Browsing by Author "Yazgan, I"

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    Comparison of Blueberry and Dandelion Aqueous Extracts in the Synthesis of Gold and Silver Nanostructures, and Their Applications as Anti-Pseudomonas aeruginosa Agent
    Tepe, H; Aktas, BSS; Çeter, T; Yazgan, I
    We performed a comparative study using aqueous extracts of dandelion flowers and blueberry fruits to synthesize gold- (Au) and silver- (Ag) nanostructures (NSs). The blueberry extracts gave nanowire and spherical AuNSs upon changing the ratio of the extracts to Au(3+)precursor while altering the ratio for the dandelion extracts resulted in formation of only anisotropic AuNSs. Similar results were obtained during the AgNSs, where the dandelion extracts resulted in formation of quasi-spherical AgNSs at the tested ratio (extract/AgNO3 ratio) while altering the ratio for the blueberry extracts resulted in nanorod and nanoplates formation. We argued that this could be from dominancy of a lone compound or a group of compounds and tested this claim by introducing chrysin and amino acid mixtures to the blueberry extracts. Altering the added chrysin amount triggered nanoplate and spherical AuNSs formation while alteration in amino acid mixture content did not change the morphology, and spherical AuNSs were obtained. The antibacterial studies revealed the AgNSs are toxic to Pseudomonas aeruginosa with 8 mu g/mL MBC (minimum bactericidal concentration) and 3 mu g/mL values for the blueberry and dandelion extracts synthesized AgNSs while penicillin/streptomycin sulfate mixture carrying Dandelion-AuNSs gave 12-times lower MBC value in comparison to free penicillin/streptomycin sulfate mixture.
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    Identification of Marker Molecules in Aqueous Plant Extracts Affecting the Gold Nanostructures' Morphology and Size
    Elgaleidh, MAM; Tepe, HD; Doyuk, F; Çeter, T; Yazgan, I
    This work was performed as a comparative study using nine different aqueous pollen grain extracts from eight different genera (Juniperus, Biota, Cupressus, Abies, Pinus, Cedrus, Populus and Corylus) to synthesize gold nanostructures (AuNSs) to understand if there is any possible marker that helps to predict the final morphology and size of the AuNSs. Principal component analysis (PCA) revealed that Apigenin and Pinoresinol compounds are the marker molecules in determination of the AuNSs physical characteristics while total protein, reducing carbohydrate, flavonoid and phenol contents did not show any statistically meaningful outcome. The dominancy hypothesis was tested by paying attention to the most concentrated phenolic acids and flavonoids in the control of AuNSs morphology and size, for which correlation analysis were performed. The statistical findings were tested using two new more pollen extracts to validate the models. Three main findings of the study were (i) determination of Apigenin and Pinoresinol levels in pollen extract can give an insight into the AuNSs physical characters, (ii) the most concentrated phenolic acids and flavonoids don't need to be same to pose same dictative effect on AuNSs morphology and size, rather relatively abundant ones in the extract play the key role and (iii) differences in the polymeric structures (e. g. lignin, cellulosic compounds etc.) have minor effect on the final morphology and size of the AuNSs. image
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    Modification of chitosan-bead support materials with l-lysine and l-asparagine for α-amylase immobilization
    Yazgan, I; Turner, EG; Cronmiller, LE; Tepe, M; Ozturk, TK; Elibol, M
    Maltose syrups have got wide-range utilizations in a variety of applications from bakery to drug-development. alpha-Amylases are among the most widely utilized industrial enzymes due to their high specificity in production of maltose syrup from starch. However, enzymes are not stable in ex vivo conditions towards alteration in pH, temperature, and such other parameters as high salt concentrations and impurities, where immobilization is required to advance the stability of the enzyme with which approach the requirement of isolation of the enzyme from media is eliminated as well. In this study, Termamyl(A (R)) alpha-amylase was immobilized on the none-modified chitosan beads (NMCB), l-lysine-modified chitosan beads (LMCB), and l-asparagine-modified chitosan beads (AMCB) to assess effects of the support material on optimum conditions and kinetic parameters of the alpha-amylase activity in production of maltose from starch. Immobilization on NMCB, LMCB, and AMCB puts a strong influence on optimum pH, optimum temperature, stability, and kinetic parameters of alpha-amylase. Modification of chitosan beads with l-lysine and l-asparagine dramatically altered the overall immobilization yield, and enzyme's response to pH and temperature variations and the kinetic parameters. AMCB provided the best immobilization yield (49%), while LMCB only improved the yield by 2% from 22 to 24%.
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    Surface chemistry dependent toxicity of inorganic nanostructure glycoconjugates on bacterial cells and cancer cell lines
    Sancak, S; Yazgan, I; Bayarslan, AU; Ayna, A; Evecen, S; Tasdelen, Z; Gümüs, A; Sönmez, HA; Demir, MA; Demir, S; Bakar, F; Dilek-Tepe, H; Kasemets, K; Otsus, M; Çeter, T
    Surface functionalized nanostructures have outstanding potential in biological applications owing to their target -specific design. In this study, we utilized laboratory synthesized carbohydrate-derivatives (i.e., galactose, mannose, lactose, and cellobiose derivatives) for aqueous one-pot synthesis of gold (Au) and silver (Ag) nano -structure glycoconjugates (NSs), and iron metal-organic framework glycoconjugates (FeMOFs). This work aims to test whether differences in the surface chemistry of the inorganic nanostructures play roles in revealing their toxicities towards bacterial cells and cancerous cell lines. As of the first step, biological activity of AuNSs, AgNSs, and FeMOFs were tested against a variety of gram (-) and gram (+) bacterial strains, where AgNSs possessed moderate to high antibacterial activities against all the tested bacterial strains, while AuNSs and FeMOFs showed their bacterial toxicity mostly depending on the strain. Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) determination studies were performed for the nanostructure glycoconjugates, for which mu g/mL MBC values were obtained such as (Cellobiose p-aminobenzoic acid_AgNS) CBpAB_AgNS gave 50 mu g/mL MBC value for P.aeruginosa and S.kentucy. The activity of selected sugar ligands and corresponding glycoconjugates were further tested on MDA-MB-231 breast cancer and A549 lung cancer cell lines, where se-lective anticancer activity was observed depending on the surface chemistry as well. Besides, D-penicillamine was introduced to galectin specific sugar ligand coated AuNS glycoconjugates, which showed very strong anticancer activities even at low doses. Overall, the importance of this work is that the surface chemistry of the inorganic nanostructures can be critical to reveal their toxicity towards bacterial cells and cancerous cell lines.
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    Doxorubicin functionalized metallic nanoparticles for anticancer and antibacterial applications
    Yesil, I; Atmaca, H; Degirmenci, S; Çamli-Pulat, C; Ari, M; Tepe, M; Küçük, A; Salmanoglu, DS; Sancak, Z; Kilinç, C; Ilhan, S; Yazgan, I
    In this study, we used Doxorubicin, an FDA approved drug possessing anticancer and antibacterial activity, as a model drug to functionalize sugar ligand synthesized silver/gold bimetallic nanoparticles (Ag/AuNPs) to test simultaneous antibacterial and anticancer activities under in vitro conditions. DU-145 prostate cancer cells were used as the main target while T98G glioblastoma and MDA-MB-231 breast cancer cell lines were used for selectivity test, and HEK-293 epithelial cell line was used as non-cancerous cells to test toxicity of these formulations. Three Ag/AuNP and corresponding Doxorubicin (D) functionalized ones and free Doxorubicin were tested for these four cell lines. Plain Ag/AuNP showed the highest toxicities on HEK-293 cell lines while DU-145 cell line showed the greatest vulnerability for Ag/AuNP-D formulations. However, DU-145 cells showed the lowest susceptibility for free Doxorubicin at all the tested concentrations. The antiproliferative activity was not dose dependent while an inverse relationship was obtained for a certain concentration range. Two Doxorubicin functionalized gold nanoparticles (AuNP-D) were then synthesized and applied on DU-145 cells. Interestingly, a better anticancer activity was obtained even at the minimum applied concentration (1.8 x 10-5 mu g/mL D). Antibacterial activities of these formulations were also tested for multidrug-resistant gram (-) and gram (+) bacterial species. Depending on the sugar ligand chemistry, antibacterial activity of Doxorubicin functionalized Ag/AuNPs showed a better performance in comparison to the plain Ag/AuNPs and vice-versa. Based on the results, it can be claimed that selective or semi-selective formulations targeting cancer cells and bacterial species as anti-neutropenia formulations can be developed using carbohydrate derivatives synthesized metallic nanoparticles as drug delivery agents.