Carbon dots obtained using hydrothermal treatment of formaldehyde. Cell imaging in vitro

Abstract

Highly photoluminescent carbon dots have been prepared in a one step procedure by hydrothermal treatment of formaldehyde at 180 °C. They show green fluorescence under UV light exposure and emission spectra are centered at 440 nm. Fluorescence lifetimes comprise between 0.7 and 2.70 ns, when the synthesis process lasted for 1-7 days. TEM images of nanoparticles showed a homogeneous size/shape distribution. When the thermal treatment process was carried out for a long time (30 days) formation of aggregates occurred. Carbon dots were further analyzed using (1)H and (13)C-NMR, Raman and FTIR spectroscopy techniques and XPS. Cell imaging of nanoparticles was carried out by using mouse MC3T3-E1 pre-osteoblasts as a model. The nanoparticles were selectively localized in the cytoplasm without further functionalization and could be realized by cellular phagocytosis, so that the fluorescence of these can be used for live cell imaging in vitro.

Fluorescent chemosensor for pyridine based on N-doped carbon dots

“…This experimental condition was considered as the stock solutions of this material because its higher fluorescence intensity. The study of the interaction of different chemical species with the surface of N-CDs is widely reported in the literature [14,15]. It has revealed that the luminescence properties of these nanomaterials strongly depend on their surface atoms and their environment [60].…”

“…Thus, electrochemical, combustion, thermal, hydrothermal, acidic oxidation, microwave and ultrasonic, laser ablation, have been reported as techniques used for these purposes [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Although fluorescent CDs have easily been obtained by these strategies, emission features (in terms of sensitivity, meanly) and quantum yield (QY) of CDs are still scarce and highly desirable to be improved.…”

Fluorescence characteristics of carbon nanoemitters derived from sucrose by green hydrothermal and microwave methods

“…There are ample examples of green hydrothermal or microwave methods reports wherein natural precursor such as sweet potato, grass, pomelo peel, flour, strawberry juice, citrus lemon juice, and honey have been utilized for the preparation fluorescent CNPs [13][14][15][16][17][18][19]. On the other hand, using organic precursors such as formaldehyde, dopamine, saccharide, and ascorbic acid, limited green methods are reported for their preparation [20][21][22][23]. Organic precursors are mainly utilized with acid/alkali treatment, which makes the method environment unfriendly.…”

Synthesis of fluorescent carbon dots via microwave carbonization of citric acid in presence of tetraoctylammonium ion, and their application to cellular bioimaging

“…General synthetic methodologies of carbon dots can be categorized as top-down and bottom-up protocols [16,18]. The top-down approach consists of laser ablation, arc discharge, acid dehydration, and electrochemical oxidation from carbon source [19].…”