We demonstrate that nano-hydrophobicity, which governs the biological aggressiveness of nanoparticles, is determined by the outermost regions of surface ligands. We have also successfully modulated nano-hydrophobicity using systematic surface ligand modifications and built the first computational model of nano-hydrophobicity.
Sulfamethoxazole (SMX) was used as a model substrate for electrochemical oxidation at a boron-doped diamond anode in the presence of chloride ion, which is present in many waste streams. In the absence of chloride, oxidation of SMX involves mineralization, an electrochemical advanced oxidation process (EAOP) that is initiated by attack of anode-derived hydroxyl radicals. The rate of disappearance of SMX increased monotonically upon addition of chloride ion but without inhibiting mineralization in the early stages of oxidation. This demonstrated that electrochemical hypochlorination (EH) and EAOP are not mutually exclusive reaction pathways; products of EH can undergo EAOP and vice versa. Persistent chlorinated byproducts were formed in the presence of chloride ion, indicating that chloride is a significant detriment to the success of EAOP. No mineralization was observed upon chemical hypochlorination of SMX with sodium hypochlorite.
Pharmaceutical residues in the aquatic environment represent an emerging environmental problem, because many pharmaceuticals are refractory towards conventional waste water treatment. This study focussed on the oxidation of the sulfonamide antibiotic sulfamethoxazole (SMX) at a boron-doped diamond anode, at which reactive hydroxyl radicals are formed. Electrochemical oxidation led to mineralization with high current efficiency, but without the formation of known toxic products of partial oxidation. A ''mixed'' kinetic order with respect to substrate concentration was observed; the kinetics could be shifted in the direction of either diffusion control (first order in SMX) or current control (zero order in SMX) by adjusting the substrate concentration and current density. Alternatively, the electrooxidation could be described by a model, applicable to a wide range of reaction conditions, in which the kinetic orders with respect to current and initial substrate concentration were approximately 0.4 and 0.5, respectively.
Core−shell nanostructures, specifically gold nanorods coated with porous silica (GNR@p-SiO 2 ), were successfully fabricated by surface-protected etching. The nanostructures, photothermal effects, drug loading and drug release behaviors, cellular uptake, and combined chemo− photothermal therapy were investigated. The results showed that the as-prepared GNR@p-SiO 2 had a uniform porous silica outer layer. Etching process could be modulated by adjusting the etching time, concentrations of etching agents, and concentrations of protective agents. With doxorubicin (DOX) as the model drug, the drug loading capacity reached 18.9%, which was dependent on the DOX concentrations. The drug release profiles were dual stimulus-responsive to pH and laser irradiation. In addition, the GNR@p-SiO 2 nanoparticles were biocompatible and effectively internalized by cancer cells. Compared with chemotherapy or photothermal therapy administered individually, combined chemo−photothermal therapy using GNR@p-SiO 2 exhibited higher efficiency in killing cancer cells both in vitro and in vivo. Therefore, surface-protected etching is a powerful method for preparing core−shell nanostructures capped with mesoporous silica for combined cancer chemo−photothermal therapy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.