Antibacterial Behavior Research Articles

Evaluation of surface properties of modified Ti6Al4V alloy with copper nanoparticles organic nanostructure for biomedical applications: dependency on anticorrosive, antibacterial, and biocompatibility

Abstract In this study, a novel multifunctional copper nanoparticle CuNPs in the organic biomatrix was coated to the surface of Ti6Al4V to create multifunctional features. The synthesis of CuNPs was carried out by plant-mediated green synthesis method obtained from Moringa leaf extract, and the prepared CuNPs were coated on the substrate surfaces as single and double layers with drop casting methods. Characterizations of the synthesized CuNPs were performed by UV–Vis, FTIR, XRD, and SEM methods. Characterization of the modified Ti6Al4V alloy surfaces was performed using SEM-EDS and surface roughness analysis. The electrochemical corrosion, antibacterial behavior, and cytotoxic effects of coated and noncoated Ti6Al4V as a function of biocompatibility properties were also tested. The synthesized CuNPs have a homogeneously dispersed spherical shape. Biocorrosion tests have clearly demonstrated that the coating forms a protective film on the substrate surface, and the resistance increased by 49 %. Antibacterial results show that the single and double-coated Ti6Al4V alloy samples with CuNPs organic nanostructure had improved biocompatibility. However, it was determined that the cytotoxic effect increases proportionally with the coating. The obtained results show the importance of surface modification in the appropriate nanostructure to obtain multifunctional nanoplatforms that show promise in biomedical applications.

Pillar[5]arene stabilized gold nanoparticles for the enhanced light-triggered nitric oxide release with antibacterial and antibiofilm activities

The reactivity of guests confined in well-defined host cavities act significantly different from that in bulk systems. In this work, pillar[5]arene not only works as a stabilizer for the fabrication of gold nanoparticles, but also act as an accelerator for the enhanced photo-triggered release of gaseous nitric oxide (NO) from encapsulated NO donor. The host–guest complex can dramatically improve the photoactivity of loaded guest molecule to generate antibacterial NO molecules through the confinement effect of pillar[5]arene cavity. The synergistic photo-triggered localized NO release and photo-thermal effect of host–guest complex demonstrated impressive antibacterial behaviors against Gram-negative bacterial strain Escherichia coli, Gram-positive bacterial strain Staphylococcus aureus and methicillin-resistant Staphylococcus aureus. Moreover, this biocompatible photo-responsive complex can also inhibit bacterial biofilm formation and disrupt the pre-existing biofilms.

Environmentally stable and multi-functional conductive gelatin/PVA/black wattle bark tannin based organogel as strain, temperature and bioelectric sensor for multi-mode sensing

Conductive hydrogels are regarded as ideal candidates for the application of flexible sensors owing to their excellent flexibility, portability and conductivity. However, it is still challenging and meaningful to prepare multifunctional (self-healing, adhesion, anti-freezing, biocompatibility, antibacterial and conductivity properties) and multi-mode sensing hydrogel-based sensors. Herein, we developed an environmentally stable and multi-functional conductive organogel via dynamic crosslinks based on biomass materials gelatin, black wattle bark tannin and PVA in the propylene glycol/water binary solvent system. Thanks to the dynamic interactions in the system, the good mechanical strength and self-healing performance of the obtained organogel are simultaneously realized. Meanwhile, the organogel integrates many crucial properties such as adhesion, environmental stability (anti-freezing and water retention), biocompatibility, antibacterial behavior and conductivity capacity. Significantly, the organogel can be assembled as three-mode sensors for strain, bioelectricity and temperature sensing. This three-mode sensor can effectively monitor human health data, resulting in providing supplement human health information and conditions. This work displays an interesting approach to construct an intelligent multi-functional conductive biomass organogel based multi-mode flexible sensors.

Characterization of anti bacterial biocomposite films based on poly lactic acid and prosopis juliflora bark powder

Biocomposites can be a solution for environmental pollution and sustainability by acting as an alternative to petroleum-based products used in the field of packaging and biomedical applications. Herein, an attempt to valorize the potential of Prosopis juliflora plant to fabricate Polylactic acid (PLA) based biocomposites. The biocomposites comprised of Prosopis juliflora bark powder (PJBP) and PLA were fabricated by solution casting method with various weight percentages (Wt%) of PJBP. PJBP/PLA films show uniform functional group interactions through FTIR analysis. The 25 % PJBP/ PLA biocomposite shows the highest crystalline size of 8.9 nm. The 25 wt% included PJBP increases the thermal stability by 6.9 %, surface roughness by 212 %, and tensile strength by 45.5 % compared to PLA film. The 25 % PJBP film shows increment in the water absorption and water vapor permeability test. In addition, the antibacterial behavior of 25 % PJBP bio composite shows higher inhibition zones against the gram-positive and gram-negative pathogens. Biocomposite films with PJBP content show 40 % degradation in soil for degradation analysis. This PLA/25 % PJBP biodegradable film can be used as an alternative for petroleum-based products in the field of packaging as well as the biomedical field.

Role of Charge Density and Surface Area of Tailored Ionic Porous Organic Polymers for Adsorption and Antibacterial Actions.

The development of high-performance adsorbents for environmental remediation is a current need, and ionic porous organic polymers (iPOPs), due to their high physicochemical stability, high surface area, added electrostatic interaction, and easy reusability, have already established themselves as a better adsorbent. However, research on the structural design of high-performance iPOP-based adsorbents is still nascent. This study explored the building blocks' role in optimizing the polymers' charge density and surface area to develop better polymeric adsorbents. Among the three synthesized polymers, iPOP-ZN1, owing to its high surface area and high charge density in its active sites, proved to be the best adsorbent for adsorbing inorganic and organic pollutants in an aqueous medium. The polymers were efficient enough to capture and store iodine vapor in the solid state. Further, this study tried to address using iodine-loaded polymers in antibacterial action. Iodine-loaded iPOPs show impressive antibacterial behavior against E. coli, B. subtilis, and H. pylori.

Fabrication and characterization of new hot extruded ZK60/CNTs+AgNPs nanocomposites for biomedical applications

Magnesium (Mg), with properties such as biodegradability and having a density and elasticity coefficient close to the bones of the body, has attracted a lot of attention as a serious option for orthopedic applications. However, the low compressive strength of Mg compared to the human bone and its weak antibacterial function limit its applications as a substitute for temporary implants to be used under load-bearing conditions. The aim of this paper is to evaluate the synergistic effect of CNTs + AgNPs nanofillers on the in vitro degradation, mechanical and antibacterial behavior of new ZK60/xCNTs + xAgNPs(x: 0, 0.25, 0.5, 1) composites made using semi powder metallurgy, followed by hot extrusion method. The ZK60/0.5CNTs+0.5 AgNPs (CA2) composite boasts a higher ultimate compressive strength (UCS) of 371 ± 15 MPa compared to 297 ± 6 MPa for ZK60 based alloys. The CA2 composite also exhibits a grain size of 9.8 μm and a microhardness of 81 HV.Also, the antibacterial activity assessment demonstrated that adding CNTs + AgNPs hybrid nanofillers to the Mg matrix could notably prevent growing and penetration of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), which indicates the synergy between antibacterial mechanisms of CNTs and AgNPs. Cytotoxicity studies confirm that composites with low amounts of CNTs + AgNPs did not show cytotoxic behavior against MG63 cells, although higher loading of CNTs + AgNPs caused toxicity. Also, the examination of osteogenic activity is consistent with other results. In general, according to the results, the potential application of CA2 composite for under load bearing implant application and bone infection treatment is proved.

Investigating the catalytic and antibacterial behavior of cesium-doped MoO3 nanostructures against methylene blue dye and MDR E. coli with DFT analysis

Water pollution, exacerbated by inadequate water management practices, has compromised the effectiveness of traditional water treatment technologies. The integration of metal oxide-based nanomaterials in treatment systems has the potential to revolutionize the field of wastewater treatment, providing a sustainable and efficient solution to the growing global water crisis. This study focused on the fabrication of hexagonal cesium (Cs) doped MoO3 nanostructures (NSs) for their potential use as catalytic and antibacterial agents. Various structural, optical, and morphological analysis was conducted to examine these NSs. The UV–Vis spectroscopy results showed that as Cs concentration increased, the band gap energies of MoO3 decreased from 3.5 eV to 3.0 eV. The field emission scanning electron microscopy (FESEM) investigation revealed the plate-like structural morphology of MoO3 formed by overlapping one layer onto another. Cs doping effectively inhibited the recombination of photo-generated charge carriers, resulting in a significant reduction in PL peak intensity for Cs-doped MoO3 compared to MoO3. The prepared NS-reduced methylene blue dye in the absence of light under different pH conditions, reaching 86.8% with 2% Cs-doped MoO3. Density functional theory (DFT), utilizing the Heyd-Scuseria-Ernzerhof hybrid (HSE06) method, was employed to model and compute the interactions between methylene blue (MB) and Cs-doped MoO3 during MB adsorption. Bactericidal experiments on multidrug-resistant Escherichia coli showed that the NSs had remarkable antibacterial action, generating an inhibition zone of 9.15 mm at higher doses using 6% Cs-doped MoO3. Consequently, these findings offer potential significance for research in developing and implementing wastewater disinfection systems.

Findings and perspectives of β-Ti alloys with biomedical applications: Exploring beyond biomechanical and biofunctional behaviour

Early implant failure and bone resorption may occur in load-bearing conditions as a result of stress shielding brought on by a mismatch in the bone-Ti-implant modulus. A review with a novel multidisciplinary perspective is proposed in this work, which considers recent developments of β-Titanium alloys and new trends in novel microstructures, processing techniques, properties of dense and porous substrates, as well as the relationship between all these aspects and performance in service, in terms of improved its biomechanical and bio-functional balance. In addition to highlighting several modern and historical uses for Ti alloys, this review covers many cutting-edge novel β-Ti alloys and uses that promise to exceed historical standards. Also, it deepens through several important properties of these alloys, including toxicity of alloying elements, phase stability, thermo-mechanical processing, heat treatment, surface, and stress-induced modifications. The stiffness, hardness, fatigue and wear resistance, corrosion behaviour, biocompatibility, and manufacturing and surface modification effects on these parameters are also emphasized. In-vitro and in-vivo assays have been added to highlight important aspects of bioactivity and antibacterial behaviour, and future significant research areas are suggested along with new techniques to ensure the successful clinical application of β-Ti alloys.

Improvement of antibacterial activity of AgNPs@PVA-PVP ternary nanocomposite films followed by gamma-ray irradiation treatment for biomedical applications

Our study investigates the influence of several doses of gamma rays on the antibacterial behavior of nanocomposite of silver nanoparticles (AgNPs) doped in a blend of poly (vinyl alcohol) (PVA)-Polyvinyl Pyrrolidone (PVP). AgNPs@PVA-PVP nanocomposite films have been fabricated by laser ablation method, and then the synthesized films were subjected to various gamma ray’s doses. X-ray diffraction (XRD) data shows a diffraction peak at 2θ = 38° assigned to the existence of AgNPs. Ultraviolet–visible (UV-Vis) results confirm the characteristic peak of silver nanoparticles at 425 nm. The cell viability and antibacterial behavior results confirmed the enhancement in the performance of AgNPs@PVA-PVP composite after irradiated to gamma rays. These values of cell viability have been raised by increasing the dose of gamma rays to 94.5±6.5 % for dose at 70 kGy gamma rays. The values of the inhibition zone of microorganisms were enhanced by raising the doses of gamma rays to 19.5±0.5 and 21.3±0.6 against E. coli and S. aureus respectively specifically for nanocomposite with gamma dose 70 kGy. Thus, the improved antibacterial activity of AgNPs@PVA-PVP nanocomposite could be used in biomedical applications.

Ti3C2Tx MXene-functionalized Hydroxyapatite/Halloysite nanotube filled poly– (lactic acid) coatings on magnesium: In vitro and antibacterial applications

Magnesium (Mg) stands out in temporary biomaterial applications due to its biocompatibility, biodegradability, and low Young's modulus. However, controlling its corrosion through next-generation polymer-based functional coatings is crucial due to the rapid degradation behavior of Mg. In this study, the function of 2D lamellar Ti3C2Tx (MXene) in Hydroxyapatite (HA) and Halloysite nanotube (HNT) hybrid coatings in biodegradable poly– (lactic acid) (PLA) was investigated. The morphological and structural characterizations of the coatings on Mg were revealed through HRTEM, XPS, SEM-EDX, XRD, FTIR, and contact angle analyses/tests. Electrochemical in vitro corrosion tests (OCP, PDS, and EIS-Nyquist) were conducted for evaluate corrosion resistance under simulated body fluid (SBF) conditions. The bioactivity of the coatings in SBF have been revealed in accordance with the ISO 23,317 standard. Finally, antibacterial disk diffusion tests were conducted to investigate the functional effect of MXene in coatings. It has been determined that the presence of MXene in the coating increased not only surface wettability (131°, 85°, 77°, and 74° for uncoated, pH, PHH, and PHH/MXene coatings, respectively) but also increased corrosion resistance (1857.850, 42.357, 1.593, and 0.085 × 10–6, A/cm2 for uncoated, pH, PHH, and PHH/MXene coatings, respectively). It has been proven that the in vitro bioactivity of PLA-HA coatings is further enhanced by adding HNT and MXene, along with SEM morphologies after SBF. Finally, 2D lamellar MXene-filled coating exhibits antibacterial behavior against both E. coli and S. aureus bacteria.

Synthesis and characterization of novel carboxymethyl tamarind kernel gum - Poly (vinyl alcohol)/guar gum-based hydrogel film loaded with ciprofloxacin for biomedical applications

The current study delineates the synthesis of hydrogel films comprised of carboxymethyl tamarind kernel gum (CMTKG), poly (vinyl alcohol) (PVA), and guar gum (GG) using glutaraldehyde (GL) as cross-linker. The hydrogel films were evaluated in terms of equilibrium swelling ratio (ESR), moisture content, thickness, wetting analysis, thermal, and mechanical analysis. The tensile strength value lies in the range of 95.80 to 149.07 MPa while elongation at break value lies in the range of 1.51 to 5.20 %. The FTIR spectroscopy confirmed the presence of hydrogen bonding between CMTKG, PVA, and GG components of hydrogel film. FE-SEM micrographs indicated the rough surfaces of hydrogel film. TGA-DTA analysis confirmed that the thermal stability of hydrogel film was found to be increased by incorporating the ciprofloxacin (CFX) drug into the hydrogel matrix. CFX was embedded in the best-swelled hydrogel film and in-vitro drug release behavior was studied at alkaline pH 7.4 phosphate buffer solution. It was found that the maximum drug release was to be 73 % after 24 h at pH 7.4. Moreover, the release data was fitted in various kinetic models such as the First-order, Higuchi, and Korsmeyer-Peppas models. The best-fitted Korsmeyer-Peppas model suggested that the release of the drug follows Fickian diffusion and the value of diffusion exponent (n) was determined to be 0.38. The cytocompatibility of the hydrogel film was analyzed by MTT assay while the antibacterial behavior of the hydrogel film against E. coli and S. aureus showed clear zone of inhibition area. Thus, the overall results indicated that CMTKG/PVA/GG hydrogel film have potential to be used in the biomedical applications.

Innovative pH-triggered antibacterial nanofibrous coatings for enhanced metallic implant properties

Metallic stainless steel bone implants are widely used due to their excellent mechanical properties, low cost, and ease of fabrication. Nanofibrous composite polymers have been proposed as coatings to promote biocompatibility and osseointegration, thanks to their biomimetic morphology that resembles the extracellular matrix. However, critical practical issues are often overlooked in the literature. For instance, applying coatings to implants with different shapes presents a significant technological challenge, as does evaluating viable sterilization procedures for hybrid devices containing electrospun polymers. In addition, infections pose a risk in any surgical procedure and can lead to implant failure, there is a need for antimicrobial prevention during surgery as well as in the short term afterward. In this work, we propose a new and straightforward method for manufacturing nanofibrous composite coatings directly on thin cylindrical-shaped metallic implants. Poly(ε-caprolactone) (PCL) nanofibers containing bioactive glass microparticles were electrospun onto stainless steel wires and then post-treated using two different strategies to achieve both hydrophilicity and surface disinfection. To address antimicrobial properties, amoxicillin-loaded Eudragit®E nanofibers were co-electrospun to impart pH-selective release behavior in event of a potential infection. The resulting composite hybrid coatings were characterized morphologically, physically, chemically, and electrochemically. The antibacterial behavior was evaluated at different media, confirming the release of the antibiotic in the pH range where infection is likely to occur. The impact of this study lies in its potential to significantly enhance the safety and efficacy of orthopedic implants by offering a novel, adaptable solution to combat infection. By integrating a pH-responsive drug delivery system with antimicrobial coatings, this approach not only provides a preventive measure during and after surgery but also addresses the growing issue of antibiotic resistance by targeting specific infection conditions.

Bactericidal behavior of silver nanoparticle decorated nano-sized magnetic hydroxyapatite.

Methicillin-resistant Staphylococcus aureus (MRSA) is the most common cause of acute bacterial arthritis. Due to the increase in antibiotic resistance in these bacteria, the discovery of new antibacterial agents has become one of the hot topics in the scientific community. Here, we prepared a nano-sized porous biocompatible magnetic hydroxyapatite through a solvothermal method. Then, we adopted a post-synthesis modification strategy to modify its surface for the stabilization of Ag NPs through a green reduction by the euphorbia plant extract. Moreover, the results show that the prepared composite perfectly prevents the aggregation of Ag NPs. This composite was used as a bactericidal and antibiofilm agent against MRSA bacteria in an in vitro environment, which showed excellent results. Also, the cell viability assay indicates that the prepared composite has low cytotoxicity, making it a perfect antibacterial agent for in vivo experiments.

Anti-Oxidant and Anti-Bacterial Behavior of Sodium Alginate Patches Fortified with Polyurethane and Ag-MOF as Potential Future Wound Healing Material

ABSTRACT Sodium Alginate (SA) is a natural polysaccharide with a high degree of biocompatibility, biodegradability, water absorption properties and stiffness. The inherent brittleness of SA limits its applications in the field of wound healing. The blending of highly flexible polyurethane (PU) with SA could alter the nature of film. In addition, the incorporation of Ag-Metal Organic Framework (Ag-MOF) synthesized via the solvothermal method can help in the enhancement of stability and biological characteristics. The SA and its composite films were obtained through a feasible phase inversion technique. In addition, the Ag-MOF@SA/PU film demonstrates the strongest bacteriostatic impact on E. faecalis and P. aeruginosa, with percentages of approximately 96.9% and 96.41%, respectively. Furthermore, the film demonstrates a radical scavenging efficiency of 83.96%. Moreover, the Ag-MOF@SA/PU film exhibited a significant increase in the production of oxidative stress, attaining a value of 84.89%. Owing to the results, Ag-MOF@SA/PU was taken for in-vitro degradability analysis and visible surface erosion was observed over time. Thus, the Ag-MOF@SA/PU film could be considered for future wound healing therapy.

Quantitative study of early-stage transient bacterial adhesion to bioactive glass and glass ceramics: atomic force microscopic observations

Antimicrobial potential of bioactive glass (BAG) makes it promising for implant applications, specifically overcoming the toxicity concerns associated with traditional antibacterial nanoparticles. The 58S composition of BAG (with high Ca and absence of Na) has been known to exhibit excellent bioactivity and antibacterial behaviour, but the mechanisms behind have not been investigated in detail. In this pioneering study, we are using Atomic Force Microscopy (AFM) to gain insights into 58S BAG’s adhesive interactions with planktonic cells of both gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria; along with the impact of crystallinity on antibacterial properties. We have recorded greater bacterial inhibition by amorphous BAG compared to semi-crystalline glass–ceramics and stronger effect against gram-negative bacteria via conventional long-term antibacterial tests. AFM force distance curves has illustrated substantial bonding between bacteria and BAG within the initial one second (observed at a gap of 250 ms) of contact, with multiple binding events. Further, stronger adhesion of BAG with E.coli (~ 6 nN) compared to S. aureus (~ 3 nN) has been found which can be attributed to more adhesive nano-domains (size effect) distributed uniformly on E.coli surface. This study has revealed direct evidence of impact of contact time and 58S BAG’s crystalline phase on bacterial adhesion and antimicrobial behaviour. Current study has successfully demonstrated the mode and mechanisms of initial bacterial adhesion with 58S BAG. The outcome can pave the way towards improving the designing of implant surfaces for a range of biomedical applications.

Role of graphene in bactericidal activity and bioactivity of a Zn/graphene/chitosan coating

The antibacterial ability of an implant is governed by the interaction between the surface of the material and the cells. Nanosized features that promote bacterial killing were achieved through synthesizing a Zn/graphene/chitosan surface on a NiTi alloy. The surface morphology and microstructure of the Zn/graphene/chitosan surfaces were observed, and their antibacterial behavior was investigated. The Zn/graphene/chitosan surface exhibited 93 % antibacterial activity against Staphylococcus aureus (S. aureus), which was higher than the Zn/chitosan surface (67 %), and it inhibited bacterial adhesion. This was attributed to the fast release of Zn ions from the Zn/graphene/chitosan surfaces and the sharp morphology of graphene on the surface. In addition, the adhesion of the Zn/graphene/chitosan coating increased with the amount of graphene content. This finding suggests that the synergy of graphene improves the antibacterial ability, bioactivity, and adhesion of Zn-containing coatings.

Surface Decontamination of Titanium Dental Implants Subjected to Implantoplasty by Treatment with Citric Acid Solutions

Implantoplasty is one of the most common techniques to remove peri-implantitis from the surface of dental implants. It is a process of mechanization of the titanium surface, causing the loss of the roughness of the dental implant, which leads to difficulty in tissue regeneration. The aim of this research is to apply a decontaminant based on citric acid and add collagen and magnesium cations to promote tissue formation and have a bactericidal character. Eighty commercially pure grade 3 titanium discs were used to perform the implantoplasty protocol, like the one used in dental clinics. They were treated with four different solutions: 25% citric acid, 25% citric acid with the addition of collagen 0.25 g/L, 25% citric acid with the addition of 0.50 g/L and the latter with the addition of 1% Mg (NO3)2. The roughness was determined by confocal microscopy, the contact angle, adhesion and proliferation of HFFs fibroblasts, proliferation of SaOS-2 osteoblasts and bactericidal behavior by culturing very common bacteria in the oral cavity, Gram-positive Streptococcus sanguinis and gordonii and as Gram-negative Pseudomonas aeruginosa. The results showed that the treatment with citric acid slightly increases the roughness and decreases the contact angle from 78 to 13°, making the surface superhydrophilic. Fibroblast proliferation studies show a very significant increase at 24 h, the most favorable solution being the one containing 0.50 g/L of collagen with the presence of magnesium in a 25% citric acid solution. This same solution shows the highest cytocompatibility and osteoblastic proliferation with statistically significant differences with respect to the control and the rest of the solutions. Microbiological studies show a bactericidal effect due to the presence of citric acid, which is especially effective on Gram-positive bacteria. The results allow us to have mouthwashes that can be applied in the patient’s mouth, which will help the regeneration of tissues and avoid new bacterial colonization.

Enhancing Bactericidal Properties of Ti6Al4V Surfaces through Micro and Nano Hierarchical Laser Texturing.

Orthopedic and dental implants made from Ti6Al4V are widely used due to their excellent mechanical properties and biocompatibility. However, the long-term performance of these implants can be compromised by bacterial infections. This study explores the development of hierarchically textured surfaces with enhanced bactericidal properties to address such challenges. Hierarchical surface structures were developed by combining microscale features produced by a microsecond laser and superimposed submicron features produced using a femtosecond laser. Microscale patterns were produced by the pulsed laser surface melting process, whereas submicrometer laser-induced periodic surface structures were created on top of them by femtosecond laser processing. Escherichia coli bacterial cells were cultured on the textured surface. After 24 h, a staining analysis was performed using SYTO9 and PI dyes to investigate the samples with a confocal microscope for live dead assays. Results showed bacterial colony formation onto the microscale surface textures with live bacterial cells, whereas the hierarchical surface textures display segregated and physically damaged bacterial cell attachments on surfaces. The hierarchical surface textures showed ∼98% dead bacterial cells due to the combined effect of its multiscale surface features and oxide formation during the laser processing steps. The efficacy of hierarchical surface textures in enhancing the antibacterial behavior of Ti6Al4V implants is evident from the conducted research. Such laser-based surface treatments can find potential applications in different industrial sectors.

A green and effective anti-corrosion and anti-microbial inhibitor of citric acid-based carbon dots: Experiment and mechanism analysis

Citric acid-based carbon dots (CA-CDs) with different amounts of heteroatoms N were obtained through hydrothermal synthesis method. The microstructure, optical, antibacterial and anticorrosive behaviors were systematically analyzed. Through detection, the N atoms existed in the form of pyridine-like N, pyrrole-like N and graphitic N, and promoted the grain coarsening of carbon dots. The CA-N-CDs displayed obvious pH dependence and good stability from optical behavior analysis. The antibacterial ability of citric acid-based carbon dots was improved by inserting N atom, and the antibacterial rate was directly proportional to the amount of N atom, which was up to 95% for E. coli and S. aureus. However, the anticorrosion ability showed an initial increase followed by a decrease as the amount of N atom increased, reaching its peak at CA-N12%-CDs. At this moment, the corrosion current density (icorr) of metal was 4.68 × 10−6 A/cm2, which decreased by 122 times compared with the blank solution. Meanwhile, the corrosion inhibition rate (IE) for metal was up to 96%, which mainly depended on the tight adsorption of citric acid-based carbon dots on the metal surface.

Antibacterial Behavior of Synthesized Silica-Silver Nanocomposite for Drinking Water Purification

Antibacterial Behavior of Synthesized Silica-Silver Nanocomposite for Drinking Water Purification