Tae-Joon Park

Synthesis of Gold and Silver Nanoparticles Stabilized with Glycosaminoglycans Having Distinctive Biological Activities

Metal nanoparticles have been studied for their anticoagulant and anti-inflammatory efficacy in various models. Specifically, gold and silver nanoparticles exhibit properties that make these ideal candidates for biological applications. The typical synthesis of gold and silver nanoparticles incorporates contaminants that could pose further problems. Here we demonstrate a clean method of synthesizing gold and silver nanoparticles that exhibit biological functions. These nanoparticles were prepared by reducing AuCl(4) and AgNO(3) using heparin and hyaluronan as both reducing and stabilizing agents. The particles show stability under physiological conditions and narrow size distributions for heparin particles and wider distribution for hyaluronan particles. Studies show that the heparin nanoparticles exhibit anticoagulant properties. Additionally, either gold- or silver-heparin nanoparticles exhibit local anti-inflammatory properties without any significant effect on systemic hemostasis upon administration in carrageenan-induced paw edema models. In conclusion, gold and silver nanoparticles complexed with heparin demonstrated effective anticoagulant and anti-inflammatory efficacy, having potential in various local applications.

Preparation of synthetic wood composites using ionic liquids

Synthetic wood composite films containing cellulose, hemicelluloses, and lignin, the three major components of natural wood, were prepared in a room temperature ionic liquid solvent, 1-ethyl-3-methylimidazolium acetate, [EMIM][Ac]. Various synthetic wood composites were obtained by dissolution of individual wood components together with additives, including polyethylene glycol (PEG), chitosan, and multi-wall carbon nanotubes (MWNTs) in [EMIM][Ac]. The addition of water affords a gel that was dried in either a low humidity environment or under vacuum. Synthetic wood films showed smoother surface textures, higher water resistance, and higher tensile strengths than cellulose films formed by the same methods. Tailor-made synthetic wood composites were also prepared having a variety of desirable properties, including antimicrobial activities, controlled hydro-phobicity/philicity, high relative dielectric constant, and a high degree of cohesiveness.

Signal amplification of target protein on heparin glycan microarray

A heparin glycan chip (HepGlyChip) with a 4800-fold enhanced signal-to-noise ratio as compared with the control without heparin was developed for high-throughput analysis of heparin-protein interactions for new drug development and for screening biological samples in diagnostic applications. As a proof of concept, a heparin glycan microarray was prepared on a poly(styrene-co-maleic anhydride) (PS-MA)-coated glass slide. Heparin was covalently immobilized on poly-l-lysine (PLL) layer with multiple binding sites by sulfo-ethylene glycol bis(succinimidylsuccinate) (sulfo-EGS), increasing the signal-to-noise ratio, minimizing nonspecific binding of target proteins, and resulting in a three-dimensional (3D) structure on the HepGlyChip. This on-chip signal amplification platform was successfully demonstrated by probing the heparin microarray with the highly specific heparin-binding protein antithrombin III (AT III).

Pharmacological Applications of Biocompatible Carbon Nanotubes and Their Emerging Toxicology Issues

Since their discovery in 1991, carbon nanotubes (CNTs) have been studied for their application as diagnostic tools, chemical sensors, and vectors for drug delivery. Carbon nanotubes are of great interest because of their unique array of physical and chemical properties, including their high aspect ratio, ultralight weight, high mechanical strength, high electrical conductivity, high thermal conductivity, and high surface area. The unique properties of carbon nanotubes also raise substantial concern about their potentially toxic effects on the environment and human health. This review focuses on the current pharmacological applications and emerging toxicology issues of biocompatible carbon nanotubes. Carbon nanotubes as agents for drug delivery, cancer therapeutics, along with their in vivo challenges and potential toxicity are discussed.