TY  - JOUR
AU  - Tadić, Marin
AU  - Kralj, Slavko
AU  - Kopanja, Lazar
PY  - 2019
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5911
AB  - We report monodisperse, chain-like particles (nanochains) consisted of silica-coated maghemite (γ-Fe2O3) nanoparticle clusters prepared by colloidal chemistry and magnetic field-induced self-assembly of nanoparticle clusters. In order to quantify the shapes of chain-like particles, we have used the measure for shape convexity which is also called solidity. We functionalize the surface of the nanochains with amino (–NH2) and carboxyl groups (–COOH) in order to modify surface charge. These surfaces of nanochains provide better colloidal stability and their potential for practical applications in biomedicine. The enhanced colloidal stability of the surface modified nanochains is confirmed by Zeta potential (ζ-potential) analysis. Magnetic properties of the nanochains show superparamagnetic state at room temperature since the nanochains are composed of tiny nanoparticles as their building blocks. The measured M(H) data at room temperature have been successfully fitted by the Langevin function and magnetic moment μp = 20,526 μB for sphere-like nanoparticle clusters and μp = 20,767 μB for nanochains are determined. The determined magnetic parameters have revealed that the nanochains show a magnetic moment of the nanoparticles higher than the one of individual nanoparticle clusters. These differences can be attributed to the collective magnetic properties of superparamagnetic iron oxide nanoparticles (SPION) assembled in different morphologies (isotropic and anisotropic morphology). © 2018
T2  - Materials Characterization
T1  - Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains
EP  - 133
SP  - 123
VL  - 148
DO  - 10.1016/j.matchar.2018.12.014
ER  - 

@article{
author = "Tadić, Marin and Kralj, Slavko and Kopanja, Lazar",
year = "2019",
abstract = "We report monodisperse, chain-like particles (nanochains) consisted of silica-coated maghemite (γ-Fe2O3) nanoparticle clusters prepared by colloidal chemistry and magnetic field-induced self-assembly of nanoparticle clusters. In order to quantify the shapes of chain-like particles, we have used the measure for shape convexity which is also called solidity. We functionalize the surface of the nanochains with amino (–NH2) and carboxyl groups (–COOH) in order to modify surface charge. These surfaces of nanochains provide better colloidal stability and their potential for practical applications in biomedicine. The enhanced colloidal stability of the surface modified nanochains is confirmed by Zeta potential (ζ-potential) analysis. Magnetic properties of the nanochains show superparamagnetic state at room temperature since the nanochains are composed of tiny nanoparticles as their building blocks. The measured M(H) data at room temperature have been successfully fitted by the Langevin function and magnetic moment μp = 20,526 μB for sphere-like nanoparticle clusters and μp = 20,767 μB for nanochains are determined. The determined magnetic parameters have revealed that the nanochains show a magnetic moment of the nanoparticles higher than the one of individual nanoparticle clusters. These differences can be attributed to the collective magnetic properties of superparamagnetic iron oxide nanoparticles (SPION) assembled in different morphologies (isotropic and anisotropic morphology). © 2018",
journal = "Materials Characterization",
title = "Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains",
pages = "133-123",
volume = "148",
doi = "10.1016/j.matchar.2018.12.014"
}

Tadić, M., Kralj, S.,& Kopanja, L.. (2019). Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains. in Materials Characterization, 148, 123-133.
https://doi.org/10.1016/j.matchar.2018.12.014

Tadić M, Kralj S, Kopanja L. Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains. in Materials Characterization. 2019;148:123-133.
doi:10.1016/j.matchar.2018.12.014 .

Tadić, Marin, Kralj, Slavko, Kopanja, Lazar, "Synthesis, particle shape characterization, magnetic properties and surface modification of superparamagnetic iron oxide nanochains" in Materials Characterization, 148 (2019):123-133,
https://doi.org/10.1016/j.matchar.2018.12.014 . .

TY  - JOUR
AU  - Kopanja, Lazar
AU  - Tadić, Marin
AU  - Kralj, Slavko
AU  - Žunić, Joviša
PY  - 2018
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5877
AB  - Due to advances in electron microscopy and to the development of novel nanoparticle structures with different morphologies and the dependence of physical properties on the nanoparticle morphology, there is a need for a more precise analysis of nanoparticle structure and morphology. That should provide a simple and unambiguous comparison of nanoparticles' shapes and of material properties that depend on the shape, which has been lacking thus far. Here we study nanochains consisting of silica-coated iron oxide (maghemite, gamma-Fe2O3) nanoparticle clusters covered by an additional layer of silica (core-shell structure). We have developed an algorithm for image segmentation and a quantitative analysis of nanochain shape from real TEM images. To that end we used two distinct measures of circularity and elongation measure (the aspect ratio measure). We show that the relative position and the area of the links, as well as the links' shape lead to significant differences in the measured aspect ratio of the entire nanochain (substantially influence the elongation of nanochains). We have also analyzed the core-shell structures in nanochains, and computed the shell's share in the overall area of observed nanochains. A Matlab code was developed and used for the computation of the elongation measure of shapes appearing in electron microscopy images. Here we have investigated magnetic properties of synthetic nanochains, that revealed superparamagnetic behavior at room temperature (SPION) with the possibility of tuning the magnetization values (approx. from 19 to 46 emu/g). We have compared of magnetization M(H) curves of the anisotropic nanochains and of isotropic nanoparticle (nanochain links), with the conclusion that the nanochains have a higher magnetic susceptibility, which fact can be understood as a consequence of their anisotropic shapes. The nanochains may be applied in biomedicine and magnetic separation, due to their morphology and magnetic properties.
T2  - Ceramics International
T1  - Shape and aspect ratio analysis of anisotropic magnetic nanochains based on TEM micrographs
EP  - 12351
IS  - 11
SP  - 12340
VL  - 44
DO  - 10.1016/j.ceramint.2018.04.021
ER  - 

@article{
author = "Kopanja, Lazar and Tadić, Marin and Kralj, Slavko and Žunić, Joviša",
year = "2018",
abstract = "Due to advances in electron microscopy and to the development of novel nanoparticle structures with different morphologies and the dependence of physical properties on the nanoparticle morphology, there is a need for a more precise analysis of nanoparticle structure and morphology. That should provide a simple and unambiguous comparison of nanoparticles' shapes and of material properties that depend on the shape, which has been lacking thus far. Here we study nanochains consisting of silica-coated iron oxide (maghemite, gamma-Fe2O3) nanoparticle clusters covered by an additional layer of silica (core-shell structure). We have developed an algorithm for image segmentation and a quantitative analysis of nanochain shape from real TEM images. To that end we used two distinct measures of circularity and elongation measure (the aspect ratio measure). We show that the relative position and the area of the links, as well as the links' shape lead to significant differences in the measured aspect ratio of the entire nanochain (substantially influence the elongation of nanochains). We have also analyzed the core-shell structures in nanochains, and computed the shell's share in the overall area of observed nanochains. A Matlab code was developed and used for the computation of the elongation measure of shapes appearing in electron microscopy images. Here we have investigated magnetic properties of synthetic nanochains, that revealed superparamagnetic behavior at room temperature (SPION) with the possibility of tuning the magnetization values (approx. from 19 to 46 emu/g). We have compared of magnetization M(H) curves of the anisotropic nanochains and of isotropic nanoparticle (nanochain links), with the conclusion that the nanochains have a higher magnetic susceptibility, which fact can be understood as a consequence of their anisotropic shapes. The nanochains may be applied in biomedicine and magnetic separation, due to their morphology and magnetic properties.",
journal = "Ceramics International",
title = "Shape and aspect ratio analysis of anisotropic magnetic nanochains based on TEM micrographs",
pages = "12351-12340",
number = "11",
volume = "44",
doi = "10.1016/j.ceramint.2018.04.021"
}

Kopanja, L., Tadić, M., Kralj, S.,& Žunić, J.. (2018). Shape and aspect ratio analysis of anisotropic magnetic nanochains based on TEM micrographs. in Ceramics International, 44(11), 12340-12351.
https://doi.org/10.1016/j.ceramint.2018.04.021

Kopanja L, Tadić M, Kralj S, Žunić J. Shape and aspect ratio analysis of anisotropic magnetic nanochains based on TEM micrographs. in Ceramics International. 2018;44(11):12340-12351.
doi:10.1016/j.ceramint.2018.04.021 .

Kopanja, Lazar, Tadić, Marin, Kralj, Slavko, Žunić, Joviša, "Shape and aspect ratio analysis of anisotropic magnetic nanochains based on TEM micrographs" in Ceramics International, 44, no. 11 (2018):12340-12351,
https://doi.org/10.1016/j.ceramint.2018.04.021 . .

TY  - JOUR
AU  - Miljković, Miona
AU  - Davidović, Slađana
AU  - Kralj, Slavko
AU  - Šiler-Marinković, Slavica
AU  - Rajilić-Stojanović, Mirjana
AU  - Dimitrijević-Branković, Suzana
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3632
AB  - The production of dextransucrase (DS) by Leuconostoc mesenteroides T3, novel isolate from water kefir grain, was studied and optimized. Bacterial supernatant reached activity of 3.1 U/ml when the culture was grown at 23 degrees C and under static culture condition using classical Tsuchiya medium for DS production. The increase of sucrose concentration to 7% led to an increase of DS activity by 52% compared to the control. Medium with 2% beef extract and 1% yeast extract resulted in 4.52 U/ml, which was 47% higher than in the control (with 2% yeast extract). Finally, the increase of K2HPO4 concentration from 2 to 3% resulted in the increased enzyme activity by 28%. Enzyme purified by polyethylene glycol 400 fractionation displayed maximum activity at 30 degrees C and pH 5.4. Zymogram analysis confirmed the presence of DS of approximately 180 kDa. The addition of divalent cations Ca2+, Mg2+, Fe2+ and Co2+ led to a minor increase of DS activity, while the addition of Mn2+ was the most prominent with 73% increase. These findings classify dextransucrase from Leuconostoc mesenteroides T3 as promising candidate for production of dextran, which has numerous applications in various industries.
PB  - Savez hemijskih inženjera, Beograd
T2  - Hemijska industrija
T1  - Characterization of dextransucrase from Leuconostoc mesenteroides T3, water kefir grains isolate
EP  - 360
IS  - 4
SP  - 351
VL  - 71
DO  - 10.2298/HEMIND160421046M
ER  - 

@article{
author = "Miljković, Miona and Davidović, Slađana and Kralj, Slavko and Šiler-Marinković, Slavica and Rajilić-Stojanović, Mirjana and Dimitrijević-Branković, Suzana",
year = "2017",
abstract = "The production of dextransucrase (DS) by Leuconostoc mesenteroides T3, novel isolate from water kefir grain, was studied and optimized. Bacterial supernatant reached activity of 3.1 U/ml when the culture was grown at 23 degrees C and under static culture condition using classical Tsuchiya medium for DS production. The increase of sucrose concentration to 7% led to an increase of DS activity by 52% compared to the control. Medium with 2% beef extract and 1% yeast extract resulted in 4.52 U/ml, which was 47% higher than in the control (with 2% yeast extract). Finally, the increase of K2HPO4 concentration from 2 to 3% resulted in the increased enzyme activity by 28%. Enzyme purified by polyethylene glycol 400 fractionation displayed maximum activity at 30 degrees C and pH 5.4. Zymogram analysis confirmed the presence of DS of approximately 180 kDa. The addition of divalent cations Ca2+, Mg2+, Fe2+ and Co2+ led to a minor increase of DS activity, while the addition of Mn2+ was the most prominent with 73% increase. These findings classify dextransucrase from Leuconostoc mesenteroides T3 as promising candidate for production of dextran, which has numerous applications in various industries.",
publisher = "Savez hemijskih inženjera, Beograd",
journal = "Hemijska industrija",
title = "Characterization of dextransucrase from Leuconostoc mesenteroides T3, water kefir grains isolate",
pages = "360-351",
number = "4",
volume = "71",
doi = "10.2298/HEMIND160421046M"
}

Miljković, M., Davidović, S., Kralj, S., Šiler-Marinković, S., Rajilić-Stojanović, M.,& Dimitrijević-Branković, S.. (2017). Characterization of dextransucrase from Leuconostoc mesenteroides T3, water kefir grains isolate. in Hemijska industrija
Savez hemijskih inženjera, Beograd., 71(4), 351-360.
https://doi.org/10.2298/HEMIND160421046M

Miljković M, Davidović S, Kralj S, Šiler-Marinković S, Rajilić-Stojanović M, Dimitrijević-Branković S. Characterization of dextransucrase from Leuconostoc mesenteroides T3, water kefir grains isolate. in Hemijska industrija. 2017;71(4):351-360.
doi:10.2298/HEMIND160421046M .

Miljković, Miona, Davidović, Slađana, Kralj, Slavko, Šiler-Marinković, Slavica, Rajilić-Stojanović, Mirjana, Dimitrijević-Branković, Suzana, "Characterization of dextransucrase from Leuconostoc mesenteroides T3, water kefir grains isolate" in Hemijska industrija, 71, no. 4 (2017):351-360,
https://doi.org/10.2298/HEMIND160421046M . .

TY  - JOUR
AU  - Tadić, Marin
AU  - Kopanja, Lazar
AU  - Panjan, Matjaž
AU  - Kralj, Slavko
AU  - Nikodinović Runić, Jasmina
AU  - Stojanović, Zoran S.
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5854
AB  - Hematite core-shell nanoparticles with plate-like morphology were synthesized using a one-step hydrothermal synthesis. An XRPD analysis indicates that the sample consist of single-phase α-Fe2O3 nanoparticles. SEM and TEM measurements show that the hematite sample is composed of uniform core-shell nanoplates with 10–20 nm thickness, 80–100 nm landscape dimensions (aspect ratio ∼5) and 3–4 nm thickness of the surface shells. We used computational methods for the quantitative analysis of the core–shell particle structure and circularity shape descriptor for the quantitative shape analysis of the nanoparticles from TEM micrographs. The calculated results indicated that a percentage of the shell area in the nanoparticle area (share [%]) is significant. The determined values of circularity in the perpendicular and oblique perspective clearly show shape anisotropy of the nanoplates. The magnetic properties revealed the ferromagnetic-like properties at room temperature with high coercivity HC = 2340 Oe, pointing to the shape and surface effects. These results signify core-shell hematite nanoparticles’ for practical applications in magnetic devices. The synthesized hematite plate-like nanoparticles exhibit low cytotoxicity levels on the human lung fibroblasts (MRC5) cell line demonstrating the safe use of these nanoparticles for biomedical applications.
T2  - Applied Surface Science
T1  - Synthesis of core-shell hematite (α-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity
EP  - 634
SP  - 628
VL  - 403
DO  - 10.1016/j.apsusc.2017.01.115
UR  - https://hdl.handle.net/21.15107/rcub_dais_2349
ER  - 

@article{
author = "Tadić, Marin and Kopanja, Lazar and Panjan, Matjaž and Kralj, Slavko and Nikodinović Runić, Jasmina and Stojanović, Zoran S.",
year = "2017",
abstract = "Hematite core-shell nanoparticles with plate-like morphology were synthesized using a one-step hydrothermal synthesis. An XRPD analysis indicates that the sample consist of single-phase α-Fe2O3 nanoparticles. SEM and TEM measurements show that the hematite sample is composed of uniform core-shell nanoplates with 10–20 nm thickness, 80–100 nm landscape dimensions (aspect ratio ∼5) and 3–4 nm thickness of the surface shells. We used computational methods for the quantitative analysis of the core–shell particle structure and circularity shape descriptor for the quantitative shape analysis of the nanoparticles from TEM micrographs. The calculated results indicated that a percentage of the shell area in the nanoparticle area (share [%]) is significant. The determined values of circularity in the perpendicular and oblique perspective clearly show shape anisotropy of the nanoplates. The magnetic properties revealed the ferromagnetic-like properties at room temperature with high coercivity HC = 2340 Oe, pointing to the shape and surface effects. These results signify core-shell hematite nanoparticles’ for practical applications in magnetic devices. The synthesized hematite plate-like nanoparticles exhibit low cytotoxicity levels on the human lung fibroblasts (MRC5) cell line demonstrating the safe use of these nanoparticles for biomedical applications.",
journal = "Applied Surface Science",
title = "Synthesis of core-shell hematite (α-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity",
pages = "634-628",
volume = "403",
doi = "10.1016/j.apsusc.2017.01.115",
url = "https://hdl.handle.net/21.15107/rcub_dais_2349"
}

Tadić, M., Kopanja, L., Panjan, M., Kralj, S., Nikodinović Runić, J.,& Stojanović, Z. S.. (2017). Synthesis of core-shell hematite (α-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity. in Applied Surface Science, 403, 628-634.
https://doi.org/10.1016/j.apsusc.2017.01.115
https://hdl.handle.net/21.15107/rcub_dais_2349

Tadić M, Kopanja L, Panjan M, Kralj S, Nikodinović Runić J, Stojanović ZS. Synthesis of core-shell hematite (α-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity. in Applied Surface Science. 2017;403:628-634.
doi:10.1016/j.apsusc.2017.01.115
https://hdl.handle.net/21.15107/rcub_dais_2349 .

Tadić, Marin, Kopanja, Lazar, Panjan, Matjaž, Kralj, Slavko, Nikodinović Runić, Jasmina, Stojanović, Zoran S., "Synthesis of core-shell hematite (α-Fe2O3) nanoplates: Quantitative analysis of the particle structure and shape, high coercivity and low cytotoxicity" in Applied Surface Science, 403 (2017):628-634,
https://doi.org/10.1016/j.apsusc.2017.01.115 .,
https://hdl.handle.net/21.15107/rcub_dais_2349 .

TY  - JOUR
AU  - Kopanja, Lazar
AU  - Kralj, Slavko
AU  - Žunić, Dragiša
AU  - Lončar, Boris B.
AU  - Tadić, Marin
PY  - 2016
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/5810
AB  - For the first time, particle shape analysis of silica coated iron oxide (maghemite/magnetite) nanoparticle clusters (core-shell nanostructures) is discussed using computational methods. We analyzed three samples of core-shell nanostructures synthesized with different thickness of the silica shell. A new computational method is presented and successfully applied to the segmentation of the core-shell nanoparticles, as one of the main problems in image analysis of the TEM micrographs. We have introduced the circularity coefficient, marked with k(circ) and defined as the ratio of circularity measure C-2(S) of nanoparticles core and circularity measure core-shell nanoparticles in order to answer the question how the shell affects the overall shape of the final core-shell structure, with respect to circularity. More precisely, the circularity coefficient determines whether the circularity of the core-shell nanoparticle is higher, lower or equal to the circularity of the core. We have also determined the shells share in the overall area of the core-shell nanoparticle. The core-shell nanoparticle clusters here investigated exhibit superparamagnetic properties at room temperature, thus emphasizing their potential for use in practical applications such as in biomedical and particle separation. We show that the saturation magnetization strength can be easily adjusted by controlling the thickness of the silica shell. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
PB  - Elsevier
T2  - Ceramics International
T1  - Core-shell superparamagnetic iron oxide nanoparticle (SPION) clusters: TEM micrograph analysis, particle design and shape analysis
EP  - 10984
IS  - 9
SP  - 10976
VL  - 42
DO  - 10.1016/j.ceramint.2016.03.235
ER  - 

@article{
author = "Kopanja, Lazar and Kralj, Slavko and Žunić, Dragiša and Lončar, Boris B. and Tadić, Marin",
year = "2016",
abstract = "For the first time, particle shape analysis of silica coated iron oxide (maghemite/magnetite) nanoparticle clusters (core-shell nanostructures) is discussed using computational methods. We analyzed three samples of core-shell nanostructures synthesized with different thickness of the silica shell. A new computational method is presented and successfully applied to the segmentation of the core-shell nanoparticles, as one of the main problems in image analysis of the TEM micrographs. We have introduced the circularity coefficient, marked with k(circ) and defined as the ratio of circularity measure C-2(S) of nanoparticles core and circularity measure core-shell nanoparticles in order to answer the question how the shell affects the overall shape of the final core-shell structure, with respect to circularity. More precisely, the circularity coefficient determines whether the circularity of the core-shell nanoparticle is higher, lower or equal to the circularity of the core. We have also determined the shells share in the overall area of the core-shell nanoparticle. The core-shell nanoparticle clusters here investigated exhibit superparamagnetic properties at room temperature, thus emphasizing their potential for use in practical applications such as in biomedical and particle separation. We show that the saturation magnetization strength can be easily adjusted by controlling the thickness of the silica shell. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Core-shell superparamagnetic iron oxide nanoparticle (SPION) clusters: TEM micrograph analysis, particle design and shape analysis",
pages = "10984-10976",
number = "9",
volume = "42",
doi = "10.1016/j.ceramint.2016.03.235"
}

Kopanja, L., Kralj, S., Žunić, D., Lončar, B. B.,& Tadić, M.. (2016). Core-shell superparamagnetic iron oxide nanoparticle (SPION) clusters: TEM micrograph analysis, particle design and shape analysis. in Ceramics International
Elsevier., 42(9), 10976-10984.
https://doi.org/10.1016/j.ceramint.2016.03.235

Kopanja L, Kralj S, Žunić D, Lončar BB, Tadić M. Core-shell superparamagnetic iron oxide nanoparticle (SPION) clusters: TEM micrograph analysis, particle design and shape analysis. in Ceramics International. 2016;42(9):10976-10984.
doi:10.1016/j.ceramint.2016.03.235 .

Kopanja, Lazar, Kralj, Slavko, Žunić, Dragiša, Lončar, Boris B., Tadić, Marin, "Core-shell superparamagnetic iron oxide nanoparticle (SPION) clusters: TEM micrograph analysis, particle design and shape analysis" in Ceramics International, 42, no. 9 (2016):10976-10984,
https://doi.org/10.1016/j.ceramint.2016.03.235 . .