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Five different Ag dots arrays (16 to 400 dots/mm 2 ) were fabricated on a continuous platinum, palladium, or iridium thin film and for comparison also on titanium film by sputter deposition and photolithographic patterning. To analyze the antibacterial activity of these microstructured films Staphylococcus aureus ( S. aureus ) were placed onto the array surfaces and cultivated overnight. To analyze the viability of planktonic as well as surface adherent bacteria, the applied bacterial fluid was subsequently aspirated, plated on blood agar plates and adherent bacteria were detected by fluorescence microscopy. A particular antibacterial effect towards S. aureus was induced by Ag dot arrays on each of the platinum group thin film (sacrificial anode system for Ag) in contrast to Ag dot arrays fabricated on the Ti thin films (non-sacrificial anode system for Ag). Among platinum group elements the Ir-Ag system exerted the highest antibacterial activity which was accompanied by most advanced dissolution of the Ag dots and Ag ion release compared to Ag dots on Pt or Pd. [ABSTRACT FROM AUTHOR]

The relationship between microbe populations that are active on engineered-product surfaces and their relationship to surface corrosion or human health is increasingly being recognized by the materials engineering community as a critically important study-direction. Microbial contamination from biofilms and germ colonies leads to costs that are reported to be extremely high every year in infection control, epidemics, corrosion loss and energy/infrastructure materials loss throughout the world. Nanostructured surfaces, particularly those that are hard-surface nanoporous (pore radii between 2 and 1000 nm), are an emerging class of surfaces that have recently been recognized as important for the prevention of microbial colony growth and biofilm formation. Such nanostructured/nanoporous surfaces, whether made with deposited nanoparticles (welded nanoparticles), or formed by ion-assisted growth on a surface have been found to display biocidal activity with varying efficacy that depends on both the microbe and the nanosurface features. The rate of mortality from common pathogens that are resident in ubiquitous bio-films when attached to common engineering surfaces made of steels, titanium and zirconium appears to be increasing. In this short review, we look at methods of manufacture of durable (i.e., highly scratch resistant) nanostructuring on commonly used engineering surfaces. The microstructures, energy dispersive X-ray analysis, X-ray photo-electron spectroscopy and other types of characterization of a few such surfaces are presented. Simple tests are required by the surface engineering community for understanding the efficacy of a surface for antimicrobial action. These are reviewed. The surface drying rate and the dynamics of the droplet spread have been proposed in the literature as quick methods that correlate well with the residual antimicrobial activity efficacy even after some surface abrasion of the nanostructured surface. A categorization of a surface against short-term antimicrobial action and long-term action is proposed in this review article. Test periods that span time-frames greater than 5 years have demonstrated a high efficacy of the nanoporous nanostructures for preventing bio-film formation. New comparative results for diamond- and graphite-containing surfaces are presented. A brief discussion on a recently developed plasma application technique for creating durable nanoporous surfaces is presented. Although considerable information is now available regarding tunable surface nanofeatures for antimicroabial efficacy, there is a need for more research activity, particularly directed toward the low cost manufacture and rapid characterization of durable (wear and chemical resistant) surfaces that display permanent antimicrobial behavior. [ABSTRACT FROM AUTHOR]

Bacterial adhesion and subsequent biofilm formation on the surfaces of synthetic materials imposes a significant burden in various fields, which can lead to infections in patients or reduce the service life of industrial devices. Therefore, there is increasing interest in imbuing surfaces with antibacterial properties. Bioinspired superhydrophobic surfaces with high water contact angles (>150°) exhibit excellent surface repellency against contaminations, thereby preventing initial bacterial adhesion and inhibiting biofilm formation. However, conventional superhydrophobic surfaces typically lack long-term durability and are incapable of achieving persistent efficacy against bacterial adhesion. To overcome these limitations, in recent decades, dual-function superhydrophobic antibacterial surfaces with both bacteria-repelling and bacteria-killing properties have been developed by introducing bactericidal components. These surfaces have demonstrated improved long-term antibacterial performance in addressing the issues associated with surface-attached bacteria. This review summarizes the recent advancements of these dual-function superhydrophobic antibacterial surfaces. First, a brief overview of the fabrication strategies and bacteria-repelling mechanism of superhydrophobic surfaces is provided and then the dual-function superhydrophobic antibacterial surfaces are classified into three types based on the bacteria-killing mechanism: i) mechanotherapy, ii) chemotherapy, and iii) phototherapy. Finally, the limitations and challenges of current research are discussed and future perspectives in this promising area are proposed., (© 2023 Wiley-VCH GmbH.)

The lack of site-specific chemotherapeutic agents after osteosarcoma surgeries often induces severe side effects. We propose the utilization of curcumin as an alternative natural chemo-preventive drug for tumor-specific delivery systems with 3D printed tricalcium phosphate (TCP) based artificial bone grafts. The poor bioavailability and hydrophobic nature of curcumin restrict its clinical use. We have used polydopamine (PDA) coating with Zn 2+ functionalization to enhance the curcumin release in the biological medium. The obtained PDA-Zn 2+ complex is characterized by X-ray photoelectron spectroscopy (XPS). The presence of PDA-Zn 2+ coating leads to ~2 times enhancement in curcumin release. We have computationally predicted and validated the optimized surface composition by a novel multi-objective optimization method. The experimental validation of the predicted compositions indicates that the PDA-Zn 2+ coated curcumin immobilized delivery system leads to a ~12 folds decrease in osteosarcoma viability on day 11 as compared to only TCP. The osteoblast viability shows ~1.4 folds enhancement. The designed surface shows the highest ~90 % antibacterial efficacy against gram-positive and gram-negative bacteria. This unique strategy of curcumin delivery with PDA-Zn 2+ coating is expected to find application in low-load bearing critical-sized tumor-resection sites., Competing Interests: Declaration of competing interest The authors do not have any possible conflict of interest. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Health., (Copyright © 2023 Elsevier B.V. All rights reserved.)

In this work laser micro polishing (LMP) of cold rolled 0.3 mm thick 304 stainless steel with a pulsed fibre laser is studied, for applications where antibacterial properties are required. Due to its production method, the initial surface roughness of the tested material was considerably low (Sa=85.3±2.8 μm), rendering a demanding case for the laser polishing process. Accordingly, process feasibility under three different atmospheric conditions, namely ambient, Ar and N 2 atmosphere, was investigated. A large set of process parameter combinations was tested and initial analysis was carried out to identify the polishing feasibility by inspection under an optical microscope. Once the feasibility window was determined, a primary characterization was made on selected surfaces for roughness and waviness. Results show that in some process conditions belonging to the explored feasibility range, surface roughness could be decreased by 50%. [ABSTRACT FROM AUTHOR]

In this study, a high-efficiency antibacterial surface with both antimicrobial and antiadhesive functionality was fabricated on a silicon substrate by combining a zwitterionic poly-(sulphobetaine methacrylate) (PSBMA) brush and triclosan (TCS). The uniform PSBMA polymer brush on the substrate was successfully prepared using surface-initiated atom transfer radical polymerization (SI-ATRP). A series grafting ratios of TCS was covalently conjugated to the polymer brush. The surface’s antibacterial performance was evaluated using the Actinomyces naeslundii and Escherichia coli attachment tests. Bacterial adhesion to the surface was significantly reduced following PSBMA brush modification, but the remaining bacteria on the surface were not necessarily killed. After coupling the TCS to the PSBMA brush, the surface had a high-efficiency antibacterial performance from the combination of resisting bacterial adhesion and possessing bactericidal activity. [ABSTRACT FROM AUTHOR]

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[Display omitted] • A silver antibacterial surface was realized by combining a femtosecond laser and PDA. • Hierarchical surface structures of porous Ti6Al4V regulate silver ion release. • Microgrooves on implant surfaces made cells show a certain orientation. Bacterial infection of porous implants at an early stage of healing is one of the causes of bone implant failure since the porous structure will increase the adhesion of bacteria. In general, antimicrobial agents can be added to the surface of the implant to kill bacteria. However, the regulation of surface topography on the release of antimicrobial agents from porous implants is still unclear. In this work, a strategy combining a hierarchical microgroove structure constructed by a femtosecond laser and silver adhered by polydopamine (PDA) is developed on a porous titanium alloy. This study finds that the surface parameters of the hierarchical structure control the total amount and rate of silver release, and PDA improves the total amount of absorbed silver. The synergistic effect of PDA and the hierarchical structure realizes the adjustability of silver adsorption and release. In vitro tests show that the modified surface has better antibacterial properties than the original surface, and it allows the cells on the surface to display a certain orientation. This surface strategy has great potential for morphologically regulated ion release and can be applied to bone regeneration. [ABSTRACT FROM AUTHOR]

Insects and plants exhibit bactericidal properties through surface nanostructures, such as nanospikes, which physically kill bacteria without antibiotics or chemicals. This is a promising new avenue for achieving antibacterial surfaces. However, the existing methods for fabricating nanospikes are incapable of producing uniform nanostructures on a large scale and in a cost-effective manner. In this paper, a scalable nanofabrication method involving the application of nanosphere lithography and reactive ion etching for constructing nanospike surfaces is demonstrated. Low-cost silicon nanospikes with uniform spacing that were sized similarly to biological nanospikes on cicada wings with a 4-inch wafer scale were fabricated. The spacing, tip radius, and base diameter of the silicon nanospikes were controlled precisely by adjusting the nanosphere diameters, etching conditions, and diameter reduction. The bactericidal properties of the silicon nanospikes with 300 nm spacing were measured quantitatively using the standard viability plate count method; they killed E. coli cells with 59 % efficiency within 30 h. The antibacterial ability of the nanospike surface was further indicated by the morphological differences between bacteria observed in the scanning electron microscopic images as well as the live/dead stains of fluorescence signals. The fabrication process combined the advantages of both top-down and bottom-up methods and was a significant step toward affordable bio-inspired antibacterial surfaces. [Display omitted] • A hybrid method combining top-down reactive ion etching and bottom-up nanosphere lithography for producing silicon nanospikes. • Kill E. Coli physically without using antibiotics by disrupting bacterial membranes. • Provide well-controlled silicon nanospikes geometry in a 4-inch wafer scale in a low-cost fashion. [ABSTRACT FROM AUTHOR]

Mussel-inspired polydopamine (PDA) deposition offers a promising route to fabricate multifunctional coatings for various materials. However, PDA deposition is generally a time-consuming process, and PDA coatings are unstable in acidic and alkaline media, as well as in polar organic solvents. We report a strategy to realize the rapid deposition of PDA by using CuSO4/H2O2 as a trigger. Compared to the conventional processes, our strategy shows the fastest deposition rate reported to date, and the PDA coatings exhibit high uniformity and enhanced stability. Furthermore, the PDA-coated porous membranes have excellent hydrophilicity, anti-oxidant properties, and antibacterial performance. This work demonstrates a useful method for the environmentally friendly, cost-effective, and time-saving fabrication of PDA coatings. [ABSTRACT FROM AUTHOR]

• AgNPs were green synthesized using leaf extracts of P. boldus and incorporated into an nPSi structure by capillary suction. • Composite thin films of nPSi/AgNPs were chemically and morphologically characterized. • Antibacterial activity of nPSi/AgNPs layers was successfully evaluated using a wide fan of bacterial strains. This work is about the fabrication of composite thin films of nanoporous silicon/green synthesized silver nanoparticles and their potential use as antibacterial surfaces. To obtain the composite layers, silver nanoparticles were synthesized using leaf extracts of P. boldus , and subsequently integrated on nanoporous silicon matrix. The achieved samples were characterized microscopically (TEM and AFM), and physiochemically (UV–vis spectroscopy, LIBS, and XRD). Moreover, the antibacterial activity of the composite layers was studied using different strains of Gram-positive (S. aureus and S. epidermidis) and Gram-negative (K. pneumoniae , E. coli , and P. aeruginosa) bacteria. The experimental results showed the potential of these composite thin films as antibacterial surfaces for biomedical applications. [ABSTRACT FROM AUTHOR]

The adhesion and proliferation of bacteria on metallic surfaces in different places such as health centers, industries and even homes increase the risk of human infections. In the present research, mild steel as a substrate was coated with a Ni–P layer through electroless plating to prevent surface corrosion of the steel. In order to achieve an antibacterial metallic surface, simultaneous sono-synthesis and deposition of ZnO nanoparticles (NPs) were performed on this Ni–P coating. The morphology and chemical composition of the ZnO coated plate were characterized by the use of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The X-ray diffraction (XRD) pattern confirmed that the ZnO was pure and showed a hexagonal structure. The antibacterial activity assay of the electroless Ni–P coating against Escherichia coli O157:H7 showed some biological activity but the plate containing ZnO NPs effectively prohibited the growth of E. coli . It is concluded that the attached ZnO surface could be utilized for antibacterial purposes by reduction of colonization. [ABSTRACT FROM AUTHOR]

An innovative multi-layer coating comprising a bioactive compound layer (consisting of hydroxyapatite and calcium titanate) with an underlying titanium oxide layer (in the form of anatase and rutile) has been developed on Grade 4 quality commercially pure titanium via a single step micro-arc oxidation process. Deposition of a multi-layer coating on titanium enhanced the bioactivity, while providing antibacterial characteristics as compared its untreated state. Furthermore, introduction of silver (4.6 wt.%) into the multi-layer coating during micro-arc oxidation process imposed superior antibacterial efficiency without sacrificing the bioactivity. [ABSTRACT FROM AUTHOR]

Ten different Ag dot arrays (16 to 625 microstructured dots per square mm) were fabricated on a continuous Au thin film and for comparison also on Ti film by sputter deposition and photolithographic patterning. To analyze the antibacterial activity of these microstructured films Escherichia coli and Staphylococcus aureus were placed onto the array surfaces and cultivated overnight. To analyze the viability of planktonic as well as surface adherent bacteria, the applied bacterial fluid was subsequently aspirated, plated on blood agar plates and adherent bacteria were detected by fluorescence microscopy. A particular antibacterial effect towards both bacterial strains was induced by Ag dot arrays on fabricated Au thin film (sacrificial anode system for Ag), due to the release of Ag ions from dissolution of Ag dots in contrast to Ag dot arrays fabricated on the Ti thin films (non-sacrificial anode system for Ag) which remained intact to the original dot shape. The required number of Ag dots on gold film to achieve complete bactericidal effects for both bacterial strains was seven times lower than that observed with Ag dot arrays on Ti film. [ABSTRACT FROM AUTHOR]

Infection is the most common factor that leads to dental titanium implant failure. Antibacterial implant surfaces based on nano-scale modifications of the titanium appear as an attractive strategy for control of peri-implantitis. In the present work, the preparation and antibacterial properties of a novel composite coating for titanium based on nanoporous silica and silver nanoparticles are presented. Starch-capped silver nanoparticles (AgNPs) were synthesized and then incorporated into sol–gel based solution system. The AgNP-doped nanoporous silica coatings were prepared on titanium surface using a combined sol–gel and evaporation-induced self-assembly (EISA) method. The coating nanostructure was characterized by XRD, SEM–EDX, and HR-TEM. Antibacterial activity was evaluated against Aggregatibacter actinomycetemcomitans , a representative pathogen of dental peri-implantitis. Colony-forming units (CFUs) were counted within the biofilm and at the planktonic state. Biofilm development was quantified using crystal violet staining and viability of adherent bacteria was confirmed with the Live/Dead fluorescence assay. Silica-based composite coating containing AgNPs (AgNP/NSC) was prepared on titanium surface by direct incorporation of AgNP suspension into the sol–gel system. The self-assembly technique enabled the spontaneous formation of a highly ordered nanoporosity in the coating structure, which is a desired property for osseointegration aspects of titanium implant surface. AgNP/NSC coating produces a strong antibacterial effect on titanium surface by not only killing the adherent bacteria but also reducing the extent of biofilm formation. Biofilm survival is reduced by more than 70% on the AgNP/NSC-modified titanium surface, compared to the control. This antibacterial effect was verified for up to 7 days of incubation. The long-term antibacterial activity exhibited by the nanostructured AgNP/NSC-titanium surface against A. actinomycetemcomitans suggests that this type of nano-scale surface modification is a promissory strategy to control infections associated with dental implant rehabilitation. [ABSTRACT FROM AUTHOR]

Silver nanoparticles synthesized on titanium dioxide (Ag/TiO 2 ), an effective antibacterial additive, were added to a commercial paint and its antimicrobial activity was evaluated. Microbiological tests against Escherichia coli and Methicillin-resistant Staphylococcus aureus were performed under high relative humidity (RH>90%) and low (RH≈14%). A remarkable difference in cell recovery under high and low humidity was found. [ABSTRACT FROM AUTHOR]

The effective and widely tested biocides: Benzalkonium chloride, bronopol, chitosan, chlorhexidine and irgasan were added in different concentrations to atelocollagen matrices. In order to assess how these antibacterial agents influence keratinocytes cell growth, cell viability and proliferation were determined by using MTT assay. Acquired data indicated a low toxicity by employing any of these chemical substances. Furthermore, cell viability and proliferation were comparatively similar to the samples where there were no biocides. It means that regardless of the agent, collagen-cell-attachment properties are not drastically affected by the incorporation of those biocides into the substrate. Therefore, these findings suggest that these atelocollagen substrates enhanced by the addition of one or more of these agents may render effectiveness against bacterial stains and biofilm formation, being the samples referred to herein as "antimicrobial substrates" a promising view in the design of novel antimicrobial biomaterials potentially suitable for tissue engineering applications. [ABSTRACT FROM AUTHOR]

The adhesion of pathogenic bacteria and the consequent formation of biofilms on biomedical materials and devices continue to be a significant concern in biomedical applications. Thus, it is critical to design antibacterial surfaces that limit bacterial adhesion and biofilm formation. The current study effectively fabricates a universal dual-functional antibacterial film with antifouling and photothermal bactericidal activity using a simple and ecologically friendly sequential deposition of polydopamine (PDA) layer and phase-transited bovine serum albumin (PTB) film. Because of the excellent antifouling characteristic of PTB film, hybrid surfaces can resist the initial attachment of majority of bacteria, however, a small number of bacteria adhering to the surface will be killed by near-infrared (NIR) irradiation due to the excellent photothermal effect of PDA layer. Compared to single-functional antibacterial surfaces with either antifouling or bactericidal qualities, this dual-functional surface demonstrated superior antibacterial performance and antibiofilm ability. Additionally, the hybrid surface can be utilized for many substrata despite the surface chemistry or topography. It exhibits negligible cytotoxicity and high histocompatibility, presenting a novel approach to eliminate surface-attached bacteria occurring in various healthcare applications. [ABSTRACT FROM AUTHOR]

Protonable polyethyleneimine (PEI) and citric acid (CA) based C-dots were prepared via a hydrothermal process, yielding particles with a hydrodynamic diameter of ~100 and ~80 nm, and zeta potential of − 2.3 ± 0.1 and + 23.4 ± 0.2 mV for PEI-CA C-dots and their protonated form, respectively. Treating Staphylococcus aureus with these C-dots resulted in a statistically significant reduction in bacterial growth, specifically growth in the planktonic phase as well as in the development of bacterial biofilm when compared to untreated (p < 0.05). When 24 h matured S. aureus biofilms were treated with C-dots, a significant disruption and dispersion of bacteria from the existing biofilms was noted as compared to untreated (p < 0.05). Other Gram-positive microorganisms (B. cereus, S. epidermidis, S. pyogenes) and Gram-negative (P. mirabilis, E. coli, and P. aeruginosa) were also susceptible to the antimicrobial activity of the PEI-CA C-dots with significant inhibition of bacterial growth noted for all organisms after C-dot treatment. Only for B. cereus, S. epidermidis, and P. aeruginosa was this reduction in total growth reflected in decreased planktonic growth. However, biofilm formation by all organisms was reduced significantly upon treatment with the C-dots, including those for which planktonic growth was not impacted. [Display omitted] • Fluorescent N-doped C-dots can be readily prepared via a facile solvothermal method. • Positively charged N-doped C-dots are effective as anti-biofilm agents. • C-dots successfully inhibit bacterial proliferation in the planktonic growth phase. • C-dots stop biofilm formation by several bacteria and disrupt established biofilms. [ABSTRACT FROM AUTHOR]

In this paper, effect of the excimer laser irradiation on bacterial adhesion of the polycarbonate films was investigated. For this purpose, the surface roughness and wettability as two important factors are examined following laser treatment. The samples were irradiated by a KrF laser with the wavelength of 248 nanometers and pulse duration of about 25 ns. Scanning electron spectroscopy was used for investigating the changes in surface morphology. Finally, the results show that excimer laser irradiation with a proper irradiation parameters improve the antibacterial properties of polycarbonate surface. [ABSTRACT FROM AUTHOR]

There is a pressing need to control the occurrences of nosocomial infections due to their detrimental effects on patient well-being and the rising treatment costs. To prevent the contact transmission of such infections via health-critical surfaces, a prophylactic surface system that consists of an interdigitated array of oppositely charged silver electrodes with polymer separations and utilizes oligodynamic iontophoresis has been recently developed. This paper presents a systematic study that empirically characterizes the effects of the surface system parameters on its antibacterial efficacy, and validates the system's effectiveness. In the first part of the study, a fractional factorial design of experiments (DOE) was conducted to identify the statistically significant system parameters. The data were used to develop a first-order response surface model to predict the system's antibacterial efficacy based on the input parameters. In the second part of the study, the effectiveness of the surface system was validated by evaluating it against four bacterial species responsible for several nosocomial infections - Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Enterococcus faecalis - alongside non-antibacterial polymer (acrylic) control surfaces. The system demonstrated statistically significant efficacy against all four bacteria. The results indicate that given a constant total effective surface area, the system designed with micro-scale features (minimum feature width: 20 μm) and activated by 15 μA direct current will provide the most effective antibacterial prophylaxis. [ABSTRACT FROM AUTHOR]

Abstract: The vermiculite from Brazil (fy Grena in Czech Republic) was used as clay mineral nanofiller to polyethylene. Two vermiculite size fractions were prepared in a planetary ball mill and in the jet mill. The vermiculite/polyethylene nanocomposites were prepared with 7mass% and 3.5mass% of vermiculite nanofillers using melt compounding procedure without additives. The characterization of vermiculite nanofillers and their corresponding clay polymer nanocomposites (CPN) was made based on the results obtained using the X-ray powder diffraction, particle size distribution and specific surface area measurements. The surfaces of CPN plates were studied using atomic force microscopy. The arrangement of the PE chains near the vermiculite structure was investigated by molecular modeling. Finding that the CPN have an effect on bacterial growth was confirmed by long-term evaluation of the living/deceased Enterococcus faecalis bacteria on the surface plates of the CPN. [Copyright &y& Elsevier]

Abstract: We performed a systematic study of the bactericide and bacterial anti-adhesive properties of nanocrystalline diamond (NCD) and microcrystalline diamond (MCD) in comparison to other important industrial materials, such as copper, silver, polyethylene (Poly), and stainless steel (SS). The data show that NCD has better bactericide and bacterial anti-adhesive activity than Ag, but not as good as Cu. MCD, on the other hand, does not appear to have significant anti-bacterial activity. The superlative properties of NCD, such as mechanical hardness, resistance to oxidation and corrosion, and biological compatibility with blood and tissue, enable its use as antibacterial coating for medical implants. This is an application that cannot be achieved by Cu, which is known to be a highly effective antibacterial material but is not biocompatible. We also discuss possible underlying mechanisms to help understand the bactericide and bacterial anti-adhesive properties of the NCD surface. [Copyright &y& Elsevier]

Abstract: Diamond-like carbon (DLC) is known to be a versatile coating material for biomedical applications like endoprosthesis and dental implants. It provides mechanical robustness and cell-compatibility at the same time. To even more broaden this range of beneficial properties, it is tried to add antibacterial properties by incorporating silver nanoparticles. In this paper we discuss a novel approach to producing such coatings, capable of circumventing typical drawbacks of conventional deposition methods. To investigate the potential antibacterial properties an in vitro adhesion assay was created. Thereto Streptococcus sanguinis (DSM 20068) responsible for initial biofilm formation in peri-implant infection has been used. The results clearly show that silver nanoparticles are crucial for the antimicrobial effect as long as they are incorporated in the DLC-surface so that the adhering bacteria are directly exposed. [Copyright &y& Elsevier]

Abstract: A two-step, easy synthetic strategy in solution has been optimized to prepare authentic monolayers of silver nanoparticles (NP) on MPTS-modified glass surfaces, that were investigated by AFM imaging and by quantitative silver determination techniques. NP in the monolayers remain firmly grafted (i.e. not released) when the surfaces are exposed to air, water or in the physiological conditions mimicked by phosphate saline buffer, as UV–Vis spectroscopy and AFM studies demonstrate. About 15% silver release as Ag+ ions has been found after 15days when the surfaces are exposed to water. The released silver cations are responsible of an efficient local microbicidal activity against Escherichia coli and Staphylococcus aureus bacterial strains. [ABSTRACT FROM AUTHOR]

Antibacterial polymer was grafted onto silica nanoparticle and the surface properties of various composites filled with the silica were investigated. The grafting of antibacterial polymer, poly(vinylbenzyltributylphosphonium chloride) (poly(St-CH2P+(Bu)3Cl-)), onto silica surface was achieved by two methods: one is treatment of poly(vinylbenzylchloride) (poly(St-CH2Cl))-grafted silica with tributylphosphine and the other is direct grafting of poly(St-CH2P+(Bu)3Cl-) by radical graft polymerization of the corresponding monomer. The grafting of poly(St-CH2Cl) and poly(St-CH2P+(Bu)3Cl-) onto silica surface were initiated by the system consisting of trichloroacetyl groups on the silica surface and Mo(CO)6. Trichloroacetyl groups were introduced onto the silica surface by the reaction of amino groups on the silica surface with trichloroacetyl isocyanate. The percentage of poly(St-CH2Cl) grafting during the graft polymerization initiated by the system increased with progress of the polymerization reached 116%. The grafting of poly(St-CH2P+(Bu)3Cl-) onto silica surfaces was confirmed by FT-IR spectra, thermal decomposition gas chromatograms and mass spectra (GC-MS), and 13C-CP/MAS NMR. The surfaces of silicone rubber, polystyrene film, and paints filled with the poly(St-CH2P+(Bu)3Cl-)-grafted silica shows strong antibacterial activity. These composites retained the antibacterial activity even after the boiling in water for 24 h. [ABSTRACT FROM AUTHOR]

For tissue engineering applications, porous/biocompatible scaffolds are crucial. Some novel composites, Cu-MOF@PDMS, were fabricated by incorporating Cu-MOF into a PDMS sponge. Then, a layer of chitosan was coated on the Cu-MOF@PDMS sponges by the dip-coating method. The nanocomposites can be benefited by the flexibility characteristic of PDMS, the porosity of the Cu-MOF, and the bactericidal activity of chitosan. Morphological and chemical characterization of the as-obtained materials were investigated using FT-IR, XRD, SEM, EDS mapping, and TEM techniques. The obtained results exhibited that Cu-MOFs and chitosan are attached to the PDMS surface. TEM analysis exhibited the incorporation of Cu-MOF nanoparticles on the PDMS surface. The effect of Cu-MOF and chitosan on the antibacterial activities and cytotoxicity of sponges were also studied. Chitosan enhanced the antibacterial efficacy of the Cu-MOF@PDMS sponges against Staphylococcus aureus and Escherichia coli. The Chitosan@Cu-MOF@PDMS sponge resulted in a marked decrease in the number of viable bacteria cells (>4.5 log 10 CFU). Biological studies exhibited that the experimented sponges including the Cu-MOF@PDMS and the Chitosan@Cu-MOF@PDMS scaffolds provided proper surfaces for cell adhesion, proliferation, and viability compared with the pure PDMS sponge. Additionally, the obtained results confirmed that the presence of the Cu-MOF and chitosan in the nanocomposites have significant importance in cell attachment and viability. The as-fabricated chitosan-coated Cu-MOF@PDMS sponges are green, biocompatible, and potential scaffolds for antibacterial and tissue engineering applications. [Display omitted] • Composite sponge of Cu-MOF, chitosan, and polydimethylsiloxane have been prepared. • Composites showed higher antibacterial activity than pure polydimethylsiloxane. • Composites resulted in a marked decrease in the number of viable bacteria cells. • Composites provided proper surfaces for cell adhesion, proliferation, and viability. [ABSTRACT FROM AUTHOR]

Antibacterial polymer was grafted onto nano-sized silica surface and the surface properties of silicone rubber filled with the silica were investigated, The grafting of antibacterial polymer was carried out by two-step reactions as follows. Poly(p-styrene sodirm sulfate) (poly(St-SO3-Na+)) was successfully grafted onto nano-sized silica surface by the radical polymerization of St-SO3-Na+ initiated by the system consisting of trichloroacetyl groups on the silica surface and Mo(CO)6: trichloroacetyl groups were introduced onto the silica surtace by the reaction of amino groups with trichloroacetyl isocyanate. The percentage of poly(St-SO3-Na+) grafting increased with progress of the polymerization and reached about 30%. The poly(St-SO3-Na+)-grafted silica was treated with tributyltetradecylphosphonium chloride (Bu3RP+CI-) to convert the SO3-Na+ groups to alkyl phosphonium salt. SO3-P+ Bu3R, groups. The grafting of poly(St-SO3-P+Bu3R) onto the silica surface was confirmed by IR spectra. The poly(St-SO3-P+ Bu3R)-grafted silica gave a stable dispersion in DMSO and poly(dimethylsiloxane). It was found that silicone rubber filled with the poly(St-SO3-P+Bu3R)-grafted silica shows extremely strong antibacterial activity. The silicone rubber surface has an ability to inhibit the reproduction of a Staphylococcus aureus and an Escherichia coli. [ABSTRACT FROM AUTHOR]

The antimicrobial compound dodecyl-di(aminoethyl)-glycine was immobilized in a silicon oxide xerogel matrix and used for glass surface coating. Coated glasses were tested for surface antimicrobial activity. The utilization of tetraethoxysilane (TEOS) as a silicon oxide polymer precursor, using the dip-coating process, allowed for the generation of transparent thin films over glass surfaces. Different concentrations of the antimicrobial compound were used to generate the coatings. The presence of dodecyl-di(aminoethyl)-glycine on coated and uncoated slides was analyzed by FT-IR spectra. Coated glass slides were exposed to suspensions of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus for 24 h. Surface contamination was evaluated by the microbial plate count technique. When antimicrobial-coated glasses were compared with antimicrobial-free coated glasses, the former showed greater than 99% reduction of colony-forming units (cfu) for E. coli and P. aeruginosa, when 1% of antimicrobial was present in the coating solution. The same percentage of reduction for S. aureus was achieved when 1.5% of the antimicrobial was present in the coating solution. In a direct inhibition test on agar plates, no inhibitory zone was observed, indicating that the antimicrobial did not diffuse into the media. [ABSTRACT FROM AUTHOR]

Microbial colonization of catheter surfaces is responsible for most healthcare-associated infections. Quaternized chitin and chitosan have excellent antimicrobial and biocompatible properties and can be used to provide safe and prolonged protection for biomedical catheters. Herein, we prepared quaternized β-chitin derivative (QC)- and quaternized chitosan derivative (QCS)-based antimicrobial surfaces. The quaternized polysaccharides modified TPU surfaces exhibited hydrophilicity, good biocompatibility. Among these, QCS2-modified TPU exhibited excellent antibacterial properties against Gram-positive and Gram-negative bacteria, and prevented the adherence of bacteria compared with pristine TPU. The antibacterial activity of QCS2-modified surfaces maintained for 8 weeks under the condition of immersion in serum. An in vivo subcutaneous implantation experiment revealed 99.87% reduction of bacteria and reduced expression of inflammation-related factors in the surrounding tissue five days after implantation with QCS2-modified TPU. Therefore, quaternized polysaccharide-modified surfaces have promising potential in preventing medical catheter-associated infections. • A series of quaternized chitin-based derivative antimicrobial surfaces were prepared. • QCS2-modified TPU exhibited hydrophilic and good biocompatibility. • Excellent antibacterial properties of TPU-QCS2 against E. coli , S. aureus and MRSA. • TPU-QCS2 maintained long-term antibacterial activity for 8 weeks. • TPU-QCS2 can prevent infection in the in vivo implantation experiment. [ABSTRACT FROM AUTHOR]

Adhesion of bacteria on biomedical implant surfaces is a prerequisite for biofilm formation, which may increase the chances of infection and chronic inflammation. In this study, we employed a novel electrospray-based technique to develop an antibacterial surface by efficiently depositing silica homogeneously onto polyethylene terephthalate (PET) film to achieve hydrophobic and anti-adhesive properties. We evaluated its potential application in inhibiting bacterial adhesion using both Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) bacteria. These silica-deposited PET surfaces could provide hydrophobic surfaces with a water contact angle greater than 120° as well as increased surface roughness (root mean square roughness value of 82.50 ± 16.22 nm and average roughness value of 65.15 ± 15.26 nm) that could significantly reduce bacterial adhesion by approximately 66.30% and 64.09% for E. coli and S. aureus, respectively, compared with those on plain PET surfaces. Furthermore, we observed that silica-deposited PET surfaces showed no detrimental effects on cell viability in human dermal fibroblasts, as confirmed by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide and live/dead assays. Taken together, such approaches that are easy to synthesize, cost effective, and efficient, and could provide innovative strategies for preventing bacterial adhesion on biomedical implant surfaces in the clinical setting. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new UHPLC-MS method was used assuring a faster sophorolipids analysis. • Automatic Flash Chromatography allowed the purification of several SLs. • Purified L-C18:0 and L-C18:1 diacetylated SLs showed higher antimicrobial activity. • Antiadhesive properties of surface-bonded acidic SLs reduced biofilm formation. • L-C18:1 diacateylated SL release was the most promising regarding efficacy and safety. Staphylococcus aureus medical devices related-infections, such as blood stream catheter are of major concern. Their prevention is compulsory and strategies, not prone to the development of resistance, to prevent S. aureus biofilms on catheter surfaces (e.g. silicone) are needed. In this work two different approaches using sophorolipids were studied to prevent S. aureus biofilm formation on medical grade silicone: i) an antiadhesive strategy through covalent bond of sophorolipids to the surface; ii) and a release strategy using isolated most active sophorolipids. Sophorolipids produced by Starmerella bombicola , were characterized by UHPLC-MS and RMN, purified by automatic flash chromatography and tested for their antimicrobial activity towards S. aureus. Highest antimicrobial activity was observed for C18:0 and C18:1 diacetylated lactonic sophorolipids showing a MIC of 50 μg mL−1. Surface modification with acidic or lactonic sophorolipids when evaluating the anti-adhesive or release strategy, respectively, was confirmed by contact angle, FTIR-ATR and AFM analysis. When using a mixture of acidic sophorolipids covalently bonded to silicone surface as antiadhesive strategy cytocompatible surfaces were obtained and a reduction of 90 % on biofilm formation was observed. Nevertheless, if a release strategy is adopted with purified lactonic sophorolipids a higher effect is achieved. Most promising compound was C18:1 diacateylated lactonic sophorolipid that showed no cellular viability reduction when a concentration of 1.5 mg mL−1 was selected and a reduction on biofilm around 5 log units. Results reinforce the applicability of these antimicrobial biosurfactants on preventing biofilms and disclose that their antimicrobial effect is imperative when comparing to their antiadhesive properties. [ABSTRACT FROM AUTHOR]

In this study, assessment of the antimicrobial activity of a novel, plasma-cured 2.5% (w/v) Cu(NO3)2-containing sol–gel surface was performed. In contrast to state-of-the-art sol–gel coatings, the plasma curing led to a gradient in cross-linking with the highest values at the top of the coating. As a result, the coating behaved simultaneously hard, scratch-resistant, and tough, the latter due to the more flexible bulk of the coating toward the substrate. Further, the diffusion and permeation through the coating also increased toward the substrate. In our study, tests according to ISO 22196 showed antibacterial activity of the 2.5% (w/v) Cu(NO3)2-containing sol–gel surface against all bacterial strains tested, and we expanded the testing further using a "dry" evaluation without an aqueous contact phase, which confirmed the antimicrobial efficacy of the 2.5% (w/v) Cu(NO3)2-containing sol–gel surface. However, further investigation under exposure to soiling with the addition of 0.3% albumin, used to simulate organic load, led to a significant impairment in the antibacterial effect under both tested conditions. Furthermore, re-testing of the surface after disinfection with 70% ethanol led to a total loss of antibacterial activity. Our results showed that besides the mere application of an antimicrobial agent to a surface coating, it is also necessary to consider the future use of these surfaces in the experimental phase combining industry and science. Therefore, a number of tests corresponding to the utilization of the surface should be obligative on the basis of this assessment. [ABSTRACT FROM AUTHOR]