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 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.
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.