We designed a series of porous graphene as the separation membrane of H 2 /N 2 . The selectivity and permeability could be controlled by drilling various nanopores with different shapes and sizes. The mechanisms of hydrogen and nitrogen to permeate through the porous graphene are different. The small nanopore (pore-11) can only allow the hydrogen molecules to permeate due to the size restriction. In the systems of bigger nanopores (e.g., pore-13, pore-14, etc.), where the pore size is big enough to allow nitrogen molecules to permeate without any restriction, we observed more permeation events of nitrogen than that of hydrogen molecules. The reason is that the van der Waals interactions with the graphene membrane make the nitrogen molecules accumulate on the surface of graphene. When the pore size further increases, the flow of hydrogen molecules exhibits the linear dependence on the pore area, while there is no obvious correlation between the flow of nitrogen molecules and the pore area.

Carbon nanotubes are promising for use in biomedical and pharmaceutical sciences. Therefore, it becomes imperative to know the basic biological properties of carbon nanotubes in vivo. We labeled the water-soluble hydroxylated carbon single-wall nanotubes with radioactive 125I atoms, and then the tracer was used to study the distribution of hydroxylated carbon single-wall nanotubes in mice. They moved easily among the compartments and tissues of the body, behaving as small active molecules though their apparent mean molecular weight is tremendously large. This study, for the first time, affords a quantitative analysis of carbon nanotubes accumulated in animal tissues.

The broad potential applications of manufactured nanomaterials call for urgent assessment of their environmental and biological safety. However, most of the previous work focused on the cell level performance; little was known about the consequences of nanomaterial exposure at the whole-body and organ levels. In the present paper, the radiotracer technique was employed to study the pulmonary deposition and the translocation to secondary target organs after ceria nanoparticles (nano-ceria) were intratracheally instilled into Wistar rats. It was found that 63.9 +/- 8.2% of the instilled nano-ceria remained in the lung by 28 d postexposure and the elimination half-life was 103 d. At the end of the test period, only 1/8-1/3 of the daily elimination of nano-ceria from the lung was cleared via the gastrointestinal tract, suggesting that phagocytosis by alveolar macrophages (AMs) with subsequent removal towards the larynx was no longer the predominant route for the elimination of nano-ceria from the lung. The whole-body redistribution of nano-ceria demonstrated that the deposited nano-ceria could penetrate through the alveolar wall into the systemic circulation and accumulate in the extrapulmonary organs. In vitro study suggested that nano-ceria would agglomerate and form sediments in the bronchoalveolar aqueous surrounding while binding to protein would be conducive to the redispersion of nano-ceria. The decrease in the size of agglomerates might enhance the penetration of nano-ceria into the systemic circulation. Our findings suggested that the effect of nanomaterial exposure, even at low concentration, should be assessed because of the potential lung and systemic cumulative toxicity of the nanomaterials.

We functionalized double-walled carbon nanotubes (DWCNTs) as artificial water channel proteins. For the first time, molecular dynamics simulations show that the bilayer structure of DWCNTs is advantageous for carbon nanotube based transmembrane channels. The shielding of the amphiphilic outer layer could guarantee biocompatibility of the synthetic channel and protect the inner tube (functional part) from disturbance of the membrane environment. This novel design could promote more sophisticated nanobiodevices which could function in a bioenvironment with high biocompatibility.

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The relationship between stabilities and shape configurations of carbon and boron nitride (BN) nanographenes (NGs) was studied at the B3LYP/6-31G* level of theory. The HOMO-LUMO energy gaps of rectangularshaped carbon nanographenes (CNGs) decrease as the graphene sizes increase with a direct inverse dependence on the length of zigzag edge. Due to the double zigzag edge boundaries, the CNGs with long zigzag edges have open-shell singlet ground states; in contrast, the HOMO-LUMO energy gaps of BN nanographenes (BNNGs) have a weak dependence with size; all BNNGs have closed-shell singlet ground states, and those with long zigzag edges have slightly larger energy gaps. CNGs with long zigzag edges are less favorable energetically than their structural isomers with long armchair edges, while the BNNGs have the opposite preference. Chemical modifications that change the long zigzag edge into armchair type can efficiently stabilize the kinetically unstable CNGs (with open-shell singlet ground states) and modify their energy gaps.

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Traditional injection and extraction devices often appear painful and cumbersome for patients. In recent years, polymer microneedles (MNs) have become a novel tool in the field of clinical medicine and health. However, the cost of building MNs into any shapes still remains a challenge. In this paper, we proposed hydrogel microneedles fabricated by high-precision digital light processing (H-P DLP) 3D printing system. Benefits from the sharp protuberance and micro-porous of the hydrogel microneedle, the microneedle performed multifunctional tasks such as drug delivery and detection with minimally invasion. Critical parameters for the fabrication process were analyzed, and the mechanical properties of MNs were measured to find a balance between precision and stiffness. Results shows that the stiffness and precision were significantly influenced by exposure time of each layer, and optimized printing parameters provided a balance between precision and stiffness. Bio-compatible MNs based on our H-P DLP system was able to execute drug injection and drug detection in our experiments. This work provided a low-cost and fast method to build MNs with 3D building, qualified the mechanical performance, drug injection, drug detection ability of MNs, and may be helpful for the potential clinical application.