Improvement of DNA Vector Delivery of DOTAP Lipoplexes by Short-Chain Aminolipids.

Cellular delivery of DNA vectors for the expression of therapeutic proteins is a promising approach to treat monogenic disorders or cancer. Significant efforts in a preclinical and clinical setting have been made to develop potent nonviral gene delivery systems based on lipoplexes composed of permanently cationic lipids. However, transfection efficiency and tolerability of such systems are in most cases not satisfactory. Here, we present a one-pot combinatorial method based on double-reductive amination for the synthesis of short-chain aminolipids. These lipids can be used to maximize the DNA vector delivery when combined with the cationic lipid 1,2-dioleoyl-3-trimethylammonium propane (DOTAP). We incorporated various aminolipids into such lipoplexes to complex minicircle DNA and screened these systems in a human liver-derived cell line (HuH7) for gene expression and cytotoxicity. The lead aminolipid AL-A12 showed twofold enhanced gene delivery and reduced toxicity compared to the native DOTAP:cholesterol lipoplexes. Moreover, AL-A12-containing lipoplexes enabled enhanced transgene expression in vivo in the zebrafish embryo model.

Enhanced Base-Free Formic Acid Production from CO2 on Pd/g-C3 N4 by Tuning of the Carrier Defects.

CO2 hydrogenation is attracting increasing attention as a sustainable route to produce formic acid, a commodity and potential energy vector. Here, bifunctional catalysts comprising metal nanoparticles deposited on bulk graphitic carbon nitride were assessed under base-free conditions, identifying supported Pd as the best performer. The catalyst productivity was enhanced by maximizing the edge-defects of the g-C3 N4 carrier, amino groups able to activate CO2 , and by generating welldispersed 5 nm Pd particles, required to split H2 . Bottom-up synthesis methods, that is, hard-templating and carbon enrichment upon polymerization, and top-down strategies, that is, thermal exfoliation of the as-prepared solid, were explored to boost the defects, the nature and density of which were evaluated by thermal and (in situ) spectroscopic techniques. After optimization of temperature, pressure, and reaction time, a 20 times higher turnover frequency compared with the best Pd/g-C3 N4 catalyst reported producing formic acid from CO2 without base was attained. This activity level was retained upon recycling with intermediate catalyst regeneration at mild temperature.

Straightforward Synthesis of 2- and 2,8-Substituted Tetracenes.

A simple regiospecific route to otherwise problematic substituted tetracenes is described. The diverse cores (E)-1,2-Ar1 CH2 (HOCH2 )C=C(CH2 OH)I (Ar1 =Ph, 4-MePh, 4-MeOPh, 4-FPh) and (E)-1,2-I(HOCH2 )C=C(CH2 OH)I, accessed from ultra-low cost HOCH2 C≡CCH2 OH at multi-gram scales, allow the synthesis of diol libraries (E)-1,2-Ar1 CH2 (HOCH2 )C=C(CH2 OH)CH2 Ar2 (Ar2 =Ph, 4-MePh, 4-iPrPh, 4-MeOPh, 4-FPh, 4-BrPh, 4-biphenyl, 4-styryl; 14 examples) by efficient Negishi coupling. Copper-catalysed aerobic oxidation cleanly provides dialdehydes (E)-1,2-Ar1 CH2 (CHO)C=C(CHO)CH2 Ar2 , which in many cases undergo titanium(IV) chloride-induced double Bradsher closure, providing a convenient method for the synthesis of regiochemically and analytically pure tetracenes (12 examples). The sequence is typically chromatography-free, scalable, efficient and technically simple to carry out.