Incorporation of a high density of molecular-sieving nanopores in the graphene lattice by the bottom-up synthesis is highly attractive for high-performance membranes. Herein, we achieve this by a controlled synthesis of nanocrystalline graphene where incomplete growth of a few nanometer-sized, misoriented grains generates molecular-sized pores in the lattice. The density of pores is comparable to that obtained by the state-of-the-art postsynthetic etching (1012 cm−2) and is up to two orders of magnitude higher than that of molecular-sieving intrinsic vacancy defects in single-layer graphene (SLG) prepared by chemical vapor deposition. The porous nanocrystalline graphene (PNG) films are synthesized by precipitation of C dissolved in the Ni matrix where the C concentration is regulated by controlled pyrolysis of precursors (polymers and/or sugar). The PNG film is made of few-layered graphene except near the grain edge where the grains taper down to a single layer and eventually terminate into vacancy defects at a node where three or more grains meet. This unique nanostructure is highly attractive for the membranes because the layered domains improve the mechanical robustness of the film while the atom-thick molecular-sized apertures allow the realization of large gas transport. The combination of gas permeance and gas pair selectivity is comparable to that from the nanoporous SLG membranes prepared by state-of-the-art postsynthetic lattice etching. Overall, the method reported here improves the scale-up potential of graphene membranes by cutting down the processing steps.

Targeted and efficient delivery of drug to tumor is one of the crucial issues in cancer therapy. In this work, we have successfully designed and prepared the pH-sensitive magnetic nanoparticles (MNPs) as targeted anticancer drug carriers, in which the MNPs were coated by poly(acrylic acid) (PAA) and the obtained PAA@MNPs exhibited a size within 100 nm, good stability, and superparamagnetic responsibility (Ms 45.97 emu/g). Doxorubicin (DOX) can be successfully loaded onto MNPs via electrostatic interaction, and the drug loading content and loading efficiency are 26.4 and 88.1%, respectively. Moreover, the release studies showed that the drug-loaded carriers (MNPs-DOX) had excellent pH sensitivity, 75.6% of the loaded DOX was released at pH 4.0 within 48 h. Importantly, MTT assays in HUVEC and MCF-7 cells demonstrated that MNPs-DOX exhibited high anti-tumor activity, while the PAA@MNPs were practically nontoxic. Thus, our results revealed that PAA@MNPs would be a competitive candidate for biomedical application and MNPs-DOX could be used in targeted cancer therapy.

We have developed a drug-loaded, pHsensitive, nano-magnetic targeted system (DPNTS) for delivering doxorubicin (DOX) to tumor tissues through a facile route. Iron oxide (Fe 3 O 4 ) nanoparticles were used as magnetically-responsive carriers, polyethyleneglycol (PEG) as the surface-modifying agent, and polyethyleneimine (PEI) as the drugloading site whose primary amine reacts with the 13-carbonyl of DOX. The prepared DPNTS was within 20 nm and had good stability in dispersion and superparamagnetic properties. DOX was grafted to PEG/PEI@Fe 3 O 4 at up to 85 %. During in vitro release studies, nearly 81 % DOX was released from DPNTS within 72 h at pH 4.5, compared with only 28 % at pH 7.4.

Bacterial infections endure considerable morbidity and expensive healthcare costs. The prescription of broad-spectrum antimicrobial drugs results in the failure treatment or overtreatment and exacerbates the spread of multidrug-resistant pathogens. There...

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