Facile scalable one-flow synthesis of ionizable cationic lipid library as precursors of nanoparticle carriers.

A variety of ionizable and cationic lipids have been synthesized as precursors for nanoparticle carriers. However, the laborious synthetic routes in batch reactors often involve the use of toxic and carcinogenic agents, as well as challenge of removing gaseous byproducts. In this study, we present facile one-flow micro-reaction process that enables the synthesis of 11 ionizable lipids as well as 7 cationic lipids, including the well-known DODAP and DOTAP. These lipids can be scaled up to produce approximately ∼10g/h by using a straightforward size-up approach. The development of the lipid library was involved generating highly moisture-sensitive acyl chloride at 25 °C for 1.5 min. The toxic byproducts such as HCl, CO2 and CO were subsequently removed using a liquid-gas separator. The esterification with dimethylamino-1,2-diol at 25 °C for 3 min, monitored in-line with FTIR, completed the process. Additionally, the synthesized ionizable lipids were converted to cationic lipids with methyl sulfate, chloride ions via dimethyl sulfate and Steglich esterification in a continuous flow system. Finally, the produced DODAP was transformed into a uniform-sized LNPs (64 nm, PDI 0.07) and liposomal nanoparticles (72 nm, PDI 0.05) while DOTAP was converted to liposomes (55 nm, PDI 0.08) using a custom micro-mixer. This efficient platform for lipid synthesis significantly contributes to the practical applications of lipid-based nanomedicines.

Production of H2-Free Carbon Monoxide from Formic Acid Dehydration: The Catalytic Role of Acid Sites in Sulfated Zirconia.

The formic acid (CH2O2) decomposition over sulfated zirconia (SZ) catalysts prepared under different synthesis conditions, such as calcination temperature (500-650 °C) and sulfate loading (0-20 wt.%), was investigated. Three sulfate species (tridentate, bridging bidentate, and pyrosulfate) on the SZ catalysts were characterized by using temperature-programmed decomposition (TPDE), Fourier-transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The acidic properties of the SZ catalysts were investigated by the temperature-programmed desorption of iso-propanol (IPA-TPD) and pyridine-adsorbed infrared (Py-IR) spectroscopy and correlated with their catalytic properties in formic acid decomposition. The relative contributions of Brønsted and Lewis acid sites to the formic acid dehydration were compared, and optimal synthetic conditions, such as calcination temperature and sulfate loading, were proposed.

Rapid Single-Step Growth of MOF Exoskeleton on Mammalian Cells for Enhanced Cytoprotection.

Mammalian cells are promising agents for cell therapy, diagnostics, and drug delivery. For full utilization of the cells, development of an exoskeleton may be beneficial to protecting the cells against the environmental stresses and cytotoxins to which they are susceptible. We report here a rapid single-step method for growing metal-organic framework (MOF) exoskeletons on a mammalian cell surface under cytocompatible conditions. The MOF exoskeleton coating on the mammalian cells was developed via a one-pot biomimetic mineralization process. With the exoskeleton on, the individual cells were successfully protected against cell protease (i.e., Proteinase K), whereas smaller-sized nutrient transport across the exoskeleton was maintained. Moreover, vital cellular activities mediated by transmembrane GLUT transporter proteins were also unaffected by the MOF exoskeleton formation on the cell surfaces. Altogether, this ability to control the access of specific molecules to a single cell through the porous exoskeleton, along with the cytoprotection provided, should be valuable for biomedical applications of mammalian cells.

Rational Design of Pomegranate-like Base-Acid Bifunctional ß Zeolite by Steam-Assisted Crystallization for the Tandem Deacetalization-Knoevenagel Condensation.

A highly crystalline pomegranate-like base-acid bifunctional beta zeolite was successfully synthesized by the steam-assisted crystallization method using a basic nitrided N-beta as the starting material. The secondary crystal growth of a beta zeolite generating acid functionality occurred over the outer surface and intercrystalline void spaces of the N-beta zeolite. The pomegranate-like N-beta@H-beta zeolite had a high surface area and base-acid dual functionality because of the well-connected framework topologies of the H-beta and N-beta crystallites. The N-beta@H-beta zeolite exhibited a superior yield of benzylidenemalononitrile during the tandem deacetalization-Knoevenagel condensation of benzaldehyde dimethyl acetal and malononitrile compared to H-beta, N-beta, and their physical mixture. This is likely due to the isolated and balanced activity of the base- and acid-catalyzed reactions.