Doo Sung Lee

Injectable biodegradable copolymer hydrogels, which exhibit a sol-gel phase transition in response to external stimuli, such as temperature changes or both pH and temperature (pH/temperature) alterations, have found a number of uses in biomedical and pharmaceutical applications, such as drug delivery, cell growth, and tissue engineering. These hydrogels can be used in simple pharmaceutical formulations that can be prepared by mixing the hydrogel with drugs, proteins, or cells. Such formulations

The BAB-type triblock copolymers composed of a central poly(ethylene oxide) (PEO, M̄nPEO = 1 000) block and two poly[(D,L-lactic acid)-co-(glycolic acid)] end blocks with molecular weights between 900 and 1 600 exhibited an interesting phase transition behavior. The copolymer aqueous solution can form micelles with PLGA loops in the core and a PEO shell and groups of micelles because of bridging between micelles caused by the PLGA blocks with raising temperature. A possible micellar gelation mec

Polymeric nanoparticles are promising candidates as drug and gene carriers. Among polymeric nanoparticles, those that are responsive to internal or external stimuli are of greater interest because they allow more efficient delivery of therapeutics to pathological regions. Stimulus-sensitive polymeric nanoparticles have been fabricated based on numerous nanostructures, including micelles, vesicles, crosslinked nanoparticles, and hybrid nanoparticles. The changes in chemical or physical properties

Drug and gene delivery systems based on nanoparticles, microparticles and hydrogels have been widely studied for cancer treatment in the past decade. To achieve an efficient and safe delivery, selection of drug and gene delivery carrier is critical. Biocompatible polymeric nanoparticles are considerably promising carrier candidates in delivery of drugs and genes because of their unique chemical and physical properties. However, delivery of a drug or gene sometimes cannot achieve a satisfactory t

Poly(ethylene oxide)-b-poly(L-lactic acid) (PEO-PLLA) diblock copolymers were synthesized via a ring opening polymerization from poly(ethylene oxide) and l-lactide. Stannous octoate was used as a catalyst in a solution polymerization with toluene as the solvent. Their physicochemical properties were investigated by using infrared spectroscopy, 1H-NMR spectroscopy, gel permeation chromatography, and differential scanning calorimetry, as well as the observational data of gel-sol transitions in aqu