Yeon Lee

A new type of polyion complex (PIC) micelle was prepared from lysozyme and the block copolymer, PEG-pAsp(EDA-Cit), that can switch the charge from anionic to cationic at the endosomal pH. The charge-conversion was due to the degradation of the citraconic amide side chain at pH 5.5. This abrupt charge-conversion can make the PIC micelles promptly release the internal protein in response to the endosomal pH. This pH-sensitive charge-conversion polymer is promising for the future design of nanocarr

Special delivery! Polyionic complex (PIC) micelles that contain the charge-conversional moieties citaconic amide or cis-aconitic amide were developed for cytoplasmic protein delivery. The increase of the charge density on the protein cargo helped the stability of the PIC micelles without cross-linking, and the charge-conversion in endosomes induced the dissociation of the PIC micelles to result in efficient endosomal release (see picture).

Wrapped for special delivery: A ternary polyplex, with an endosomal disruption moiety based on the charge-conversion polymer pAsp(DET-Aco), showed negative charges for serum stability and low cytotoxicity, but the charges became positive and the endosome disruption moiety was exposed (see picture). High transfection efficiency and minimal cytotoxicity were observed with primary cells.

Stand and deliver! Immunoglobulin G (IgG) can be delivered into the cytoplasm of living cells by charge-conversional modification followed by treatment with a cationic block copolymer to form polyion complex (PIC) micelles (see picture). The bioactivity of the IgG selectively recovers in the cell in a pH-dependent manner, thereby controlling the growth of human hepatoma cells through IgG binding to intracellular target molecules.

Polyethylenimine (PEI) shows high transfection efficiency and cytoxicity due to its high amine density. The new disulfide cationic polymer, linear poly(ethylenimine sulfide) (l-PEIS), was synthesized for efficient and safe gene delivery. As the amine density of l-PEIS increased, the transfection efficiency also increased. l-PEIS-6 and l-PEIS-8 show transfection efficiencies that are similar to that of PEI. However, cytotoxicity of l-PEIS was not observed due to the biodegradable disulfide bond.

The application of polyion complex (PIC) micelles into therapeutic fields is rapidly increasing due to simple and efficient encapsulation of biopharmaceuticals and outstanding biocompatibility among various polymer-based drug delivery carriers. Ionic biopharmaceuticals, such as DNA, RNA, and proteins can interact with ionic block copolymers to form PIC micelles with a core-shell structure. In this review, the development of smart PIC micelles that can respond to biosignals and the application of

Poly(ethylene oxide sulfide) (PEOS), polymers consisting of an internal ethylene oxide oligomer and disulfide linkage, were synthesized and characterized. The degree of polymerization was dependent upon temperature, dimethyl sulfoxide condition, and monomer hydrophobicity. The stability of PEOS was measured by the size exclusion chromatography method after the incubation both with and without 5 mM glutathione. The disulfide bond was stable in the extracellular condition but completely degraded i

BACKGROUND: The development of an efficient method to improve the wound healing process is urgently required for diabetic patients suffering a threat of limb amputations. Various growth factors have been proposed for treatment; however, more research still has to be carried out to maintain their curative effect. In the present study, we describe a simple nonviral gene therapy method for improving wound healing. METHODS: Minicircle plasmid DNA encoding vascular endothelial growth factor (VEGF) wa

Abstract Tissue expansion techniques physically expand swellable gel‐embedded biological specimens to overcome the resolution limit of light microscopy. As the benefits of expansion come at the expense of signal concentration, imaging volume and time, and mechanical integrity of the sample, the optimal expansion ratio may widely differ depending on the experiment. However, existing expansion methods offer only fixed expansion ratios that cannot be easily adjusted to balance the gain and loss ass

Spezialverpackung: Das Schema illustriert den Übergang eines ternären Polyplexes vom negativen, serumstabilen und wenig zytotoxischen Zustand in den positiven Zustand mit freigesetzter endosomaler Spaltungseinheit, der bei Primärzellen eine hohe Transfektionseffizienz bei sehr geringer Zytotoxizität aufweist.

Osmosis can be controlled reversibly and effectively by mild temperature changes based on novel thermosensitive solutes with LCST transition. The nBu-TAEA thermosensitive solution can draw fresh water from seawater at temperatures less than the phase separation temperature, and the osmotic flow was reversed at higher temperatures.