Totally Phospholipidic Mesoporous Particles

Medical science is one of the areas where mesoporous materials can offer important advances despite the stringent safety requirements for potentially useful materials. Here we report totally phospholipidic mesoporous particles which may be used as a novel drug carrier. This material is anticipated to be safe for human internal use since it is composed solely of phosphatidylcholine (PC) which is a major component of biological membranes and is approved for use in humans by the US Food and Drug Administration (FDA). We have established a simple production methodology of mesoporous phospholipid particles (MPPs) in which PC is dissolved in two-component solvent mixtures, followed by incubation of the resulting solutions at depressed temperatures, which induces liquid–liquid demixing and leads to the agglomeration of PC as spherical particles. A mesoporous form was then obtained by removing ice crystals through freeze-drying of the particles. MPP could accommodate both hydrophilic and hydrophobic guest molecules in the lamellar structure and the mesopores. It might be applied as a novel drug carrier in a complementary or even a replacement technology of liposomes

Molecular Complex Composed of β‑Cyclodextrin-Grafted Chitosan and pH-Sensitive Amphipathic Peptide for Enhancing Cellular Cholesterol Efflux under Acidic pH

Excess of cholesterol in peripheral cells is known to lead to atherosclerosis. In this study, a molecular complex composed of β-cyclodextrin-grafted chitosan (BCC) and cellular cholesterol efflux enhancing peptide (CEEP), synthesized by modifying pH sensitive amphipathic GALA peptide, is introduced with the eventual aim of treating atherosclerosis. BCC has a markedly enhanced ability to induce cholesterol efflux from cell membranes compared to β-cyclodextrin, and the BCC-CEEP complex exhibited a 2-fold increase in cellular cholesterol efflux compared to BCC alone under weakly acidic conditions. Isothermal titration calorimetry and fluorescence spectroscopy measurements demonstrated that the random coil structure of CEEP at neutral pH converted to the α-helical structure at acidic pH, resulting in a three-order larger binding constant to BCC (<i>K</i> = 3.7 × 10⁷ at pH 5.5) compared to that at pH 7.4 (<i>K</i> = 7.9 × 10⁴). Such high-affinity binding of CEEP to BCC at acidic pH leads to the formation of 100-nm-sized aggregate with positive surface charge, which would efficiently interact with cell membranes and induce cholesterol efflux. Since the cholesterol efflux ability of HDL is thought to be impaired under acidic environments in advanced atherosclerotic lesions, the BCC-CEEP complex might serve as a novel nanomaterial for treating atherosclerosis

Nanoporous Carbon Sensor with Cage-in-Fiber Structure: Highly Selective Aniline Adsorbent toward Cancer Risk Management

Carbon nanocage-embedded nanofibrous film works as a highly selective adsorbent of carcinogen aromatic amines. By using quartz crystal microbalance techniques, even ppm levels of aniline can be repetitively detected, while other chemical compounds such as water, ammonia, and benzene give negligible responses. This technique should be applicable for high-throughput cancer risk management