Evaluation of the antibacterial activity of dental adhesive containing biogenic silver nanoparticles decorated nanographene oxide nanocomposites (Ag@nGO NCs) and effect on bond strength to dentine

Our study aimed to evaluate the antibacterial activities and dentin bond strengths of silver nanoparticles (Ag NPs) and silver nano-graphene oxide nanocomposites (Ag@nGO NCs) produced by green and chemical synthesis methods added to the dental adhesive. Ag NPs were produced by green synthesis (biogenic) (B-Ag NPs) and chemical synthesis methods (C–Ag NPs) and deposited on nGO (nano-graphene oxide). Ag NPs and Ag@nGO NCs (0.05% w/w) were added to the primer and bond (Clearfil SE Bond). Group 1: control, Group 2: nGO, Group 3: B-Ag NPs, Group 4: B-Ag@nGO NCs, Group 5: C–Ag NPs, Group 6: C–Ag@nGO NCs. Streptococcus mutans (S. mutans) live/dead assay analysis, MTT metabolic activity test, agar disc diffusion test, lactic acid production, and colony forming units (CFUs) tests were performed. Bond strength values were determined by the microtensile bond strength test (μTBS). Failure types were determined by evaluating with SEM. Statistical analysis was performed using one-way ANOVA and two-way ANOVA (p 0.05), but there was a difference between the other groups (p 0.05). As a result, although the antibacterial activity of B-Ag NPs and B-Ag@nGO Ag NPs obtained by green synthesis is lower than that of chemically synthesis obtained C–Ag NPs and C–Ag@nGO NCs, they provided higher antibacterial activity compared to the control group and did not reduce μTBS. The addition of biogenic Ag NPs to the adhesive system increased the antibacterial effect by maintaining the bond strength of the adhesive. Antibacterial adhesives can increase the restoration life by protecting the tooth-adhesive interface

A facile and one-pot aqueous phase transfer of oleylamine capped Au NP with aminophenylboronic acid used as transfer and targeting ligand

Although various phase transfer techniques have been used to make hydrophobic nanoparticles (NPs) watersoluble. However, these techniques have been limited by inefficient surface modification strategy that often stable NPs in aqueous solutions. Herein, we report the use of 3-aminophenylboronic acid (3-APBA) as a hydrophilic ligand for phase transfer of oleylamine (OA) capped Au NPs (OA@Au NPs) from non-hydrolytic system into aqueous solutions. The 3-APBA capped Au NPs (3-APBA@Au NPs) was mainly characterized using different analytical techniques to substantiate the efficiency of the phase transfer procedure. In this simple procedure, 3APBA molecule was simultaneously used as both phase transfer and targeting ligand for bacteria recognition in one step. In principle, while free electron pair of amin (:NH2) group of 3-APBAbind to surface of hydrophobic Au NPs for phase transfer, diol group can bind to glycan on the membrane of Staphylococcus aureus and Methicillinresistant Staphylococcus aureus (MRSA) through proper cis-diol configuration. In addition, the resulting 3APBA@Au NP can effectively catalyze the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride (NaBH4) in aqueous solution

Silver Nanoparticles Biosynthesized from Vaccinium myrtillus L. against Multiple Antibiotic Resistance and Biofilm Forming Escherichia coli and Pseudomonas aeruginosa

Background: Despite new innovations and process improvements, biofilm forming bacterial infections still pose a serious threat to patients. Silver nanoparticles (AgNPs) have been shown to have antibacterial properties and have been applied for surface manufacturing of many permanent medical devices at the same time. Therefore, we attempted to compare the performance of green synthesis of AgNPs and Vaccinium myrtillus L. plant extracts in terms of antibacterial and antibiofilm potential against multi drug resistant (MDR) biofilm forming Pseudomonas aeruginosa and Escherichia coli clinical strains. Materials and Methods: The biosynthesized AgNPs were characterized by UV-Visible spectroscopy. The antibacterial activity of the nanoparticles was determined by using disc diffusion and broth micro dilution method. Antibiofilm properties of nanoparticles have also been investigated by using scanning electron microscopy (SEM) and tissue culture plate (TCP) method. Results: Both extract and AgNP showed comparable bactericidal (p<0,0001) and antibiofilm activity (p<0,0001), but the mode of bacterial interaction and the degree of damage were completely different. Conclusion: For the first time with this study, extracts and also nanoparticles obtained from V. myrtillus were found to be effective in strains that have high biofilm activity and multiple drug resistance. Biosynthesized AgNPs were found to reduce planktonic cells as well as biofilm growth in a dose dependent manner. The results also supported the antibiofilm potential of AgNPs. This finding thus provides an idea of the development of silver nanoparticle-based biomaterials for use as effective surface modifying agents

DNA Aptamer-Conjugated Magnetic Graphene Oxide for Pathogenic Bacteria Aggregation: Selective and Enhanced Photothermal Therapy for Effective and Rapid Killing

Methicillin-resistant Staphylococcus aureus ( MRSA), often called "superbug", is a nosocomial and multidrug resistance bacterium that shows resistance to beta-lactam antibiotics. There has been high demand to develop an alternative treatment model to antibiotics for efficiently fighting MRSA. Herein, we developed DNA aptamer-conjugated magnetic graphene oxide (Apt@MGO) as a multifunctional and biocompatible nanoplatform for selective and rapid eradication of MRSA and evaluated heat generation and cell death performance of Apt@MGO for the first time under dispersed and aggregated states. The aptamer sequence was specifically selected for MRSA and acted as a molecular targeting probe for selective MRSA recognition and antibiotic-free therapy. Magnetic graphene oxide (MGO) serves as a nanoplatform for aptamer conjugation and as a photothermal agent by converting near-infrared (NIR) light to heat. Iron oxide nanoparticles (Fe3O4 NPs) are formed on GO to prepare MGO, which shows magnetic properties for collecting MRSA cells in a certain area in the reaction tube by an external magnet. The collected MGO induces remarkably high local heating and eventual MRSA cell death under NIR laser irradiation. We demonstrate that Apt@MGO resulted in similar to 78% MRSA and over >97% MRSA cell inactivation in dispersed and aggregated states, respectively, under 200 seconds (sn) exposure of NIR irradiation (808 nm, 1.1 W cm(-2)). An in vitro study highlights that Apt@ MGO is considered a targeted, biocompatible, and light-activated photothermal agent for efficient and rapid killing of MRSA in the aggregated state under NIR light

A New Strategy for Enhancing Acanthamoebicidal Activity with Synthesis of Nanoflower of Laurocerausus officinalis Roemer (Cherry laurel) Fruit Extracts

Pathogenic Acanthamoeba species often cause infection known as Acanthamoeba keratitis among people who use contact lenses. It is a type of infection that can result in corneal ulceration, visual loss or even blindness, if not treated. There are various therapeutic options available in the treatment of Acanthamoeba infections but they are usually tough treatments with limited efficacy. For instance, hydrogen peroxide (H2O2) is a commonly used contact lens disinfectant which is effective against Acanthamoeba but it is toxic to the cornea. For these reasons, new and more efficacious treatment options are required for Acanthamoeba infections. In this context, plants are considered natural resources for the discovery of new drugs. Laurocerasus officinalis Roem. (cherry laurel) (Rosaceae) grows in Black Sea region; and it is known as "Taflan", "Laz kirazi" or "Karayemis". Local people are using the seeds against diabetes, while the fruits are consuming as food, and used fordiuretic and passing kidney stones. It has also been reported that the seeds of the cherry laurel are used as an antiparasitic agent in this area. The aim of the study was to confirm the traditionally use of antiparasitic activity of this fruit and to increase the potential effect by means of organic-inorganic hybrid synthesis. Total phenol contents of methanol extracts prepared from endocarp, mesocarp and seeds of the fruit were calculated. The effects of methanol extracts and nano flower (NFs) plants synthesized from these extracts on the proliferation of Acanthamoeba castellanii were investigated. Thus, for the first time, novel organic-inorganic nanobio-antiparasitic agents called NFs were produced from cherry laurel and the increase in the amoebicidal activity of the NFs was elucidated. The characterization of NFs were determined with Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrometer (FT-IR) and Energy-Dispersive X-ray (EDX) techniques. In addition, the catalytic activity of the fruit extracts and the NFs were measured against guaiacol in the presence of H2O2. The viability testing of A. castellaniicysts used for amoebicidal activity was performed using 4% trypan blue. Methanol extracts and nano-flowers were prepared at concentrations of 32, 16, 8, 4, 2 and 1 mg/ml in 0.9% saline and distributed 200 pl each in tubes and incubated in the room temperature with the addition of 200 pl of 98% viable A.castellani parasites. The results were evaluated using the SPSS V.22.0 program and it was determined that there was a significant increase in the amoebicidal activity of NFs compared with the other extracts according to variance analysis (p <= 0.05). In the study, it was determined that samples killed parasites or reduced parasite proliferation at certain times. As a result, NFs synthesized from fruit extracts were demonstrated about three times more effective than the non hybrid extracts for amoebicidal activity. This situation can be explained as high proliferative effect of a new nano-bio-antiparasitic agent known as nanoflower against A.castellani

Synthesis of taurine-Cu-3(PO4)(2) hybrid nanoflower and their peroxidase-mimic and antimicrobial properties

Herein, we report the synthesis of taurine incorporated (sulfur containing organic molecule derived from methionine and cysteine) hybrid nanoflowers (thNFs) with an intrinsic peroxidase-mimic and antimicrobial activities in the presence of H2O2. Formation of thNFs using non-enzyme molecules was for the first time and systematically studied as a function of the taurine concentration, types of metal ions (Cu2+, Fe2+ and Fe3+) and pH values of reaction solution. The peroxidase like activities of thNFs rely on Fenton-like reaction against guaiacol used as a model substrate. The efficiency of Fenton reaction can be attributed to porous structure and presence of ions of transition elements in the thNFs. The thNFs were further characterized using FTIR, XRD, SEM and EDX. The thNFs also showed remarkable antimicrobial properties against S. aureus, E. coli, B. cereus and C. albicans. We claim that nonprotein-based NFs can be considered as new generation nano-biocatalysts as an alternative to enzymes and can be used in various medicinal, biochemical, immunological, biotechnological, and industrial applications