Ceramic scaffolds enriched with gentamicin loaded poly(lactide- co -glycolide) microparticles for prevention and treatment of bone tissue infections

Antibacterial and Osteogenic Dual-Functional Micronano Composite Scaffold Fabricated via Melt Electrowriting and Solution Electrospinning for Bone Tissue Engineering

The utilization of micronano composite scaffolds has been extensively demonstrated to confer the superior advantages in bone repair compared to single nano- or micron-sized scaffolds. Nevertheless, the enhancement of bioactivities within these composite scaffolds remains challenging. In this study, we propose a novel approach to combine melt electrowriting (MEW) and solution electrospinning (SES) techniques for the fabrication of a composite scaffold incorporating hydroxyapatite (HAP), an osteogenic component, and roxithromycin (ROX), an antibacterial active component. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) confirmed the hierarchical architecture of the nanofiber-microgrid within the scaffold, as well as the successful loading of HAP and ROX. The incorporation of HAP enhanced the water absorption capacity of the composite scaffold, thus promoting cell adhesion and proliferation, as well as osteogenic differentiation. Furthermore, ROX resulted in effective antibacterial capability without any observable cytotoxicity. Finally, the scaffolds were applied to a rat calvarial defect model, and the results demonstrated that the 20% HAP group exhibited superior new bone formation without causing adverse reactions. Therefore, our findings present a promising strategy for designing and fabricating bioactive scaffolds for bone regeneration.

Research Progress of Design Drugs and Composite Biomaterials in Bone Tissue Engineering

Bone, like most organs, has the ability to heal naturally and can be repaired slowly when it is slightly injured. However, in the case of bone defects caused by diseases or large shocks, surgical intervention and treatment of bone substitutes are needed, and drugs are actively matched to promote osteogenesis or prevent infection. Oral administration or injection for systemic therapy is a common way of administration in clinic, although it is not suitable for the long treatment cycle of bone tissue, and the drugs cannot exert the greatest effect or even produce toxic and side effects. In order to solve this problem, the structure or carrier simulating natural bone tissue is constructed to control the loading or release of the preparation with osteogenic potential, thus accelerating the repair of bone defect. Bioactive materials provide potential advantages for bone tissue regeneration, such as physical support, cell coverage and growth factors. In this review, we discuss the application of bone scaffolds with different structural characteristics made of polymers, ceramics and other composite materials in bone regeneration engineering and drug release, and look forward to its prospect.

Advanced Procedure of Simultaneous Electrodeposition from a Natural Deep Eutectic Solvent of a Drug and a Polymer Used to Improve TiZr Alloy Behavior

This paper presents research about the embedding and release of gentamicin from an electrochemical deposition of polypyrrole from ionic liquids such as choline chloride on TiZr bioalloy. The electrodeposited films were morphologically investigated using scanning electron microscopy (SEM) with an EDX module, and polypyrrole and gentamicin were both identified using structural FT-IR analysis. The film's characterization was completed with an evaluation of hydrophilic-hydrophobic balance, with electrochemical stability measurements in PBS and with antibacterial inhibition. A decrease in the value of the contact angle was observed from 47.06° in the case of the uncoated sample to 8.63° in the case of the sample covered with PPy and GS. Additionally, an improvement in the anticorrosive properties of the coating was observed by increasing the efficiency to 87.23% in the case of TiZr-PPy-GS. A kinetic study of drug release was performed as well. The drug molecule might be provided by the PPy-GS coatings for up to 144 h. The highest amount released was calculated to be 90% of the entire drug reservoir capacity, demonstrating the effectiveness of the coatings. A non-Fickian behavior was established as a mechanism for the release profiles of the gentamicin from the polymer layer.

Surface Multifunctionalization of Inert Ceramic Implants by Calcium Phosphate Biomimetic Coating Doped with Nanoparticles Encapsulating Antibiotics

Aseptic loosening and periprosthetic infections are complications that can occur at the interface between inert ceramic implants and natural body tissues. Therefore, the need for novel materials with antibacterial properties to prevent implant-related infection is evident. This study proposes multifunctionalizing the inert ceramic implant surface by biomimetic calcium phosphate (CaP) coating decorated with antibiotic-loaded nanoparticles for bioactivity enhancement and antibacterial effect. This study aimed to coat zirconium dioxide (ZrO₂) substrates with a bioactive CaP-layer containing drug-loaded degradable polymer nanoparticles (NPs). The NPs were loaded with two antibiotics, gentamicin or bacitracin. The immobilization of NPs happened by two deposition methods: coprecipitation and drop-casting. X-ray diffraction (XRD), scanning electron microscopy (SEM), and cross-section analyses were used to characterize the coatings. MG-63 osteoblast-like cells and human mesenchymal stem cells (hMSC) were chosen for in vitro tests. Antibacterial activity was assessed with S. aureus and E. coli. The coprecipitation method allowed for a favorable homogeneous distribution of the NPs within the CaP coating. The CaP coating was constituted of hydroxyapatite and octacalcium phosphate; its thickness was 3.8 ± 1 μm with cavities of around 1 μm suitable for hosting NPs with a size of 200 nm. Antibiotics were released from the coatings in a controlled manner for 1 month. The cell culture study has confirmed the excellent behavior of the coprecipitated coating, showing cytocompatibility and a homogeneous distribution of the cells on the coated surfaces. The increase in alkaline phosphatase activity showed osteogenic differentiation. The materials were found to inhibit the growth of bacteria. Newly developed coatings with antibacterial and bioactive properties are promising candidates to prevent peri-implant infectious bone diseases.

Recent Advancements in Metallic Drug-Eluting Implants

Over the past decade, metallic drug-eluting implants have gained significance in orthopedic and dental applications for controlled drug release, specifically for preventing infection associated with implants. Recent studies showed that metallic implants loaded with drugs were substituted for conventional bare metal implants to achieve sustained and controlled drug release, resulting in a desired local therapeutic concentration. A number of secondary features can be provided by the incorporated active molecules, including the promotion of osteoconduction and angiogenesis, the inhibition of bacterial invasion, and the modulation of host body reaction. This paper reviews recent trends in the development of the metallic drug-eluting implants with various drug delivery systems in the past three years. There are various types of drug-eluting implants that have been developed to meet this purpose, depending on the drug or agents that have been loaded on them. These include anti-inflammatory drugs, antibiotics agents, growth factors, and anti-resorptive drugs.

Bioceramic-based scaffolds with antibacterial function for bone tissue engineering: A review

Bone defects caused by trauma, tumor, congenital abnormality and osteoarthritis, etc. have been substantially impacted the lives and health of human. Artificial bone implants, like bioceramic-based scaffolds, provide significant benefits over biological counterparts and are critical for bone repair and regeneration. However, it is highly probable that bacterial infections occur in the surgical procedures or on bioceramic-based scaffolds. Therefore, it is of great significance to obtain bioceramic-based scaffolds with integrative antibacterial and osteogenic functions for treating bone implant-associated infection and promoting bone repair. To fight against infection problems, bioceramic-based scaffolds with various antibacterial strategies are developed for bone repair and regeneration and also have made great progresses. This review summarizes recent progresses in bioceramic-based scaffolds with antibacterial function, which include drug-induced, ion-mediated, physical-activated and their combined antibacterial strategies according to specific antibacterial mechanism. Finally, the challenges and opportunities of antibacterial bioceramic-based scaffolds are discussed.

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Bioceramic-based scaffolds with antibacterial function (BSAF) are reviewed.

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BSAF have a great potential in treating bone infection and promoting bone repair.

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Antibacterial strategies of BSAF include drug, ion, physical and combined ways.

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The combined strategy may be the optimal approach in fighting bone infection.

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Limitations, challenges and perspectives of BSAF are discussed.

Insight in Superiority of the Hydrophobized Gentamycin in Terms of Antibiotics Delivery to Bone Tissue

Bone infections are a serious problem to cure, as systemic administration of antibiotics is not very effective due to poor bone vascularization. Therefore, many drug delivery systems are investigated to solve this problem. One of the potential solutions is the delivery of antibiotics from poly(L-actide-co-glycolide) (PLGA) nanoparticles suspended in the gellan gum injectable hydrogel. However, the loading capacity and release kinetics of the system based on hydrophilic drugs (e.g., gentamycin) and hydrophobic polymers (e.g., PLGA) may not always be satisfying. To solve this problem, we decided to use hydrophobized gentamycin obtained by ion-pairing with dioctyl sulfosuccinate sodium salt (AOT). Herein, we present a comparison of the PLGA nanoparticles loaded with hydrophobic or hydrophilic gentamycin and suspended in the hydrogel in terms of physicochemical properties, drug loading capacity, release profiles, cytocompatibility, and antibacterial properties. The results showed that hydrophobic gentamycin may be combined in different formulations with the hydrophilic one and is superior in terms of encapsulation efficiency, drug loading, release, and antibacterial efficacy with no negative effect on the NPs morphology or hydrogel features. However, the cytocompatibility of hydrophobic gentamycin might be lower, consequently more extensive study on its biological properties should be provided to evaluate a safe dose.

Smart biomaterials and their potential applications in tissue engineering

Smart biomaterials have been rapidly advancing ever since the concept of tissue engineering was proposed. Interacting with human cells, smart biomaterials can play a key role in novel tissue morphogenesis. Various aspects of biomaterials utilized in or being sought for the goal of encouraging bone regeneration, skin graft engineering, and nerve conduits are discussed in this review. Beginning with bone, this study summarizes all the available bioceramics and materials along with their properties used singly or in conjunction with each other to create scaffolds for bone tissue engineering. A quick overview of the skin-based nanocomposite biomaterials possessing antibacterial properties for wound healing is outlined along with skin regeneration therapies using infrared radiation, electrospinning, and piezoelectricity, which aid in wound healing. Furthermore, a brief overview of bioengineered artificial skin grafts made of various natural and synthetic polymers has been presented. Finally, by examining the interactions between natural and synthetic-based biomaterials and the biological environment, their strengths and drawbacks for constructing peripheral nerve conduits are highlighted. The description of the preclinical outcome of nerve regeneration in injury healed with various natural-based conduits receives special attention. The organic and synthetic worlds collide at the interface of nanomaterials and biological systems, producing a new scientific field including nanomaterial design for tissue engineering.

Allicin-Loaded Hydroxyapatite: Enhanced Release, Cytocompatibility, and Antibacterial Properties for Bone Tissue Engineering Applications

Allicin, the active compound of garlic extract, is a naturally sourced biomolecule, which promotes a vast range of health benefits. However, the limited stability of allicin restricts its applications in tissue engineering. Additionally, the detailed effects of allicin in bone health are yet to be explored. Our work reports on the fabrication of a novel allicin-loaded hydroxyapatite drug delivery system with enhanced biological properties. The fabricated system shows excellent antibacterial efficiency against S. aureus after 36 h of bacterial interaction with a sample. The allicin release kinetics are enhanced with polycaprolactone (PCL). The obtained results after 20 days of drug release study indicate that PCL coating leads to an increase in cumulative allicin release from ~ 35% to 70% at a physiological pH of 7.4. These scaffolds maintain stability during the whole period of drug release. Cytocompatibility of tested compositions with osteoblasts indicates enhanced cell viability and good filopodial attachment on the sample surface at day 7. These allicin-loaded antibacterial and cytocompatible scaffolds can find applications as localized delivery vehicles for bone tissue engineering.

Alginate-based Composites Microspheres: Preparations and Applications for Bone Tissue Engineering

Alginate-based biomaterials have been extensively studied for bone tissue engineering. Scaffolds, microspheres, and hydrogels can be developed using alginate, which is biocompatible, biodegradable, and able to deliver growth factors and drugs. Alginate microspheres can be produced using crosslinking, microfluidic, three-dimensional printing, extrusion, and emulsion methods. The sizes of the alginate microspheres range from 10 µm to 4 mm. This review describes the chemical characterization and mechanical assessment of alginate-based microspheres. Combinations of alginate with hydroxyapatite, chitosan, collagen, polylactic acid, polycaprolactone, and bioglass were discussed for bone tissue repair and regeneration. In addition, alginate combinations with bone morphogenetic proteins, vascular endothelial growth factor, transforming growth factor beta-3, other growth factors, cells, proteins, drugs, and osteoinductive drugs were analyzed for tissue engineering applications. Furthermore, the biocompatibility of developed alginate microspheres was discussed for different cell lines. Finally, alginate microsphere-based composites with stem cell interaction for bone tissue regeneration were presented. In the present review, we have assessed the preclinical research on in vivo models of alginate-based microspheres for bone tissue repair and regeneration. Overall, alginate-based microspheres are potential candidates for graft substitutes and the treatment of various bone-related diseases.

Recent advances in the local antibiotics delivery systems for management of osteomyelitis

Chronic osteomyelitis is a challenging disease due to its serious rates of mortality and morbidity while the currently available treatment strategies are suboptimal. In contrast to the adopted systemic treatment approaches after surgical debridement in chronic osteomyelitis, local drug delivery systems are receiving great attention in the recent decades. Local drug delivery systems using special carriers have the pros of enhancing the feasibility of penetration of antimicrobial agents to bone tissues, providing sustained release and localized concentrations of the antimicrobial agents in the infected area while avoiding the systemic side effects and toxicity. Most important, the incorporation of osteoinductive and osteoconductive materials in these systems assists bones proliferation and differentiation, hence the generation of new bone materials is enhanced. Some of these systems can also provide mechanical support for the long bones during the healing process. Most important, if the local systems are designed to be injectable to the affected site and biodegradable, they will reduce the level of invasion required for implantation and can win the patients’ compliance and reduce the healing period. They will also allow multiple injections during the course of therapy to guard against the side effect of the long-term systemic therapy. The current review presents different available approaches for delivering antimicrobial agents for the treatment of osteomyelitis focusing on the recent advances in researches for local delivery of antibiotics.

HIGHLIGHTS

Chronic osteomyelitis is a challenging disease due to its serious mortality and morbidity rates and limited effective treatment options.

Local drug delivery systems are receiving great attention in the recent decades.

Osteoinductive and osteoconductive materials in the local systems assists bones proliferation and differentiation

Local systems can be designed to provide mechanical support for the long bones during the healing process.

Designing the local system to be injectable to the affected site and biodegradable will reduces the level of invasion and win the patients’ compliance.

Periodic charge matching driven immobilization of gentamicin in nanoclays for stable and long-term antibacterial coating

Matching of charge periodicity between a guest and a host enabled effective immobilization of highly water-soluble antibiotic drug, gentamicin C, in a bentonite clay by cation exchange. X-ray diffraction, infrared spectroscopy and CHNS analysis revealed the immobilization manner of gentamicin C, which was immobilized between bentonite layers via periodic charge-charge interaction with tilted arrangement, as a trication. Both gentamicin alone and a gentamicin/bentonite hybrid were coated onto a polyurethane substrate using water-borne polyurethane binder. The antibiotic character of both films was investigated as prepared or after immersion in phosphate-buffered saline till 5 days against E. coli and B. subtilis bacteria. It was clearly shown that the gentamicin/bentonite hybrid-coated film showed sustained antibacterial efficacy even after exposure to phosphate-buffered saline, while gentamicin only-coated film gradually lost its performance under the same condition.

Biocompatible hyaluronic acid-divinyl sulfone injectable hydrogels for sustained drug release with enhanced antibacterial properties against Staphylococcus aureus

Hyaluronic acid (HA) solutions were crosslinked with divinyl sulfone (DVS) and subsequently loaded with antibiotic molecules to obtain biocompatible and antibacterial injectable hydrogels. The crosslinking degree of the hydrogels was modulated by varying the reaction time and the HA:DVS weight ratio. Synthesized HA-DVS hydrogels were characterized by their rheological properties, pore size, swelling capacity and hydrolytic and thermal degradation. Biocompatibility was assessed by measuring pH, osmolality and by in vitro cytotoxic assay. Acetyl salicylic (AAS) loaded hydrogels display anti-inflammatory properties in vitro, whereas cefuroxime (CFX), tetracycline (TCN) and amoxicillin (AMX) loaded hydrogels show in vitro antibacterial activity against Staphylococcus aureus. The combine use of antibiotics and AAS produces a synergic effect that reduces the S. aureus population up to a log10 reduction (R) of 5.55. Overall results show that antibiotic/AAS loaded HA-DVS hydrogels could be effectively used to combat S. aureus infections and to increase the antibacterial activity of antibiotics commonly used against S. aureus.

Sodium alendronate loaded poly(l-lactide- co-glycolide) microparticles immobilized on ceramic scaffolds for local treatment of bone defects

Bone tissue regeneration in critical-size defects is possible after implantation of a 3D scaffold and can be additionally enhanced once the scaffold is enriched with drugs or other factors supporting bone remodelling and healing. Sodium alendronate (Aln), a widely used anti-osteoporosis drug, exhibits strong inhibitory effect on bone resorption performed by osteoclasts. Thus, we propose a new approach for the treatment of bone defects in craniofacial region combining biocompatible titanium dioxide scaffolds and poly(l-lactide-co-glycolide) microparticles (MPs) loaded with Aln. The MPs were effectively attached to the surface of the scaffolds’ pore walls by human recombinant collagen. Drug release from the scaffolds was characterized by initial burst (24 ± 6% of the drug released within first 24 h) followed by a sustained release phase (on average 5 µg of Aln released per day from Day 3 to Day 18). In vitro tests evidenced that Aln at concentrations of 5 and 2.5 µg/ml was not cytotoxic for MG-63 osteoblast-like cells (viability between 81 ± 6% and 98 ± 3% of control), but it prevented RANKL-induced formation of osteoclast-like cells from macrophages derived from peripheral blood mononuclear cells, as shown by reduced fusion capability and decreased tartrate-resistant acid phosphatase 5b activity (56 ± 5% reduction in comparison to control after 8 days of culture). Results show that it is feasible to design the scaffolds providing required doses of Aln inhibiting osteoclastogenesis, reducing osteoclast activity, but not affecting osteoblast functions, which may be beneficial in the treatment of critical-size bone tissue defects.

Melt electrohydrodynamic 3D printed poly (ε-caprolactone)/polyethylene glycol/roxithromycin scaffold as a potential anti-infective implant in bone repair

Implanted scaffold or bone substitute is a common method to treat bone defects. However, the possible bone infection caused by orthopaedic surgery has created a challenging clinical problem and generally invalidate bone repair and regeneration. In this study, a poly (ε-caprolactone) (PCL)/polyethylene glycol (PEG)/roxithromycin (ROX) composite scaffold was prepared via melt electrohydrodynamic (EHD) 3D printing. Fourier transform infrared spectroscopy (FTIR) spectroscopy was performed to verify the existence of PEG and ROX in the scaffolds. By water contact angle measurement, the addition of both PEG and ROX was found to improve the hydrophilicity of the scaffolds. By in vitro drug release assay, the PCL/PEG/ROX scaffolds showed an initial burst drug release and subsequent long-term sustained release behaviour, which is favourable for the prevention and treatment of bone infections. The antibacterial assays against E. coli and S. aureus demonstrated that the composite scaffold with ROX possessed effective antibacterial activity, especially for S. aureus, the main cause of bone infection. The immunostaining and MTT assay with human osteoblast-like cells (MG63) indicated that cells showed good viability and growth on the scaffolds. Therefore, the melt EHD 3D printed PCL/PEG/ROX scaffold could be a promising anti-infective implant for bone tissue engineering.

Biomaterials for bone tissue engineering scaffolds: a review

Bone tissue engineering has been continuously developing since the concept of "tissue engineering" has been proposed. Biomaterials that are used as the basic material for the fabrication of scaffolds play a vital role in bone tissue engineering. This paper first introduces a strategy for literature search. Then, it describes the structure, mechanical properties and materials of natural bone and the strategies of bone tissue engineering. Particularly, it focuses on the current knowledge about biomaterials used in the fabrication of bone tissue engineering scaffolds, which includes the history, types, properties and applications of biomaterials. The effects of additives such as signaling molecules, stem cells, and functional materials on the performance of the scaffolds are also discussed.

Synergistic treatment strategies to combat resistant bacterial infections using Schiff base modified nanoparticulate - hydrogel system

Antibiotic resistance is of much prevalence and is one of the alarming realities for the rise in morbidity and mortality. Antibiotics; once regarded as wonder drugs have lost its credit of combating bacteria due to the rapid rise in variety of nosocomial pathogens. The underlying cause for the resistance spread is due to sudden drift in genetic mutation and the recalcitrant behavior of bacterial species. On the other hand, illegal and overconsumption of drugs fuels up the issue, wherein resistance development is directly proportional to the rate of drug consumption. Our pursuit was in reviving antibiotic, and further repurposing them into more potent formulation with reduced side effects to completely deplete resistant bacteria. In this work we present gentamicin encapsulated zein nanoparticle modified with Schiff base incorporated in immobilized chitosan-polyvinyl alcohol gel matrix([GM-ZNP]PG CsPVA) resulting in synergistic antibacterial activity. Schiff base modified zein nanoparticle exhibited an average diameter of 240 ± 8 nm and stability of -29.85 ± 2 mV. The nanocomposite system exhibited enhanced penetration rate when applied to dermis eliciting combinatorial antibacterial activity. Gentamicin in combination with Schiff base was found to lyse bacteria by ruining its cell integrity as depicted by SEM analysis. The formulation upon application stays intact to the impaired dermal tissues and releases drug in a sustained manner without the need of recurrent administration. The gel system was extremely biocompatible towards L929 cells without any toxicity. Overall, the work reports use of [GM-ZNP]PG CsPVA for resistant bacterial infections.

Poly (fumaroyl bioxirane) maleate: A potential functional scaffold for bone regeneration

Proper scaffolds combined with mesenchymal stem cells (MSCs) represent a promising strategy for repairing bone defects. In a previous study, poly (fumaroyl bioxirane) maleate (PFM), a newly developed functional polymer with numerous functional groups, exhibited excellent biocompatibility and enhanced the alkaline phosphatase (ALP) activity of osteoblasts in vitro. Here, to provide further and comprehensive insight into the application of PFM in bone tissue engineering, we investigated the osteoinductive potential of PFM cultured with rat adipose-derived mesenchymal stem cells (rADSCs). The results showed that PFM resulted in greater proliferation of rADSCs and that the PFM substrate had stronger osteoinductivity than PLGA and the control, as indicated by the significant upregulation of osteogenesis-related genes, proteins and calcium mineralization in vitro. Next, PFM was combined with rADSCs to repair a critical-sized calvarial defect in rats. Compared to the PLGA scaffold, the PFM scaffold significantly promoted new bone formation and exhibited excellent effects in repairing rat calvarial defects. In conclusion, PFM possesses strong osteoinductivity, which could markedly enhance bone regeneration, suggesting that PFM could serve as a promising and effective optimization method for traditional scaffolds in bone regeneration.