Synergetic Antibacterial Effect Research Articles

A CuS@g-C3N4 heterojunction endows scaffold with synergetic antibacterial effect.

Graphitic carbon nitride (g-C3N4) had aroused tremendous attention in photodynamic antibacterial therapy due to its excellent energy band structure and appealing optical performance. Nevertheless, the superfast electron-hole recombination and dense biofilm formation abated its photodynamic antibacterial effect. To this end, a nanoheterojunction was synthesized via in-situ growing copper sulfide (CuS) on g-C3N4 (CuS@g-C3N4). On the one hand, CuS could form Fermi level difference with g-C3N4 to accelerate carrier transfer and thus facilitate electron-hole separation. On the other hand, CuS could respond near-infrared light to generate localized thermal to disrupt biofilm. Then the CuS@g-C3N4 nanoparticle was introduced into the poly-l-lactide (PLLA) scaffold. The photoelectrochemistry results demonstrated that the electron-hole separation efficiency was apparently enhanced and thereby brought an approximate sevenfold increase in reactive oxygen species (ROS) production. The thermal imaging indicated that the scaffold possesses a superior photothermal effect, which effectively eradicated the biofilm by disrupting its extracellular DNA and thereby facilitated to the entry of ROS. The entered ROS could effectively kill the bacteria by causing protein, K+, and nucleic acid leakage and glutathione consumption. As a consequence, the scaffold displayed an antibacterial rate of 97.2% and 98.5% against E. coli and S. aureus, respectively.

Ferrocene-based porous polymer as advanced environmental remediation material for self-enhanced synergetic photothermal-enzymatic antibacterial and reversible iodine capture

Water pollution, associated with both the modern productions and pathogen contamination, has become a worldwide safety concern, seriously threatening the health of living beings. Herein, a multifunctional porous polymer, denoted as Fc-PP-POP, composed by porphyrin (PP) and Ferrocene (Fc) unites, capable of self-enhanced synergetic antibacterial effect, as well as reversible capture of iodine pollutants, was facilely prepared through the simple but efficient Alder-Longo method via direct polymerization of pyrrole with Ferrocene dialdehyde. Fc-PP-POP integrated the features of Porphyrin (photoactivity) and Ferrocene (enzymatic activity), simultaneously, can serve as a broad-spectrum antibacterial agent, which could not only realize the rapidly and efficiently converting of light energy into local thermal energy for photothermal therapy (PTT), but also the transformation of low concentration of H2O2 into toxic hydroxyl radical (•OH) for the enzyme therapy. The as-generated local heat could further improve the enzymatic activity, displaying a remarkably enhanced synergistic therapeutic effect, realizing the efficient sterilization at low concentrations (300 μg/mL). In vivo assay revealed Fc-PP-POP can significantly promote the healing of infected wounds. Meanwhile, Fc-PP-POP can function as an efficient adsorbent, capturing the iodine contaminants from the environment. This work opens up a new mean for the application of low-cost POPs in the field of environmental remediation and public health.

Co-Loading of Inorganic Nanoparticles and Natural Oil in the Electrospun Janus Nanofibers for a Synergetic Antibacterial Effect.

Side-by-side electrospinning is a powerful but challenging technology that can be used to prepare Janus nanofibers for various applications. In this work, cellulose acetate (CA) and polycaprolactone (PCL) were used as polymer carriers for silver nanoparticles (Ag NPs) and lavender oil (LO), respectively, processing these into two-compartment Janus fibers. A bespoke spinneret was used to facilitate the process and prevent the separation of the working fluids. The process of side-by-side electrospinning was recorded with a digital camera, and the morphology and internal structure of the products were characterized by electron microscopy. Clear two-compartment fibers are seen. X-ray diffraction patterns demonstrate silver nanoparticles have been successfully loaded on the CA side, and infrared spectroscopy indicates LO is dispersed on the PCL side. Wetting ability and antibacterial properties of the fibers suggested that PCL-LO//CA-Ag NPs formulation had strong antibacterial activity, performing better than fibers containing only one active component. The PCL-LO//CA-Ag NPs had a 20.08 ± 0.63 mm inhibition zone for E. coli and 19.75 ± 0.96 mm for S. aureus. All the fibers had water contact angels all around 120°, and hence, have suitable hydrophobicity to prevent water ingress into a wound site. Overall, the materials prepared in this work have considerable promise for wound healing applications.

Antimicrobial hydrogel microspheres for protein capture and wound healing

Growth factors are vital to regulate cellular responses for wound healing process. Engineered microspheres provide a promising tool for developing effective growth factor-loaded matrix for regenerative medicine therapy. Here, we report a novel multifunctional chitosan microsphere that enables facile one-step capture and efficient growth factor delivery for enhanced wound repair. The microfluidic technique was used to fabricate magnetic chitosan (MCS) microspheres. By immobilization with Zn2+ ions, the biohybrid MCS allowed for the flexible operation to capture histidine-tagged vascular endothelial growth factor (VEGF) produced in Escherichia coli (E. coli). The VEGF-conjugated MCS were then applied onto the wounds to examine their capabilities in promoting wound healing. Zn2+ and chitosan in MCS exhibited a synergetic antibacterial effect towards both Gram-positive and Gram-negative bacteria. Using a rat model, we further demonstrated that the microspheres significantly promoted wound healing process, as evidenced by rapid wound closure, induced epithelialization and angiogenesis, and reduced inflammation response. Together, our data indicated the presented MCS as a versatile tool for capturing and locally delivering growth factors, which can be applied to wound repair. Moreover, with the functional flexibility, this biohybrid MCS could be empolyed in a wide range of biomedical applications by conjugating proteins of interest.

Green cinnamaldehyde and thymol modified zinc oxide with double synergistic antibacterial effects in polypropylene

AbstractThe green cinnamaldehyde (CA) and thymol (THY) separately or successively modified O‐ZnO (O‐ZnO‐CA, O‐ZnO‐THY, and O‐ZnO‐CA‐THY) were prepared after (3‐aminopropyl) triethoxysilane (KH550) was grafted to the surface of ZnO (O‐ZnO) and characterized by FTIR, TGA, and SEM. Polypropylene composites (PP/O‐ZnO‐CA, PP/O‐ZnO‐THY, and PP/O‐ZnO‐CA‐THY) were prepared by melting the modified O‐ZnO and PP. The antibacterial tests showed that the antibacterial rate of PP/O‐ZnO‐CA and PP/O‐ZnO‐THY against S. aureus and E. coli was obviously enhanced. It indicated an excellent synergetic antibacterial effect of O‐ZnO and the little CA or THY grafted on the surface of O‐ZnO. The antibacterial effect of O‐ZnO‐CA and O‐ZnO‐THY was related to the hydrophobic and hydrophilic groups contained in CA and THY. Importantly, CA and THY in O‐ZnO‐CA‐THY exhibited another excellent synergetic antibacterial effect against both S. aureus and E. coli. The antibacterial rate of three PP composites containing 4 phr O‐ZnO‐CA‐THY against S. aureus and E. coli reached 95% and 90%, respectively. The mechanism was regarded as that CA and THY grafted onto the same O‐ZnO improved the contact probability between antibacterial agents and bacteria. Moreover, O‐ZnO‐CA, O‐ZnO‐THY, and O‐ZnO‐CA‐THY had excellent migration resistance in the PP matrix.

Photothermal-assisted antibacterial application of graphene oxide-Ag nanocomposites against clinically isolated multi-drug resistant Escherichia coli.

In the field of public health, treatment of multidrug-resistant (MDR) bacterial infection is a great challenge. Herein, we provide a solution to this problem with the use of graphene oxide-silver (GO-Ag) nanocomposites as antibacterial agent. Following established protocols, silver nanoparticles were grown on graphene oxide sheets. Then, a series of in vitro studies were conducted to validate the antibacterial efficiency of the GO-Ag nanocomposites against clinical MDR Escherichia coli (E. coli) strains. GO-Ag nanocomposites showed the highest antibacterial efficiency among tested antimicrobials (graphene oxide, silver nanoparticles, GO-Ag), and synergetic antibacterial effect was observed in GO-Ag nanocomposites treated group. Treatment with 14.0 µg ml−1 GO-Ag could greatly inhibit bacteria growth; remaining bacteria viabilities were 4.4% and 4.1% for MDR-1 and MDR-2 E. coli bacteria, respectively. In addition, with assistance of photothermal effect, effective sterilization could be achieved using GO-Ag nanocomposites as low as 7.0 µg ml−1. Fluorescence imaging and morphology characterization uncovered that bacteria integrity was disrupted after GO-Ag nanocomposites treatment. Cytotoxicity results of GO-Ag using human-derived cell lines (HEK 293T, Hep G2) suggested more than 80% viability remained at 7.0 µg ml−1. All the results proved that GO-Ag nanocomposites are efficient antibacterial agent against multidrug-resistant E. coli.

A novel copper-based 3D porous nanocomposite for electrochemical detection and inactivation of pathogenic bacteria

An economical and reliable theranostic unit is essential for the detection and treatment of bacterial infections. MRSA is one of the most prevalent superbugs in the world at present, hence requires urgent attention. Here, we present a novel copper-based 3-D porous nanocomposite modified with vancomycin (Van) for simultaneous detection and treatment of methicillin-resistant S. aureus (MRSA). The composite contains copper/copper oxide nanoparticles which are reduced by the hydroxyl groups of β-cyclodextrin (β-CD). On addition of graphene oxide (GO), it achieves a porous structure due to π-π stacking and formation of hydrogen bonds between β-cyclodextrin (β-CD) and reduced graphene oxide sheets. Conjugation of Van to the composite provides highly specific binding towards gram-positive bacteria. Differential pulse voltammetry (DPV) was used to carry out the electrochemical detection of MRSA and achieved a very low limit of detection (LOD) 5 CFU mL−1 along with a minimum inhibitory concentration (MIC) value of 1.93 μg mL−1. The low LOD and MIC values are due to the good electrochemical response of the composite and the synergetic antibacterial effect of vancomycin and copper/copper oxide nanoparticles, respectively. The current work provides a more effective and economic unit as electrode modifier simultaneous detection and powder for the elimination of pathogenic bacteria.

Prooxidant and antimicrobic effects of iron and titanium oxide nanoparticles and thalicarpine.

The aim is to evaluate the prooxidant and antimicrobial effects of Fe3O4 and TiO2 nanoparticles and thalicarpine by luminescent and standard microbiological assays. Their effect on the kinetics of free-radical oxidation reactions (at pH 7.4 and pH 8.5) is studied in the following model systems, using activated chemiluminescence: chemical, with Fenton's reagent (H2O2-FeSO4)-for the generation of hydroxyl radicals (.OH); chemical, with oxidant hydrogen peroxide (H2O2); chemical (NAD.H-PhMS), for the generation of superoxide radicals (O2.-). Fe3O4 nanoparticles exhibit highly pronounced antioxidant properties; TiO2 nanoparticles exhibit mild to moderate prooxidant properties at neutral and alkaline conditions. Those properties are tested by the chemiluminescent method for the first time. Thalicarpine and its combination with TiO2 nanoparticles exhibit pronounced antioxidant activities at pH 8.5 which are lost and transformed into well-presented prooxidant effects at pH 7.4. That is a result-supported proof on the observed typical properties of thalicarpine and TiO2, namely antibacterial, organic-preserving and anti-pathogenic activities. The antimicrobial effect is tested on Gram-positive and Gram-negative bacteria: two strains of Escherichia coli, Bacillus cereus 1095 and Staphylococcus aureus. All bacteria are destroyed after the application of TiO2, but not Fe3O4 nanoparticles, showing their antibacterial effect. Thalicarpine, in combination with TiO2, showed even synergetic antibacterial effect.

Glancing Angle Deposition of Zn-Doped Calcium Phosphate Coatings by RF Magnetron Sputtering

Zn-substituted hydroxyapatite with antibacterial effect was used in radiofrequency (RF) magnetron deposition of calcium phosphate coating onto Ti- and Si-inclined substrates. The development of surface nanopatterns for direct bacteria killing is a growing area of research. Here, we combined two approaches for possible synergetic antibacterial effect by manufacturing a patterned surface of Zn-doped calcium phosphate using glancing angle deposition (GLAD) technique. A significant change in the coating morphology was revealed with a substrate tilt angle of 80°. It was shown that an increase in the coating crystallinity for samples deposited at a tilt angle of 80° corresponds to the formation of crystallites in the bulk structure of the thin film. The variation in the coating thickness, uniformity, and influence of sputtered species energy on Si substrates was analyzed. Coatings deposited on tilted samples exhibit higher scratch resistance. The coating micro- and nano-roughness and overall morphology depended on the tilt angle and differently affected the rough Ti and smooth Si surfaces. GLAD of complex calcium phosphate material can lead to the growth of thin films with significantly changed morphological features and can be utilized to create self-organized nanostructures on various types of surfaces.

Evaluation of Synergetic Antibacterial Effect of Gaseous Ozone and Ozonated Water against Enterococcus Faecalis in Human Root Canals

Evaluation of Synergetic Antibacterial Effect of Gaseous Ozone and Ozonated Water against Enterococcus Faecalis in Human Root Canals

Antibacterial Activity of Emulsified Pomelo (Citrus grandis Osbeck) Peel Oil and Water-Soluble Chitosan on Staphylococcus aureus and Escherichia coli.

This study utilized pomelo steam distillation to isolate pomelo peel essential oil. The constituents were then analyzed through gas chromatography-mass spectrometry (GC-MS), and the antibacterial activity of the essential oil emulsions at different homogenizer speed conditions and concentrations of water-soluble chitosan (degree of acetylation, DA = 54.8%) against S. aureus and E. coli was examined. Analysis of the essential oil composition identified a total of 33 compounds with the main constituent, limonene accounting for 87.5% (940.07 mg/g) of the total. The pomelo peel oil was emulsified through homogenization at 24,000 rpm, resulting in a minimal inhibitory concentration (MIC) for E. coli that was 1.9 times lower than that of the essential oil without homogenization. In addition, a mixture of 0.4% essential oil emulsion and 0.03% water-soluble chitosan had the strongest synergetic antibacterial effect on S. aureus and E. coli at pH 7.4. In comparison with chitosan alone, the MIC value of this mixture was significantly 2.4 and 2.5 times lower. Hence, this study suggests using a mixture of emulsified pomelo peel oil and water-soluble chitosan to develop a novel natural food preservative, and that the processability of food, as well as the economic value of the byproducts of the Taiwan Matou pomelo and chitosan, could be increased.

Biofouling mitigation of TFC membrane by in-situ grafting of PANI/Cu couple nanoparticle

This work deals with the simple and eco-friendly approach for the surface modification of thin film composite (TFC) membranes to have biofouling resistant effect for desalination of the water source. Coupled polyaniline/copper nanoparticle as an effective potential biocide was simultaneously grafted onto TFC Filmtec membrane. To confirm the presence of the novel couple nanoparticle over the thin polyamide layer without negative structural effect, the modified membranes were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic-force microscopy (AFM), fourier transform infrared spectroscopy (FTIR) and zeta potential. The synergetic antibacterial effect of the couple nanoparticle was determined via SEM, colony forming unit (CFU) counting and bacterial inhibition zone by applying Escherichia Coli (E. coli) bacteria. The prepared membranes allowed nanoparticle reloading during desalination process with no need for disassembling and existence of any stabilizing agent. The Polyaniline/copper-thin film nanocomposite (PANI/Cu-TFN) membrane showed special anti-biofouling properties with water flux and NaCl rejection of 17.24 Kg/m2h and 99.82%, respectively. The water flux recovery of the obtained membrane was 89.24% and water contact angle showed 37 ± 0.09 °

Modified Mesoporous Silica Nanoparticles with a Dual Synergetic Antibacterial Effect.

Application of mesoporous silica nanoparticles (MSNs) as antifouling/antibacterial carriers is limited and specifically with a dual synergetic effect. In the present work, MSNs modified with quaternary ammonium salts (QASs) and loaded with the biocide Parmetol S15 were synthesized as functional fillers for antifouling/antibacterial coatings. From the family of the MSNs, MCM-48 was selected as a carrier because of its cubic pore structure, high surface area, and high specific pore volume. The QASs used for the surface modification of MCM-48 were dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride and dimethyltetradecyl[3-(triethoxysilyl)propyl]ammonium chloride. The QAS-modified MCM-48 reveals strong covalent bonds between the QAS and the surface of the nanoparticles. The surface functionalization was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis, and ζ-potential measurements. Additional loading of the QAS-modified MCM-48 with a commercially available biocide (Parmetol S15) resulted in a synergetic dual antibacterial/antifouling effect. Either loaded or unloaded QAS-modified MSNs exhibited high antibacterial performance confirming their dual activity. The QAS-modified MCM-48 loaded with the biocide Parmetol S15 killed all exposed bacteria after 3 h of incubation and presented 100% reduction at the antibacterial tests against Gram-negative and Gram-positive bacteria. Furthermore, the QAS-modified MCM-48 without Parmetol S15 presented 77-89% reduction against the exposed Gram-negative bacteria and 78-94% reduction against the exposed Gram-positive bacteria. In addition, the modified MCM-48 was mixed with coating formulations, and its antifouling performance was assessed in a field test trial in northern Red Sea. All synthesized paints presented significant antifouling properties after 5 months of exposure in real seawater conditions, and the dual antifouling effect of the nanoparticles was confirmed.

Inactivation performance and mechanism of Escherichia coli in aqueous system exposed to iron oxide loaded graphene nanocomposites

The challenge to achieve efficient disinfection and microbial control without harmful disinfection byproducts calls for developing new technologies. Magnetic-graphene oxide (M-GO) with magnetic iron oxide nanoparticles well dispersed on graphene oxide (GO) nanosheets exerted excellent antibacterial activity against Escherichia coli. The antibacterial performance of M-GO was dependent on the concentration and the component mass ratio of M/GO. The synergetic antibacterial effect of M-GO was observed with M/GO mass ratio of 9.09. TEM images illustrated the interaction between E. coli cells and M-GO nanocomposites. M-GO nanomaterials were possible to deposit on or penetrate into cells leading to leakage of intercellular contents and loss of cell integrity. The inactivation mechanism of E. coli by M-GO was supposed to result from both the membrane stress and oxidation stress during the incubation period. M-GO with excellent antibacterial efficiency against E. coli and separation-convenient property from water could be potent bactericidal nanomaterials for water disinfection.

In Vitro Evaluation of the Antibacterial Activities of MTAD in Combination with Nisin against Enterococcus faecalis

Introduction MTAD is a common intracanal irrigant. Although MTAD inhibits Enterococcus faecalis in root canals, its bactericidal effect against E. faecalis remains to be improved. Nisin, an antibacterial peptide, possesses a strong bactericidal effect. The study evaluated the synergetic action between MTAD and nisin against E. faecalis. Methods The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were used to measure the antibacterial activities of MTAD, MTAN (substitution of doxycycline with nisin), and MTADN (nisin in combination with doxycycline), respectively. The synergetic effect between nisin and doxycycline was evaluated by fractional inhibitory concentration (FIC) and time-killing curves. Furthermore, morphologic changes in E. faecalis were observed by scanning electron microscopy after E. faecalis was treated with MTAD, MTAN, or MTADN for 24 hours. Results The MBC of MTADN against E. faecalis was lower than that of MTAD and MTAN. The combination of nisin and doxycycline had a significantly synergetic antibacterial effect on E. faecalis. Among the 3 antimicrobial treatments, MTADN caused the most severe damage to E. faecalis. Conclusions The combination of nisin and doxycycline has a synergetic antibacterial effect on E. faecalis, and MTAD in conjunction with nisin inhibits E. faecalis better than MTAD alone.

Structure and synergetic antibacterial effect of zinc and cerium carried sodium zirconium phosphates

Zinc and cerium carried zirconium phosphates (Zn-Ce/ZrPs) were prepared by exchanging zinc and cerium cations into sodium zirconium phosphate (NaZrP) through the ion-exchange method and characterized by X-ray diffraction(XRD), energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM). Furthermore, the specific surface area, zeta potential and antibacterial activity were tested. The results showed that Zn-Ce/ZrPs were with hexagonal crystal system, and the surface area of Zn-Ce/ZrPs increased much more than that of NaZrP. Zn-Ce/ZrPs showed obvious synergetic antibacterial effect, and have the potential to be used as antibacterial agents in environmental control.