Hierarchical Composite Nanoarchitectonics with a Graphitic Core, Dendrimer and Fluorocarbon Domains, and a Poly(ethylene glycol) Shell as O₂ Reservoirs for Reactive Oxygen Species Production

Abstract

Graphene oxide (GO), single-walled carbon nanohorn (CNHox), and nitrogen-doped CNH (N-CNH) were functionalized with fluorinated poly(ethylene glycol) (F-PEG) and/or with a fluorinated dendrimer (F-DEN) to prepare a series of assembled nanocomposites (GO/F-PEG, CNHox/F-PEG, N-CNH/F-PEG, N-CNH/F-DEN, and N-CNH/F-DEN/F-PEG) that provide effective multisite O 2 reservoirs. In all cases, the O 2 uptake increased with time and saturated after 10−20 min. When graphitic carbons (GO and CNHox) were coated with F-PEG, the O 2 uptake doubled. The O 2 loading was slightly higher in N-CNH compared to CNHox. Notably, coating N-CNH with F-DEN or F-PEG, or with both F-DEN and F-PEG, was more effective. The best performance was obtained with the N-CNH/F-DEN/F-PEG nanocomposite. The O 2 uptake kinetics and mechanisms were analyzed in terms of the Langmuir adsorption equation based on a multibinding site assumption. This allowed the precise determination of multiple oxygen binding sites, including on the graphitic structure and in the dendrimer, F-DEN, and F-PEG. After an initial rapid, relatively limited release, the amount of O 2 trapped in the nanomaterials remained high (>95%). This amount was marginally lower for the functionalized composites, but the oxygen stored was reserved for longer times. Finally, it is shown that these systems can generate singlet oxygen after irradiation by a light-emitting diode, and this production correlates with the amount of O 2 loaded. Thus, it was anticipated that the present nanocomposites hierarchically assembled from components with different characters and complementary affinities for oxygen can be useful as O 2 reservoirs for singlet oxygen generation to kill bacteria and viruses and to perform photodynamic therapy.

Higher-order mesoscopic self-assembly of fluorinated surfactants on water surfaces

“…As shown in Fig. 6c, the self-assembly of oleophobic fluoroalkyl moieties can further be used to design even more complex composite nanomaterials by coating graphene oxide (GO) or oxidized single-walled carbon "nanohorn" with the layers of (i) fluorinated dendrimer (F-DEN) and (ii) fluorinated poly(ethylene glycol) (F-PEG) 87 . The various components/building blocks contribute additively to O 2 adsorption, and the highest O 2loading capacity attained by the combination of nanohorns coated with F-DEN and F-PEG.…”

“…These nanocomposites have proven efficacy as O 2 reservoirs for reactive oxygen species production to kill bacteria and perform photodynamic therapy. Adapted from ref 87. .…”

About Perfluoropolyhedranes, Their Electron‐Accepting Ability and Questionable Supramolecular Hosting Capacity

“…Fluorinated graphene has an application potential in gas-sensing devices [168] and as potential O 2 reservoirs for oxygen radical generation. [169]…”

“…Microbubbles coated with fluorinated nanodiamonds could thus be prepared with potential in nanomedicine. Fluorinated graphene has an application potential in gas‐sensing devices [168] and as potential O 2 reservoirs for oxygen radical generation [169] …”

Chemistry of Materials Nanoarchitectonics for Two-Dimensional Films: Langmuir–Blodgett, Layer-by-Layer Assembly, and Newcomers

“…Unit processes include chemical and physical material transformation (including organic synthesis), manipulation of atoms, molecules, and nanomaterials, self-assembly and self-organization, alignment and orientation by external forces and fields, nanofabrication/microfabrication, and biological processes. Some of these processes are selected and combined to architect materials and structures. , In many cases, it is more suitable for forming hierarchical structures − than structure building by self-assembly using single equilibrium processes. Especially, phenomena and properties for materials in the nanoscale often show much different features from those observed in macroscopic materials.…”