A simple and efficient process for the synthesis of 2D carbon nitrides and related materials

We describe here a new process for the synthesis of very high quality 2D Covalent Organic Frameworks (COFs), such a C2N and CN carbon nitrides. This process relies on the use of a metallic surface as both a reagent and a support for the coupling of small halogenated building blocks. The conditions of the assembly reaction are chosen so as to leave the inorganic salts by-products on the surface, to further confine the assembly reaction on the surface and increase the quality of the 2D layers. We found that under these conditions, the process directly returns few layers material. The structure/quality of these materials is demonstrated by extensive cross-characterizations at different scales, combining optical microscopy, Scanning Electron Microscopy (SEM)/Transmission Electron Microscopy (TEM) and Energy Dispersive Spectroscopy (EDS). The availability of such very large, high-quality layers of these materials opens interesting perspectives, for example in photochemistry and electronics (intrinsic transport properties, high gap substrate for graphene, etc...).

η-Carbides (Co, Mo, or W) Nanoparticles from Octacyanometalates Precursors-Based Network

This paper describes a simple, two-steps chemical pathway to obtain bimetallic carbide nanoparticles (NPs) of general formula MxM″yC, also called η-carbides. This process allows for a control of the chemical composition of metals present in the carbides (M = Co and M″ = Mo or W). The first step involves the synthesis of a precursor consisting of a network of octacyanometalates. The second step consists in a thermal degradation of the previously obtained octacyanometalates networks under neutral atmosphere (Ar or N2 ). It is shown that this process results in the formation of carbide NPs with diameter of ≈ 5nm, and the stoichiometries Co3 M'3 C, Co6 M'6 C, Co2 M'4 C for the CsCoM' systems.

Synthesis of functional tetrathiafulvalene-terpyridine dyad for metal cation recognition

A new protected hydroxyl functionalized TTF derivative with an effective electronic communication between the TTF moiety and the Terpy unit for optical and electrochemical sensors.

Uptake and transcytosis of functionalized superparamagnetic iron oxide nanoparticles in an in vitro blood brain barrier model

Two major hurdles in nanomedicine are the limited strategies for synthesizing stealth nanoparticles and the poor efficacy of the nanoparticles in translocating across the blood brain barrier (BBB). Here we examined the uptake and transcytosis of iron oxide nanoparticles (IONPs) grafted with biomimetic phosphorylcholine (PC) brushes in an in vitro BBB model system, and compared them with bare, PEG or PC-PEG mixture grafted IONPs. Hyperspectral imaging indicated IONP co-localization with cells. Quantitative analysis with total reflection X-ray fluorescence spectrometry showed that after 24 h, 78% of PC grafted, 68-69% of PEG or PC-PEG grafted, and 30% of bare IONPs were taken up by the BBB. Transcytosis of IONPs was time-dependent and after 24 h, 16-17% of PC or PC-PEG mixture grafted IONPs had passed the BBB model, significantly more than PEG grafted or bare IONPs. These findings point out that grafting of IONPs with PC is a viable strategy for improving the uptake and transcytosis of nanoparticles.

Human plasma proteome association and cytotoxicity of nano-graphene oxide grafted with stealth polyethylene glycol and poly(2-ethyl-2-oxazoline)

Polyethylene glycol (PEG) is a gold standard against protein fouling. However, recent studies have revealed surprising adverse effects of PEG, namely its immunogenicity and shortened bio-circulation upon repeated dosing. This highlights a crucial need to further examine 'stealth' polymers for controlling the protein 'corona', a new challenge in nanomedicine and bionanotechnology. Poly(2-ethyl-2-oxazoline) (PEtOx) is another primary form of stealth polymer that, despite its excellent hydrophilicity and biocompatibility, has found considerably less applications compared with PEG. Herein, we performed label-free proteomics to compare the associations of linear PEG- and PEtOx-grafted nano-graphene oxide (nGO) sheets with human plasma proteins, complemented by cytotoxicity and haemolysis assays to compare the cellular interactions of these polymers. Our data revealed that nGO-PEG enriched apolipoproteins, while nGO-PEtOx displayed a preferred binding with pro-angiogenic and structural proteins, despite high similarities in their respective top-10 enriched proteins. In addition, nGO-PEG and nGO-PEtOx exhibited similar levels of enrichment of complement proteins. Both PEG and PEtOx markedly reduced nGO toxicity to HEK 293 cells while mitigating nGO haemolysis. This study provides the first detailed profile of the human plasma protein corona associated with PEtOx-grafted nanomaterials and, in light of the distinctions of PEtOx in chemical adaptability, in vivo clearance and immunogenicity, validates the use of PEtOx as a viable stealth alternative to PEG for nanomedicines and bionanotechnologies.

Thermoresponsive hybrid double-crosslinked networks using magnetic iron oxide nanoparticles as crossing points

Preparation and characterization of stimuli-sensitive hybrid double-crosslinked hydrogels based on iron oxide nanoparticles as the nano-crosslinkers and a difuran-functionalized PEO as the diene partner for the thermoreversible Diels–Alder reaction.

Brushed polyethylene glycol and phosphorylcholine for grafting nanoparticles against protein binding

To provide a molecular insight for guiding polymer coating in surface science and nanotechnology, here we examined the structures of brushed polyethylene glycol(bPEG)- and phosphorylcholine(bPC)-grafted iron oxide nanoparticles and analyzed their protein avoiding properties. We show bPC as an advantageous biomimetic alternative to PEG in rendering stealth nanostructures.

Synthesis and in vitro properties of iron oxide nanoparticles grafted with brushed phosphorylcholine and polyethylene glycol

A new and facile strategy for grafting IONPs by phosphonic acic terminated PC brushes has been demonstrated and characterized in vitro.