實驗室簡介 |
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Lab interest:
Nano- & Bio-materials Lab. Chih Kuang Wang, Ph.D. Research Assistant Professor
B.S.
Department of Materials Science and
Engineering,
1990,Feng Chia University
Email:
ckwang@kmu.edu.tw
TEL:+886-07-3121101 ext. 2677 FAX:+886-07-3125339
高雄醫學大學
醫藥暨應用化學系
Research Interests ※Design and fabrication of scaffold materials for tissue engineering ※Polymeric micelle micro-, nano-particle system for drug/gene delivery ※Bone specific drug delivery system
Laboratory Bone/Cartilage Tissue EngineeringTissue engineering is the generation of tissues to replace those that have been damaged or lost by disease. The ability to repair or replace tissue opens to door to the treatment of debilitating diseases and disorders such as Parkinson's disease, diabetes and traumatic injury - indications where current treatments are limited or nonexistent. Tissue engineered products, such as those to repair skin or cartilage, have been developed, but they have met with limited success. In order for the promise of tissue engineering to come to fruition, significant technical and market advances are required. Recent developments in stem cell technology, understanding the role of extracellular matrix (ECM) in correct tissue growth, and improved production methods are some factors in this exciting field.
Tissue engineering consists of three categories: scaffold, cell and signals. We focus on optimization of scaffold design and fabrication to mimic the in vivo natural environment, to aid and induce tissue regeneration. In our lab, bioceramics, polymer and polymeric composite scaffolds with different composition, geometry structure and shapes are fabricated, especially for surface functionalization, and controlled release of biological molecules in porous scaffolds using different techniques, and their effect on bone cell/chondrocyte and bone/cartilage tissue have been evaluated. That is to understand scaffold biomaterials-cell interactions, and the signal and substrate requirements for cell proliferation and tissue regeneration in three dimensions to create functional tissues.
Polymeric micelle microparticle delivery system The desirability of coating medical devices such as, inter alia, surgical implants, sutures and wound dressings with pharmaceutical agents is well known. Such coated devices provide a means for locally delivering pharmaceutical or therapeutic agents at the site of medical intervention to treat a variety of diseases. For example, surgical implants or sutures coated with antibiotics can provide local delivery of antibiotic directly to an implantation or suture site, thereby decreasing the onset of infection following the surgical intervention. Thus, there is an increasing interest in developing a drug delivery system which is both safe and which provides a high biological availability of the drug, i.e. to maximize pharmaceutical activity of known drugs as well as to minimize the side effects thereof. Due to their uniform release rate during a given time period and the non-toxic property of degradation products, biodegradable polymers have been widely investigated as drug carriers. Biodegradable polymer drug carriers are especially useful for delivering drugs requiring continuous and sustained release with a single bolus administration, e.g. peptide or protein drugs, which should be administered daily because of quick loss of activity in the body. Aliphatic polyesters, such as poly(lactic acid) (PLA), poly(glycolic acid) (PGA), copolymers of PLA and PGA (PLGA) or poly(carprolactone) (PCL), and polyanhydrides have been widely used for biodegradable polymers. They can be formulated as various shapes, such as films, strips, fibers, gels or microspheres, and the physiologically active agents are incorporated into the formulations and administered intramuscularly or subcutaneously. However, microspheres have been a particularly preferred formulation because the drug release rate can be easily controlled and the small microsphere particle sizes of 0.1 ~ 500µm by conventional methods. Preparation methods, however, to achieve uniform particle size of the microspheres and effective loading of drugs are still under investigation. Microspheres have been prepared by various methods such as emulsion solvent evaporation, phase separation, spray-drying, or solvent extraction. However, improved methods for preparing microspheres having uniform particle size and effective drug loading are desirable. According to the emulsion solvent evaporation method, a hydrophobic polymer is dissolved in a water-immiscible organic solvent, such as dichloromethane, chloroform, or ethyl acetate, to give a polymer solution. Then, a physiologically active agent is dissolved or suspended in the polymer solution. The resulting solution is added into an aqueous solution of a surfactant to form an emulsion system, and microspheres are obtained by evaporating the solvent under vacuum or heating. Although this method is useful for very poorly water-soluble drugs it has very low loading efficiency for water-soluble drugs. Ogawa et al. disclose a w/o/w double emulsion method for incorporating a water-soluble drug into microspheres. Accordingly, a biodegradable polymer is dissolved in a water-immiscible organic solvent to give a polymer solution, and a water-soluble physiologically active agent is emulsified into the polymer solution to give a w/o emulsion system. This emulsion is emulsified again into an aqueous solution of a surfactant to produce the w/o/w double emulsion system. The microspheres containing the water-soluble physiologically active agent are obtained by evaporating the solvent. Currently our research is in the field of controlled biodegradable rate of biopolymer, thereby achieving a controlled release rate of growth factor and drugs.
Polymeric micelle nanoparticle delivery system Micelles formed by self-assembly of amphiphilic block copolymers (5-200 nm) in aqueous solutions are of great interest for drug delivery applications. The drugs can be physically entrapped in the core of block copolymer micelles and transported at concentrations that can exceed their intrinsic water- solubility. Moreover, the hydrophilic blocks can form hydrogen bonds with the aqueous surroundings and form a tight shell around the micellar core. As a result, the contents of the hydrophobic core are effectively protected against hydrolysis and enzymatic degradation. In addition, the corona may prevent recognition by the reticuloendothelial system and therefore preliminary elimination of the micelles from the bloodstream. A final feature that makes amphiphilic block copolymers attractive for drug delivery applications is the fact that their chemical composition, total molecular weight and block length ratios can be easily changed, which allows control of the size and morphology of the micelles. Functionalization of block copolymers with crosslinkable groups can increase the stability of the corresponding micelles and improve their temporal control. Substitution of block copolymer micelles with specific ligands is a very promising strategy to a broader range of sites of activity with a much higher selectivity. In addition, we are interested in applying the developing nanoparticle for bone specific diseases such as osteoporosis and cancer therapy. Current ongoing projects(01)骨質疏鬆症及骨質壞死症醫療技術之創新研發三年計畫（第三年度）之子計畫 ”攜帶生長因子之控制徐放型骨材之研發”, 經濟部, 2007/07/01至2008/06/30。 (02)利用自體脂肪幹細胞與生醫材料重建關節軟骨缺損之組織工程研究, 國科會, 2007/08/01至2008/07/31。 (03)HA改質型高孔隙微奈米纖維支架在重建關節軟骨缺損之組織工程研究, in house study。 Other areas of interest:
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