Carbon dots are often synthesized in the presence of a carbon source and passivating agents in which they are crucial for an enhanced fluorescence. The solvent choice and/or combination to be used in the synthesis of these nanoparticles can influence their surface chemical composition, morphology, and fluorescence properties. In this study, highly fluorescent carbon dots were synthesized using deep eutectic solvents of different compositions as green solvent media and doping agent. Resulting carbon dots were then separated by their hydrophilicity/hydrophobicity using a three-phase solvent system (water/acetone/chloroform) and compared with traditional centrifugation-based separation method. Carbon dots with a size below 20 nm and quantum yield reaching 50% were obtained. Many properties of them including surface functional groups, optical, fluorescence, and electric properties were shown to be determined by the deep eutectic solvent composition.
Journal of Materials Science 53(4) (2018) DOI: 10.1007/s10853-018-2723-4
Multi-colored, water soluble fluorescent carbon nanodots (C-Dots) with quantum yield
changing from 4.6 to 18.3% were synthesized in multi-gram using dated cola beverage
through a simple thermal synthesis method and implemented as conductive and ion
donating supercapacitor component. Various properties of C-Dots, including size, crystal
structure, morphology and surface properties along with their Raman and electron
paramagnetic resonance spectra were analyzed and compared by means of their
fluorescence and electronic properties. α-Manganese Oxide-Polypyrrole (PPy) nanorods
decorated with C-Dots were further conducted as anode materials in a supercapacitor.
Reduced graphene oxide was used as cathode along with the dicationic bis-imidazolium
based ionic liquid in order to enhance the charge transfer and wetting capacity of …
Scientific Reportsvolume 7, Article number: 11222 (2017)
In this study, iron oxide (Fe 3 O 4) magnetic nanoparticles (MNPs) were loaded into poly (ε-
caprolactone)(PCL) nanofıber mats via electrospinning method and the composite materials
were characterized. MNPs were synthesized by a conventional co-precipitation method and
treated by oleic acid to obtain hydrophobic nanoparticles. The MNPs were added to PCL
solution before electrospinning at varying MNP feed concentrations (1: 25, 2: 25, 4: 25, 8: 25,
16: 25 and 32: 25; weight ratio of MNPs: polymer). The chemical structure of the nanofibrous
membranes was investigated by Fourier transform infrared spectroscopy (FTIR). Scanning
electron microscopy (SEM), and analyses by optical and confocal microscopes
demonstrated that MNP-loaded PCL nanofibers (MNP@ PCL NFs) were homogeneously
distributed in the membranes. Fiber diameter changed and bead formation occurred as …
Cite this article as:Demir, D., Güreş, D., Tecim, T. et al. Appl Nanosci (2018). https://doi.org/10.1007/s13204-018-0830-9
In this study, comparative evaluation of fluorescent carbon nanodots (C-Dots) prepared using carob molasses was reported by screening various biocompatible macromolecules as passivating agent (PA). Incorporation of PAs with different molecular weight, polarity, and chemical structure was examined, and compared with the polyethylene glycol (PEG, Mn = 10 kN) passivated and pristine C-Dots. Not only the fluorescence properties but also many other features including size, crystal structure, colloidal conductivity, resistance to photobleaching, quantum yield, and UV-modulated surface interaction of them with the reactive oxygen species (ROS) as well as ROS production were investigated. Photoluminescence (PL) capacity of C-Dots was found to be associated with the number of surface alkyl groups and polymeric hydrogen bonding present on the C-Dot surface (increased number is associated with decreased PL) while the surface conductivity of C-Dots in water was proportional to the PL intensity. More importantly, C-Dots with relatively poorer fluorescent were investigated in various organic solvents (hexane, methanol, acetone, ethanol, dimethylformamide (DMF), and DMSO). As happens with the fluorescent dyes, their PL intensities were significantly enhanced (even for pristine C-Dots) depending on the solvent characteristics. All of the C-Dots synthesized were further evaluated by means of UV-induced generation of ROS and inhibition of ROS by using H2O2 as a model. In contrary to other carbonaceous nanomaterials, they did not show any ROS generation, on the contrary, they showed ROS scavenging activity that can be modulated by UV-irradiation (λexc = 365 nm). PEG and alginate passivated C-Dots inhibited H2O2 activity at LC50 values below 10 mg/mL.
Cite this article as: Alas, M.O. & Genc, R. J Nanopart Res (2017) 19: 185. doi:10.1007/s11051-017-3863-1
In this research article , synthesis of fluorescent carbon nanoparticles from a natural carbon source, carob molasses, was investigated. To this end, thermal synthesis methodology as a green synthesis method with the easiness to carry out and being economical was followed and polyethylene glycol of different molecular weight (PEG Mn: 300~20000) was used as surface passivating agent. Synthesized fluorescent carbon nanoparticles (FCNPs) were then characterized by field emission scanning electron microscope (FE-SEM), transmission electron microsocope (TEM), X-Ray Diffraction Analysis (XRD), UV spectrophotometer, fluorescence spectrophotometer, dynamic light scattering (DLS) methods. Results showed that surface properties of nanoparticles and fluorescent properties as a result were found to be determined by the molecular weight of the passivation agent. Moreover, hydrodynamic size of nanoparticles with core diameter measured as 10-15 nm was also found to be increased with increased polymer Mn.
As a comprehensive resource on nanotechnology in the agri-food industry, this book presents the principles and safety applications of biosensor nanotechnology.
Sibel Barbaros, Zeynep Meray, Tugba Tecim, Rukan Genc*
In this study, hierarchical self-assembly of photocatalytic nanodisks through non-covalent interactions between spinach-extracted chlorophyll molecules and trimethylammonium hydroxide-coated magnetic iron oxide nanoparticles was discussed. Combination of chlorophyll molecules with iron oxide nanoparticles generated an alteration in light absorption at both visible and near-IR region with accompanying enhancement in fluorescence emission. Further, photocatalytic role of resulting molecular assembly was studied by means of the photoinduced degradation of methylene blue dye under UV light and direct sun irradiation at neutral pH. In order to enhance the long-term stability of the hybrid nanocatalyst, commercially available cellulose membrane was used as a support and magnetic recovery and reusability was achieved where the nanocatalyst retained more than 90 % of its efficiency even after four cycles. This simple strategy could initiate the development of new materials for wastewater treatment including membrane-based technologies. On the other hand, their sunlight-induced photocatalytic activity could easily be conducted to dye-synthesized solar cells or their enhanced photoluminescence can provide a strong basis for future bioimaging tools.
Sibel Barbaros, Rukan Genç*
Dokuz Eylul Universitesi Muhendislik Dergisi, 18(1) pp31-3., 2016, DOI:10.21205/deufmd.20165217543.
In this study, magnetic alginate beads were successfully synthesized by integrating superparamagnetic iron oxide nanoparticles (Fe3O4) in sodium alginate microbeads during the synthesis. The as-obtained dried samples were analyzed by means of their water detention capacity and drug encapsulation efficiency. Further, an anti-inflammatory drug (Cefazolin), mostly used for the treatment of joint inflammations after surgery, was used as a model drug in order to evaluate the stimuli-responsive properties of macrocomposites under magnetic field for the development of on-site drug delivery system. To do so, their drug release kinetics at changing environmental conditions, such as pH, temperature, and magnetic field were investigated and compared with bare alginate beads.