NanoZnO-modified titanium implants for enhanced anti-bacterial activity, osteogenesis and corrosion resistance

Layer-by-layer self-assembly of PLL/CPP-ACP multilayer on SLA titanium surface: Enhancing osseointegration and antibacterial activity in vitro and in vivo

Dental Implants are expected to possess both excellent osteointegration and antibacterial activity because poor osseointegration and infection are two major causes of titanium implant failure. In this study, we constructed layer-by-layer self-assembly films consisting of anionic casein phosphopeptides-amorphous calcium phosphate (CPP-ACP) and cationic poly (L-lysine) (PLL) on sandblasted and acid etched (SLA) titanium surfaces and evaluated their osseointegration and antibacterial performance in vitro and in vivo. The surface properties were examined, including microstructure, elemental composition, wettability, and Ca2+ ion release. The impact the surfaces had on the adhesion, proliferation and differentiation abilities of MC3T3-E1 cells were investigated, as well as the material's antibacterial performance after exposure to the oral microorganisms such as Porphyromonas gingivalis (P. g) and Actinobacillus actinomycetemcomitans (A. a). For the in vivo studies, SLA and Ti (PLL/CA-3.0)10 implants were inserted into the extraction socket immediately after extracting the rabbit mandibular anterior teeth with or without exposure to mixed bacteria solution (P. g & A. a). Three rabbits in each group were sacrificed to collect samples at 2, 4, and 6 weeks of post-implantation, respectively. Radiographic and histomorphometry examinations were performed to evaluate the implant osseointegration. The modified titanium surfaces were successfully prepared and appeared as a compact nano-structure with high hydrophilicity. In particular, the Ti (PLL/CA-3.0)10 surface was able to continuously release Ca2+ ions. From the in vitro and in vivo studies, the modified titanium surfaces expressed enhanced osteogenic and antibacterial properties. Hence, the PLL/CPP-ACP multilayer coating on titanium surfaces was constructed via a layer-by-layer self-assembly technology, possibly improving the biofunctionalization of Ti-based dental implants.

Machine Learning Tools to Assist the Synthesis of Antibacterial Carbon Dots

Introduction

The emergence and rapid spread of multidrug-resistant bacteria (MRB) caused by the excessive use of antibiotics and the development of biofilms have been a growing threat to global public health. Nanoparticles as substitutes for antibiotics were proven to possess substantial abilities for tackling MRB infections via new antimicrobial mechanisms. Particularly, carbon dots (CDs) with unique (bio)physicochemical characteristics have been receiving considerable attention in combating MRB by damaging the bacterial wall, binding to DNA or enzymes, inducing hyperthermia locally, or forming reactive oxygen species.

Methods

Herein, how the physicochemical features of various CDs affect their antimicrobial capacity is investigated with the assistance of machine learning (ML) tools.

Results

The synthetic conditions and intrinsic properties of CDs from 121 samples are initially gathered to form the raw dataset, with Minimum inhibitory concentration (MIC) being the output. Four classification algorithms (KNN, SVM, RF, and XGBoost) are trained and validated with the input data. It is found that the ensemble learning methods turn out to be the best on our data. Also, ε-poly(L-lysine) CDs (PL-CDs) were developed to validate the practical application ability of the well-trained ML models in a laboratory with two ensemble models managing the prediction.

Discussion

Thus, our results demonstrate that ML-based high-throughput theoretical calculation could be used to predict and decode the relationship between CD properties and the anti-bacterial effect, accelerating the development of high-performance nanoparticles and potential clinical translation.

Bioactive coating provides antimicrobial protection through immunomodulation and phage therapeutics

Medical implant-associated infections (IAI) is a growing threat to patients undergoing implantation surgery. IAI prevention typically relies on medical implants endowed with bactericidal properties achieved through surface modifications with antibiotics. However, the clinical efficacy of this traditional paradigm remains suboptimal, often necessitating revision surgery and posing potentially lethal consequences for patients. To bolster the existing anti-IAI arsenal, we propose herein a chitosan-based bioactive coating, i.e., ChitoAntibac, which exerts bacteria-inhibitory effects either through immune modulation or phage-directed microbial clearance, without relying on conventional antibiotics. The immuno-stimulating effects and phage-induced bactericidal properties can be tailored by engineering the loading dynamic of macrophage migration inhibitory factor (MIF), which polarizes macrophages towards the proinflammatory subtype (M1) with enhanced bacterial phagocytosis, and Staphylococcal Phage K, resulting in rapid and targeted pathogenic clearance (>99.99%) in less than 8 h. Our innovative antibacterial coating opens a new avenue in the pursuit of effective IAI prevention through immuno-stimulation and phage therapeutics.

Multifunctional Prosthesis Surface: Modification of Titanium with Cinnamaldehyde-Loaded Hierarchical Titanium Dioxide Nanotubes

Orthopedic prostheses are the ultimate therapeutic solution for various end-stage orthopedic conditions. However, aseptic loosening and pyogenic infections remain as primary complications associated with these devices. In this study, a hierarchical titanium dioxide (TiO2) nanotube drug delivery system loaded with cinnamaldehyde for the surface modification of titanium implants, is constructed. These specially designed dual-layer TiO2 nanotubes enhance material reactivity and provide an extensive drug-loading platform within a short time. The introduction of cinnamaldehyde enhances the bone integration performance of the scaffold (simultaneously promoting bone formation and inhibiting bone resorption), anti-inflammatory capacity, and antibacterial properties. In vitro experiments have demonstrated that this system promoted osteogenesis by upregulating both Wnt/β-catenin and MAPK signaling pathways. Furthermore, it inhibits osteoclast formation, suppresses macrophage-mediated inflammatory responses, and impedes the proliferation of Staphylococcus aureus and Escherichia coli. In vivo experiments shows that this material enhances bone integration in a rat model of femoral defects. In addition, it effectively enhances the antibacterial and anti-inflammatory properties in a subcutaneous implant in a rat model. This study provides a straightforward and highly effective surface modification strategy for orthopedic Ti implants.

Novel antibacterial titanium implant healing abutment with dimethylaminohexadecyl methacrylate to combat implant-related infections

OBJECTIVE

Implant-related infections from the adhesion and proliferation of dental plaque are a major challenge for dental implants. The objectives of this study were to: (1) develop novel antibacterial titanium (Ti) healing abutment; (2) investigate the inhibition of implant infection-related pathogenic bacteria and saliva-derived biofilm, and evaluate the biocompatibility of the new material for the first time.

METHODS

Dimethylaminohexadecyl methacrylate (DMAHDM) and hydroxyapatite (HAP) were polymerized via polydopamine (PDA) on Ti. Staphylococcus aureus (S. aureus), Streptococcus sanguinis (S. sanguinis) and human saliva-derived biofilms were tested. After 4 weeks of DMAHDM release, the antibacterial efficacy of the DMAHDM remaining on Ti surface and the DMADHM in medium was tested. Biocompatibility was determined using human gingival fibroblasts (HGFs) and periodontal ligament stem cells (PDLSCs).

RESULTS

The DMAHDM-loaded coating filled into the nano-voids in Ti surfaces. The modified Ti showed potent antibacterial activity, reducing the CFU of S. aureus, S. sanguinis and saliva-derived biofilms by 8, 7 and 4 log, respectively (P < 0.05). After 4 weeks of release, the modified Ti was still able to reduce S. aureus and S. sanguinis biofilm CFU by 1-3 log (P < 0.05). This provided strong antibacterial function for more than 4 weeks, which were the high-risk period for implant infections. The new material showed excellent biocompatibility when compared to control (P > 0.05).

CONCLUSION

Novel DMAHDM-loaded Ti healing abutment had strong antibacterial effects, reducing biofilm CFUs by orders of magnitude, and lasting for over four weeks to cover the high-risk period for implant infections. The novel antibacterial Ti is promising to combat implant-related infections in dental, craniofacial and orthopedic applications.

Recent Progress in antibacterial hydrogel coatings for targeting biofilm to prevent orthopedic implant-associated infections

The application of orthopedic implants for bone tissue reconstruction and functional restoration is crucial for patients with severe bone fractures and defects. However, the abiotic nature of orthopedic implants allows bacterial adhesion and colonization, leading to the formation of bacterial biofilms on the implant surface. This can result in implant failure and severe complications such as osteomyelitis and septic arthritis. The emergence of antibiotic-resistant bacteria and the limited efficacy of drugs against biofilms have increased the risk of orthopedic implant-associated infections (OIAI), necessitating the development of alternative therapeutics. In this regard, antibacterial hydrogels based on bacteria repelling, contact killing, drug delivery, or external assistance strategies have been extensively investigated for coating orthopedic implants through surface modification, offering a promising approach to target biofilm formation and prevent OIAI. This review provides an overview of recent advancements in the application of antibacterial hydrogel coatings for preventing OIAI by targeting biofilm formation. The topics covered include: (1) the mechanisms underlying OIAI occurrence and the role of biofilms in exacerbating OIAI development; (2) current strategies to impart anti-biofilm properties to hydrogel coatings and the mechanisms involved in treating OIAI. This article aims to summarize the progress in antibacterial hydrogel coatings for OIAI prevention, providing valuable insights and facilitating the development of prognostic markers for the design of effective antibacterial orthopedic implants.

Titanium particles in peri-implantitis: distribution, pathogenesis and prospects

Peri-implantitis is one of the most important biological complications in the field of oral implantology. Identifying the causative factors of peri-implant inflammation and osteolysis is crucial for the disease's prevention and treatment. The underlying risk factors and detailed pathogenesis of peri-implantitis remain to be elucidated. Titanium-based implants as the most widely used implant inevitably release titanium particles into the surrounding tissue. Notably, the concentration of titanium particles increases significantly at peri-implantitis sites, suggesting titanium particles as a potential risk factor for the condition. Previous studies have indicated that titanium particles can induce peripheral osteolysis and foster the development of aseptic osteoarthritis in orthopedic joint replacement. However, it remains unconfirmed whether this phenomenon also triggers inflammation and bone resorption in peri-implant tissues. This review summarizes the distribution of titanium particles around the implant, the potential roles in peri-implantitis and the prevalent prevention strategies, which expects to provide new directions for the study of the pathogenesis and treatment of peri-implantitis.

Highly Hydrophobic Gelatin Nanocomposite Film Assisted by Nano-ZnO/(3-Aminopropyl) Triethoxysilane/Stearic Acid Coating for Liquid Food Packaging

Biodegradable gelatin (G) food packaging films are in increasing demand as the substitution of petroleum-based preservative materials. However, G packaging films universally suffer from weak hydrophobicity in practical applications. Constructing a hydrophobic micro/nanocoating with low surface energy is an effective countermeasure. However, the poor compatibility with the hydrophilic G substrate often leads to the weak interfacial adhesion and poor durability of the hydrophobic coating. To overcome this obstacle, we used (3-aminopropyl) triethoxysilane (APS) as an interfacial bridging agent to prepare a highly hydrophobic, versatile G nanocomposite film. Specifically, tannic acid (TA)-modified nanohydroxyapatite (n-HA) particles (THA) were introduced in G matrix (G-THA) to improve the mechanical properties. Micro/nanostructure with low surface energy composed of nanozinc oxide (Nano-ZnO)/APS/stearic acid (SA) (NAS) was constructed on the surface of G-THA film (G-THA/NAS) through one-step spray treatment. Consequently, as-prepared G-THA/NAS film presented excellent mechanics (tensile strength: 7.6 MPa, elongation at break: 292.7%), water resistance ability (water contact angle: 150.4°), high UV-shielding (0% transmittance at 200 nm), degradability (100% degradation rate after buried in the natural soil for 15 days), antioxidant (78.8% of 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity), and antimicrobial (inhibition zone against Escherichia coli: 15.0 mm and Staphylococcus aureus: 16.5 mm) properties. It should be emphasized that the bridging function of APS significantly improves the interfacial adhesion ability of the NAS coating with more than 95% remaining area after the cross-cut adhesion test. Meanwhile, the G-THA/NAS film could maintain stable and long-lasting hydrophobic surfaces against UV radiation, high temperature, and abrasion. Based on these multifunctional properties, the G-THA/NAS film was successfully applied as a liquid packaging material. To sum up, we provide a feasible and effective method to prepare high-performance green packaging films.

The current status of stimuli-responsive nanotechnologies on orthopedic titanium implant surfaces

With the continuous innovation and breakthrough of nanomedical technology, stimuli-responsive nanotechnology has been gradually applied to the surface modification of titanium implants to achieve brilliant antibacterial activity and promoted osteogenesis. Regarding to the different physiological and pathological microenvironment around implants before and after surgery, these surface nanomodifications are designed to respond to different stimuli and environmental changes in a timely, efficient, and specific way/manner. Here, we focus on the materials related to stimuli-responsive nanotechnology on titanium implant surface modification, including metals and their compounds, polymer materials and other materials. In addition, the mechanism of different response types is introduced according to different activation stimuli, including magnetic, electrical, photic, radio frequency and ultrasonic stimuli, pH and enzymatic stimuli (the internal stimuli). Meanwhile, the associated functions, potential applications and developing prospect were discussion.

Recent Development of Polyhydroxyalkanoates (PHA)-Based Materials for Antibacterial Applications: A Review

The diseases caused by microorganisms are innumerable existing on this planet. Nevertheless, increasing antimicrobial resistance has become an urgent global challenge. Thus, in recent decades, bactericidal materials have been considered promising candidates to combat bacterial pathogens. Recently, polyhydroxyalkanoates (PHAs) have been used as green and biodegradable materials in various promising alternative applications, especially in healthcare for antiviral or antiviral purposes. However, it lacks a systematic review of the recent application of this emerging material for antibacterial applications. Therefore, the ultimate goal of this review is to provide a critical review of the state of the art recent development of PHA biopolymers in terms of cutting-edge production technologies as well as promising application fields. In addition, special attention was given to collecting scientific information on antibacterial agents that can potentially be incorporated into PHA materials for biological and durable antimicrobial protection. Furthermore, the current research gaps are declared, and future research perspectives are proposed to better understand the properties of these biopolymers as well as their possible applications.

Promotional Effect and Molecular Mechanism of Synthesized Zinc Oxide Nanocrystal on Zirconia Abutment Surface for Soft Tissue Sealing

Studies have confirmed that tooth loss is closely related to systemic diseases, such as obesity, diabetes, cardiovascular diseases, some types of tumors, and Alzheimer's disease. Among many methods for tooth restoration, implant restoration is the most commonly used method. After implantation, long-term stability of implants requires not only good bone bonding but also good soft tissue sealing between implants and surrounding soft tissues. The zirconia abutment is used in clinical implant restoration treatment, but due to the strong biological inertia of zirconia, it is difficult to form stable chemical or biological bonds with surrounding tissues. In this study, we investigated synthesized zinc oxide (ZnO) nanocrystal on the zirconia abutment surface by the hydrothermal method to make it more beneficial for soft tissue early sealing and the molecular mechanism. In vitro experiments found that different hydrothermal treatment temperatures affect the formation of ZnO crystals. The crystal diameter of ZnO changes from micron to nanometer at different temperatures, and the crystal morphology also changes. In vitro, scanning electron microscopy, energy dispersive spectrometry, and real-time polymerase chain reaction results show that ZnO nanocrystal can promote the attachment and proliferation of oral epithelial cells on the surface of zirconia by promoting the binding of laminin 332 and integrin β4, regulating the PI3K/AKT pathway. In vivo, ZnO nanocrystal ultimately promotes the formation of soft tissue seals. Collectively, ZnO nanocrystal can be synthesized on a zirconia surface by hydrothermal treatment. It can help to form a seal between the implant abutment and surrounding soft tissue. This method is beneficial to the long-term stability of the implant and also can be applied to other medical fields.

Physicochemical properties of a calcium aluminate cement containing nanoparticles of zinc oxide

Objectives

This study evaluated the effect of different nanoparticulated zinc oxide (nano-ZnO) and conventional-ZnO ratios on the physicochemical properties of calcium aluminate cement (CAC).

Materials and Methods

The conventional-ZnO and nano-ZnO were added to the cement powder in the following proportions: G1 (20% conventional-ZnO), G2 (15% conventional-ZnO + 5% nano-ZnO), G3 (12% conventional-ZnO + 3% nano-ZnO) and G4 (10% conventional-ZnO + 5% nano-ZnO). The radiopacity (R_ad), setting time (S_et), dimensional change (D_c), solubility (S_ol), compressive strength (C_st), and pH were evaluated. The nano-ZnO and CAC containing conventional-ZnO were also assessed using scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Radiopacity data were analyzed by the 1-way analysis of variance (ANOVA) and Bonferroni tests (p < 0.05). The data of the other properties were analyzed by the ANOVA, Tukey, and Fisher tests (p < 0.05).

Results

The nano-ZnO and CAC containing conventional-ZnO powders presented particles with few impurities and nanometric and micrometric sizes, respectively. G1 had the highest R_ad mean value (p < 0.05). When compared to G1, groups containing nano-ZnO had a significant reduction in the S_et (p < 0.05) and lower values of D_c at 24 hours (p < 0.05). The C_st was higher for G4, with a significant difference for the other groups (p < 0.05). The S_ol did not present significant differences among groups (p > 0.05).

Conclusions

The addition of nano-ZnO to CAC improved its dimensional change, setting time, and compressive strength, which may be promising for the clinical performance of this cement.

Novel Titanium Implant: A 3D Multifunction Architecture with Charge-Trapping and Piezoelectric Self-Stimulation

Implant-associated infection and inflammation are the main causes of implant failure, causing irreversible damage and significantly increasing clinical risks and economic losses. In this study, a 3D multifunctional architecture is constructed that consisted of hierarchical TiO₂ nanotubes (NTs) and electrospun polyvinylidene fluoride nanofiber layers on the surface of a titanium implant. The movement of bacteria through the nanofiber layer is facilitated by its appropriate pore sizes and electrostatic interactions to reach the NT layer where the bacteria are killed by positive charge traps. In contrast, the macrophages tend to adhere to the nanofiber layer. The mechanical interactions between the macrophages and piezoelectric nanofibers generate a self-stimulated electric field that regulated an anti-inflammatory phenotype. This study provides a new method for multifunctional implant materials with antibacterial, piezoelectrically self-stimulated anti-inflammatory, and osteointegration properties that are driven by electrical stimulation.

Antibacterial quaternary ammonium chitosan/carboxymethyl starch/alginate sponges with enhanced hemostatic property for the prevention of dry socket

Tooth extraction commonly leads to postoperative wound bleeding, bacterial infection, and even the occurrence of dry socket. Therefore, developing a biomedical material with favorable antibacterial and excellent hemostatic properties to prevent the post-extraction dry socket is necessary. Herein, quaternary ammonium chitosan/ carboxymethyl starch/alginate (ACQ) sponges are developed via Ca²⁺ cross-linking, electrostatic interaction, and lyophilization methods. The results show that the bio-multifunctional sponges exhibit interconnected porous structures with significant fluid absorption rates and suitable water vapor transmission rates. In vitro cellular and hemolysis experiments indicate that the developed sponges have acceptable biocompatibility. Notably, the constructed sponges effectively inhibit the growth of E. coli, S. aureus, and C. albicans, as well as achieve rapid hemostasis in the mouse liver injury and mini-pig tooth extraction models by absorbing blood and promoting red blood cell adhesion. Thus, the created bio-multifunctional sponges show tremendous promise as a hemostatic material for wound management after tooth extraction.

Phyto-assisted synthesis of zinc oxide nanoparticles for developing antibiofilm surface coatings on central venous catheters

Medical devices such as Central Venous Catheters (CVCs), are routinely used in intensive and critical care settings. In the present scenario, incidences of Catheter-Related Blood Stream Infections (CRBSIs) pose a serious challenge. Despite considerable advancements in the antimicrobial therapy and material design of CVCs, clinicians continue to struggle with infection-related complications. These complications are often due colonization of bacteria on the surface of the medical devices, termed as biofilms, leading to infections. Biofilm formation is recognized as a critical virulence trait rendering infections chronic and difficult to treat even with 1,000x, the minimum inhibitory concentration (MIC) of antibiotics. Therefore, non-antibiotic-based solutions that prevent bacterial adhesion on medical devices are warranted. In our study, we report a novel and simple method to synthesize zinc oxide (ZnO) nanoparticles using ethanolic plant extracts of Eupatorium odoratum. We investigated its physio-chemical characteristics using Field Emission- Scanning Electron Microscopy and Energy dispersive X-Ray analysis, X-Ray Diffraction (XRD), Photoluminescence Spectroscopy, UV-Visible and Diffuse Reflectance spectroscopy, and Dynamic Light Scattering characterization methods. Hexagonal phase with wurtzite structure was confirmed using XRD with particle size of ∼50 nm. ZnO nanoparticles showed a band gap 3.25 eV. Photoluminescence spectra showed prominent peak corresponding to defects formed in the synthesized ZnO nanoparticles. Clinically relevant bacterial strains, viz., Proteus aeruginosa PAO1, Escherichia coli MTCC 119 and Staphylococcus aureus MTCC 7443 were treated with different concentrations of ZnO NPs. A concentration dependent increase in killing efficacy was observed with 99.99% killing at 500 μg/mL. Further, we coated the commercial CVCs using green synthesized ZnO NPs and evaluated it is in vitro antibiofilm efficacy using previously optimized in situ continuous flow model. The hydrophilic functionalized interface of CVC prevents biofilm formation by P. aeruginosa, E. coli and S. aureus. Based on our findings, we propose ZnO nanoparticles as a promising non-antibiotic-based preventive solutions to reduce the risk of central venous catheter-associated infections.

Development of ε-poly(L-lysine) carbon dots-modified magnetic nanoparticles and their applications as novel antibacterial agents

Magnetic nanoparticles (MNPs) are widely applied in antibacterial therapy owing to their distinct nanoscale structure, intrinsic peroxidase-like activities, and magnetic behavior. However, some deficiencies, such as the tendency to aggregate in water, unsatisfactory biocompatibility, and limited antibacterial effect, hindered their further clinical applications. Surface modification of MNPs is one of the main strategies to improve their (bio)physicochemical properties and enhance biological functions. Herein, antibacterial ε-poly (L-lysine) carbon dots (PL-CDs) modified MNPs (CMNPs) were synthesized to investigate their performance in eliminating pathogenic bacteria. It was found that the PL-CDs were successfully loaded on the surface of MNPs by detecting their morphology, surface charges, functional groups, and other physicochemical properties. The positively charged CMNPs show superparamagnetic properties and are well dispersed in water. Furthermore, bacterial experiments indicate that the CMNPs exhibited highly effective antimicrobial properties against Staphylococcus aureus. Notably, the in vitro cellular assays show that CMNPs have favorable cytocompatibility. Thus, CMNPs acting as novel smart nanomaterials could offer great potential for the clinical treatment of bacterial infections.

Root-shaped antibacterial alginate sponges with enhanced hemostasis and osteogenesis for the prevention of dry socket

Tooth extraction commonly causes uncontrolled bleeding, loss of blood clots, and bacterial infection, leading to the dry socket and bone resorption. Thus, it is highly attractive to design a bio-multifunctional scaffold with outstanding antimicrobial, hemostatic, and osteogenic performances for avoiding dry sockets in clinical applications. Herein, alginate (AG)/quaternized chitosan (Qch)/diatomite (Di) sponges were fabricated via electrostatic interaction, Ca²⁺ cross-linking, as well as lyophilization methods. The composite sponges are facilely made into the shape of the tooth root, which could be well integrated into the alveolar fossa. The sponge shows a highly interconnected and hierarchical porous structure at the macro/micro/nano levels. The prepared sponges also possess enhanced hemostatic and antibacterial abilities. Moreover, in vitro cellular assessment indicates that the developed sponges have favorable cytocompatibility and significantly facilitate osteogenesis by upregulating the formation of alkaline phosphatase and calcium nodules. The designed bio-multifunctional sponges display great potential for trauma treatment after tooth extraction.

Multifunctionalized carbon-fiber-reinforced polyetheretherketone implant for rapid osseointegration under infected environment

Carbon fiber reinforced polyetheretherketone (CFRPEEK) possesses a similar elastic modulus to that of human cortical bone and is considered as a promising candidate to replace metallic implants. However, the bioinertness and deficiency of antibacterial activities impede its application in orthopedic and dentistry. In this work, titanium plasma immersion ion implantation (Ti-PIII) is applied to modify CFRPEEK, achieving unique multi-hierarchical nanostructures and active sites on the surface. Then, hybrid polydopamine (PDA)@ZnO-EDN1 nanoparticles (NPs) are introduced to construct versatile surfaces with improved osteogenic and angiogenic properties and excellent antibacterial properties. Our study established that the modified CFRPEEK presented favorable stability and cytocompatibility. Compared with bare CFRPEEK, improved osteogenic differentiation of rat mesenchymal stem cells (BMSCs) and vascularization of human umbilical vein endothelial cells (HUVECs) are found on the functionalized surface due to the zinc ions and EDN1 releasing. In vitro bacteriostasis assay confirms that hybrid PDA@ZnO NPs on the functionalized surface provided an effective antibacterial effect. Moreover, the rat infected model corroborates the enhanced antibiosis and osteointegration of the functionalized CFRPEEK. Our findings indicate that the multilevel nanostructured PDA@ZnO-EDN1 coated CFRPEEK with enhanced antibacterial, angiogenic, and osteogenic capacity has great potential as an orthopedic/dental implant material for clinical application.

Nanomaterial-Based Antimicrobial Coating for Biomedical Implants: New Age Solution for Biofilm-Associated Infections

Recently, the upsurge in hospital-acquired diseases has put global health at risk. Biomedical implants being the primary source of contamination, the development of biomedical implants with antimicrobial coatings has attracted the attention of a large group of researchers from around the globe. Bacteria develops biofilms on the surface of implants, making it challenging to eradicate them with the standard approach of administering antibiotics. A further issue of current concern is the fast resurgence of resistance to conventional antibiotics. As nanotechnology continues to advance, various types of nanomaterials have been created, including 2D nanoparticles and metal and metal oxide nanoparticles with antimicrobial properties. Researchers from all over the world are using these materials as a coating agent for biomedical implants to create an antimicrobial environment. This comprehensive and contemporary review summarizes various metals, metal oxide nanoparticles, 2D nanomaterials, and their composites that have been used or may be used in the future as an antimicrobial coating agent for biomedical implants, as well as their succinct mode of action to combat biofilm-associated infection and diseases.

Recovering Osteoblast Functionality on TiO2 Nanotube Surfaces Under Diabetic Conditions

Introduction

Titanium (Ti) and its alloys (eg, Ti₆Al₄V) are exceptional treatments for replacing or repairing bones and damaged surrounding tissues. Although Ti-based implants exhibit excellent osteoconductive performance under healthy conditions, the effectiveness and successful clinical achievements are negatively altered in diabetic patients. Concernedly, diabetes mellitus (DM) contributes to osteoblastic dysfunctionality, altering efficient osseointegration. This work investigates the beneficial osteogenic activity conducted by nanostructured TiO₂ under detrimental microenvironment conditions, simulated by human diabetic serum.

Methods

We evaluated the bone-forming functional properties of osteoblasts on synthesized TiO₂ nanotubes (NTs) by anodization and Ti6Al4V non-modified alloy surfaces under detrimental diabetic conditions. To simulate the detrimental environment, MC3T3E-1 preosteoblasts were cultured under human diabetic serum (DS) of two diagnosed and metabolically controlled patients. Normal human serum (HS) was used to mimic health conditions and fetal bovine serum (FBS) as the control culture environment. We characterized the matrix mineralization under the detrimental conditions on the control alloy and the NTs. Moreover, we applied immunofluorescence of osteoblasts differentiation markers on the NTs to understand the bone-expression stimulated by the biochemical medium conditions.

Results

The diabetic conditions depressed the initial osteoblast growth ability, as evidenced by altered early cell adhesion and reduced proliferation. Nonetheless, after three days, the diabetic damage was suppressed by the NTs, enhancing the osteoblast activity. Therefore, the osteogenic markers of bone formation and the differentiation of osteoblasts were reactivated by the nanoconfigured surfaces. Far more importantly, collagen secretion and bone-matrix mineralization were stimulated and conducted to levels similar to those of the control of FBS conditions, in comparison to the control alloy, which was not able to reach similar levels of bone functionality than the NTs.

Conclusion

Our study brings knowledge for the potential application of nanostructured biomaterials to work as an integrative platform under the detrimental metabolic status present in diabetic conditions.

Antibacterial Adhesion Strategy for Dental Titanium Implant Surfaces: From Mechanisms to Application

Dental implants are widely used to restore missing teeth because of their stability and comfort characteristics. Peri-implant infection may lead to implant failure and other profound consequences. It is believed that peri-implantitis is closely related to the formation of biofilms, which are difficult to remove once formed. Therefore, endowing titanium implants with anti-adhesion properties is an effective method to prevent peri-implant infection. Moreover, anti-adhesion strategies for titanium implant surfaces are critical steps for resisting bacterial adherence. This article reviews the process of bacterial adhesion, the material properties that may affect the process, and the anti-adhesion strategies that have been proven effective and promising in practice. This article intends to be a reference for further improvement of the antibacterial adhesion strategy in clinical application and for related research on titanium implant surfaces.

Polydopamine and hyaluronic acid immobilisation on vancomycin-loaded titanium nanotube for prophylaxis of implant infections

Titanium nanotube (Ti-NT) is an attractive substrate for local drug delivery, however, it is difficult to control the burst drug release and achieve sustained release from these nanotubes. In the present study, we investigated the feasibility of controlling drug release from Ti-NT within polydopamine and hyaluronic acid films, to achieve antibacterial activity and osteogenic promotion. Vancomycin was loaded into the Ti-NT by lyophilisation. Dopamine and hyaluronic acid were immobilized on the vancomycin-loaded Ti-NT surface through alternate deposition technique. The anti-infective and osteogenic abilities of the polydopamine and hyaluronic acid-modified Ti-NT were then investigated. Our results demonstrated that polydopamine and hyaluronic acid-modified Ti-NT exhibited improved drug loading and release control for 7 days. Compared with the vancomycin-loaded Ti-NT, the polydopamine and hyaluronic acid-modified Ti-NT exhibited better antibacterial ability, and the hyaluronic acid-modified Ti-NT promoted the osteogenic differentiation of rat bone marrow stem cells. Our results demonstrated that Ti-NT biofunctionalized with polydopamine and hyaluronic acid can help overcome the limitations of Ti-NT, by improving drug loading, antibacterial activity and osteogenic ability.

Antibacterial metal nanoclusters

Combating bacterial infections is one of the most important applications of nanomedicine. In the past two decades, significant efforts have been committed to tune physicochemical properties of nanomaterials for the development of various novel nanoantibiotics. Among which, metal nanoclusters (NCs) with well-defined ultrasmall size and adjustable surface chemistry are emerging as the next-generation high performance nanoantibiotics. Metal NCs can penetrate bacterial cell envelope more easily than conventional nanomaterials due to their ultrasmall size. Meanwhile, the abundant active sites of the metal NCs help to catalyze the bacterial intracellular biochemical processes, resulting in enhanced antibacterial properties. In this review, we discuss the recent developments in metal NCs as a new generation of antimicrobial agents. Based on a brief introduction to the characteristics of metal NCs, we highlight the general working mechanisms by which metal NCs combating the bacterial infections. We also emphasize central roles of core size, element composition, oxidation state, and surface chemistry of metal NCs in their antimicrobial efficacy. Finally, we present a perspective on the remaining challenges and future developments of metal NCs for antibacterial therapeutics.

Modulation of T Cell Responses by Fucoidan to Inhibit Osteogenesis

Fucoidan has sparked considerable interest in biomedical applications because of its inherent (bio)physicochemical characteristics, particularly immunomodulatory effects on macrophages, neutrophils, and natural killer cells. However, the effect of fucoidan on T cells and the following regulatory interaction on cellular function has not been reported. In this work, the effect of sterile fucoidan on the T-cell response and the subsequent modulation of osteogenesis is investigated. The physicochemical features of fucoidan treated by high-temperature autoclave sterilization are characterized by UV–visible spectroscopy, X-ray diffraction, Fourier transform infrared and nuclear magnetic resonance analysis. It is demonstrated that high-temperature autoclave treatment resulted in fucoidan depolymerization, with no change in its key bioactive groups. Further, sterile fucoidan promotes T cells proliferation and the proportion of differentiated T cells decreases with increasing concentration of fucoidan. In addition, the supernatant of T cells co-cultured with fucoidan greatly suppresses the osteogenic differentiation of MC3T3-E1 by downregulating the formation of alkaline phosphatase and calcium nodule compared with fucoidan. Therefore, our work offers new insight into the fucoidan-mediated T cell and osteoblast interplay.

Cell membrane-camouflaged inorganic nanoparticles for cancer therapy

Inorganic nanoparticles (INPs) have been paid great attention in the field of oncology in recent past years since they have enormous potential in drug delivery, gene delivery, photodynamic therapy (PDT), photothermal therapy (PTT), bio-imaging, driven motion, etc. To overcome the innate limitations of the conventional INPs, such as fast elimination by the immune system, low accumulation in tumor sites, and severe toxicity to the organism, great efforts have recently been made to modify naked INPs, facilitating their clinical application. Taking inspiration from nature, considerable researchers have exploited cell membrane-camouflaged INPs (CMCINPs) by coating various cell membranes onto INPs. CMCINPs naturally inherit the surface adhesive molecules, receptors, and functional proteins from the original cell membrane, making them versatile as the natural cells. In order to give a timely and representative review on this rapidly developing research subject, we highlighted recent advances in CMCINPs with superior unique merits of various INPs and natural cell membranes for cancer therapy applications. The opportunity and obstacles of CMCINPs for clinical translation were also discussed. The review is expected to assist researchers in better eliciting the effect of CMCINPs for the management of tumors and may catalyze breakthroughs in this area.

Mg-, Zn-, and Fe-Based Alloys With Antibacterial Properties as Orthopedic Implant Materials

Implant-associated infection (IAI) is one of the major challenges in orthopedic surgery. The development of implants with inherent antibacterial properties is an effective strategy to resolve this issue. In recent years, biodegradable alloy materials have received considerable attention because of their superior comprehensive performance in the field of orthopedic implants. Studies on biodegradable alloy orthopedic implants with antibacterial properties have gradually increased. This review summarizes the recent advances in biodegradable magnesium- (Mg-), iron- (Fe-), and zinc- (Zn-) based alloys with antibacterial properties as orthopedic implant materials. The antibacterial mechanisms of these alloy materials are also outlined, thus providing more basis and insights on the design and application of biodegradable alloys with antibacterial properties as orthopedic implants.

Regulation of T Cell Responses by Nano-Hydroxyapatite to Mediate the Osteogenesis

Nano-hydroxyapatite (nHA) has been widely applied as a tissue-engineering biomaterial and interacted with osteoblasts/stem cells to repair bone defects. In addition, T cells that coexist with osteoblasts/stem cells in the bone modulate the regulation of osteoimmunology by cytokine formation. However, the effects of nHA on T cells and the following regulatory interplay on osteogenic differentiation have been rarely examined. In this work, the physicochemical properties of needle-like nHA are characterized by field emission scanning electron microscopy, zeta potential, Fourier transform-infrared and X-ray diffraction. It is found that as the concentration of nHA increases, the proliferation of T cells gradually increases, and the proportion of apoptotic T cells decreases. The percentage of CD4⁺ T cells is higher than that of CD8⁺ T cells under the regulation of needle-like nHA. Furthermore, the supernatant of T cells co-cultured with nHA significantly inhibits the osteogenic differentiation of MC3T3-E1 by downregulating the formation of alkaline phosphatase and calcium nodule compared with the supernatant of nHA. Thus, our findings provide new insight into the nHA-mediated T cell and osteoblast interactions.

Recent progress in advanced biomaterials for long-acting reversible contraception

Unintended pregnancy is a global issue with serious ramifications for women, their families, and society, including abortion, infertility, and maternal death. Although existing contraceptive strategies have been widely used in people's lives, there have not been satisfactory feedbacks due to low contraceptive efficacy and related side effects (e.g., decreased sexuality, menstrual cycle disorder, and even lifelong infertility). In recent years, biomaterials-based long-acting reversible contraception has received increasing attention from the viewpoint of fundamental research and practical applications mainly owing to improved delivery routes and controlled drug delivery. This review summarizes recent progress in advanced biomaterials for long-acting reversible contraception via various delivery routes, including subcutaneous implant, transdermal patch, oral administration, vaginal ring, intrauterine device, fallopian tube occlusion, vas deferens contraception, and Intravenous administration. In addition, biomaterials, especially nanomaterials, still need to be improved and prospects for the future in contraception are mentioned.

Preparation and Characterization of Vancomycin Hydrochloride-Loaded Mesoporous Silica Composite Hydrogels

This study aims to explore the feasibility of the novel temperature-sensitive hydrogel-based dual sustained-release system (Van/SBA-15/CS-GP-SA) in the repair and treatment of infectious jaw defects. Van/SBA-15 was prepared using the mesoporous silica (SBA-15) as a carrier for vancomycin hydrochloride (Van), and Van/SBA-15 was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET), and Barrett-Joyner-Halenda (BJH). The characterization results confirm that Van is loaded in SBA-15 successfully. Van/SBA-15/CS-GP-SA is constructed by encapsulating Van/SBA-15 in chitosan-sodium glycerophosphate-sodium alginate hydrogel (CS-GP-SA). The microstructures, sustained-release ability, biocompatibility, and antibacterial properties of Van/SBA-15/CS-GP-SA were systematically studied. Van/SBA-15/CS-GP-SA is found to have promising sustained-release ability, outstanding biocompatibility, and excellent antibacterial properties. This study provides new ideas for the management of infectious jaw defects.

Polymeric Dental Nanomaterials: Antimicrobial Action

This review aims to describe and critically analyze studies published over the past four years on the application of polymeric dental nanomaterials as antimicrobial materials in various fields of dentistry. Nanoparticles are promising antimicrobial additives to restoration materials. According to published data, composites based on silver nanoparticles, zinc(II), titanium(IV), magnesium(II), and copper(II) oxide nanoparticles, chitosan nanoparticles, calcium phosphate or fluoride nanoparticles, and nanodiamonds can be used in dental therapy and endodontics. Composites with nanoparticles of hydroxyapatite and bioactive glass proved to be of low efficiency for application in these fields. The materials applicable in orthodontics include nanodiamonds, silver nanoparticles, titanium(IV) and zinc(II) oxide nanoparticles, bioactive glass, and yttrium(III) fluoride nanoparticles. Composites of silver nanoparticles and zinc(II) oxide nanoparticles are used in periodontics, and nanodiamonds and silver, chitosan, and titanium(IV) oxide nanoparticles are employed in dental implantology and dental prosthetics. Composites based on titanium(IV) oxide can also be utilized in maxillofacial surgery to manufacture prostheses. Composites with copper(II) oxide nanoparticles and halloysite nanotubes are promising materials in the field of denture prosthetics. Composites with calcium(II) fluoride or phosphate nanoparticles can be used in therapeutic dentistry for tooth restoration.