TY  - JOUR
AU  - Trpkov, Đorđe
AU  - Sredojević, Dušan
AU  - Pajović, Jelena
AU  - Tošić, Dragana
AU  - Božanić, Dušan K.
AU  - Đoković, Vladimir
PY  - 2024
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13176
AB  - Nitrogen-doped carbon dots (NCD) were synthesized using a simple and fast hydrothermal route, employing citric acid and urea as precursors. The resulting NCDs were non-covalently functionalized (conjugated) with aromatic amino acids, namely phenylalanine (Phe) and tryptophan (Trp). Atomic force microscopy revealed that the NCDs exhibit a disk-like morphology with an average diameter of approximately 60 nm and an average height of about 0.5 nm. Following conjugation, the particle height increased to around 3 nm. UV–vis spectroscopy analysis indicated successful conjugation of the amino acids to the NCD nanostructures. Additionally, DFT numerical calculations based on three differently N-doped clusters were performed to elucidate the nature of the non-covalent interactions between NCDs and the corresponding amino acids. Photoluminescent spectra demonstrated a stable and strong fluorescence signal for both hybrids in the UV region. The most significant changes were observed in the case of Trp-conjugation. In contrast to phenylalanine, the non-covalent bonding of tryptophan to NCDs strongly influenced the visible emission (around 500 nm) originating from surface states of the dots.
T2  - Colloids and Surfaces B: Biointerfaces
T1  - Hybrid nanostructures of nitrogen-doped carbon dots and aromatic amino acids: Synthesis, interactions at interfaces and optical properties
VL  - 238
SP  - 113878
DO  - 10.1016/j.colsurfb.2024.113878
ER  - 

@article{
author = "Trpkov, Đorđe and Sredojević, Dušan and Pajović, Jelena and Tošić, Dragana and Božanić, Dušan K. and Đoković, Vladimir",
year = "2024",
abstract = "Nitrogen-doped carbon dots (NCD) were synthesized using a simple and fast hydrothermal route, employing citric acid and urea as precursors. The resulting NCDs were non-covalently functionalized (conjugated) with aromatic amino acids, namely phenylalanine (Phe) and tryptophan (Trp). Atomic force microscopy revealed that the NCDs exhibit a disk-like morphology with an average diameter of approximately 60 nm and an average height of about 0.5 nm. Following conjugation, the particle height increased to around 3 nm. UV–vis spectroscopy analysis indicated successful conjugation of the amino acids to the NCD nanostructures. Additionally, DFT numerical calculations based on three differently N-doped clusters were performed to elucidate the nature of the non-covalent interactions between NCDs and the corresponding amino acids. Photoluminescent spectra demonstrated a stable and strong fluorescence signal for both hybrids in the UV region. The most significant changes were observed in the case of Trp-conjugation. In contrast to phenylalanine, the non-covalent bonding of tryptophan to NCDs strongly influenced the visible emission (around 500 nm) originating from surface states of the dots.",
journal = "Colloids and Surfaces B: Biointerfaces",
title = "Hybrid nanostructures of nitrogen-doped carbon dots and aromatic amino acids: Synthesis, interactions at interfaces and optical properties",
volume = "238",
pages = "113878",
doi = "10.1016/j.colsurfb.2024.113878"
}

Trpkov, Đ., Sredojević, D., Pajović, J., Tošić, D., Božanić, D. K.,& Đoković, V.. (2024). Hybrid nanostructures of nitrogen-doped carbon dots and aromatic amino acids: Synthesis, interactions at interfaces and optical properties. in Colloids and Surfaces B: Biointerfaces, 238, 113878.
https://doi.org/10.1016/j.colsurfb.2024.113878

Trpkov Đ, Sredojević D, Pajović J, Tošić D, Božanić DK, Đoković V. Hybrid nanostructures of nitrogen-doped carbon dots and aromatic amino acids: Synthesis, interactions at interfaces and optical properties. in Colloids and Surfaces B: Biointerfaces. 2024;238:113878.
doi:10.1016/j.colsurfb.2024.113878 .

Trpkov, Đorđe, Sredojević, Dušan, Pajović, Jelena, Tošić, Dragana, Božanić, Dušan K., Đoković, Vladimir, "Hybrid nanostructures of nitrogen-doped carbon dots and aromatic amino acids: Synthesis, interactions at interfaces and optical properties" in Colloids and Surfaces B: Biointerfaces, 238 (2024):113878,
https://doi.org/10.1016/j.colsurfb.2024.113878 . .

TY  - CONF
AU  - Đoković, Vladimir
AU  - Pajović, Jelena
AU  - Dojčilović, Radovan
AU  - Božanić, Dušan
AU  - Tošić, Dragana
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13089
AB  - This study reports on the optical properties of hybrid nanostructures that comprise gold nanoparticles (Au NPs) and biomolecule riboflavin (vitamin B2, Rb). The riboflavin is photosensitizing molecule and the generation of reactive oxygen species (ROS) by the hybrid nanoparticles was tested in various aqueous and biological environments. It was shown that the gold nanoparticles enhanced the photosensitizing activity of riboflavin. A comparison of EPR spectra obtained for the Au nanoparticle colloid, hybrid nanoparticle colloid and molecular water solution revealed that the strongest ROS signal came from the AuRb nanosystem. Furthermore, the ROS signal stability was much higher than that of the molecular solution, with a time span of several minutes. Photodynamic activity of the AuRb hybrids was tested by using gram-negative bacterium Escherichia coli as a model system. The bacteria were incubated by AuRb nanoparticles and the survival rate of the colonies was investigated by fluorescent bioimaging. The obtain results provide new insights on photosensitizer’s activities and suggest advantages of using metal-based nanoplatforms for developing of novel agents for photodynamic therapies.
PB  - Belgrade : Institute of Physics
C3  - 16th Photonics Workshop : Book of abstracts
T1  - Gold-riboflavin hybrid nanostrucutures as possible photodynamic therapy agents
SP  - 52
EP  - 52
UR  - https://hdl.handle.net/21.15107/rcub_vinar_13089
ER  - 

@conference{
author = "Đoković, Vladimir and Pajović, Jelena and Dojčilović, Radovan and Božanić, Dušan and Tošić, Dragana",
year = "2023",
abstract = "This study reports on the optical properties of hybrid nanostructures that comprise gold nanoparticles (Au NPs) and biomolecule riboflavin (vitamin B2, Rb). The riboflavin is photosensitizing molecule and the generation of reactive oxygen species (ROS) by the hybrid nanoparticles was tested in various aqueous and biological environments. It was shown that the gold nanoparticles enhanced the photosensitizing activity of riboflavin. A comparison of EPR spectra obtained for the Au nanoparticle colloid, hybrid nanoparticle colloid and molecular water solution revealed that the strongest ROS signal came from the AuRb nanosystem. Furthermore, the ROS signal stability was much higher than that of the molecular solution, with a time span of several minutes. Photodynamic activity of the AuRb hybrids was tested by using gram-negative bacterium Escherichia coli as a model system. The bacteria were incubated by AuRb nanoparticles and the survival rate of the colonies was investigated by fluorescent bioimaging. The obtain results provide new insights on photosensitizer’s activities and suggest advantages of using metal-based nanoplatforms for developing of novel agents for photodynamic therapies.",
publisher = "Belgrade : Institute of Physics",
journal = "16th Photonics Workshop : Book of abstracts",
title = "Gold-riboflavin hybrid nanostrucutures as possible photodynamic therapy agents",
pages = "52-52",
url = "https://hdl.handle.net/21.15107/rcub_vinar_13089"
}

Đoković, V., Pajović, J., Dojčilović, R., Božanić, D.,& Tošić, D.. (2023). Gold-riboflavin hybrid nanostrucutures as possible photodynamic therapy agents. in 16th Photonics Workshop : Book of abstracts
Belgrade : Institute of Physics., 52-52.
https://hdl.handle.net/21.15107/rcub_vinar_13089

Đoković V, Pajović J, Dojčilović R, Božanić D, Tošić D. Gold-riboflavin hybrid nanostrucutures as possible photodynamic therapy agents. in 16th Photonics Workshop : Book of abstracts. 2023;:52-52.
https://hdl.handle.net/21.15107/rcub_vinar_13089 .

Đoković, Vladimir, Pajović, Jelena, Dojčilović, Radovan, Božanić, Dušan, Tošić, Dragana, "Gold-riboflavin hybrid nanostrucutures as possible photodynamic therapy agents" in 16th Photonics Workshop : Book of abstracts (2023):52-52,
https://hdl.handle.net/21.15107/rcub_vinar_13089 .

TY  - CONF
AU  - Božanić, Dušan
AU  - Pajović, Jelena
AU  - Danilović, Danijela
AU  - Chowdhury, Madhusree Roy
AU  - Garcia, Gustavo
AU  - Nahon, Laurent
AU  - Đoković, Vladimir
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13049
AB  - Azobenzenes (Azo) represent a class of organic compounds composed of two phenyl rings linked by an N=N double bond that exhibit photoisomerization, i.e. change in conformation upon UV or visible light illumination. Photoisomerization in Azo is of high yield and reversible, which is why these molecules can act as molecular photoswitches in various biomedical and energy conversion applications. However, a broader application of Azo, particularly in biomedicine, requires lower energy of photoisomerization that falls further into visible or even NIR range. In our study, selected azobenzenes were conjugated to the surface of bare gold nanoparticles (Au NP) to obtain functional hybrid nanosystems in which photoisomerization of Azo can occur upon excitation of surface plasmon in Au NP. To understand the nature of the process, the valence band structure of Azo-functionalized Au NP was investigated by synchrotron radiation VUV aerosol photoemission spectroscopy. The results demonstrate that the overlap between the valence bands of Azo and Au NP is significant to allow for chare transfer process between the components in the nanosystem.
PB  - Belgrade : Institute of Physics
C3  - 16th Photonics Workshop : Book of abstracts
T1  - Valence Band Electronic Structure of Azobenzene-Functionalized Gold Nanoparticles
SP  - 51
EP  - 51
UR  - https://hdl.handle.net/21.15107/rcub_vinar_13049
ER  - 

@conference{
author = "Božanić, Dušan and Pajović, Jelena and Danilović, Danijela and Chowdhury, Madhusree Roy and Garcia, Gustavo and Nahon, Laurent and Đoković, Vladimir",
year = "2023",
abstract = "Azobenzenes (Azo) represent a class of organic compounds composed of two phenyl rings linked by an N=N double bond that exhibit photoisomerization, i.e. change in conformation upon UV or visible light illumination. Photoisomerization in Azo is of high yield and reversible, which is why these molecules can act as molecular photoswitches in various biomedical and energy conversion applications. However, a broader application of Azo, particularly in biomedicine, requires lower energy of photoisomerization that falls further into visible or even NIR range. In our study, selected azobenzenes were conjugated to the surface of bare gold nanoparticles (Au NP) to obtain functional hybrid nanosystems in which photoisomerization of Azo can occur upon excitation of surface plasmon in Au NP. To understand the nature of the process, the valence band structure of Azo-functionalized Au NP was investigated by synchrotron radiation VUV aerosol photoemission spectroscopy. The results demonstrate that the overlap between the valence bands of Azo and Au NP is significant to allow for chare transfer process between the components in the nanosystem.",
publisher = "Belgrade : Institute of Physics",
journal = "16th Photonics Workshop : Book of abstracts",
title = "Valence Band Electronic Structure of Azobenzene-Functionalized Gold Nanoparticles",
pages = "51-51",
url = "https://hdl.handle.net/21.15107/rcub_vinar_13049"
}

Božanić, D., Pajović, J., Danilović, D., Chowdhury, M. R., Garcia, G., Nahon, L.,& Đoković, V.. (2023). Valence Band Electronic Structure of Azobenzene-Functionalized Gold Nanoparticles. in 16th Photonics Workshop : Book of abstracts
Belgrade : Institute of Physics., 51-51.
https://hdl.handle.net/21.15107/rcub_vinar_13049

Božanić D, Pajović J, Danilović D, Chowdhury MR, Garcia G, Nahon L, Đoković V. Valence Band Electronic Structure of Azobenzene-Functionalized Gold Nanoparticles. in 16th Photonics Workshop : Book of abstracts. 2023;:51-51.
https://hdl.handle.net/21.15107/rcub_vinar_13049 .

Božanić, Dušan, Pajović, Jelena, Danilović, Danijela, Chowdhury, Madhusree Roy, Garcia, Gustavo, Nahon, Laurent, Đoković, Vladimir, "Valence Band Electronic Structure of Azobenzene-Functionalized Gold Nanoparticles" in 16th Photonics Workshop : Book of abstracts (2023):51-51,
https://hdl.handle.net/21.15107/rcub_vinar_13049 .