TY  - JOUR
AU  - Milenković, Mila
AU  - Ciasca, Gabriele
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera
AU  - Verbić, Tatjana
AU  - Todorović Marković, Biljana
AU  - Jovanović, Svetlana
PY  - 2024
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/6414
AB  - The widespread abuse of traditional antibiotics has led to a global rise in antibiotic-resistant bacteria, which give in return unprecedented health risks. Therefore, there is a large and urgent need for the development of new, smart antibacterial agents able to efficiently kill or inhibit bacterial growth. In this study, we investigated the antibacterial activity of S, N-doped Graphene Quantum Dots (GQDs) as a light-triggered antibacterial agent. Gamma irradiation was employed as a tool to achieve one-step modification of GQDs in the presence of L-cysteine amino acid as a source of heteroatoms. X-ray Photoelectron Spectroscopy (XPS), nuclear magnetic resonance (NMR), and zeta potential measurements provided the necessary data to clarify the structure of modified dots and verify the introduction of both S- and N-atoms in GQDs structure, but also severe changes in the aromatic, sp2 domains. Namely, γ-irradiation caused a bonding of S atoms in 1.14 at.% mainly as thiol groups, and N in 1.81 at.% as amino groups, but sp2 contribution in GQD structure was lowered from 63.00 to 4.86 at.%, as measured in dots irradiated at a dose of 200 kGy. Fluorescence quenching measurements showed that L-cysteine-modified dots are able to bind to human serum albumin. The antibacterial activity of GQDs combined with 1 and 6 h of blue light (470 nm) irradiation was tested against 8 bacterial strains. GQD-cys-25 sample provided the best results, with minimum inhibitory concentration (MIC) as low as 125 μg/mL against S. aureus, E. faecalis, and E. coli after only 1 h of blue light exposure.
PB  - Elsevier
T2  - Journal of Photochemistry and Photobiology B: Biology
T1  - Blue-light-driven photoactivity of L-cysteine-modified graphene quantum dots and their antibacterial effects
VL  - 250
SP  - 112818
DO  - 10.1016/j.jphotobiol.2023.112818
ER  - 

@article{
author = "Milenković, Mila and Ciasca, Gabriele and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera and Verbić, Tatjana and Todorović Marković, Biljana and Jovanović, Svetlana",
year = "2024",
abstract = "The widespread abuse of traditional antibiotics has led to a global rise in antibiotic-resistant bacteria, which give in return unprecedented health risks. Therefore, there is a large and urgent need for the development of new, smart antibacterial agents able to efficiently kill or inhibit bacterial growth. In this study, we investigated the antibacterial activity of S, N-doped Graphene Quantum Dots (GQDs) as a light-triggered antibacterial agent. Gamma irradiation was employed as a tool to achieve one-step modification of GQDs in the presence of L-cysteine amino acid as a source of heteroatoms. X-ray Photoelectron Spectroscopy (XPS), nuclear magnetic resonance (NMR), and zeta potential measurements provided the necessary data to clarify the structure of modified dots and verify the introduction of both S- and N-atoms in GQDs structure, but also severe changes in the aromatic, sp2 domains. Namely, γ-irradiation caused a bonding of S atoms in 1.14 at.% mainly as thiol groups, and N in 1.81 at.% as amino groups, but sp2 contribution in GQD structure was lowered from 63.00 to 4.86 at.%, as measured in dots irradiated at a dose of 200 kGy. Fluorescence quenching measurements showed that L-cysteine-modified dots are able to bind to human serum albumin. The antibacterial activity of GQDs combined with 1 and 6 h of blue light (470 nm) irradiation was tested against 8 bacterial strains. GQD-cys-25 sample provided the best results, with minimum inhibitory concentration (MIC) as low as 125 μg/mL against S. aureus, E. faecalis, and E. coli after only 1 h of blue light exposure.",
publisher = "Elsevier",
journal = "Journal of Photochemistry and Photobiology B: Biology",
title = "Blue-light-driven photoactivity of L-cysteine-modified graphene quantum dots and their antibacterial effects",
volume = "250",
pages = "112818",
doi = "10.1016/j.jphotobiol.2023.112818"
}

Milenković, M., Ciasca, G., Bonasera, A., Scopelliti, M., Marković, O., Verbić, T., Todorović Marković, B.,& Jovanović, S.. (2024). Blue-light-driven photoactivity of L-cysteine-modified graphene quantum dots and their antibacterial effects. in Journal of Photochemistry and Photobiology B: Biology
Elsevier., 250, 112818.
https://doi.org/10.1016/j.jphotobiol.2023.112818

Milenković M, Ciasca G, Bonasera A, Scopelliti M, Marković O, Verbić T, Todorović Marković B, Jovanović S. Blue-light-driven photoactivity of L-cysteine-modified graphene quantum dots and their antibacterial effects. in Journal of Photochemistry and Photobiology B: Biology. 2024;250:112818.
doi:10.1016/j.jphotobiol.2023.112818 .

Milenković, Mila, Ciasca, Gabriele, Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera, Verbić, Tatjana, Todorović Marković, Biljana, Jovanović, Svetlana, "Blue-light-driven photoactivity of L-cysteine-modified graphene quantum dots and their antibacterial effects" in Journal of Photochemistry and Photobiology B: Biology, 250 (2024):112818,
https://doi.org/10.1016/j.jphotobiol.2023.112818 . .

TY  - JOUR
AU  - Milenković, Mila
AU  - Ciasca, Gabriele
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera
AU  - Verbić, Tatjana
AU  - Todorović Marković, Biljana
AU  - Jovanović, Svetlana
PY  - 2024
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/6303
AB  - The widespread abuse of traditional antibiotics has led to a global rise in antibiotic-resistant bacteria, which give 
in return unprecedented health risks. Therefore, there is a large and urgent need for the development of new, 
smart antibacterial agents able to efficiently kill or inhibit bacterial growth. In this study, we investigated the 
antibacterial activity of S, N-doped Graphene Quantum Dots (GQDs) as a light-triggered antibacterial agent. 
Gamma irradiation was employed as a tool to achieve one-step modification of GQDs in the presence of L cysteine amino acid as a source of heteroatoms. X-ray Photoelectron Spectroscopy (XPS), nuclear magnetic 
resonance (NMR), and zeta potential measurements provided the necessary data to clarify the structure of 
modified dots and verify the introduction of both S- and N-atoms in GQDs structure, but also severe changes in 
the aromatic, sp2 domains. Namely, γ-irradiation caused a bonding of S atoms in 1.14 at.% mainly as thiol 
groups, and N in 1.81 at.% as amino groups, but sp2 contribution in GQD structure was lowered from 63.00 to 
4.86 at.%, as measured in dots irradiated at a dose of 200 kGy. Fluorescence quenching measurements showed 
that L-cysteine-modified dots are able to bind to human serum albumin. The antibacterial activity of GQDs 
combined with 1 and 6 h of blue light (470 nm) irradiation was tested against 8 bacterial strains. GQD-cys-25 
sample provided the best results, with minimum inhibitory concentration (MIC) as low as 125 μg/mL against 
S. aureus, E. faecalis, and E. coli after only 1 h of blue light exposure.
PB  - Elsevier
T2  - Journal of Photochemistry & Photobiology, B: Biology
T1  - Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects
VL  - 250
SP  - 112818
DO  - 10.1016/j.jphotobiol.2023.112818
ER  - 

@article{
author = "Milenković, Mila and Ciasca, Gabriele and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera and Verbić, Tatjana and Todorović Marković, Biljana and Jovanović, Svetlana",
year = "2024",
abstract = "The widespread abuse of traditional antibiotics has led to a global rise in antibiotic-resistant bacteria, which give 
in return unprecedented health risks. Therefore, there is a large and urgent need for the development of new, 
smart antibacterial agents able to efficiently kill or inhibit bacterial growth. In this study, we investigated the 
antibacterial activity of S, N-doped Graphene Quantum Dots (GQDs) as a light-triggered antibacterial agent. 
Gamma irradiation was employed as a tool to achieve one-step modification of GQDs in the presence of L cysteine amino acid as a source of heteroatoms. X-ray Photoelectron Spectroscopy (XPS), nuclear magnetic 
resonance (NMR), and zeta potential measurements provided the necessary data to clarify the structure of 
modified dots and verify the introduction of both S- and N-atoms in GQDs structure, but also severe changes in 
the aromatic, sp2 domains. Namely, γ-irradiation caused a bonding of S atoms in 1.14 at.% mainly as thiol 
groups, and N in 1.81 at.% as amino groups, but sp2 contribution in GQD structure was lowered from 63.00 to 
4.86 at.%, as measured in dots irradiated at a dose of 200 kGy. Fluorescence quenching measurements showed 
that L-cysteine-modified dots are able to bind to human serum albumin. The antibacterial activity of GQDs 
combined with 1 and 6 h of blue light (470 nm) irradiation was tested against 8 bacterial strains. GQD-cys-25 
sample provided the best results, with minimum inhibitory concentration (MIC) as low as 125 μg/mL against 
S. aureus, E. faecalis, and E. coli after only 1 h of blue light exposure.",
publisher = "Elsevier",
journal = "Journal of Photochemistry & Photobiology, B: Biology",
title = "Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects",
volume = "250",
pages = "112818",
doi = "10.1016/j.jphotobiol.2023.112818"
}

Milenković, M., Ciasca, G., Bonasera, A., Scopelliti, M., Marković, O., Verbić, T., Todorović Marković, B.,& Jovanović, S.. (2024). Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects. in Journal of Photochemistry & Photobiology, B: Biology
Elsevier., 250, 112818.
https://doi.org/10.1016/j.jphotobiol.2023.112818

Milenković M, Ciasca G, Bonasera A, Scopelliti M, Marković O, Verbić T, Todorović Marković B, Jovanović S. Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects. in Journal of Photochemistry & Photobiology, B: Biology. 2024;250:112818.
doi:10.1016/j.jphotobiol.2023.112818 .

Milenković, Mila, Ciasca, Gabriele, Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera, Verbić, Tatjana, Todorović Marković, Biljana, Jovanović, Svetlana, "Blue-light-driven photoactivity of L-cysteine-modified graphene quantum  dots and their antibacterial effects" in Journal of Photochemistry & Photobiology, B: Biology, 250 (2024):112818,
https://doi.org/10.1016/j.jphotobiol.2023.112818 . .

TY  - JOUR
AU  - Dorontic, Sladjana
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera S.
AU  - Bajuk Bogdanović, Danica
AU  - Ciasca, Gabriele
AU  - Romanò, Sabrina
AU  - Dimkić, Ivica
AU  - Budimir, Milica
AU  - Marinković, Dragana
AU  - Jovanovic, Svetlana
PY  - 2022
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5883
AB  - Structural modification of different carbon-based nanomaterials is often necessary to
improve their morphology and optical properties, particularly the incorporation of N-atoms in
graphene quantum dots (GQDs). Here, a clean, simple, one-step, and eco-friendly method for
N-doping of GQDs using gamma irradiation is reported. GQDs were irradiated in the presence
of the different ethylenediamine (EDA) amounts (1 g, 5 g, and 10 g) and the highest % of N was
detected in the presence of 10 g. N-doped GQDs emitted strong, blue photoluminescence (PL).
Photoluminescence quantum yield was increased from 1.45, as obtained for non-irradiated dots,
to 7.24% for those irradiated in the presence of 1 g of EDA. Modified GQDs were investigated as
a PL probe for the detection of insecticide Carbofuran (2,2-Dimethyl-2,3-dihydro-1-benzofuran-7-
yl methylcarbamate) and herbicide Amitrole (3-amino-1,2,4-triazole). The limit of detection was
5.4 µmol L−1
for Carbofuran. For the first time, Amitrole was detected by GQDs in a turn-off/turn-on
mechanism using Pd(II) ions as a quenching agent. First, Pd(II) ions were quenched (turn-off) PL
of GQDs, while after Amitrole addition, PL was recovered linearly with Amitrole concentration
(turn-on). LOD was 2.03 µmol L−1
. These results suggest that modified GQDs can be used as an
efficient new material for Carbofuran and Amitrole detection. Furthermore, the phototoxicity of dots
was investigated on both Gram-positive and Gram-negative bacterial strains. When bacterial cells
were exposed to different GQD concentrations and illuminated with light of 470 nm wavelength, the
toxic effects were not observed.
PB  - MDPI
T2  - Nanomaterials
T1  - Gamma-ray-induced structural transformation of GQDs  towards the improvement of their optical properties, monitoring of selected toxic compounds,  and photo-induced effect on bacterial strains
VL  - 12
SP  - 2714
DO  - https://doi.org/10.3390/nano12152714
ER  - 

@article{
author = "Dorontic, Sladjana and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera S. and Bajuk Bogdanović, Danica and Ciasca, Gabriele and Romanò, Sabrina and Dimkić, Ivica and Budimir, Milica and Marinković, Dragana and Jovanovic, Svetlana",
year = "2022",
abstract = "Structural modification of different carbon-based nanomaterials is often necessary to
improve their morphology and optical properties, particularly the incorporation of N-atoms in
graphene quantum dots (GQDs). Here, a clean, simple, one-step, and eco-friendly method for
N-doping of GQDs using gamma irradiation is reported. GQDs were irradiated in the presence
of the different ethylenediamine (EDA) amounts (1 g, 5 g, and 10 g) and the highest % of N was
detected in the presence of 10 g. N-doped GQDs emitted strong, blue photoluminescence (PL).
Photoluminescence quantum yield was increased from 1.45, as obtained for non-irradiated dots,
to 7.24% for those irradiated in the presence of 1 g of EDA. Modified GQDs were investigated as
a PL probe for the detection of insecticide Carbofuran (2,2-Dimethyl-2,3-dihydro-1-benzofuran-7-
yl methylcarbamate) and herbicide Amitrole (3-amino-1,2,4-triazole). The limit of detection was
5.4 µmol L−1
for Carbofuran. For the first time, Amitrole was detected by GQDs in a turn-off/turn-on
mechanism using Pd(II) ions as a quenching agent. First, Pd(II) ions were quenched (turn-off) PL
of GQDs, while after Amitrole addition, PL was recovered linearly with Amitrole concentration
(turn-on). LOD was 2.03 µmol L−1
. These results suggest that modified GQDs can be used as an
efficient new material for Carbofuran and Amitrole detection. Furthermore, the phototoxicity of dots
was investigated on both Gram-positive and Gram-negative bacterial strains. When bacterial cells
were exposed to different GQD concentrations and illuminated with light of 470 nm wavelength, the
toxic effects were not observed.",
publisher = "MDPI",
journal = "Nanomaterials",
title = "Gamma-ray-induced structural transformation of GQDs  towards the improvement of their optical properties, monitoring of selected toxic compounds,  and photo-induced effect on bacterial strains",
volume = "12",
pages = "2714",
doi = "https://doi.org/10.3390/nano12152714"
}

Dorontic, S., Bonasera, A., Scopelliti, M., Marković, O. S., Bajuk Bogdanović, D., Ciasca, G., Romanò, S., Dimkić, I., Budimir, M., Marinković, D.,& Jovanovic, S.. (2022). Gamma-ray-induced structural transformation of GQDs  towards the improvement of their optical properties, monitoring of selected toxic compounds,  and photo-induced effect on bacterial strains. in Nanomaterials
MDPI., 12, 2714.
https://doi.org/https://doi.org/10.3390/nano12152714

Dorontic S, Bonasera A, Scopelliti M, Marković OS, Bajuk Bogdanović D, Ciasca G, Romanò S, Dimkić I, Budimir M, Marinković D, Jovanovic S. Gamma-ray-induced structural transformation of GQDs  towards the improvement of their optical properties, monitoring of selected toxic compounds,  and photo-induced effect on bacterial strains. in Nanomaterials. 2022;12:2714.
doi:https://doi.org/10.3390/nano12152714 .

Dorontic, Sladjana, Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera S., Bajuk Bogdanović, Danica, Ciasca, Gabriele, Romanò, Sabrina, Dimkić, Ivica, Budimir, Milica, Marinković, Dragana, Jovanovic, Svetlana, "Gamma-ray-induced structural transformation of GQDs  towards the improvement of their optical properties, monitoring of selected toxic compounds,  and photo-induced effect on bacterial strains" in Nanomaterials, 12 (2022):2714,
https://doi.org/https://doi.org/10.3390/nano12152714 . .

TY  - JOUR
AU  - Jovanović, Svetlana
AU  - Dorontić, Slađana
AU  - Jovanović, Dragana
AU  - Ciasca, Gabriele
AU  - Budimir, Milica D.
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera S.
AU  - Todorović Marković, Biljana
PY  - 2020
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5466
AB  - Due to the low consumption of chemicals, the absence of toxic residual side products, the procedure simplicity
and time-saving aspects, gamma irradiation offers advantages over the classical chemical protocols. We suc cessfully employed gamma irradiation in order to introduce N-atoms in Graphene Quantum Dots (GQDs). By
irradiating GQDs water dispersions in the presence of isopropyl alcohol and ethylenediamine, at doses of 25, 50
and 200 kGy, we attached amino groups onto GQDs in a single synthetic step. At the same time, a chemical
reduction is achieved, too. Selected conditions induced incorporation of N-atoms within GDQs atomic lattice
(around 3 at%), at all applied doses. Additionally, the C-atoms percentage was highly increased, from 63 to 79 at
% or higher. The zeta potential of dots changed from −34.6 to +9.1 mV, due to the modification of functio nalizing groups localized at the surface. Produced chemical changes lead to the desired alteration of the GQDs
optical properties, such as an increased photoluminescence intensity, a higher photoluminescence quantum
yields (from 2.07 to 18.40%) and a narrowing of the spectral features in the emission spectra. The ability of
gamma-irradiated GQDs to quench free radical species was investigated and positively assessed; additionally,
non-enzymatic optical detection of Cu(II) ions using GQDs as a sensor was studied and the detection limits are
herein reported. These results suggest that GQDs can be potentially applied as smart photoluminescent sensors
for metal cations.
PB  - Elsevier
T2  - Ceramics International
T1  - Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing
VL  - 46
SP  - 23611
EP  - 23622
DO  - 10.1016/j.ceramint.2020.06.133
ER  - 

@article{
author = "Jovanović, Svetlana and Dorontić, Slađana and Jovanović, Dragana and Ciasca, Gabriele and Budimir, Milica D. and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera S. and Todorović Marković, Biljana",
year = "2020",
abstract = "Due to the low consumption of chemicals, the absence of toxic residual side products, the procedure simplicity
and time-saving aspects, gamma irradiation offers advantages over the classical chemical protocols. We suc cessfully employed gamma irradiation in order to introduce N-atoms in Graphene Quantum Dots (GQDs). By
irradiating GQDs water dispersions in the presence of isopropyl alcohol and ethylenediamine, at doses of 25, 50
and 200 kGy, we attached amino groups onto GQDs in a single synthetic step. At the same time, a chemical
reduction is achieved, too. Selected conditions induced incorporation of N-atoms within GDQs atomic lattice
(around 3 at%), at all applied doses. Additionally, the C-atoms percentage was highly increased, from 63 to 79 at
% or higher. The zeta potential of dots changed from −34.6 to +9.1 mV, due to the modification of functio nalizing groups localized at the surface. Produced chemical changes lead to the desired alteration of the GQDs
optical properties, such as an increased photoluminescence intensity, a higher photoluminescence quantum
yields (from 2.07 to 18.40%) and a narrowing of the spectral features in the emission spectra. The ability of
gamma-irradiated GQDs to quench free radical species was investigated and positively assessed; additionally,
non-enzymatic optical detection of Cu(II) ions using GQDs as a sensor was studied and the detection limits are
herein reported. These results suggest that GQDs can be potentially applied as smart photoluminescent sensors
for metal cations.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing",
volume = "46",
pages = "23611-23622",
doi = "10.1016/j.ceramint.2020.06.133"
}

Jovanović, S., Dorontić, S., Jovanović, D., Ciasca, G., Budimir, M. D., Bonasera, A., Scopelliti, M., Marković, O. S.,& Todorović Marković, B.. (2020). Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing. in Ceramics International
Elsevier., 46, 23611-23622.
https://doi.org/10.1016/j.ceramint.2020.06.133

Jovanović S, Dorontić S, Jovanović D, Ciasca G, Budimir MD, Bonasera A, Scopelliti M, Marković OS, Todorović Marković B. Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing. in Ceramics International. 2020;46:23611-23622.
doi:10.1016/j.ceramint.2020.06.133 .

Jovanović, Svetlana, Dorontić, Slađana, Jovanović, Dragana, Ciasca, Gabriele, Budimir, Milica D., Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera S., Todorović Marković, Biljana, "Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing" in Ceramics International, 46 (2020):23611-23622,
https://doi.org/10.1016/j.ceramint.2020.06.133 . .