Copper-containing glass ceramic with high antimicrobial efficacy

Reduction of bioburden on large area surfaces through use of a supplemental residual antimicrobial paint

Paint is a versatile material that can be used to coat surfaces for which routine disinfection practices may be lacking. EPA-registered copper-containing supplemental residual antimicrobial paints could be used to reduce the bioburden on often-neglected surfaces. An interventional study was conducted by painting the walls of a preschool restroom and metal locker surfaces in two hospital locker rooms with a copper-containing antimicrobial paint to evaluate the potential for bioburden reduction compared to a non-copper-containing control paint. The antimicrobial paint reduced the bioburden on the preschool restroom walls by 57% and on lockers in one locker room by 63% compared to the control paint; no significant difference was observed between the two paint types in the second locker room. The upper quartile bacterial counts, which drive the overall risk by increasing exposure to pathogens, also exhibited 63% and 47% reductions for the antimicrobial paint compared to the control paint in the preschool restroom and the first locker room, respectively. Because detectible levels of bioburden are found on large-area surfaces such as walls and lockers, surfaces painted with copper-containing paints may make large-area surfaces that are prone to contamination safer in a way that is practical and economical.

Unexpectedly high antibacterial ability of water in copper pot with tiny amount of plant leaves

Water disinfection by copper vessels has been prevalent over thousands of years. Unfortunately, people are still suffering from the bacterial pollution in drinking water. Here we show that, only through steeping with tiny amounts of common plant leaves, the room-temperature water in copper pots has unexpectedly high antibacterial ability. Remarkably, copper ions released from copper pots into water are in concentrations lower than the WHO safety threshold for drinking water, and have effective antibacterial ability when water contains specific leave components (polyphenols and/or lignin). Our computations show that the key to enhance antibacterial ability is the great increase in the proportion of Cu+ induced by aromatic rings in these leave components, which has been demonstrated by our experiments. The findings may disclose the mystery of copper vessels for water disinfection, and more importantly, provide effective antibacterial applications in industries and daily lives, by safely using copper ions together with biocompatible natural substances.

Efficient Self-cleaning and antibacterial ceramics with active sites fully exposed obtained from rare earth waste

The utilization of rare earth polishing powder waste (RPW) to prepare antibacterial ceramics can effectively avoid problems of pollution in the recycling process and waste of rare earth resources. Herein, a novel RPW-based antibacterial ceramics was developed, which possesses the core-shell structure with ceramics as the cores and the CeO2/BiOCl as the superficial coating. The antibacterial ceramics display notable antibacterial activity, and the inactivation rates of 3.3 log under visible light irradiation in 30 min and 2.4 log under darkness in 1 h were achieved, and the zone of inhibition values was found to be 16.6 mm for E.coil. The hardness of antibacterial ceramics was measured to be 897 (±38) HV, higher than commercial porcelain's hardness (600 HV). The antibacterial mechanism was verified by the Ce ion release, reactive species, and fluorescence-based live/dead cells. This study presents a novel antibacterial ceramic structure and green economic reuse method of rare earth waste.

Novel feed additive delivers antimicrobial copper and influences fecal microbiota in pigs

Dehydrated alginate beads formulated with copper were synthesized and tested as a feed additive to influence the microbiota in finishing pigs and potentially use them as a preharvest intervention to reduce fecal pathogen shedding. The efficacy of the copper beads was tested in vitro and in vivo. In vitro, Salmonella was significantly (P < 0.05) reduced when in contact with the copper beads solution for up to 6 h, with a 5.4 log CFU/mL reduction over the first hour. Chemical analysis of the soak solutions demonstrated the beads delivered their copper payload gradually over the same period the bactericidal effect was observed. For the in vivo experiments, pigs (n = 48) supplemented with the copper beads experienced significant shifts in their microbiota. Enterobacteriaceae (EB) increased by 1.07 log CFU/g (P < 0.05), while lactic acid bacteria (LAB) decreased by 1.22 log CFU/g (P < 0.05) during the treatment period. When beads were removed from the feed, EB and LAB concentrations returned to baseline, indicating copper beads led to measurable and significant changes in microbial loads. Fecal microbiome analysis conducted to explore additional changes by copper bead supplementation demonstrated that, at the phylum level, there was an increase in Firmicutes, Euryarchaeota, and Acidobacteriota, while at the genus level, an increase in Methanosphaera and Pseudomonas was observed. Measures of copper in swine feces showed values ~20 times higher in the treatment group than in the control group during the treatment period, suggesting that dehydrated alginate copper beads were effective in delivering antimicrobial copper to the animal hindgut.IMPORTANCECopper has long been known to have antimicrobial properties. However, when water-soluble salts are fed to livestock, the copper may rapidly dissolve in gastric contents and fail to reach the gut. Here, specially formulated copper beads are seamlessly incorporated into feed and allow copper to remain longer in the gastrointestinal tract of animals, reach deep into both the foregut and hindgut, and shift microbial populations. The technology delivers antimicrobial copper to the animal hindgut and potentially reduces pathogenic microorganisms before animal slaughter.

One-pot green solid-state synthesis of Cu2O/microcrystalline cellulose composite with high anti-pathogenic activity

Cuprous oxide (Cu2O) is proven as an excellent anti-harmful microbial material. However, the liquid and vapor pha5se preparation methods reported so far hardly make pure Cu2O-containing composites and suffer environmental issues caused by chemical reducing agents with multiple processing steps. This work develops a facile one-pot solid-state sintering method to synthesize Cu2O/microcrystalline cellulose (MCC) composite via the thermal decomposition and oxidation-reduction reactions where copper formate was reduced by MCC. The Cu2O/MCC composite exhibits superior purity, dispersibility, stability, high yield, and high efficacy of antibacterial and antiviral properties, e.g., against E. coli, S. aureus, and Equine Arteritis Viral. This work utilizes elegantly the strong reducing capability of cellulose to develop an environmentally benign method to prepare high-purity Cu2O-polymer composites with low cytotoxicity and cost, which can be incorporated readily into other substrate materials to form various forms of anti-harmful microbial materials widely used in public health care products. In addition, the preparation of Cu2O-containing composites based on the reducing capability of cellulose is also expected to be applied to other cellulose-based materials for the loading of Cu2O particles.

Fluoride anodic films on stainless-steel fomites to reduce transmission infections

The growing concern arising from viruses with pandemic potential and multi-resistant bacteria responsible for hospital-acquired infections and outbreaks of food poisoning has led to an increased awareness of indirect contact transmission. This has resulted in a renewed interest to confer antimicrobial properties to commonly used metallic materials. The present work provides a full characterization of optimized fluoride anodic films grown in stainless steel 304L as well as their antimicrobial properties. Antibacterial tests show that the anodic film, composed mainly of chromium and iron fluorides, reduces the count and the percentage of the area covered by 50% and 87.7% for Pseudomonas aeruginosa and Stenotrophomonas maltophilia, respectively. Virologic tests show that the same treatment reduces the infectivity of the coronavirus HCoV-229E-GFP, in comparison with the non-anodized stainless steel 304L.IMPORTANCEThe importance of environmental surfaces as a source of infection is a topic of particular interest today, as many microorganisms can survive on these surfaces and infect humans through direct contact. Modification of these surfaces by anodizing has been shown to be useful for some alloys of medical interest. This work evaluates the effect of anodizing on stainless steel, a metal widely used in a variety of applications. According to the study, the fluoride anodic layers reduce the colonization of the surfaces by both bacteria and viruses, thus reducing the risk of acquiring infections from these sources.

Redox Active Zn@MOFs as Spontaneous Reactive Oxygen Species Releasing Antimicrobials

The rapid development of antimicrobial resistance (AMR) among infectious pathogens has become a major threat and challenge in healthcare systems globally. A strategy distinct from minimizing the overuse of antimicrobials involves the development of novel antimicrobials with a mode of action that prevents the development of AMR microbial strains. Reactive oxygen species (ROS) are formed as a natural byproduct of the cellular aerobic metabolism. However, it becomes pathological when ROS is produced at excessive levels. Exploiting this phenomenon, research on redox-active bactericides has been demonstrated to be beneficial. Materials that release ROS via photodynamic, thermodynamic, and photocatalytic interventions have been developed as nanomedicines and are used in various applications. However, these materials require external stimuli for ROS release to be effective as biocides. In this paper, we report novel zinc-based metal organic framework (Zn@MOF) particles that promote the spontaneous release of active ROS species. The synthesized Zn@MOF spontaneously releases superoxide anions and hydrogen peroxide, exhibiting a potent antimicrobial efficacy against various microbes. Zn@MOF-incorporated plastic films and coatings show excellent, long-lasting antimicrobial potency even under continuous microbial challenge and an aging process. These disinfecting surfaces maintain their antimicrobial properties even after 500× surface wipes. Zn@MOF is also biocompatible and safe on the skin, illustrating its broad potential applications in medical technology and consumer care applications.

Hemostatic and antibacterial calcium-copper zeolite gauze for infected wound healing

The design and development of wound dressings with excellent procoagulant and antibacterial activity to achieve high wound healing effectiveness are highly desirable in clinical applications. In this work, we develop a calcium-copper zeolite gauze (CaCu-ZG) by a two-step process involving calcium and copper ion exchange in a zeolite gauze. The CaCu-ZG exhibits remarkable procoagulant and antibacterial abilities, as well as good biocompatibility. Compared with the medical gauze, the blood clotting time of CaCu-ZG significantly decreases and the antibacterial activity increases in both in vivo and in vitro experiments. The remarkable ability of wound healing has been verified using a mouse dorsal skin-infected wound model, demonstrating its great potential for wound treatment in clinical applications.

Micro-arc oxidation (MAO) and its potential for improving the performance of titanium implants in biomedical applications

Titanium (Ti) and its alloys have good biocompatibility, mechanical properties and corrosion resistance, making them attractive for biomedical applications. However, their biological inertness and lack of antimicrobial properties may compromise the success of implants. In this review, the potential of micro-arc oxidation (MAO) technology to create bioactive coatings on Ti implants is discussed. The review covers the following aspects: 1) different factors, such as electrolyte, voltage and current, affect the properties of MAO coatings; 2) MAO coatings affect biocompatibility, including cytocompatibility, hemocompatibility, angiogenic activity, corrosion resistance, osteogenic activity and osseointegration; 3) antibacterial properties can be achieved by adding copper (Cu), silver (Ag), zinc (Zn) and other elements to achieve antimicrobial properties; and 4) MAO can be combined with other physical and chemical techniques to enhance the performance of MAO coatings. It is concluded that MAO coatings offer new opportunities for improving the use of Ti and its alloys in biomedical applications, and some suggestions for future research are provided.

Cobalt-containing borate bioactive glass fibers for treatment of diabetic wound

Impaired angiogenesis is one of the predominant reasons for non-healing diabetic wounds. Cobalt is well known for its capacity to induce angiogenesis by stabilizing hypoxia-inducible factor-1α (HIF-1α) and subsequently inducing the production of vascular endothelial growth factor (VEGF). In this study, Co-containing borate bioactive glasses and their derived fibers were fabricated by partially replacing CaO in 1393B3 borate glass with CoO. Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) analyses were performed to characterize the effect of Co incorporation on the glass structure, and the results showed that the substitution promoted the transformation of [BO3] into [BO4] units, which endow the glass with higher chemical durability and lower reaction rate with the simulated body fluid (SBF), thereby achieving sustained and controlled Co2+ ion release. In vitro biological assays were performed to assess the angiogenic potential of the Co-containing borate glass fibers. It was found that the released Co2+ ion significantly enhanced the proliferation, migration and tube formation of the Human Umbilical Vein Endothelial Cells (HUVECs) by upregulating the expression of angiogenesis-related proteins such as HIF-1α and VEGF. Finally. In vivo results demonstrated that the Co-containing fibers accelerated full-thickness skin wound healing in streptozotocin (STZ)-induced diabetic rat model by promoting angiogenesis and re-epithelialization.

Development of Nano-Sized Copper-Deposited Antimicrobial Air Filters Using a Mixed Melt-Blown Process

Air purification devices, such as air purifiers, provide fresh air by filtering out airborne pollutants, dust, and other harmful substances using various filter systems. While air filters are generally effective in filtering pollutants such as dust, they encounter a challenge when filtering harmful microorganisms such as mites, bacteria, mold, and viruses. These microorganisms, which are present in public transport and public indoor spaces, tend to proliferate on the surface of the filter media, eventually reintroducing themselves into the air or causing unpleasant odors. To address this issue, herein, copper particles were prepared as one masterbatch and deposited on polypropylene (PP) pellets through plasma vacuum deposition to effectively filter dust and microorganisms and prevent their growth on the surface of the filter media. After adding 3-10 wt.% of the masterbatch to conventional PP pellets to fabricate a filter media, the distribution of copper on the surface of the filter media was observed through a scanning electron microscope. To verify the safety and effectiveness of the antimicrobial material, the filter media containing antimicrobial particles was tested using Escherichia coli (E. coli) and Staphylococcus aureus through a filter emission test.

Enhancing Biocidal Capability in Cuprite Coatings

The SARS-CoV-2 global pandemic has reinvigorated interest in the creation and widespread deployment of durable, cost-effective, and environmentally benign antipathogenic coatings for high-touch public surfaces. While the contact-kill capability and mechanism of metallic copper and its alloys are well established, the biocidal activity of the refractory oxide forms remains poorly understood. In this study, commercial cuprous oxide (Cu2O, cuprite) powder was rapidly nanostructured using high-energy cryomechanical processing. Coatings made from these processed powders demonstrated a passive "contact-kill" response to Escherichia coli (E. coli) bacteria that was 4× (400%) faster than coatings made from unprocessed powder. No viable bacteria (>99.999% (5-log10) reduction) were detected in bioassays performed after two hours of exposure of E. coli to coatings of processed cuprous oxide, while a greater than 99% bacterial reduction was achieved within 30 min of exposure. Further, these coatings were hydrophobic and no external energy input was required to activate their contact-kill capability. The upregulated antibacterial response of the processed powders is positively correlated with extensive induced crystallographic disorder and microstrain in the Cu2O lattice accompanied by color changes that are consistent with an increased semiconducting bandgap energy. It is deduced that cryomilling creates well-crystallized nanoscale regions enmeshed within the highly lattice-defective particle matrix. Increasing the relative proportion of lattice-defective cuprous oxide exposed to the environment at the coating surface is anticipated to further enhance the antipathogenic capability of this abundant, inexpensive, robust, and easily handled material for wider application in contact-kill surfaces.

Tissue-engineered small-diameter vascular grafts containing novel copper-doped bioactive glass biomaterials to promote angiogenic activity and endothelial regeneration

Small-diameter vascular grafts frequently fail because of obstruction and infection. Despite the wide range of commercially available vascular grafts, the anatomical uniqueness of defect sites demands patient-specific designs. This study aims to increase the success rate of implantation by fabricating bilayer vascular grafts containing bioactive glasses (BGs) and modifying their composition by removing hemostatic ions to make them blood-compatible and to enhance their antibacterial and angiogenesis properties. The porous vascular graft tubes were 3D printed using polycaprolactone, polyglycerol sebacate, and the modified BGs. The polycaprolactone sheath was then wrapped around the 3D-printed layer using the electrospinning technique to prevent blood leakage. The results demonstrated that the incorporation of modified BGs into the polymeric matrix not only improved the mechanical properties of the vascular graft but also significantly enhanced its antibacterial activity against both gram-negative and gram-positive strains. In addition, no hemolysis or platelet activity was detected after incorporating modified BGs into the vascular grafts. Copper-releasing vascular grafts significantly enhanced endothelial cell proliferation, motility, and VEGF secretion. Additionally, In vivo angiogenesis (CD31 immunofluorescent staining) and gene expression experiments showed that copper-releasing vascular grafts considerably promoted the formation of new blood vessels, low-grade inflammation (decreased expression of IL-1β and TNF-α), and high-level angiogenesis (increased expression of angiogenic growth factors including VEGF, PDGF-BB, and HEBGF). These observations indicate that the use of BGs with suitable compositional modifications in vascular grafts may promote the clinical success of patient-specific vascular prostheses by accelerating tissue regeneration without any coagulation problems.

Nanomaterials for the treatment of bacterial infection by photothermal/photodynamic synergism

In the past few decades, great progress has been made in the field of nanomaterials against bacterial infection. However, with the widespread emergence of drug-resistant bacteria, people try their best to explore and develop new antibacterial strategies to fight bacteria without obtaining or increasing drug resistance. Recently, multi-mode synergistic therapy has been considered as an effective scheme for the treatment of bacterial infections, especially the combination of photothermal therapy (PTT) and photodynamic therapy (PDT) with controllable, non-invasive, small side effects and broad-spectrum antibacterial characteristics. It can not only improve the efficiency of antibiotics, but also do not promote antibiotic resistance. Therefore, multifunctional nanomaterials which combine the advantages of PTT and PDT are more and more used in the treatment of bacterial infections. However, there is still a lack of a comprehensive review of the synergistic effect of PTT and PDT in anti-infection. This review first focuses on the synthesis of synergistic photothermal/photodynamic nanomaterials and discusses the ways and challenges of photothermal/photodynamic synergism, as well as the future research direction of photothermal/photodynamic synergistic antibacterial nanomaterials.

Novel Antibacterial Metals as Food Contact Materials: A Review

Food contamination caused by microorganisms is a significant issue in the food field that not only affects the shelf life of food, but also threatens human health, causing huge economic losses. Considering that the materials in direct or indirect contact with food are important carriers and vectors of microorganisms, the development of antibacterial food contact materials is an important coping strategy. However, different antibacterial agents, manufacturing methods, and material characteristics have brought great challenges to the antibacterial effectiveness, durability, and component migration associated with the use security of materials. Therefore, this review focused on the most widely used metal-type food contact materials and comprehensively presents the research progress regarding antibacterial food contact materials, hoping to provide references for exploring novel antibacterial food contact materials.

Realizing Both Antibacterial Activity and Cytocompatibility in Silicocarnotite Bioceramic via Germanium Incorporation

The treatment of infective or potentially infectious bone defects is a critical problem in the orthopedic clinic. Since bacterial activity and cytocompatibility are always contrary factors, it is hard to have them both in one material. The development of bioactive materials with a good bacterial character and without sacrificing biocompatibility and osteogenic activity, is an interesting and valuable research topic. In the present work, the antimicrobial characteristic of germanium, GeO2 was used to enhance the antibacterial properties of silicocarnotite (Ca5(PO4)2SiO4, CPS). In addition, its cytocompatibility was also investigated. The results demonstrated that Ge–CPS can effectively inhibit the proliferation of both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and it showed no cytotoxicity to rat bone marrow-derived mesenchymal stem cells (rBMSCs). In addition, as the bioceramic degraded, a sustainable release of germanium could be achieved, ensuring long-term antibacterial activity. The results indicated that Ge–CPS has excellent antibacterial activity compared with pure CPS, while no obvious cytotoxicity was observed, which could make it a promising candidate for the bone repair of infected bone defects.

Nano-antivirals: A comprehensive review

Nanoparticles can be used as inhibitory agents against various microorganisms, including bacteria, algae, archaea, fungi, and a huge class of viruses. The mechanism of action includes inhibiting the function of the cell membrane/stopping the synthesis of the cell membrane, disturbing the transduction of energy, producing toxic reactive oxygen species (ROS), and inhibiting or reducing RNA and DNA production. Various nanomaterials, including different metallic, silicon, and carbon-based nanomaterials and nanoarchitectures, have been successfully used against different viruses. Recent research strongly agrees that these nanoarchitecture-based virucidal materials (nano-antivirals) have shown activity in the solid state. Therefore, they are very useful in the development of several products, such as fabric and high-touch surfaces. This review thoroughly and critically identifies recently developed nano-antivirals and their products, nano-antiviral deposition methods on various substrates, and possible mechanisms of action. By considering the commercial viability of nano-antivirals, recommendations are made to develop scalable and sustainable nano-antiviral products with contact-killing properties.

Antibacterial Inorganic Coating of Calcium Silicate Hydrate Substrates by Copper Incorporation

Under environmental conditions, biofilms can oftentimes be found on different surfaces, accompanied by the structural degradation of the substrate. Since high-copper-content paints were banned in the EU, a solution for the protection of these surfaces has to be found. In addition to hydrophobation, making the surfaces inherently biofilm-repellent is a valid strategy. We want to accomplish this via the metal exchange in calcium silicate hydrate (CSH) substrates with transition metals. As has been shown with Europium, even small amounts of metal can have a great influence on the material properties. To effectively model CSH surfaces, ultrathin CSH films were grown on silicon wafers using Ca(OH)2 solutions. Subsequently, copper was incorporated as an active component via ion exchange. Biofilm development is quantified using a multiple-resistant Pseudomonas aeruginosa strain described as a strong biofilm former cultivated in the culture medium for 24 h. Comprehensive structural and chemical analyses of the substrates are done by environmental scanning electron microscopy (ESEM), transmission Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Results do not show any structural deformation of the substrates by the incorporation of the Cu combined with three-dimensional (3D) homogeneous distribution. While the copper-free CSH phase shows a completely random distribution of the bacteria in biofilms, the samples with copper incorporation reveal lower bacterial colonization of the modified surfaces with an enhanced cluster formation.

Surfaces with instant and persistent antimicrobial efficacy against bacteria and SARS-CoV-2

Surfaces contaminated with bacteria and viruses contribute to the transmission of infectious diseases and pose a significant threat to global public health. Modern day disinfection either relies on fast-acting (>3-log reduction within a few minutes), yet impermanent, liquid-, vapor-, or radiation-based disinfection techniques, or long-lasting, but slower-acting, passive antimicrobial surfaces based on heavy metal surfaces, or metallic nanoparticles. There is currently no surface that provides instant and persistent antimicrobial efficacy against a broad spectrum of bacteria and viruses. In this work, we describe a class of extremely durable antimicrobial surfaces incorporating different plant secondary metabolites that are capable of rapid disinfection (>4-log reduction) of current and emerging pathogens within minutes, while maintaining persistent efficacy over several months and under significant environmental duress. We also show that these surfaces can be readily applied onto a variety of desired substrates or devices via simple application techniques such as spray, flow, or brush coating.

Silver-Polymethylhydrosiloxane-Quaternary Ammonium Coating on Anodized Aluminum with Excellent Antibacterial Property

Multidrug-resistant bacteria are known to survive on high-touch surfaces for days, weeks, and months, contributing to the rise in nosocomial infections. Inducing antibacterial property in such surfaces can presumably reduce the overall microbial burden and subsequent nosocomial infections in hygiene critical environments. In the present study, a one-pot sol-gel process has been deployed to incorporate silver (Ag) and quaternary ammonium salt (QUAT) bactericides in a polymethylhydrosiloxane (PMHS) matrix. The Ag-PMHS-QUAT nanocomposite was coated on anodized aluminum (AAO/Al) by a simple ultrasound-assisted deposition process. The morphological features and chemical composition of the Ag-PMHS-QUAT nanocomposite have been characterized using SEM, XRD spectroscopy, and attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) to confirm the formation of Ag-QUAT nanocomposites within the polymeric network of PMHS. The Ag-PMHS-QUAT nanocomposite coating on anodized aluminum oxide (AAO/Al) coupon exhibited superior antibacterial property with a 6-log bacterial reduction compared to the 5-log reduction for the commercially available antimicrobial copper coupon.

Cu-Ce oxide Co-loaded silicon nanocapsules for hydrogen peroxide self-supplied Fenton-like catalysis and synergistically antibacterial therapy

Antibacterial strategies based on reactive oxygen species (ROS) have opened up a new avenue for overcoming the great challenges of antibiotics topic including lack of broad-spectrum antibiotics and the emergence of super-resistant bacteria. Herein, we leveraged a strategy of constructing synergistic catalytic active sites to develop a simple yet efficient Fenton-like active nanocomposite, and investigated its catalysis mechanism and antibacterial performance thoroughly. This strategy provides a new direction for boosting the catalytic activity of nanocomposite catalysts for wide application. Specifically, by uniformly loading copper oxide and ceria onto the surface of silica nanocapsules (SiO₂ NCs), we fabricated a bimetallic oxide nanocomposite Cu_0.75Ce_0.62O₂@SiO₂ NC, which performed superior Fenton-like capability in a wide pH range without additional exogenetic hydrogen peroxide (H₂O₂). Such excellent catalytic activity was originated from the charge interaction between the two metal oxide components, where formation of Cu⁺ and oxygen vacancies (OVs) was mutually reinforcing, resulting in a synergistic effect to produce H₂O₂ and catalyze the generation of •OH under the slight acid condition (pH = 6.0). In view of the outstanding Fenton-like activity, the Cu_0.75Ce_0.62O₂@SiO₂ NC was employed in antimicrobial testing, which demonstrated exceptional high in vitro antimicrobial efficacy against both the S. aureus and E. coli in a neutral environment (pH = 7.4). The excellent performance of the bimetallic nanocomposite Cu_0.75Ce_0.62O₂@SiO₂ NC, including its facile and mild preparation, high water-solubility and stability, superior catalytic and antimicrobial performances, manifests a promising broad-spectrum antibiotic that can be anticipated to deal with the contamination of the environment by bacteria.

Enhanced antibacterial behavior of a novel Cu-bearing high-entropy alloy

Contact infection of bacteria and viruses has been a critical threat to human health. The worldwide outbreak of COVID-19 put forward urgent requirements for the research and development of the self-antibacterial materials, especially the antibacterial alloys. Based on the concept of high-entropy alloys, the present work designed and prepared a novel Co_0.4FeCr_0.9Cu_0.3 antibacterial high-entropy alloy with superior antibacterial properties without intricate or rigorous annealing processes, which outperform the antibacterial stainless steels. The antibacterial tests presented a 99.97% antibacterial rate against Escherichia coli and a 99.96% antibacterial rate against Staphylococcus aureus after 24 h. In contrast, the classic antibacterial copper-bearing stainless steel only performed the 71.50% and 80.84% antibacterial rate, respectively. The results of the reactive oxygen species analysis indicated that the copper ion release and the immediate contact with copper-rich phase had a synergistic effect in enhancing antibacterial properties. Moreover, this alloy exhibited excellent corrosion resistance when compared with the classic antibacterial stainless steels, and the compression test indicated the yield strength of the alloy was 1015 MPa. These findings generate fresh insights into guiding the designs of structure-function-integrated antibacterial alloys.

Antimicrobial Properties of TiO2 Microparticles Coated with Ca- and Cu-Based Composite Layers

The ability of TiO₂ to generate reactive oxygen species under UV radiation makes it an efficient candidate in antimicrobial studies. In this context, the preparation of TiO₂ microparticles coated with Ca- and Cu-based composite layers over which Cu(II), Cu(I), and Cu(0) species were identified is presented here. The obtained materials were characterized by a wide range of analytical methods, such as X-ray diffraction, electron microscopy (TEM, SEM), X-ray photoelectron (XPS), and UV-VIS spectroscopy. The antimicrobial efficiency was evaluated using qualitative and quantitative standard methods and standard clinical microbial strains. A significant aspect of this composite is that the antimicrobial properties were evidenced both in the presence and absence of the light, as result of competition between photo and electrical effects. However, the antibacterial effect was similar in darkness and light for all samples. Because no photocatalytic properties were found in the absence of copper, the results sustain the antibacterial effect of the electric field (generated by the electrostatic potential of the composite layer) both under the dark and in light conditions. In this way, the composite layers supported on the TiO₂ microparticles’ surface can offer continuous antibacterial protection and do not require the presence of a permanent light source for activation. However, the antimicrobial effect in the dark is more significant and is considered to be the result of the electric field effect generated on the composite layer.

Degradable Tumor-Responsive Iron-Doped Phosphate-Based Glass Nanozyme for H2O2 Self-Supplying Cancer Therapy

Tumor microenvironment (TME)-responsive chemodynamic therapy (CDT) mediated by nanozymes has been extensively studied both experimentally and theoretically, but the low catalytic efficiency due to insufficient H₂O₂ in the TME and the poor biodegradability of the nanozymes are still main challenges for clinical translation of nanozymes. Herein, we designed a H₂O₂ self-supplying nanozyme bearing glucose oxidase (GOX) and polyethyleneimine based on a degradable iron-doped phosphate-based glass (FePBG) nanomimic (FePBG@GOX), which can convert endogenous glucose into toxic hydroxyl radicals. The GOX loaded on the nanozyme can effectively consume glucose in tumor cells to produce a large amount of H₂O₂ to make up for the lack of H₂O₂ in the TME. Thereafter, enormous hydroxyl radicals, based on a Fenton reaction of FePBG without any exogenous H₂O₂, are generated to induce severe apoptosis of tumor cells. The nanozyme exhibits enhanced in vitro cytotoxicity in a high-glucose medium than in a low-glucose medium, illustrating sufficient generation of H₂O₂ by GOX. The excellent in vivo antitumor efficacy is manifested by a high tumor growth inhibition ratio of 94.65% in model mice. Excellent intrinsic biodegradability owing to its phosphate-based glass nature is a remarkable advantage of the prepared FePBG nanozyme over most other reported nanozymes. Big concerns about side effects caused by long-time residence in living organisms are eliminated since it degrades not only in an acid medium but also in a neutral physiological environment. Therefore, this novel strategy of the TME-responsive H₂O₂ self-supplying nanozyme based on an endogenous cascade catalytic reaction opens up an avenue for designing degradable nanozymes in CDT.

Anodized Aluminum Surface with Topography-Mediated Antibacterial Properties

Topography-mediated antibacterial surfaces that inactivate bacteria by physical contact have gained attention in recent years. Contrary to conventional antibacterial coatings, topography-mediated antibacterial surfaces do not suffer from coating instability and possible toxicity problems. In this study, a one-step hard anodization process has been deployed to fabricate a topography-mediated antibacterial aluminum surface. By optimizing anodization parameters, such as the concentration of the electrolyte, current density, and anodization time, desirable features of micronanoscale morphology were achieved. The optimum conditions of anodized aluminum that provided pores of a diameter of 151 ± 37 nm effectively killed 100% of E. coli bacteria.

Antiviral Activities of High Energy E-Beam Induced Copper Nanoparticles against H1N1 Influenza Virus

The pandemic outbreak of COVID-19 in the year of 2020 that drastically changed everyone's life has raised the urgent and intense need for the development of more efficacious antiviral material. This study was designed to develop copper nanoparticles (Cu NPs) as an antiviral agent and to validate the antiviral activities of developed copper NP. The Cu NPs were synthesized using a high energy electron beam, and the characteristic morphologies and antiviral activities of Cu NPs were evaluated. We found that Cu NPs are of spherical shape and uniformly distributed, with a diameter of around 100 nm, as opposed to the irregular shape of commercially available copper microparticles (Cu MPs). An X-ray diffraction analysis showed the presence of Cu and no copper oxide II and I in the Cu NPs. A virus inactivation assay revealed no visible viral DNA after 10- and 30-min treatment of H1N1 virus with the Cu NPs. The infectivity of the Cu NPs-treated H1N1 virus significantly decreased compared with that of the Cu MPs-treated H1N1 virus. The viability of A549 bronchial and Madin-Darby Canine Kidney (MDCK) cells infected with Cu NPs-treated H1N1 was significantly higher than those infected with Cu MPs-treated H1N1 virus. We also found cells infected with Cu NPs-treated H1N1 virus exhibited a markedly decreased presence of virus nucleoprotein (NuP), an influenza virus-specific structural protein, compared with cells infected with Cu MPs-treated H1N1 virus. Taken together, our study shows that Cu NPs are a more effective and efficacious antiviral agent compared with Cu MPs and offer promising opportunities for the prevention of devastatingly infectious diseases.

Robust bulk micro-nano hierarchical copper structures possessing exceptional bactericidal efficacy

Conventional copper (Cu) metal surfaces are well recognized for their bactericidal properties. However, their slow bacteria-killing potency has historically excluded them as a rapid bactericidal material. We report the development of a robust bulk superhydrophilic micro-nano hierarchical Cu structure that possesses exceptional bactericidal efficacy. It resulted in a 4.41 log₁₀ reduction (>99.99%) of the deadly Staphylococcus aureus (S. aureus) bacteria within 2 min vs. a 1.49 log₁₀ reduction (96.75%) after 240 min on common Cu surfaces. The adhered cells exhibited extensive blebbing, loss of structural integrity and leakage of vital intracellular material, demonstrating the rapid efficacy of the micro-nano Cu structure in destructing bacteria membrane integrity. The mechanism was attributed to the synergistic degradation of the cell envelope through enhanced release and therefore uptake of the cytotoxic Cu ions and the adhesion-driven mechanical strain due to its rapid ultimate superhydrophilicity (contact angle drops to 0° in 0.18 s). The scalable fabrication of this micro-nano Cu structure was enabled by integrating bespoke precursor alloy design with microstructure preconditioning for dealloying and demonstrated on 2000 mm² Cu surfaces. This development paves the way to the practical exploitation of Cu as a low-cost antibiotic-free fast bactericidal material.

Antiviral properties of copper and its alloys to inactivate covid-19 virus: a review

Copper (Cu) and its alloys are prospective materials in fighting covid-19 virus and several microbial pandemics, due to its excellent antiviral as well as antimicrobial properties. Even though many studies have proved that copper and its alloys exhibit antiviral properties, this research arena requires further research attention. Several studies conducted on copper and its alloys have proven that copper-based alloys possess excellent potential in controlling the spread of infectious diseases. Moreover, recent studies indicate that these alloys can effectively inactivate the covid-19 virus. In view of this, the present article reviews the importance of copper and its alloys in reducing the spread and infection of covid-19, which is a global pandemic. The electronic databases such as ScienceDirect, Web of Science and PubMed were searched for identifying relevant studies in the present review article. The review starts with a brief description on the history of copper usage in medicine followed by the effect of copper content in human body and antiviral mechanisms of copper against covid-19. The subsequent sections describe the distinctive copper based material systems such as alloys, nanomaterials and coating technologies in combating the spread of covid-19. Overall, copper based materials can be propitiously used as part of preventive and therapeutic strategies in the fight against covid-19 virus.

High-Resolution Microscopical Studies of Contact Killing Mechanisms on Copper-Based Surfaces

The mechanisms of bacterial contact killing induced by Cu surfaces were explored through high-resolution studies based on combinations of the focused ion beam (FIB), scanning transmission electron microscopy (STEM), high-resolution TEM, and nanoscale Fourier transform infrared spectroscopy (nano-FTIR) microscopy of individual bacterial cells of Gram-positive Bacillus subtilis in direct contact with Cu metal and Cu5Zn5Al1Sn surfaces after high-touch corrosion conditions. This approach permitted subcellular information to be extracted from the bioinorganic interface between a single bacterium and Cu/Cu5Zn5Al1Sn surfaces after complete contact killing. Early stages of interaction between individual bacteria and the metal/alloy surfaces include cell leakage of extracellular polymeric substances (EPSs) from the bacterium and changes in the metal/alloy surface composition upon adherence of bacteria. Three key observations responsible for Cu-induced contact killing include cell membrane damage, formation of nanosized copper-containing particles within the bacteria cell, and intracellular copper redox reactions. Direct evidence of cell membrane damage was observed upon contact with both Cu metal and Cu5Zn5Al1Sn surfaces. Cell membrane damage permits copper to enter into the cell interior through two possible routes, as small fragmentized Cu₂O particles from the corrosion product layer and/or as released copper ions. This results in the presence of intracellular copper oxide nanoparticles inside the cell. The nanosized particles consist primarily of CuO with smaller amounts of Cu₂O. The existence of two oxidation states of copper suggests that intracellular redox reactions play an important role. The nanoparticle formation can be regarded as a detoxification process of copper, which immobilizes copper ions via transformation processes within the bacteria into poorly soluble or even insoluble nanosized Cu structures. Similarly, the formation of primarily Cu(II) oxide nanoparticles could be a possible way for the bacteria to deactivate the toxic effects induced by copper ions via conversion of Cu(I) to Cu(II).

Evaluation of the ZnO Nanopillar Surface for Disinfection Applications

Much attention has been devoted to the synthesis and antimicrobial studies of nanopatterned surfaces. However, factors contributing to their potential and eventual application, such as large-scale synthesis, material durability, and biocompatibility, are often neglected in such studies. In this paper, the ZnO nanopillar surface is found to be amenable to synthesis in large forms and stable upon exposure to highly accelerated lifetime tests (HALT) without any detrimental effect on its antimicrobial activity. Additionally, the material is effective against clinically isolated pathogens and biocompatible in vivo. These findings illustrate the broad applicability of ZnO nanopillar surfaces in the common equipment used in health-care and consumer industries.

Nanostructured Copper Surface Kills ESKAPE Pathogens and Viruses in Minutes

In the search for a fast contact-killing antimicrobial surface to break the transmission pathway of lethal pathogens, nanostructured copper surfaces were found to exhibit the desired antimicrobial properties. Compared with plain copper, these nanostructured copper surfaces with Cu(OH)₂ nano-sword or CuO nano-foam were found to completely eliminate pathogens at a fast rate, including clinically isolated drug resistant species. Additionally these nanostructured copper surfaces demonstrated potential antiviral properties when assessed against bacteriophages, as a viral surrogate, and murine hepatitis virus, a surrogate for SARS-CoV-2. The multiple modes of killing, physical killing and copper ion mediated killing contribute to the superior and fast kinetics of antimicrobial action against common microbes, and ESKAPE pathogens. Prototypes for air and water cleaning with current nanostructured copper surface have also been demonstrated.

Copper-impregnated three-layer mask efficiently inactivates SARS-CoV2

The present study investigates the potential of SARS-CoV-2 inactivation by a copper sulfide (CuS) incorporated three-layer mask design. The mask consisted of the outer, middle, and inner layers to give comfort, strength, shape, and safety. The outer layer contained a total of 4.4% CuS (w/w) (2.2% CuS coated & 2.2% CuS impregnated) nylon fibers and the middle entrapment area contain a total of 17.6% CuS (w/w) impregnated nylon. No CuS was present in the inner layer. The antiviral efficacy assessment revealed, CuS incorporated mask is highly effective in inactivating SARS-CoV-2 within 30 min exposure. After, 1h and 2 h exposure, near-complete elimination of virus were observed by cytopathy, fluorescence, and viral copy number. The antiviral activity of the mask material was derived by incorporated solid-state CuS. Noticeably, the antiviral activity of CuS against SARS-CoV-2 was in the form of solid-state CuS, but not as Cu2+ ionic form derived by dissolved CuSO4. The kinetics of droplet entrapment revealed, that the three-layered mask almost completely block virus-containing droplet pass-through for short exposure periods of 1-2 min, and 80% efficacy for longer exposure times of 5-10 min. We also demonstrated the incorporated CuS is evenly distributed all over the fibers assuring the uniformity of potential antiviral activity and proves, CuS particles are not easily shed out of the fabric fibers. The inactivation efficacy demonstrated against SARS-CoV-2 proves that the CuS incorporated three-layer mask will be a lifesaver during the present intense global pandemic.

The Synergy of Topographical Micropatterning and Ta|TaCu Bilayered Thin Film on Titanium Implants Enables Dual-Functions of Enhanced Osteogenesis and Anti-Infection

Poor osteogenesis and implant-associated infection are the two leading causes of failure for dental and orthopedic implants. Surface design with enhanced osteogenesis often fails in antibacterial activity, or vice versa. Herein, a surface design strategy, which overcomes this trade-off via the synergistic effects of topographical micropatterning and a bilayered nanostructured metallic thin film is presented. A specific microgrooved pattern is fabricated on the titanium surface, followed by sequential deposition of a nanostructured copper (Cu)-containing tantalum (Ta) (TaCu) layer and a pure Ta cap layer. The microgrooved patterns coupled with the nanorough Ta cap layer shows strong contact guidance to preosteoblasts and significantly enhances the osteogenic differentiation in vitro, while the controlled local sustained release of Cu ions is responsible for high antibacterial activity. Importantly, rat calvarial defect models in vivo further confirm that the synergy of microgrooved patterns and the Ta|TaCu bilayered thin film on titanium surface could effectively promote bone regeneration. The present effective and versatile surface design strategy provides significant insight into intelligent surface engineering that can control biological response at the site of healing in dental and orthopedic implants.

Antibacterial Titanium Implants Biofunctionalized by Plasma Electrolytic Oxidation with Silver, Zinc, and Copper: A Systematic Review

Patients receiving orthopedic implants are at risk of implant-associated infections (IAI). A growing number of antibiotic-resistant bacteria threaten to hamper the treatment of IAI. The focus has, therefore, shifted towards the development of implants with intrinsic antibacterial activity to prevent the occurrence of infection. The use of Ag, Cu, and Zn has gained momentum as these elements display strong antibacterial behavior and target a wide spectrum of bacteria. In order to incorporate these elements into the surface of titanium-based bone implants, plasma electrolytic oxidation (PEO) has been widely investigated as a single-step process that can biofunctionalize these (highly porous) implant surfaces. Here, we present a systematic review of the studies published between 2009 until 2020 on the biomaterial properties, antibacterial behavior, and biocompatibility of titanium implants biofunctionalized by PEO using Ag, Cu, and Zn. We observed that 100% of surfaces bearing Ag (Ag-surfaces), 93% of surfaces bearing Cu (Cu-surfaces), 73% of surfaces bearing Zn (Zn-surfaces), and 100% of surfaces combining Ag, Cu, and Zn resulted in a significant (i.e., >50%) reduction of bacterial load, while 13% of Ag-surfaces, 10% of Cu-surfaces, and none of Zn or combined Ag, Cu, and Zn surfaces reported cytotoxicity against osteoblasts, stem cells, and immune cells. A majority of the studies investigated the antibacterial activity against S. aureus. Important areas for future research include the biofunctionalization of additively manufactured porous implants and surfaces combining Ag, Cu, and Zn. Furthermore, the antibacterial activity of such implants should be determined in assays focused on prevention, rather than the treatment of IAIs. These implants should be tested using appropriate in vivo bone infection models capable of assessing whether titanium implants biofunctionalized by PEO with Ag, Cu, and Zn can contribute to protect patients against IAI.

Effective Antibacterial Activity of Degradable Copper-Doped Phosphate-Based Glass Nanozymes

Copper-containing antimicrobials are highly valuable in the field of medical disinfectants owing to their well-known high antimicrobial efficacy. Artificially synthesized nanozymes which can increase the level of reactive oxygen species (ROS) in the bacterial system have become research hotspots. Herein, we describe the design and fabrication of degradable Cu-doped phosphate-based glass (Cu-PBG) nanozyme, which can achieve excellent antibacterial effects against Gram-positive and Gram-negative bacteria. The antibacterial mechanism is based on the generation of ROS storm and the release of copper. It behaves like a peroxidase in wounds which are acidic and exerts lethal oxidative stress on bacteria via catalyzing the decomposition of H₂O₂ into hydroxyl radicals (^•OH). Quite different from any other reported nanozymes, the Cu-PBG is intrinsically degradable due to its phosphate glass nature. It gradually degrades and releases copper ions in a physiological environment, which further enhances the inhibition efficiency. Satisfactory antibacterial effects are verified both in vitro and in vivo. Being biodegradable, the prepared Cu-PBG exhibits excellent in vivo biocompatibility and does not cause any adverse effects caused by its long-time residence time in living organisms. Collectively, these results indicate that the Cu-PBG nanozyme could be used as an efficient copper-containing antimicrobial with great potential for clinical translation.

MSNs-Based Nanocomposite for Biofilm Imaging and NIR-Activated Chem/Photothermal/Photodynamic Combination Therapy

Bacterial infections caused by biofilms are severe clinical problems, resulting in high drug resistance by limiting the penetration of antibiotics. Herein, a near-infrared (NIR)-activated chem/photodynamic/photothermal combined therapeutic agent is proposed by loading fluorescein isothiocyanate (FITC), ultrasmall copper sulfide nanoparticles (Cu_2-xSNPs), and ε-polylysine (PLL) onto mesoporous silica nanoparticles (MSNs) through a layer-by-layer self-assembly approach. FITC-doped MSNs are prepared to monitor the permeability and accumulation of nanocomposites into biofilms. MSNs can also act as hosts for the synthesis of ultrasmall Cu_2-xSNPs, which has effective photodynamic and photothermal ablation against bacteria under NIR light irradiation. Moreover, biodegradable PLL introduced can not only enhance adhesion toward the bacterial surface to increase the effectiveness of phototherapy but also damage bacteria through electrostatic interaction. As a result, the prepared nanocomposites could not only penetrate biofilms but also ablate biofilms through combined chem/photodynamic/photothermal effects under NIR light irradiation. Furthermore, the nanocomposites could treat bacterial infections in vivo with negligible tissue toxicity. Overall, the finely designed nanocomposites are anticipated to display promising applications in imaging-guided chem/photodynamic/photothermal combined therapy for bacterial infections.

Antibacterial and Antiviral Functional Materials: Chemistry and Biological Activity toward Tackling COVID-19-like Pandemics

The ongoing worldwide pandemic due to COVID-19 has created awareness toward ensuring best practices to avoid the spread of microorganisms. In this regard, the research on creating a surface which destroys or inhibits the adherence of microbial/viral entities has gained renewed interest. Although many research reports are available on the antibacterial materials or coatings, there is a relatively small amount of data available on the use of antiviral materials. However, with more research geared toward this area, new information is being added to the literature every day. The combination of antibacterial and antiviral chemical entities represents a potentially path-breaking intervention to mitigate the spread of disease-causing agents. In this review, we have surveyed antibacterial and antiviral materials of various classes such as small-molecule organics, synthetic and biodegradable polymers, silver, TiO2, and copper-derived chemicals. The surface protection mechanisms of the materials against the pathogen colonies are discussed in detail, which highlights the key differences that could determine the parameters that would govern the future development of advanced antibacterial and antiviral materials and surfaces.

Electrospun pectin/modified copper-based metal-organic framework (MOF) nanofibers as a drug delivery system

Pectin has been regarded as a drug carrier accelerating the healing process due to its bioactivities, abundance and lower cost of resources. However, a big challenge related to its practical application is its poor mechanical strength. In this study the modified Cu-based MOF containing Folic acid was synthesized and incorporated in the suitable pectin electrospun nanofibers which not only improved the copper ions release behavior but also made the fiber mat stronger, antibacterial and induce angiogenesis, fibroblast migration, and proliferation due to loaded copper ions and folic acid. The nanofibers composing of 75% pectin and 4000 kDa -PEO were chosen after morphological and mechanical characterization. Finally, the effect of MOF incorporation on the nanocomposite samples was characterized in terms of morphological, physiochemical and biological properties. The nanofibrous mats were evaluated by tensile testing, antibacterial and cytotoxicity. The release behavior of copper ions and folic acid was controlled and their burst release alleviated reducing cytotoxicity in vitro. It was found that the Young's moduli of the pectin nanofibers were improved to 19.13 MPa by the addition of Cu-based MOFs. Moreover, nanocomposite pectin nanofibers were found to be antibacterial and biocompatible. These results demonstrate that MOF-contained pectin nanofibers are promising for biomedical applications.

Nanotherapeutics for regeneration of degenerated tissue infected by bacteria through the multiple delivery of bioactive ions and growth factor with antibacterial/angiogenic and osteogenic/odontogenic capacity

Therapeutic options are quite limited in clinics for the successful repair of infected/degenerated tissues. Although the prevalent treatment is the complete removal of the whole infected tissue, this leads to a loss of tissue function and serious complications. Herein the dental pulp infection, as one of the most common dental problems, was selected as a clinically relevant case to regenerate using a multifunctional nanotherapeutic approach. For this, a mesoporous bioactive glass nano-delivery system incorporating silicate, calcium, and copper as well as loading epidermal growth factor (EGF) was designed to provide antibacterial/pro-angiogenic and osteo/odontogenic multiple therapeutic effects. Amine-functionalized Cu-doped bioactive glass nanospheres (Cu-BGn) were prepared to be 50-60 nm in size, mesoporous, positive-charged and bone-bioactive. The Cu-BGn could release bioactive ions (copper, calcium and silicate ions) with therapeutically-effective doses. The Cu-BGn treatment to human umbilical vein endothelial cells (HUVEC) led to significant enhancement of the migration, tubule formation and expression of angiogenic gene (e.g. vascular endothelial growth factor, VEGF). Furthermore, the EGF-loaded Cu-BGn (EGF@Cu-BGn) showed pro-angiogenic effects with antibacterial activity against E. faecalis, a pathogen commonly involved in the pulp infection. Of note, under the co-culture condition of HUVEC with E. faecalis, the secretion of VEGF was up-regulated. In addition, the osteo/odontogenic stimulation of the EGF@Cu-BGn was evidenced with human dental pulp stem cells. The local administration of the EGF@Cu-BGn in a rat molar tooth defect infected with E. faecalis revealed significant in vivo regenerative capacity, highlighting the nanotherapeutic uses of the multifunctional nanoparticles for regenerating infected/damaged hard tissues.

Antibacterial, proangiogenic, and osteopromotive nanoglass paste coordinates regenerative process following bacterial infection in hard tissue

Bacterial infection raises serious concerns in tissue repair settings involved with implantable biomaterials, devastating the regenerative process and even life-threatening. When hard tissues are infected with bacteria (called 'osteomyelitis'), often the cases in open fracture or chronic inflammation, a complete restoration of regenerative capacity is significantly challenging even with highly-dosed antibiotics or surgical intervention. The implantable biomaterials are thus needed to be armored to fight bacteria then to relay regenerative events. To this end, here we propose a nanoglass paste made of ~200-nm-sized silicate-glass (with Ca, Cu) particles that are hardened in contact with aqueous medium and multiple-therapeutic, i.e., anti-bacterial, pro-angiogenic and osteopromotive. The nanoglass paste self-hardened via networks of precipitated nano-islands from leached ions to exhibit ultrahigh surface area (~300 m²/g), amenable to fill tunable defects with active biomolecular interactions. Also, the nanoglass paste could release multiple ions (silicate, calcium, and copper) at therapeutically relevant doses and sustainably (for days to weeks), implying possible roles in surrounding cells/tissues as a therapeutic-ions reservoir. The osteopromotive effects of nanoglass paste were evidenced by the stimulated osteogenic differentiation of MSCs. Also, the nanoglass paste promoted angiogenesis of endothelial cells in vitro and vasculature formation in vivo. Furthermore, the significant bactericidal effect of nanoglass paste, as assessed with E. coli and S. aureus, highlighted the role of copper played in elevating ROS level and destroying homeostasis, which salvaged tissue cells from co-cultivated bacteria contamination. When administered topically to rat tibia osteomyelitis defects, the nanoglass paste enhanced in vivo bone healing and fracture resistance. The developed nanoglass paste, given its self-setting property and the coordinated therapeutic actions, is considered to be a promising drug-free inorganic biomaterial platform for the regenerative therapy of bacteria-infected hard tissues.

Copper containing silicocarnotite bioceramic with improved mechanical strength and antibacterial activity

Copper is well known for its multifunctional biological effects including antibacterial and angiogenic activities, while silicon-containing bioceramic has proved to possess superior biological properties to hydroxyapatite (HA). In this work, CuO was introduced to silicocarnotite (Ca₅(PO₄)₂SiO₄, CPS) to simultaneously enhance its mechanical and antibacterial properties, and its cytocompatibility was also evaluated. Results showed that CuO could significantly facilitate the densification process of CPS bioceramic through liquid-phase sintering. The bending strength of CPS with the addition of 3.0 wt% CuO improved from 29.2 MPa to 63.4 MPa after sintered at 1200 °C. Moreover, Cu-CPS bioceramics demonstrated superior in vitro antibacterial property against both S. aureus and E. coli strains by destroying their membrane integrity, and the antibacterial activity augmented with CuO content. Meanwhile, the released Cu ions from Cu-CPS bioceramics could promote the proliferation of human umbilical vein endothelial cells (HUVECs), and the in vitro cytocompatibility exhibited concentration dependence on Cu ions. These suggest that Cu-CPS bioceramics might be promising candidates for bone tissue regeneration with an ability to prevent postoperative infections.

The Beneficial Mechanical and Biological Outcomes of Thin Copper-Gallium Doped Silica-Rich Bio-Active Glass Implant-Type Coatings

Silica-based bioactive glasses (SBG) hold great promise as bio-functional coatings of metallic endo-osseous implants, due to their osteoproductive potential, and, in the case of designed formulations, suitable mechanical properties and antibacterial efficacy. In the framework of this study, the FastOs®BG alkali-free SBG system (mol%: SiO2—38.49, CaO—36.07, P2O5—5.61, MgO—19.24, CaF2—0.59), with CuO (2 mol%) and Ga2O3 (3 mol%) antimicrobial agents, partially substituting in the parent system CaO and MgO, respectively, was used as source material for the fabrication of intentionally silica-enriched implant-type thin coatings (~600 nm) onto titanium (Ti) substrates by radio-frequency magnetron sputtering. The physico-chemical and mechanical characteristics, as well as the in vitro preliminary cytocompatibility and antibacterial performance of an alkali-free silica-rich bio-active glass coating designs was further explored. The films were smooth (RRMS < 1 nm) and hydrophilic (water contact angle of ~65°). The SBG coatings deposited from alkali-free copper-gallium co-doped FastOs®BG-derived exhibited improved wear performance, with the coatings eliciting a bonding strength value of ~53 MPa, Lc3 critical load value of ~4.9 N, hardness of ~6.1 GPa and an elastic modulus of ~127 GPa. The Cu and Ga co-doped SBG layers had excellent cytocompatibility, while reducing after 24 h the Staphylococcus aureus bacterial development with 4 orders of magnitude with respect to the control situations (i.e., nutritive broth and Ti substrate). Thereby, such SBG constructs could pave the road towards high-performance bio-functional coatings with excellent mechanical properties and enhanced biological features (e.g., by coupling cytocompatibility with antimicrobial properties), which are in great demand nowadays.

The Influence of Ozonated Olive Oil-Loaded and Copper-Doped Nanohydroxyapatites on Planktonic Forms of Microorganisms

The research has been carried out with a focus on the assessment of the antimicrobial efficacy of pure nanohydroxyapatite, Cu²⁺-doped nanohydroxyapatite, ozonated olive oil-loaded nanohydroxyapatite, and Cu²⁺-doped nanohydroxyapatite, respectively. Their potential antimicrobial activity was investigated against Streptococcus mutans, Lactobacillus rhamnosus, and Candida albicans. Among all tested materials, the highest efficacy was observed in terms of ozonated olive oil. The studies were performed using an Ultraviolet–Visible spectrophotometry (UV-Vis), electron microscopy, and statistical methods, by determining the value of Colony-Forming Units (CFU/mL) and Minimal Inhibitory Concentration (MIC).

Antimicrobial Copper-Based Materials and Coatings: Potential Multifaceted Biomedical Applications

Surface contamination by microbes leads to several detrimental consequences like hospital- and device-associated infections. One measure to inhibit surface contamination is to confer the surfaces with antimicrobial properties. Copper's antimicrobial properties have been known since ancient times, and the recent resurgence in exploiting copper for application as antimicrobial materials or coatings is motivated by the growing concern about antibiotic resistance and the pressure to reduce antibiotic use. Copper, unlike silver, demonstrates rapid and high microbicidal efficacy against pathogens that are in close contact under ambient indoor conditions, which enhances its range of applicability. This review highlights the mechanisms behind copper's potent antimicrobial property, the design and fabrication of different copper-based antimicrobial materials and coatings comprising metallic copper/copper alloys, copper nanoparticles or ions, and their potential for practical applications. Finally, as the antimicrobial coatings market is expected to grow, we offer our perspectives on the implications of increased copper release into the environment and the potential ecotoxicity effects and possibility of development of resistant genes in pathogens.

Thermal-Disrupting Interface Mitigates Intercellular Cohesion Loss for Accurate Topical Antibacterial Therapy

Bacterial infections remain a leading threat to global health because of the misuse of antibiotics and the rise in drug-resistant pathogens. Although several strategies such as photothermal therapy and magneto-thermal therapy can suppress bacterial infections, excessive heat often damages host cells and lengthens the healing time. Here, a localized thermal managing strategy, thermal-disrupting interface induced mitigation (TRIM), is reported, to minimize intercellular cohesion loss for accurate antibacterial therapy. The TRIM dressing film is composed of alternative microscale arrangement of heat-responsive hydrogel regions and mechanical support regions, which enables the surface microtopography to have a significant effect on disrupting bacterial colonization upon infrared irradiation. The regulation of the interfacial contact to the attached skin confines the produced heat and minimizes the risk of skin damage during thermoablation. Quantitative mechanobiology studies demonstrate the TRIM dressing film with a critical dimension for surface features plays a critical role in maintaining intercellular cohesion of the epidermis during photothermal therapy. Finally, endowing wound dressing with the TRIM effect via in vivo studies in S. aureus infected mice demonstrates a promising strategy for mitigating the side effects of photothermal therapy against a wide spectrum of bacterial infections, promoting future biointerface design for antibacterial therapy.