Mikyung Shin

Comparative study of physical methods for lipid oxidation measurement in oils

For the determination of lipid oxidation in oils, electrical, optical, spectroscopic and extraction methods were investigated using rice bran oil and doubly-fractionated palm olein as model systems. The oxidized polar components and dielectric constant of rice bran oil increased very similarly with those of double-fractionated palm olein. In the case of rice bran oil, all of the test methods were shown to possess good statistical correlations. Polar components, dielectric constant, refractive index and polymer content showed relatively better correlations. It was shown that diene and triene content determined by spectroscopic methods was not suitable for more saturated oils such as palm olein.

STAPLE: Stable Alginate Gel Prepared by Linkage Exchange from Ionic to Covalent Bonds

S. H. Hong, Dr. J. H. Ryu, Prof. H. Lee Department of Chemistry Korea Advanced Institute of Science and Technology (KAIST) 291 Daehak-ro , Yuseong-gu , Daejeon 305-701 , South Korea E-mail: haeshin@kaist.ac.kr M. Shin Graduate School of Nanoscience and Technology Korea Advanced Institute of Science and Technology (KAIST) 291 Daehak-ro , Yuseong-gu , Daejeon 305-701 , South Korea Dr. J. Lee, S. Lee, Dr. W. D. Kim Department of Nature-Inspired Nano Convergence Systems Korea Institute of Machinery and Materials(KIMM) 156 Gajeongbuk-Ro, Yuseong-gu , Daejeon 305-343 , South Korea Prof. J. W. Yang Department of Ophthalmology Inje University Pusan Paik Hospital Inje University College of Medicine Busan , South Korea

SpONGE: spontaneous organization of numerous-layer generation by electrospray.

Advanced technologies that can mimic hierarchical architectures found in nature can provide pivotal clues for elucidating numerous biological mechanisms. Herein, a novel technology, spontaneous organization of numerous-layer generation by electrospray (SpONGE), was developed to create self-assembled and multilayered fibrous structures. The simple inclusion of salts in a polymer solution prior to electrospraying was key to mediating the structural versatilities of the fibrous structures. The SpONGE matrix demonstrated great potential as a crucial building block capable of inducing sequential, localized drug delivery or orchestrating cellular distribution in vivo, thereby expanding its scope of use to cover a variety of biomedical applications.

Targeting protein and peptide therapeutics to the heart via tannic acid modification

Systemic injection into blood vessels is the most common method of drug administration. However, targeting drugs to the heart is challenging, owing to its dynamic mechanical motions and large cardiac output. Here, we show that the modification of protein and peptide therapeutics with tannic acid—a flavonoid found in plants that adheres to extracellular matrices, elastins and collagens—improves their ability to specifically target heart tissue. Tannic-acid-modified (TANNylated) proteins do not adsorb on endothelial glycocalyx layers in blood vessels, yet they penetrate the endothelium to thermodynamically bind to myocardium extracellular matrix before being internalized by myoblasts. In a rat model of myocardial ischaemia-reperfusion injury, TANNylated basic fibroblast growth factor significantly reduced infarct size and increased cardiac function. TANNylation of systemically injected therapeutic proteins, peptides or viruses may enhance the treatment of heart diseases.The modification of protein and peptide therapeutics with tannic acid improves their ability to specifically target heart tissue, as shown with a rat model of myocardial ischaemia-reperfusion injury.

A visible light-curable yet visible wavelength-transparent resin for stereolithography 3D printing

Herein, a new polymeric resin for stereolithography (SLA) three-dimensional printing (SLA-3DP) is reported. An ultraviolet (UV) or visible (VIS) light source is critical for SLA printing technology. UV light can be used to manufacture 3D objects in SLA-3DP, but there are significant occupational safety and health issues (particularly for eyes). These issues prevent the widespread use of SLA-3DP at home or in the office. Through the use of VIS light, the safety and health issues can largely be solved, but only non-transparent 3D objects can be manufactured, which prevents the application of 3DP to the production of various common transparent consumer products. For these reasons, we developed a VIS light-curable yet visibly transparent resin for SLA-3DP, which also retains UV curability. The key was to identify the photoinitiator diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (DPTBP). DPTBP was originally designed as a UV photoinitiator, but we found that VIS light irradiation is sufficient to split DPTBP and generate radicals due to its slight VIS light absorption up to 420 nm. The cured resin displays high transparency and beautiful transparent colors by incorporating various dyes; additionally, its mechanical properties are superior to those of commercial resins (Arario 410) and photoinitiators (Irgacure 2959).3D printing: a visible shift for see-through plasticsA custom-designed polymer resin makes it possible to safely print transparent 3D objects in machines designed for homes or offices. Stereolithography printers use ultraviolet lasers to initiate free-radical photopolymerization inside liquid resins, enabling layer-by-layer assembly into solid shapes. Haeshin Lee from the Korea Advanced Institute of Science and Technology, Daejeon, and colleagues now report a polymer mix containing diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (DPTBP) that can be printed using visible light, a shift that lessens the risks of eye damage from accidental exposures. The DPTBP/polymer mixture at an optimized ratio has the additional advantage of being colorless, a property absent from most stereolithography resins. The team showed that a blend of the transparent photo-initiator with acrylic polymers allowed 3D printing of complex items such as chess pieces with desirable optical transparency and mechanical properties superior to commercial resins.In this study, the transparent polymer resin in visible wavelength ranges yet ironically be curable by visible light is introduced for stereolithography three-dimensional printings. The key is to use the photoinitiator, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (DPTBP), which generates radicals at the edge wavelength of visible light ranges (~420 nm). The developed resin has high transparency, commercial dyes incorporations, and superior mechanical strength to the existing resins.