TY - JOUR
T1 - Facile synthesis of L-cysteine functionalized graphene quantum dots as a bioimaging and photosensitive agent
AU - Milenković, Mila
AU - Mišović, Aleksandra
AU - Jovanović, Dragana
AU - Bijelić, Ana Popović
AU - Ciasca, Gabriele
AU - Romanò, Sabrina
AU - Bonasera, Aurelio
AU - Mojsin, Marija
AU - Pejić, Jelena
AU - Stevanović, Milena
AU - Jovanović, Svetlana
PY - 2021
Y1 - 2021
N2 - Nowadays, a larger number of aggressive and corrosive chemical reagents as well as toxic solvents are used to achieve structural modification and cleaning of the final products. These lead to the production of residual, waste chemicals, which are often reactive, cancerogenic, and toxic to the environment. This study shows a new approach to the modification of graphene quantum dots (GQDs) using gamma irradiation where the usage of reagents was avoided. We achieved the incorporation of S and N atoms in the GQD structure by selecting an aqueous solution of L-cysteine as an irradiation medium. GQDs were exposed to gamma-irradiation at doses of 25, 50 and 200 kGy. After irradiation, the optical, structural, and morphological properties, as well as the possibility of their use as an agent in bioimaging and photodynamic therapy, were studied. We measured an enhanced quantum yield of photoluminescence with the highest dose of 25 kGy (21.60%). Both S- and N-functional groups were detected in all gamma-irradiated GQDs: amino, amide, thiol, and thione. Spin trap electron paramagnetic resonance showed that GQDs irradiated with 25 kGy can generate singlet oxygen upon illumination. Bioimaging on HeLa cells showed the best visibility for cells treated with GQDs irradiated with 25 kGy, while cytotoxicity was not detected after treatment of HeLa cells with gamma-irradiated GQDs.
AB - Nowadays, a larger number of aggressive and corrosive chemical reagents as well as toxic solvents are used to achieve structural modification and cleaning of the final products. These lead to the production of residual, waste chemicals, which are often reactive, cancerogenic, and toxic to the environment. This study shows a new approach to the modification of graphene quantum dots (GQDs) using gamma irradiation where the usage of reagents was avoided. We achieved the incorporation of S and N atoms in the GQD structure by selecting an aqueous solution of L-cysteine as an irradiation medium. GQDs were exposed to gamma-irradiation at doses of 25, 50 and 200 kGy. After irradiation, the optical, structural, and morphological properties, as well as the possibility of their use as an agent in bioimaging and photodynamic therapy, were studied. We measured an enhanced quantum yield of photoluminescence with the highest dose of 25 kGy (21.60%). Both S- and N-functional groups were detected in all gamma-irradiated GQDs: amino, amide, thiol, and thione. Spin trap electron paramagnetic resonance showed that GQDs irradiated with 25 kGy can generate singlet oxygen upon illumination. Bioimaging on HeLa cells showed the best visibility for cells treated with GQDs irradiated with 25 kGy, while cytotoxicity was not detected after treatment of HeLa cells with gamma-irradiated GQDs.
KW - atomic force microscopy
KW - bioimaging
KW - photoluminescence
KW - graphene quantum dots
KW - photodynamic therapy
KW - gamma irradiation
KW - atomic force microscopy
KW - bioimaging
KW - photoluminescence
KW - graphene quantum dots
KW - photodynamic therapy
KW - gamma irradiation
UR - http://hdl.handle.net/10807/231504
U2 - 10.3390/nano11081879
DO - 10.3390/nano11081879
M3 - Meeting Abstract
SN - 2079-4991
VL - 11
SP - 1879
EP - 1879
JO - Nanomaterials
JF - Nanomaterials
ER -