Recent Article Published: An investigation into the role of macromolecules of different polarity as passivating agent on the physical, chemical and structural properties of fluorescent carbon nanodots

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.

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Cite this article as: Alas, M.O. & Genc, R. J Nanopart Res (2017) 19: 185. doi:10.1007/s11051-017-3863-1

Recent Article Published: Shape directed biomineralization of gold nanoparticles using self-assembled lipid structures

Rukan Genc*, Gael Clergeaud, Mayreli Ortiz and Ciara O’Sullivan*

Biomater. Sci., 2014, Advance Article DOI: 10.1039/C4BM00025K, Paper 

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As one of the building blocks of the cell membrane, lipids and their interaction with neighboring lipids and other molecules, as well as their ability to form different kinds of structures, have garnered immense interest. By exploiting the effective shape and thermal-phase behavior of lipids, we have prepared lipid superstructures such as twisted ribbons and rectangular and hexagonal shaped lipidic nanostructures using the curvature tuned preparation method. These lipidic superstructures were then used as nanoreactor templates for the inorganic synthesis of diversely shaped and sized gold nanostructures exploring different administration routes of reducing agents, citrate, and tetrachloroauric acid, which as a result formed different organizations of gold nanoparticles aligned and guided by the template structure. Tailor-designed metallic nanostructures can be obtained through a careful selection of lipids and conditions for lipid superstructure preparation and their consequent use as template nanoreactors. The diversely sized and shaped gold nanostructures obtained have great potential for catalysis and plasmonics.