Feray Bakan | Sabanci University (original) (raw)

Papers by Feray Bakan

Research paper thumbnail of Nanostructuring applications for functionalization of polymer surfaces with focused ion beam

Pamukkale University Journal of Engineering Sciences, 2017

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Chapter 9 Gene Delivery by Hydroxyapatite and Calcium Phosphate Nanoparticles : A Review of Novel and Recent Applications

Gene therapy is a targeted therapy which can be used in the treatment of various acquired and inh... more Gene therapy is a targeted therapy which can be used in the treatment of various acquired and inherited diseases. Inhabitation of a gene function, restoring or improving a gene, or gaining a new function can be achieved by gene therapy strategies. The most crucial step in this therapy is delivering the therapeutic material to the target. Nanosized calcium phosphates (CaPs) have been considered as promising carriers due to their excellent biocompatibility. In this chapter, the delivery of DNA, siRNA, and miRNA by using CaP nanocarriers were compiled in detail and the main parameters which can affect the carrier properties and thus the gene transfer efficiency were also discussed.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Evaluation of cytotoxic, oxidative stress and genotoxic responses of hydroxyapatite nanoparticles on human blood cells

Journal of Applied Toxicology, 2014

The present study was designed to investigate genotoxic and cytotoxic effects and oxidative damag... more The present study was designed to investigate genotoxic and cytotoxic effects and oxidative damage of increasing concentrations of nano-hydroxyapatite (5, 10, 20, 50, 75, 100, 150, 300, 500 and 1000 ppm) in primary human blood cell cultures. Cell viability was detected by [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] assay and lactate dehydrogenase release, while total antioxidant capacity and total oxidative stress levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed by sister chromatid exchange, micronuclei, chromosome aberration assays and 8-oxo-2-deoxyguanosine level as indicators of genotoxicity. The results of [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] and lactate dehydrogenase assays showed that the higher concentrations (150, 300, 500 and 1000 ppm) of hydroxyapatite nanoparticles (HAP NPs) decreased cell viability. HAP NPs led to increases of total oxidative stress (300, 500 and 1000 ppm) levels and decreased total antioxidant capacity (150, 300, 500 and 1000 ppm) levels in cultured human blood cells. On the basis of increasing concentrations, HAP NPs caused significant increases of sister chromatid exchange, micronuclei, chromosome aberration rates and 8-oxo-2-deoxyguanosine levels as compared to untreated culture. In conclusion, the obtained in vitro results showed that HAP NPs had dose-dependent effects on inducing oxidative damage, genotoxicity and cytotoxicity in human blood cells.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Size and Dispersion Control of Pt Nanoparticles Grown upon Graphite-Derived Nanosheets

ABSTRACT Graphite oxide nanosheets (GO), graphene nanosheets (GNS), and nanocomposites comprising... more ABSTRACT Graphite oxide nanosheets (GO), graphene nanosheets (GNS), and nanocomposites comprising of GO or GNS coated with polypyrrole (PPy) were prepared and assessed for their ability to influence the surface deposition and growth of Pt nanoparticles. GO was obtained from graphite via oxidation and exfoliation, and GNS was obtained from GO in a subsequent reduction. Both GO and GNS were coated with PPy via in situ polymerization of pyrrole (Py), forming surface-enhanced materials. SEM, EDX, TEM, EELS, Raman, and AFM findings showed that the Pt nanoparticle loading, agglomeration size, aggregate morphology and surface dispersion varied according to the nanosheet surface, nanocomposite type, and Py/nanosheet feed ratio. Surface oxygen functionalization along GO, GNS and their nanocomposites influenced the loading, dispersivity and morphology of nanoparticle agglomerates. PPy/GO nanocomposites yielded an improved nanoagglomerate surface dispersion and loading compared to samples. The PPy-coated substrates offered a greater intrinsic propensity for redox processes, resulting in higher Pt loadings. Additionally, these nanocomposites provided more surface reduction sites compared to bare nanosheets, and the additional sites contributed towards forming smaller, more homogeneously dispersed Pt nanoparticle agglomerates. Bringing together the electrical properties of PPy and physico-mechanical traits of carbon nanosheets, it follows to reason that the nanocomposites produced, particularly GO-based nanocomposites, offer promise as a nanoparticle support material for use in catalysis, electrocatalysis, and hydrogen storage.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Size and Dispersion Control of Pt Nanoparticles Grown upon Graphite-Derived Nanosheets

Chemical Engineering Communications, 2014

ABSTRACT Graphite oxide nanosheets (GO), graphene nanosheets (GNS), and nanocomposites comprising... more ABSTRACT Graphite oxide nanosheets (GO), graphene nanosheets (GNS), and nanocomposites comprising of GO or GNS coated with polypyrrole (PPy) were prepared and assessed for their ability to influence the surface deposition and growth of Pt nanoparticles. GO was obtained from graphite via oxidation and exfoliation, and GNS was obtained from GO in a subsequent reduction. Both GO and GNS were coated with PPy via in situ polymerization of pyrrole (Py), forming surface-enhanced materials. SEM, EDX, TEM, EELS, Raman, and AFM findings showed that the Pt nanoparticle loading, agglomeration size, aggregate morphology and surface dispersion varied according to the nanosheet surface, nanocomposite type, and Py/nanosheet feed ratio. Surface oxygen functionalization along GO, GNS and their nanocomposites influenced the loading, dispersivity and morphology of nanoparticle agglomerates. PPy/GO nanocomposites yielded an improved nanoagglomerate surface dispersion and loading compared to samples. The PPy-coated substrates offered a greater intrinsic propensity for redox processes, resulting in higher Pt loadings. Additionally, these nanocomposites provided more surface reduction sites compared to bare nanosheets, and the additional sites contributed towards forming smaller, more homogeneously dispersed Pt nanoparticle agglomerates. Bringing together the electrical properties of PPy and physico-mechanical traits of carbon nanosheets, it follows to reason that the nanocomposites produced, particularly GO-based nanocomposites, offer promise as a nanoparticle support material for use in catalysis, electrocatalysis, and hydrogen storage.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A novel low temperature sol–gel synthesis process for thermally stable nano crystalline hydroxyapatite

Powder Technology, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The effects of postdeposition annealing conditions on structure and created defects in Zn0.90Co0.10O thin films deposited on Si(100) substrate

Journal of Materials Research, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Evaluation of cytotoxic, oxidative stress and genotoxic responses of hydroxyapatite nanoparticles on human blood cells

Journal of Applied Toxicology, 2014

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Dissolution kinetics of natural magnesite in lactic acid solutions

International Journal of Mineral Processing, 2006

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Investigation of dissolution kinetics of natural magnesite in gluconic acid solutions

Chemical Engineering Journal, 2006

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Study of the boron levels in serum after implantation of different ratios nano-hexagonal boron nitride–hydroxy apatite in rat femurs

Materials Science and Engineering: C, 2016

Boron and its derivatives are effective in bone recovery and osteointegration. However, increasin... more Boron and its derivatives are effective in bone recovery and osteointegration. However, increasing the boron levels in body liquids may cause toxicity. The aim of our study is to investigate serum boron levels using ICP-MS after implantation of different ratios of nano-hBN-HA composites in rat femurs. All rats were (n=126) divided into five experimental groups (n=24) and one healthy group (6 rats); healthy (Group1), femoral defect+%100HA (Group2), femoral defect+%2.5hBN+%97.5HA (Group3), femoral defect+%5hBN+%95HA (Group4), femoral defect+%10hBN+%90 HA (Group5), femoral defect+%100hBN (Group6). The femoral defect was created in the distal femur (3mm drill-bit). Each implant group was divided into four different groups (n=24) also 6 rats sacrificed for each groups in one week intervals during four weeks. In our results; at 1, 2, 3, and 4weeks after implantation near bone tissue, serum levels of boron were evaluated using ICP-MS. We demonstrated that neither short-term nor long-term implantation of hBN-HA composite resulted in statistically increased serum boron levels in experimental groups compared to healthy group. In conclusion, this study investigated the implant material produced form hBN-HA for the first time. Our data suggest that hBN is a new promising target for biomaterial and implant bioengineers.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Nanostructuring applications for functionalization of polymer surfaces with focused ion beam

Pamukkale University Journal of Engineering Sciences, 2017

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Chapter 9 Gene Delivery by Hydroxyapatite and Calcium Phosphate Nanoparticles : A Review of Novel and Recent Applications

Gene therapy is a targeted therapy which can be used in the treatment of various acquired and inh... more Gene therapy is a targeted therapy which can be used in the treatment of various acquired and inherited diseases. Inhabitation of a gene function, restoring or improving a gene, or gaining a new function can be achieved by gene therapy strategies. The most crucial step in this therapy is delivering the therapeutic material to the target. Nanosized calcium phosphates (CaPs) have been considered as promising carriers due to their excellent biocompatibility. In this chapter, the delivery of DNA, siRNA, and miRNA by using CaP nanocarriers were compiled in detail and the main parameters which can affect the carrier properties and thus the gene transfer efficiency were also discussed.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Evaluation of cytotoxic, oxidative stress and genotoxic responses of hydroxyapatite nanoparticles on human blood cells

Journal of Applied Toxicology, 2014

The present study was designed to investigate genotoxic and cytotoxic effects and oxidative damag... more The present study was designed to investigate genotoxic and cytotoxic effects and oxidative damage of increasing concentrations of nano-hydroxyapatite (5, 10, 20, 50, 75, 100, 150, 300, 500 and 1000 ppm) in primary human blood cell cultures. Cell viability was detected by [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] assay and lactate dehydrogenase release, while total antioxidant capacity and total oxidative stress levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed by sister chromatid exchange, micronuclei, chromosome aberration assays and 8-oxo-2-deoxyguanosine level as indicators of genotoxicity. The results of [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] and lactate dehydrogenase assays showed that the higher concentrations (150, 300, 500 and 1000 ppm) of hydroxyapatite nanoparticles (HAP NPs) decreased cell viability. HAP NPs led to increases of total oxidative stress (300, 500 and 1000 ppm) levels and decreased total antioxidant capacity (150, 300, 500 and 1000 ppm) levels in cultured human blood cells. On the basis of increasing concentrations, HAP NPs caused significant increases of sister chromatid exchange, micronuclei, chromosome aberration rates and 8-oxo-2-deoxyguanosine levels as compared to untreated culture. In conclusion, the obtained in vitro results showed that HAP NPs had dose-dependent effects on inducing oxidative damage, genotoxicity and cytotoxicity in human blood cells.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Size and Dispersion Control of Pt Nanoparticles Grown upon Graphite-Derived Nanosheets

ABSTRACT Graphite oxide nanosheets (GO), graphene nanosheets (GNS), and nanocomposites comprising... more ABSTRACT Graphite oxide nanosheets (GO), graphene nanosheets (GNS), and nanocomposites comprising of GO or GNS coated with polypyrrole (PPy) were prepared and assessed for their ability to influence the surface deposition and growth of Pt nanoparticles. GO was obtained from graphite via oxidation and exfoliation, and GNS was obtained from GO in a subsequent reduction. Both GO and GNS were coated with PPy via in situ polymerization of pyrrole (Py), forming surface-enhanced materials. SEM, EDX, TEM, EELS, Raman, and AFM findings showed that the Pt nanoparticle loading, agglomeration size, aggregate morphology and surface dispersion varied according to the nanosheet surface, nanocomposite type, and Py/nanosheet feed ratio. Surface oxygen functionalization along GO, GNS and their nanocomposites influenced the loading, dispersivity and morphology of nanoparticle agglomerates. PPy/GO nanocomposites yielded an improved nanoagglomerate surface dispersion and loading compared to samples. The PPy-coated substrates offered a greater intrinsic propensity for redox processes, resulting in higher Pt loadings. Additionally, these nanocomposites provided more surface reduction sites compared to bare nanosheets, and the additional sites contributed towards forming smaller, more homogeneously dispersed Pt nanoparticle agglomerates. Bringing together the electrical properties of PPy and physico-mechanical traits of carbon nanosheets, it follows to reason that the nanocomposites produced, particularly GO-based nanocomposites, offer promise as a nanoparticle support material for use in catalysis, electrocatalysis, and hydrogen storage.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Size and Dispersion Control of Pt Nanoparticles Grown upon Graphite-Derived Nanosheets

Chemical Engineering Communications, 2014

ABSTRACT Graphite oxide nanosheets (GO), graphene nanosheets (GNS), and nanocomposites comprising... more ABSTRACT Graphite oxide nanosheets (GO), graphene nanosheets (GNS), and nanocomposites comprising of GO or GNS coated with polypyrrole (PPy) were prepared and assessed for their ability to influence the surface deposition and growth of Pt nanoparticles. GO was obtained from graphite via oxidation and exfoliation, and GNS was obtained from GO in a subsequent reduction. Both GO and GNS were coated with PPy via in situ polymerization of pyrrole (Py), forming surface-enhanced materials. SEM, EDX, TEM, EELS, Raman, and AFM findings showed that the Pt nanoparticle loading, agglomeration size, aggregate morphology and surface dispersion varied according to the nanosheet surface, nanocomposite type, and Py/nanosheet feed ratio. Surface oxygen functionalization along GO, GNS and their nanocomposites influenced the loading, dispersivity and morphology of nanoparticle agglomerates. PPy/GO nanocomposites yielded an improved nanoagglomerate surface dispersion and loading compared to samples. The PPy-coated substrates offered a greater intrinsic propensity for redox processes, resulting in higher Pt loadings. Additionally, these nanocomposites provided more surface reduction sites compared to bare nanosheets, and the additional sites contributed towards forming smaller, more homogeneously dispersed Pt nanoparticle agglomerates. Bringing together the electrical properties of PPy and physico-mechanical traits of carbon nanosheets, it follows to reason that the nanocomposites produced, particularly GO-based nanocomposites, offer promise as a nanoparticle support material for use in catalysis, electrocatalysis, and hydrogen storage.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A novel low temperature sol–gel synthesis process for thermally stable nano crystalline hydroxyapatite

Powder Technology, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of The effects of postdeposition annealing conditions on structure and created defects in Zn0.90Co0.10O thin films deposited on Si(100) substrate

Journal of Materials Research, 2013

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Evaluation of cytotoxic, oxidative stress and genotoxic responses of hydroxyapatite nanoparticles on human blood cells

Journal of Applied Toxicology, 2014

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Dissolution kinetics of natural magnesite in lactic acid solutions

International Journal of Mineral Processing, 2006

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Investigation of dissolution kinetics of natural magnesite in gluconic acid solutions

Chemical Engineering Journal, 2006

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Study of the boron levels in serum after implantation of different ratios nano-hexagonal boron nitride–hydroxy apatite in rat femurs

Materials Science and Engineering: C, 2016

Boron and its derivatives are effective in bone recovery and osteointegration. However, increasin... more Boron and its derivatives are effective in bone recovery and osteointegration. However, increasing the boron levels in body liquids may cause toxicity. The aim of our study is to investigate serum boron levels using ICP-MS after implantation of different ratios of nano-hBN-HA composites in rat femurs. All rats were (n=126) divided into five experimental groups (n=24) and one healthy group (6 rats); healthy (Group1), femoral defect+%100HA (Group2), femoral defect+%2.5hBN+%97.5HA (Group3), femoral defect+%5hBN+%95HA (Group4), femoral defect+%10hBN+%90 HA (Group5), femoral defect+%100hBN (Group6). The femoral defect was created in the distal femur (3mm drill-bit). Each implant group was divided into four different groups (n=24) also 6 rats sacrificed for each groups in one week intervals during four weeks. In our results; at 1, 2, 3, and 4weeks after implantation near bone tissue, serum levels of boron were evaluated using ICP-MS. We demonstrated that neither short-term nor long-term implantation of hBN-HA composite resulted in statistically increased serum boron levels in experimental groups compared to healthy group. In conclusion, this study investigated the implant material produced form hBN-HA for the first time. Our data suggest that hBN is a new promising target for biomaterial and implant bioengineers.

Bookmarks Related papers MentionsView impact