Control of DNA Adsorption and Releasing Behaviors by Layer-by-Layer Assembly Technique

• Main Authors: Yung-jen Chen, 陳勇任
• Other Authors: Wei-wen Hu
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/81391498021042180593

碩士 === 國立中央大學 === 化學工程與材料工程研究所 === 99 === Layer-by-layer (LBL) assembly technique was used to immobilize chitosan and plasmid DNA on material surface using electrostatic forces. The chemistry and physical properties of polyelectrolyte multilayer (PEM) was analyzed by FT-IR and contact angle analysis. UV spectrometry and quartz crystal microbalance (QCM ) were applied to quantify the absorbing amounts of DNA and chitosan. Different molecular weights of chitosan and the pH value of chitosan solutions were examined to determine their effects to the DNA adsorption and release profiles. Because 10k Da chitosan had the highest DNA releasing ability, it was used to prepare PEM for transfecting human embryonic kidney 293T cells (HEK 293T cells). MTS assay suggested that chitosan did not reduce the cell viability. Increasing bilayer numbers and pH values of chitosan solutions may enhance cell transfection efficiencies and elongate gene expression. It may be due to that more chitosan molecules adsorbed on substrates during LBL assembly at pH 6 than at pH 4 conditions. More chitosan molecules may result in more complex formation and thus facilitate gene delivery. Furthermore, higher bilayer numbers prolonged gene expression. Compared to the cells transfected by DNA-chitosan nanoparticles, cells in situ transfected on PEM demonstrated an improved and extended gene expression. These results suggested that the LBL method should be a potential strategy to control gene delivery.