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Öğe Antioxidative and antimicrobial edible chitosan films blended with stem, leaf and seed extracts of Pistacia terebinthus for active food packaging(Royal Soc Chemistry, 2018) Kaya, Murat; Khadem, Sanaz; Cakmak, Yavuz Selim; Mujtaba, Muhammad; Ilk, Sedef; Akyuz, Lalehan; Salaberria, Asier M.Methanol extracts of stem, leaf, and seed obtained from Pistacia terebinthus which are rich in phenolic compounds were used for the first time to produce chitosan-based antioxidative and antimicrobial films. All the produced films were characterized by FT-IR, TGA, DSC, SEM, contact angle measurements, and UV-Vis spectroscopy and mechanically. As was expected, incorporation of the plant extracts into chitosan films enhanced the antioxidant and antimicrobial activities effectively. Also, the elasticity of chitosan-seed and chitosan-stem films was improved. The eco-friendly nature of the produced blend films was determined through soil and water degradation analyses. All these findings lead to the conclusion that the produced blend films with Pistacia terebinthus extracts can be applied as alternative food packaging material.Öğe Antioxidative and antiproliferative effects of propolis-reduced silver nanoparticles(Techno-Press, 2021) Tan, Gamze; Ilk, Sedef; Foto, Fatma Z.; Foto, Egemen; Saglam, NecdetIn this study, phytochemicals present in Propolis Extract (PE) were employed as reducing and stabilizing reagents to synthesize silver nanoparticles. Three propolis-reduced silver nanoparticles (P-AgNPs1-3) were synthesized using increasing amounts of PE. P-AgNPs were treated with different cancer cells -lung (A549), cervix (HeLa) and colon (WiDr) for 24, 48 and 72 h to evaluate their anti -proliferative activities. A non-cancerous cell type (L929) was also used to test whether suppressive effects of P-AgNPs on cancer cell proliferation were due to a general cytotoxic effect. The characterization results showed that the bioactive contents in propolis successfully induced particle formation. As the amount of PE increased, the particle size decreased; however, the size distribution range expanded. The antioxidant capacity of the particles increased with increased propolis amounts. P-AgNP1 exhibited almost equal inhibitory effects across all cancer cell types; however, P-AgNP2 was more effective on HeLa cells. P-AgNPs3 showed greater inhibitory effects in almost all cancer cells compared to other NPs and pure propolis. Consequently, the biological effects of P-AgNPs were highly dependent on PE amount, NP concentration, and cell type. These results suggest that AgNPs synthesized utilizing propolis phytochemicals might serve as anti -cancer agents, providing greater efficacy against cancer cells.Öğe Biocompatible non-leachable antimicrobial polymers with a nonionic hyperbranched backbone and phenolic terminal units(Royal Soc Chemistry, 2022) Arza, Carlos R.; Li, Xiaoya; Ilk, Sedef; Liu, Yang; Demircan, Deniz; Zhang, BaozhongThis work aimed to develop biocompatible non-leachable antimicrobial polymers without ionic structures. A series of nonionic hyperbranched polymers (HBPs) with an isatin-based backbone and phenolic terminal units were synthesized and characterized. The molecular structures and thermal properties of the obtained HBPs were characterized by SEC, NMR, FTIR, TGA and DSC analyses. Disk diffusion assay revealed significant antibacterial activity of the obtained phenolic HBPs against nine different pathogenic bacteria. The presence of a methoxy or long alkyl group close to the phenolic unit enhanced the antibacterial effect against certain Gram positive and negative bacteria. The obtained nonionic HBPs were blended in polyester poly(hexamethylene terephthalate) films, which showed no noticeable leakage after being immersed in water for 5 days. Finally, these HBPs showed no cytotoxicity effect to MG-63 osteoblast-like human cells according to MTT analysis, and negligible hemolytic effect.Öğe Bioremediation Applications with Fungi(Springer International Publishing Ag, 2018) Saglam, Necdet; Yesilada, Ozfer; Saglam, Semran; Apohan, Elif; Sam, Mesut; Ilk, Sedef; Emul, Ezgi[Abstract Not Available]Öğe Bovine serum albumin-mediated synthesis and quorum sensing inhibitory properties of Ag-Ag2S nanoparticles(Taylor & Francis Ltd, 2022) Ghaffarlou, Mohammadreza; Ilk, Sedef; Rahimi, Hossein; Danafar, Hossein; Barsbay, Murat; Sharafi, AliAim: Quorum sensing (QS) is a density-dependent chemical process of cell-to-cell communication in which certain signals are activated, leading to the coordination of pathogenic behaviors and the regulation of virulence in bacteria. Inhibition of QS can prevent biofilm formation and reduce virulence behaviors of bacteria. Herein, bovine serum albumin (BSA)-coated silver nanoparticles (NPs) (Ag-Ag2S@BSA NPs) were synthesized and studied as an anti-QS agent. Materials & methods: Ag-Ag2S NPs prepared through a BSA-mediated biomineralization process under ambient aqueous conditions and their physicochemical properties were characterized. The anti-QS activity of the resulting BSA-coated NPs (Ag-Ag2S@BSA NPs) was investigated for the first time. Results & conclusion: The result confirmed the potential of Ag-Ag2S@BSA NPs as novel and useful therapeutic tools for antibacterial purposes. Plain language summaryThe overuse of antibiotics has caused the development of drug-resistant strains of bacteria. Nowadays, drug resistance is one of the main challenges in the treatment and prevention of microbial diseases. In general, many bacterial species communicate with each other through a population-dependent mechanism called quorum sensing to control their physiological activities. Therefore, inhibiting the quorum sensing mechanism is an attractive alternative to antibiotics and also reduces the risk of drug resistance, and this can be achieved by nanoparticles (NPs). Among these nanostructures, Ag NPs have received particular attention due to their antimicrobial, antibiofilm, anticancer and antioxidant properties. Herein, we report a method that applies a BSA-guided green and one-pot approach for achieving Ag-Ag2S NPs as potential antibacterial agents.Öğe Cellulose-Organic Montmorillonite Nanocomposites as Biomacromolecular Quorum-Sensing Inhibitor(Amer Chemical Soc, 2017) Demircan, Deniz; Ilk, Sedef; Zhang, BaozhongThe aim of this study was to develop simple cellulose nanocomposites that can interfere with the quorum sensing (QS)-regulated physiological process of bacteria, which will provide a sustainable and inexpensive solution to the serious challenges caused by bacterial infections in various products like food packaging or biomedical materials. Three cellulose nanocomposites with 1-5 w% octadecylaminemodified montmorillonite (ODA-MMT) were prepared by regeneration of cellulose from ionic liquid solutions in the presence of ODA-MMT suspension. Structural characterization of the nanocomposites showed that the ODA-MMT can be exfoliated or intercalated, depending on the load level of the nanofiller. Thermal gravimetric analysis showed that the incorporation of ODA-MMT nanofiller can improve the thermal stability of the nanocomposites compared with regenerated cellulose. Evaluation of the anti-QS effect against a pigment-producing bacteria C. violaceum CV026 by disc diffusion assay and flask incubation assay revealed that the QS-regulated violacein pigment production was significantly inhibited by the cellulose nanocomposites without interfering the bacterial vitality. Interestingly, the nanocomposite with the lowest load of ODA-MMT exhibited the most significant anti-QS effect, which may be correlated to the exfoliation of nanofillers. To our knowledge, this is the first report on the anti-QS effect of cellulose nanocomposites without the addition of any small molecular agents. Such inexpensive and nontoxic biomaterials will thus have great potential in the development of new cellulosic materials that can effectively prevent the formation of harmful biofilms.Öğe Chitosan nanoparticles enhances the anti-quorum sensing activity of kaempferol(Elsevier Science Bv, 2017) Ilk, Sedef; Saglam, Necdet; Ozgen, Mustafa; Korkusuz, FezaQuorum sensing (QS) is a cell density dependent expression of species in bacteria mediated by compounds called autoinducers (AI). Several processes responsible for successful establishment of bacterial infection are mediated by QS. Inhibition of QS is therefore being considered as a new target for antimicrobial chemotherapy. Flavonoid compounds are strong antioxidant and antimicrobial agents but their applications are limited due to their poor dissolution and bioavailability. Our objective was to investigate the effect of kaempferol loaded chitosan nanoparticles on modulating QS mediated by AI in model bioassay test systems. For this purpose, kaempferol loaded nanoparticles were synthesized and characterized in terms of hydrodynamic diameter, hydrogen bonding, amorphous transformation and antioxidant activity. QS inhibition in time dependent manner of nanoparticles was measured in violacein pigment producing using the biosensor strain Chromobacterium violaceum CV026 mediated by AI known as acylated homoserine lactone (AHL). Our results indicated that the average kaempferol loaded chitosan/TPP nanoparticle size and zeta potential were 192.27 +/- 13.6 nm and +35 mV, respectively. The loading and encapsulation efficiency of kaempferol into chitosan/TPP nanoparticles presented higher values between 78 and 93%. Kaempferol loaded chitosan/TPP nanoparticle during the 30 storage days significantly inhibited the production of violacein pigment in Chromobacterium violaceum CV026. The observation that kaempferol encapsulated chitosan nanoparticles can inhibit QS related processes opens up an exciting new strategy for antimicrobial chemotherapy as stable QS-based anti-biofilm agents. (C) 2016 Elsevier B.V. All rights reserved.Öğe Diatomite as a novel composite ingredient for chitosan film with enhanced physicochemical properties(Elsevier Science Bv, 2017) Akyuz, Lalehan; Kaya, Murat; Koc, Behlul; Mujtaba, Muhammad; Ilk, Sedef; Labidi, Jalel; Salaberria, Asier M.Practical applications of biopolymers in different industries are gaining considerable increase day by day. But still, these biopolymers lack important properties in order to meet the industrial demands. In the same regard, in the current study, chitosan composite films are produced by incorporating diatomite soil at two different concentrations. In order to obtain a homogeneous film, glutaraldehyde was supplemented to chitosan solution as a cross-linker. Compositing diatomaceous earth to chitosan film resulted in improvement of various important physicochemical properties compared to control such as; enhanced film wettability, increase elongation at break and improved thermal stability (264-277 degrees C). The microstructure of the film was observed to haveconsisted of homogeneously distributed blister-shaped structures arised due to the incorporation of diatomite. The incorporation of diatomite did not influence the overall antioxidant activity of the composite films, which can be ascribe to the difficulty radicals formation. Chitosan film incorporated with increasing fraction of diatomite revealed a notable enhancement in the antimicrobial activity. Additionally with the present study, for the first time possible interactions between chitosan/diatomite were determined via quantum chemical calculations. Current study will be helpful in giving a new biotechnological perspective to diatom in terms of its successful application in hydrophobic composite film production. (C) 2017 Elsevier B.V. All rights reserved.Öğe Effect of different animal fat and plant oil additives on physicochemical, mechanical, antimicrobial and antioxidant properties of chitosan films(Elsevier Science Bv, 2018) Akyuz, Lalehan; Kaya, Murat; Ilk, Sedef; Cakmak, Yavuz Selim; Salaberria, Asier M.; Labidi, Jalel; Yilmaz, Bahar AkyuzPractical application of chitosan-essential oil blend films is limited due to the uneconomical extraction procedure of essential oils from plants. This study aimed to produce chitosan films blended with low cost and commercially available oils and fats consumed in daily human diet (olive, corn and sunflower oils, butter and animal fats). The study also focused on how physicochemical, biological and mechanical properties of chitosan blend films were influenced by the incorporation of oils and fats with varying unsaturation degrees. Possible interactions of chitosan film matrix with incorporated oils or fats were investigated. Chitosan-olive oil film showed better surface morphology and higher thermal stability than the films with other unsaturated oils. Tensile strength, Young's modulus and elongation at break were improved by 57.2%, 25.1% and 31.7% for chitosan-olive oil film, respectively. Chitosan-olive oil blend film had the highest antibacterial activity (almost equal to that of commercial antibiotic gentamicin). Edible films obtained from by incorporation of natural oils and fats into chitosan can help produce an environmentally friendly packaging material that is low cost and easily manufactured. (C) 2018 Elsevier B.V. All rights reserved.Öğe Electropolymerizations of two novel EDOT-BODIPY zinc oxide nanocomposites and evaluation of their in vitro antibacterial activities(Wiley, 2021) Kilavuz, Esra; Turac, Ersen; Ilk, Sedef; Sahmetlioglu, ErtugrulBoron containing materials as novel classes of antibacterial agents have been widely used in coating or medical applications due to their excellent functionality against microorganisms. In this study, two different boron dipyrromethene (BODIPY)/zinc oxide based P(M1-co-Edot)/ZnO and P(M2-co-Edot)/ZnO nanocomposite copolymer materials were prepared. The BODIPY/ZnO nanocomposite films were synthesized using potentiostat. ZnO nanoparticles were used to increase the strength and conductivity of the obtained semiconducting materials. Spectroelectrochemical analysis show that the copolymers, P(M1-co-Edot)/ZnO and P(M2-co-Edot)/ZnO, have electronic band gaps at 1.56 and 2.51 eV and optical band gaps at 2.11 and 2.00 eV, respectively. The synthesized nanocomposite films were characterized by Raman, nuclear magnetic resonance (NMR) and FT-IR spectroscopies. The optical properties of the synthesized monomers and their nanocomposite copolymers were demonstrated using UV-Vis and fluorescence spectroscopy. SEM and AFM images show the surface morphologies of nanocomposite copolymer films and surface roughness of P(M1-co-Edot)/ZnO and P(M2-co-Edot)/ZnO were calculated as Ra = 84.6 nm Rq = 106 nm and 120 nm, respectively. Antibacterial activities of the obtained nanocomposite films prepared in ultrapure water with different concentrations (2.5-0.25 mg/mL) were discovered against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) bacteria by using disc diffusion method. The antibacterial activities of obtained films were found to be higher against Gram negative bacteria compared to that of Gram positives. Obtained results show that synthesized nanocomposites with easy production and nontoxic properties can be used as functional bioengineering materials for antibacterial electrochromical materials.Öğe Evaluation of the role of Nrf2/Keap1 pathway-associated novel mutations and gene expression on antioxidant status in patients with deep vein thrombosis(Spandidos Publ Ltd, 2020) Akin-Bali, Dilara Fatma; Eroglu, Tamer; Ilk, Sedef; Egin, Yonca; Kankilic, TeomanDeep vein thrombosis (DVT) is a type of venous thromboembolism and a clinically complex vascular disease. Oxidative stress serves a key role in the pathogenesis of numerous cardiovascular diseases, particularly in endothelial dysfunction-associated syndromes. Nuclear factor erythroid-2-like 2(Nrf2) transcription factor is the primary regulator of antioxidant responses. The levels of reactive oxygen species (ROS) are regulated by Nrf2 and its suppressor protein Kelch-like ECH-associated protein 1 (Keap1). However, to the best of our knowledge, genetic abnormalites in the Nrf2/Keap1 pathway in DVT syndrome have not been thoroughly investigated. The aim of the present study was to investigate the association between the Nrf2/Keap1 pathway and antioxidant responses in DVT. Mutations and expression levels of genes involved in the Nrf2/Keap1 pathway were measured in 27 patients with DVT via DNA sequencing analysis and reverse transcription-quantitative PCR, respectively. The Polymorphism Phenotyping v2 program was used to identify the pathogenic mutations. Total antioxidant activity levels were determined by measuring the effect of serum samples from 27 patients with DVT on oxidation of the 2,2'-azino-bis (3-ethylbenz-thiazoline-6-sulfonic acid) system. A total of 23 mutations, including seven novel mutations, were detected in the Nrf2/Keap1 pathway in 24 (89%) of the 27 patients with DVT. Keap1 mRNA expression levels were significantly higher compared with Nrf2 expression levels in patients with DVT (P=0.02). Analysis of molecular characteristics and gene expression levels demonstrated that Nrf2/Keap1-associated mutations and total antioxidant levels can be used as precursor markers in the diagnosis of DVT.Öğe False flax (Camelina sativa) seed oil as suitable ingredient for the enhancement of physicochemical and biological properties of chitosan films(Elsevier, 2018) Gursoy, Mehtap; Sargin, Idris; Mujtaba, Muhammad; Akyuz, Bahar; Ilk, Sedef; Akyuz, Lalehan; Kaya, MuratTo overcome the drawbacks of synthetic films in food packaging industry, researchers are turned to natural bio-based edible films enriched with various plant additives. In current study chitosan blend films were produced by incorporating Camelina sativa seed oil at varying concentrations to chitosan matrix. The chitosan blend films were characterized both physicochemically (structural, morphological, thermal, optical and mechanical) and biologically (antimicrobial and antioxidant activity). The incorporation of C sativa seed oil notably enhanced thermal stability, antioxidative, anti-quorum sensing and antimicrobial activity. Except elongation at break, other mechanical properties of the blend films were not affected by incorporation of C sativa seed oil. The surface morphology of blend films was recorded as slightly rough, non-porous and fibre-free surface. As it was expected the optical transmittance in visible region was gradually decreased with increasing fraction of seed oil. Interestingly the hydrophilicity of the blend films revealed a swift increase which can be explained by the formation of micelle between glycerol and Tween 40 in blend films. This study provides valuable information for C sativa seed oil to be used as a blending ingredient in chitosan film technology. (C) 2018 Elsevier B.V. All rights reserved.Öğe Green and Facile Synthesis of Pullulan-Stabilized Silver and Gold Nanoparticles for the Inhibition of Quorum Sensing(Amer Chemical Soc, 2022) Ghaffarlou, Mohammadreza; Ilk, Sedef; Hammamchi, Hamideh; Kirac, Feyza; Okan, Meltem; Guven, Olgun; Barsbay, MuratPullulan (Pull) decorated with monodisperse Ag and Au nanoparticles (NPs) was synthesized by a simple and green method. Samples were characterized by FTIR, UV-vis, NMR, XRD, TGA, SEM, XPS, DLS, and TEM. SEM images showed highly oriented microforms reported for the first time for Pull, because of the supramolecular self-assembling behavior of Pull chains. Antimicrobial and quorum sensing (QS) inhibition activities were tested against six pathogen bacteria and reporter and biomonitor strain. Pull decorated with NPs, in particular, Ag-modified ones, outperformed pristine Pull. The cell proliferation was tested with an MTT assay. NPs-decorated Pull was studied for the first time as an inhibitory agent against bacterial signal molecules and found to be a good candidate. The promising performance of AgNPs@Pull compared to the commercial antibiotic gentamicin showed that it has great potential as a therapeutic approach to overcome the bacterial resistance that has developed against conventional antibiotics.Öğe Immobilization of laccase onto a porous nanocomposite: application for textile dye degradation(SCIENTIFIC TECHNICAL RESEARCH COUNCIL TURKEY-TUBITAK, 2016) Ilk, Sedef; Demircan, Deniz; Saglam, Semran; Saglam, Necdet; Rzayev, Zakir M. O.Poly(MA-alt-MVE)-g-PLA/ODA-MMT nanocomposite was prepared by self-catalytic interlamellar graft copolymerization of L-lactic acid (LA) onto poly(maleic anhydride-alt-methyl vinyl ether) copolymer in the presence of octadecyl amine-montmorillonite (ODA-MMT) organoclay. FTIR, H-1 (C-13) NMR, XRD, and SEM-TEM were utilized for characterizing the resultant nanocomposite. Lactase from Trametes versicolor was immobilized onto the prepared nanocomposite by adsorption or covalent coupling. Decolorization of Reactive Red 3 from aqueous solution by laccase immobilized on the nanocomposite was studied in different conditions (pH, temperature, dye concentration, and reaction time) to investigate the decolorization activity with repeated use and storage. The results indicated that more than 77% of the activity of laccase immobilized systems was retained at the end of 10 cycles. The final decolorization capacity of the immobilized laccase was significantly higher (65%) than that of free laccase (33%) in the chosen optimized conditions (pH 5, 20 degrees C, 0.05 mg/mL laccase concentration, and 90 min).Öğe Innovation of Strategies and Challenges for Fungal Nanobiotechnology(SPRINGER INTERNATIONAL PUBLISHING AG, 2016) Saglam, Necdet; Yesilada, Ozfer; Cabuk, Ahmet; Sam, Mesut; Saglam, Semran; Ilk, Sedef; Gurel, Ekrem; Prasad, RNanotechnology involves the study and use of materials under the 100 nm scale, exploiting the different physiochemical properties exhibited by these materials at the nanoscale level. Microorganisms are the best model and role of action for the nano/biotechnological applications. This technology has become increasingly important for the biotechnology and the related sectors. Promising applications have been already employed in the areas of drug delivery systems using bioactive nanoencapsulation, biosensors to detect and quantify pathogens, chemical and organic compounds, alteration of food compositions, and high-performance sensors and film to preserve fruits and vegetables. Moreover, the taste of food and food safety can be improved by new nano-materials from the microbiological sources. The huge benefits from this technology have led to increases in the market investments in nanoscience and nanoproducts in several areas.Öğe INVESTIGATION OF USE IN WASTEWATER TREATMENT OF NANOFIBERS OBTAINED FROM OSAGE ORANGE FRUIT(STEF92 TECHNOLOGY LTD, 2016) Ilk, Sedef; Battaloglu, Rifat; Yalcin, M. Gurhan; Ozgen, MustafaThe aim of this study was to prepare electrospun chitosan-based nanofiber mats and to incorporate the fruit extracts of Osage Orange (Madura Pomifera) into the mats. Chitosan-ethylenediaminetetraacetic acid/polyvinyl alcohol (CS-EDTA/PVA) was selected as the polymers. The osage orange extracts with 3 wt% were incorporated into the CS-EDTA/PVA solution and electrospun to obtain nanofibers. The morphology and diameters of the mats were analyzed using scanning electron microscopy (SEM). The chemical bonding properties were investigated by fourier transform infrared spectroscopy (FT-IR). Finally, the sorption potential of Osage Orange loaded nanofibers for the removal of common metallic pollutants, cadmium (Cd2+), cobalt (Co2+), copper (Cu2+), nickel (Ni2+) and lead (Pb2+) was also investigated. The results indicated that the diameters of the fibers were on the nanoscale and that no crystals of the extract were observed in the mats. Osage Orange loaded chitosan based nanofiber adsorbent presented good absorption capacity for all tested metals ranged between 29-34%. In conclusion, our experiments demonstrated that biomaterials composed of osage orange loaded CS EDTA nanofibers have a potential adsorbent for heavy metal.Öğe Investigation the potential use of silver nanoparticles synthesized by propolis extract as N-acyl-homoserine lactone-mediated quorum sensing systems inhibitor(Tubitak Scientific & Technological Research Council Turkey, 2020) Ilk, Sedef; Tan, Gamze; Emul, Ezgi; Saglam, NecdetBackground/aim: Quorum sensing (QS) is a chemical communication process that bacteria use to regulate virulence. Inhibition of QS (antiQS) overcomes the pathogenicity of bacteria. Silver nanoparticles (AgNPs) have been used as antimicrobials against pathogens, but have not been used against QS-mediated bacterial infection. Also, studies have been carried out on the inhibitory effects of propolis based structures on pathogen growth, but no studies have been found on their potential use as QS inhibitor. The present study aims to investigate the synthesis and characterization of silver nanoparticles (AgNPs) reduced with propolis extract (P-AgNPs) and evaluation of their antimicrobial and, for the first time, antiQS activity. Materials and methods: P-AgNPs were synthesized using with different volumes (1, 2.5 and 5 mL) of propolis extract (PE) by biological method via reduction of silver nitrate. Synthesized P-AgNPs were characterized in terms of hydrodynamic, chemical, morphological, physical, and antioxidant properties. Disc diffusion and flask incubation assays were used to evaluate the antimicrobial effect against Gram-negative bacteria (Escherichia coli, Proteus mirabilis, Proteus vulgaris, Salmonella typhimurium, Enterobacter aerogenes, Pseudomonas aeruginosa) and Gram-positive bacteria (Staphylococcus aureus, Streptococcus mutans, Bacillus thuringiensis) and QS-regulated biofilm activity against biosensor strain Chromobacterium violaceum CV026. Results: AgNPs were successfully synthesized by biological method via PE. The violacein pigment production based on the QS system was greatly inhibited by the P-AgNPs (inhibition zones: 16.22-21.48 mm and violacein inhibition: 63.16 +/- 2.4-75.24 +/- 3.5 %) without interfering with the growth of bacteria, which is the first report on the antiQS effect of P-AgNPs. Conclusion: Our results suggest that P-AgNPs may be potentially used to inhibit bacterial physiological processes due to the signal molecules regulates important collective behavior of bacteria. The development of such nontoxic biomaterials may have great potential to evaluate for the new medicinal substance that inhibits the pathogenic biofilms.Öğe Kaempferol loaded lecithin/chitosan nanoparticles: preparation, characterization, and their potential applications as a sustainable antifungal agent(TAYLOR & FRANCIS LTD, 2017) Ilk, Sedef; Saglam, Necdet; Ozgen, MustafaFlavonoid compounds are strong antioxidant and antifungal agents but their applications are limited due to their poor dissolution and bioavailability. The use of nanotechnology in agriculture has received increasing attention, with the development of new formulations containing active compounds. In this study, kaempferol (KAE) was loaded into lecithin/chitosan nanoparticles (LC NPs) to determine antifungal activity compared to pure KAE against the phytopathogenic fungus Fusarium oxysporium to resolve the bioavailability problem. The influence of formulation parameters on the physicochemical properties of KAE loaded lecithin chitosan nanoparticles (KAE-LC NPs) were studied by using the electrostatic self-assembly technique. KAE-LC NPs were characterized in terms of physicochemical properties. KAE has been successfully encapsulated in LC NPs with an efficiency of 93.8 +/- 4.28% and KAE-LC NPs showed good physicochemical stability. Moreover, in vitro evaluation of the KAE-LC NP system was made by the release kinetics, antioxidant and antifungal activity in a time-dependent manner against free KAE. Encapsulated KAE exhibited a significantly inhibition efficacy (67%) against Fusarium oxysporium at the end of the 60 day storage period. The results indicated that KAE-LC NP formulation could solve the problems related to the solubility and loss of KAE during use and storage. The new nanoparticle system enables the use of smaller quantities of fungicide and therefore, offers a more environmentally friendly method of controlling fungal pathogens in agriculture.Öğe New biobased non-ionic hyperbranched polymers as environmentally friendly antibacterial additives for biopolymers(Royal Soc Chemistry, 2018) Arza, Carlos R.; Ilk, Sedef; Demircan, Deniz; Zhang, BaozhongThe aim of this research was to develop new biobased non-ionic polymeric additives with significant bacterial inhibition and low leaching potential, so that they can be used to produce biopolymer materials for various applications such as biomedical devices, surgical textile, or food packaging. Two new non-ionic hyperbranched polymers (HBPs) were prepared by a facile solvent-free polymerization of an AB2monomer derived from naturally existing molecular building blocks 2-phenylethanol, isatin, and anisole. The molecular structures and thermal properties of the obtained HBPs were characterized by GPC, NMR, FTIR, HRMS, MALDI-TOF, TGA and DSC analyses. Disk diffusion tests revealed that the two obtained HBPs showed more significant antibacterial activity against 9 different food and human pathogenic bacteria, compared with small molecular antibiotics. The maximal antibacterial effect of HBPs was achieved at 2 ae g per disk (or 0.1 mg mL-1), which was significantly lower (similar to 1/15) compared to the linear antibacterial polymer chitosan. Such enhanced antibacterial properties can be attributed to the unique highly branched structures and effectively amplified functionalities of HBPs. Finally, the prepared HBPs were added into natural polymers cellulose and polyhydroxybutyrate (PHB), and the resulting biopolymer films showed no significant leakage after being merged in water for 5 days. This was in sharp contrast to the biopolymer films containing a small model compound, which leaked out significantly under the same conditions. To our knowledge, this is the first report on non-ionic bio-based dendritic macromolecules with significant bacteria inhibition and low leakage.Öğe Nonionic nontoxic antimicrobial polymers: indole-grafted poly(vinyl alcohol) with pendant alkyl or ether groups(Royal Soc Chemistry, 2022) Li, Xiaoya; Ilk, Sedef; Liu, Yang; Raina, Deepak Bushan; Demircan, Deniz; Zhang, BaozhongA series of new nonionic antimicrobial polymers with a biodegradable polyvinyl alcohol (PVA) backbone grafted with indole units and different hydrophobic alkyl or ether groups were synthesized by facile esterification. The chemical structures and thermal properties of the obtained polymers were characterized by GPC, NMR, FTIR, WAXD, TGA and DSC analyses. All these nonionic polymers showed a significant antibacterial effect similar to gentamicin against 9 food and human pathogenic bacteria according to the disk diffusion assay. The presence of alkyl or ether groups in most cases did not significantly affect the antibacterial effect compared to the polymer with unsubstituted indole units (with N-H moieties). The impacts of the OH conversion and molecular weight of the obtained polymers on their antimicrobial and anti-quorum sensing effects were also preliminarily investigated. Finally, the obtained indole-grafted PVAs were subjected to MTT assay using a mammalian cell line and hemolysis investigations, and the results showed excellent biocompatibility, particularly for those with ether substituents.
