC-AgNp still lacks biodegradability and bioactivity. Hence, we investigated doping with bioactive glasses (BGs) to create a new bioactive BC characterized by time-varying porosity and gradual release of AgNp. The BC Cemex was used as the base material and modified simultaneously with the AgNp and BGs: melted 45S5 and 13-93B3 glasses with various particle sizes and sol-gel derived SiO₂/CaO microparticles. The effect of BG addition was examined by microscopic analysis, an assessment of setting parameters, wettability, FTIR and UV-VIS spectroscopy, mechanical testing, and hemo- and cytocompatibility and antibacterial efficiency studies. The results show that it is possible to incorporate various BGs into BC-AgNp, which leads to different properties depending on the type and size of BGs. The smaller particles of melted BGs showed higher porosity and better antibacterial properties with the moderate deterioration of mechanical properties. The sol-gel derived BGs, however, displayed a tendency for agglomeration and random distribution in BC-AgNp. The BGs with greater solubility more efficiently improve the antibacterial properties of BC-AgNp. Besides, the unreacted MMA monomer release could negatively influence the cellular response. Despite that, cements doped with different BGs are suitable for medical applications.

Antibacterial biomaterials in bone tissue engineering

Bone infection is a devastating disease characterized by recurrence, drug-resistance, and high morbidity, that has prompted clinicians and scientists to develop novel approaches to combat it. Currently, although numerous biomaterials that possess excellent biocompatibility, biodegradability, porosity, and mechanical strength have been developed, their lack of effective antibacterial ability substantially limits bone-defect treatment efficacy. There is, accordingly, a pressing need to design antibacterial biomaterials for effective bone-infection prevention and treatment. This review focuses on antibacterial biomaterials and strategies; it presents recently reported biomaterials, including antibacterial implants, antibacterial scaffolds, antibacterial hydrogels, and antibacterial bone cement types, and aims to provide an overview of these antibacterial materials for application in biomedicine. The antibacterial mechanisms of these materials are discussed as well.

Influence of several biodegradable components added to pure and nanosilver-doped PMMA bone cements on its biological and mechanical properties

Acrylic bone cements (BC) are wildly used in medicine. Despite favorable mechanical properties, processability and inject capability, BC lack bioactivity. To overcome this, we investigated the effects of selected biodegradable additives to create a partially-degradable BC and also we evaluated its combination with nanosilver (AgNp). We hypothesized that using above strategies it would be possible to obtain bioactive BC. The Cemex was used as the base material, modified at 2.5, 5 or 10 wt% with either cellulose, chitosan, magnesium, polydioxanone or tricalcium-phosphate. The resulted modified BC was examined for surface morphology, wettability, porosity, mechanical and nanomechanical properties and cytocompatibility. The composite BC doped with AgNp was also examined for its release and antibacterial properties. The results showed that it is possible to create modified cement and all studied modifiers increased its porosity. Applying the additives slightly decreased BC wettability and mechanical properties, but the positive effect of the additives was observed in nanomechanical research. The relatively poor cytocompatibility of modified BC was attributed to the unreacted monomer release, except for polydioxanone modification which increased cells viability. Furthermore, all additives facilitated AgNp release and increased BC antibacterial effectiveness. Our present studies suggest the optimal content of biodegradable component for BC is 5 wt%. At this content, an improvement in BC porosity is achieved without significant deterioration of BC physical and mechanical properties. Polydioxanone and cellulose seem to be the most promising additives that improve porosity and antibacterial properties of antibiotic or nanosilver-loaded BC. Partially-degradable BC may be a good strategy to improve their antibacterial effectiveness, but some caution is still required regarding their cytocompatibility. STATEMENT OF SIGNIFICANCE: The lack of bone cement bioactivity is the main limitation of its effectiveness in medicine. To overcome this, we have created composite cements with partially-degradable properties. We also modified these cements with nanosilver to provide antibacterial properties. We examined five various additives at three different contents to modify a selected bone cement. Our results broaden the knowledge about potential modifiers and properties of composite cements. We selected the optimal content and the most promising additives, and showed that the combination of these additives with nanosilver would increase cements` antibacterial effectiveness. Such modified cements may be a new solution for medical applications.

Synthesis of antibacterial polyurethane film and its properties

Polyurethane (PU) is a polymer widely used in the biomedical field with excellent mechanical properties and good biocompatibility. However, it usually exhibits poor antibacterial properties for practical applications. Efforts are needed to improve the antibacterial activities of PU films for broader application prospect and added application values. In the present work, two PU films, TDI-P(E-co-T) and TDI-N-100-P(E-co-T), were prepared. Silver nanoparticles (AgNPs) were composited into the TDI-N-100-P(E-co-T) film for better mechanical properties and antibacterial activities, and resultant PU/AgNPs composite film was systematically characterized and studied. The as-prepared PU/AgNPs composite film exhibits much better antibacterial properties than the traditional PU membrane, exhibiting broader application prospect.

Implant system for treatment of the orbital floor defects of blowout fractures in the maxillofacial region using polypropylene yarn and bioactive bone cement

Fractures in the craniofacial region are a serious problem in terms of treatment. The most reasonable solution is the use of individual implants dedicated to a specific patient. The aim of this study was to develop the implant system specifically for treatment of the orbital floor defects of blowout fractures of maxillofacial region, using polypropylene yarn and bone cement. Three types of bone cement were used to fix the polypropylene yarn: unmodified, antibiotic-loaded, and modified with nanometals. The following research was carried out: selection of cement production parameters, assessment of the curing time, measurement of polymerization temperature, an analysis of microstructure and surface topography, evaluation of wettability, measurement of microhardness, and studies of bactericidal effectiveness. The research confirms the possibility of using bone cement and polypropylene yarn for an individual implant, dedicated to the fractures treatment in the maxillofacial region. Moreover, the bactericidal properties of the proposed modifications for bone cement have been verified; hence, bioactive cements are recommended for use in the case of infectious complications.

PMMA-Based Bone Cements and the Problem of Joint Arthroplasty Infections: Status and New Perspectives

Polymethyl methacrylate (PMMA)-based bone cement is a biomaterial that has been used over the last 50 years to stabilize hip and knee implants or as a bone filler. Although PMMA-based bone cement is widely used and allows a fast-primary fixation to the bone, it does not guarantee a mechanically and biologically stable interface with bone, and most of all it is prone to bacteria adhesion and infection development. In the 1970s, antibiotic-loaded bone cements were introduced to reduce the infection rate in arthroplasty; however, the efficiency of antibiotic-containing bone cement is still a debated issue. For these reasons, in recent years, the scientific community has investigated new approaches to impart antibacterial properties to PMMA bone cement. The aim of this review is to summarize the current status regarding antibiotic-loaded PMMA-based bone cements, fill the gap regarding the lack of data on antibacterial bone cement, and explore the progress of antibacterial bone cement formulations, focusing attention on the new perspectives. In particular, this review highlights the innovative study of composite bone cements containing inorganic antibacterial and bioactive phases, which are a fascinating alternative that can impart both osteointegration and antibacterial properties to PMMA-based bone cement.

The Effect of Surface Modification of Ti13Zr13Nb Alloy on Adhesion of Antibiotic and Nanosilver-Loaded Bone Cement Coatings Dedicated for Application as Spacers

Spacers, in terms of instruments used in revision surgery for the local treatment of postoperative infection, are usually made of metal rod covered by antibiotic-loaded bone cement. One of the main limitations of this temporary implant is the debonding effect of metal-bone cement interface, leading to aseptic loosening. Material selection, as well as surface treatment, should be evaluated in order to minimize the risk of fraction and improve the implant-cement fixation the appropriate manufacturing. In this study, Ti13Zr13Nb alloys that were prepared by Selective Laser Melting and surface treated were coated with bone cement loaded with either gentamicin or nanosilver, and the effects of such alloy modifications were investigated. The SLM-made specimens of Ti13Zr13Nb were surface treated by sandblasting, etching, or grounding. For each treatment, Scanning Electron Microscope (SEM), contact profilometer, optical tensiometer, and nano-test technique carried out microstructure characterization and surface analysis. The three types of bone cement i.e., pure, containing gentamicin and doped with nanosilver were applied to alloy surfaces and assessed for cement cohesion and its adhesion to the surface by nanoscratch test and pull-off. Next, the inhibition of bacterial growth and cytocompatibility of specimens were investigated by the Bauer-Kirby test and MTS assay respectively. The results of each test were compared to the two control groups, consisting of commercially available Ti13Zr13Nb and untreated SLM-made specimens. The highest adhesion bone cement to the titanium alloy was obtained for specimens with high nanohardness and roughness. However, no explicit relation of adhesion strength with wettability and surface energy of alloy was observed. Sandblasting or etching were the best alloys treatments in terms of the adhesion of either pure or modified bone cements. Antibacterial additives for bone cement affected its properties. Gentamicin and nanosilver allowed for adequate anti-bacterial protection while maintaining the overall biocompatibility of obtained spacers. However, they had different effects on the cement's adhesive capacity or its own cohesion. Furthermore, the addition of silver nanoparticles improved the nanomechanical properties of bone cements. Surface treatment and method of fabrication of titanium affected surface parameters that had a significant impact on cement-titanium fixation.