Min Seon Heo

Easy Synthesis of Hierarchical Carbon Spheres with Superior Capacitive Performance in Supercapacitors

An easy template-free approach to the fabrication of pure carbon microspheres has been achieved via direct pyrolysis of as-prepared polyaromatic hydrocarbons including polynaphthalene and polypyrene. The polyaromatics were synthesized from aromatic hydrocarbons (AHCs) using anhydrous zinc chloride as the Friedel-Crafts catalyst and chloromethyl methyl ether as a cross-linker. The experimental results show that the methylene bridges between phenyl rings generate a hierarchical porous polyaromatic precursor to form three-dimensionally (3D) interconnected micro-, meso-, and macroporous networks during carbonization. These hierarchical porous carbon aggregates of spherical carbon spheres exhibit faster ion transport/diffusion behavior and increased surface area usage in electric double-layer capacitors. Furthermore, micropores are present in the 3D interconnected network inside the cross-linked AHC-based carbon microspheres, thus imparting an exceptionally large, electrochemically accessible surface area for charge accumulation.

Synthesis of 2-amino-3-cyano-4H-chromen-4-ylphosphonates and their anticancer properties.

A series of 2-amino-3-cyano-4H-chromen-4-ylphosphonates have been synthesized by reacting substituted salicylaldehydes, malononitrile, and dialkylphosphites using a catalytic amount of dibutylamine as an organocatalyst employing Knoevenagel, Pinner, and phospha-Michael reactions simultaneously in ethanol. This protocol is an environmentally friendly procedure and gives high yields of the desired compounds (85-96%). In addition, no extraction or chromatography steps are needed to obtain the desired products. The compounds are tested against the viability of adenocarcinomic human alveolar basal epithelial (A549) and human epidermoid cancer (KB) cell lines using an MTT assay. Among these, diethyl 2-amino-3-cyano-4H-chromen-4-ylphosphonate and diethyl 2-amino-6-bromo-3-cyano-4H-chromen-4-ylphosphonate showed promising anticancer activity against the two tested cell lines.

Poly(2-Hydroxyethyl Methacrylate)-b -Poly(L-Lysine) Cationic Hybrid Materials for Non-Viral Gene Delivery in NIH 3T3 Mouse Embryonic Fibroblasts

In order to develop efficient and nontoxic gene delivery vectors, a series of biocompatible block copolymers, poly[(2-hydroxyethyl methacrylate)40 -block-(L-lysine)n ] (n = 40, 80, 120, 150), are prepared by combining an atom transfer radical polymerization of 2-hydroxyethyl methacrylate with a ring-opening polymerization of N(ϵ) -(carbobenzoxy)-L-lysine N-carboxyanhydride. The block copolymers are successfully condensed with plasmid DNA (pDNA) into nanosized (<200 nm) polyplexes. As a representative sample, p(HEMA)40 -b-p(lys)150 is utilized to confirm the effective cellular and nuclear uptake of pDNA. The polymer/pDNA polyplexes exhibit very low cytotoxicity and enhanced transfection activity by being easily taken up into mouse embryonic fibroblast cell line (NIH 3T3). Thus, the chimeric block copolymers provide a means for developing versatile nonviral gene vectors harboring the ideal requirements of low cytotoxicity, good stability, and high transfection efficiency for gene therapy.

Hyperbranched polyglycidol/phosphatidylcholine and phosphatidylethanolamine hybrid liposomes for the pH-sensitive delivery of doxorubicin.

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Self-aggregates of hyperbranched epoxidized 2-hydroxyethyl methacrylate conjugates of methotrexate: Synthesis and in vitro drug delivery.

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