Development of Nanomaterials-Biomolecular Conjugates and Their Applications in Biological Systems

• Main Authors: Yi-Hsin Liu, 劉怡欣
• Other Authors: Chia-Chun Chen
• Format: Others
• Language: en_US
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/78581612262487162656

博士 === 國立臺灣師範大學 === 化學系 === 99 === The applications of nanomaterials-biomolecular conjugates in DNA detection and RNA interference (RNAi) have led to ever-growing developments in the past decades. In this work, we have developed a new technique used fluorescent silica nanotubes for simple and sensitive DNA detection. The quantum dots embedded silica nanotubes (QD-SNTs) were fabricated by a sol-gel reaction using anodic aluminum oxide (AAO) as a template. The fluorescent QD-SNTs of different colors were then immobilized with single stranded DNA and used as nanoprobes to detect dye-labeled target DNA in a solution phase. The optical and structural properties of QD-SNTs nanoprobes were examined using photoluminescence spectroscopy, confocal microscopy and transmission electron microscopy (TEM). The obvious color change of the QD-SNTs nanoprobes was observed by eyes under a simple microscope after the successful detection with target DNA. The quantitative analyses indicated that ~100 attomole of target DNA in one nanoprobe can generate the distinguishable and observable color change. The detection results also demonstrated that our assay exhibited high specificity, high selectivity and very low non-specific adsorption. Our simple DNA assay based on QD-SNTs nanoprobes is expected to be quite useful for the needs of fast DNA screening and detecting applications. Furthermore, we study the kinetics of siRNA-based gene-silencing by gold nanoparticles-siRNA conjugates mediation. The kinetics factors relative to the concentrations of conjugates, dosing times of conjugates and cell doubling time were studied separately. The resulting duration time of silence (TE, a period of time that EGFP expression level was regulated down to 50 % or less) by three variables mentioned above were also investigated. We found that TE showed natural logarithm relationship with the concentrations of conjugates. But for other two variables, dosing times of conjugates and cell doubling time, TE showed linear relationship with both of them. Based on these relationships, an expected siRNA-mediated gene expression level can be designed. For the need of researches and treatments, prolonged TE can be achieved by varying concentrations and/or dosing times of conjugates. Besides, choosing of model cell (relative to cell doubling time) may be helpful for the purpose of prolonged TE. Importantly, according to these relationships, the possibility of trial and error in RNAi based applications can be much reduced. Our study holds great potential for RNAi-based therapeutic applications.