We report on the synthesis of bimodal, structured silicas by a fully chemical, templating−scaffolding route that enables independent control over small and large mesopore sizes. Mesoporous MCM-41 nanoparticles, synthesized in a first step, are cross-linked in a second step, leading to a bimodal porous material. Triblock copolymer surfactants added during the second synthesis step form assemblies, around which the nanoparticles aggregate and cross-link, considerably influencing both the average and the width of the secondary pore size distribution, without affecting the primary pore size. By changing the conditions of the second step, one can easily synthesize a broad variety of silicas with a controlled bimodal nanopore size distribution. Textural and structural properties were characterized by X-ray diffraction, high-resolution transmission electron microscopy, scanning electron microscopy, 29Si solid-state NMR spectroscopy, N2 adsorption and desorption, and thermogravimetric analysis.

Single-walled carbon nanotubes (SWCNTs) are broadly used for various biomedical applications such as drug delivery, in vivo imaging and cancer photothermal therapy due to their unique physiochemical properties. However, once they enter the cells, the effects of SWCNTs to the intracellular organelles and macromolecules are not comprehensively understood. Cytochrome c (Cyt c), as a key component of the electron transport chain in mitochondria, plays an essential role in cellular energy consumption, growth and differentiation. In this study, we found the mitochondrial membrane potential (MMP) and mitochondrial oxygen uptake were greatly decreased in human epithelial KB cells treated with SWCNTs, which accompanies the reduction of Cyt c. SWCNTs deoxidized Cyt c in a pH dependent manner as evidenced by the appearance of a 550 nm characteristic absorption peak, which intensity increased as pH increase. Circular dichroism measurement confirmed the pH-dependent conformational change, which facilitated closer association of SWCNTs with the heme pocket of Cyt c and thus expedited the reduction of Cyt c. The electron transfer of Cyt c is also disturbed by SWCNTs, as measured with electron spin resonance spectroscopy. In conclusion, the redox activity of Cyt c was affected by SWCNTs treatment due to attenuated electron transfer and conformational change of Cyt c, which consequently changed mitochondrial respiration of SWCNTs treated cells. This work is significant to SWCNTs research because it provided novel understanding to the disruption of SWCNTs to the mitochondria and has important implications for biomedical applications of SWCNTs.

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A new synthesis method is presented to prepare multistructured porous materials through a fully chemical route that allows control of the smaller and larger mesopore sizes independently.

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Aluminum hydroxide is used as a vaccine adjuvant in various human vaccines. Unfortunately, despite its favorable safety profile, aluminum hydroxide can only weakly or moderately potentiate antigen-specific antibody responses. When dispersed in an aqueous solution, aluminum hydroxide forms particulates of 1–20 µm. There is increasing evidence that nanoparticles around or less than 200 nm as vaccine or antigen carriers have a more potent adjuvant activity than large microparticles. In the present study, we synthesized aluminum hydroxide nanoparticles of 112 nm. Using ovalbumin and Bacillus anthracis protective antigen protein as model antigens, we showed that protein antigens adsorbed on the aluminum hydroxide nanoparticles induced a stronger antigen-specific antibody response than the same protein antigens adsorbed on the traditional aluminum hydroxide microparticles of around 9.3 µm. The potent adjuvant activity of the aluminum hydroxide nanoparticles was likely related to their ability to more effectively facilitate the uptake of the antigens adsorbed on them by antigen-presenting cells. Finally, the local inflammation induced by aluminum hydroxide nanoparticles in the injection sites was milder than that induced by microparticles. Simply reducing the particle size of the traditional aluminum hydroxide adjuvant into nanometers represents a novel and effective approach to improve its adjuvanticity.

The interest in the design and controllable fabrication of hollow carbon spheres (HCSs) emanates from their tremendous potential applications in adsorption, energy conversion and storage, and catalysis. However, the effective synthesis of uniform HCSs with high surface area and abundant micropores remains a challenge. In this work, HCSs with tunable microporous shells were rationally synthesized via the hard-template method using resorcinol (R) and formaldehyde (F) as a carbon precursor. HCSs with a very high surface area (1369 m/g) and abundant micropores (0.53 cm/g) can be obtained with the assistance of additional inorganic silanes (TEOS) simultaneously with the carbon source (RF). Interestingly, the extra-abundant micropores showed favorable adsorption for CO, resulting in a 1.5 times increase in the CO adsorption capacity compared to that of normal HCSs under the same conditions. Meanwhile, these HCSs hold potential for use in the separation of gases such as CO and N.