Development of Novel Drug Delivery System
RNA interference (RNAi) was first discovered in a nematode worm (Caenorhabditis elegans) . Double-stranded RNA (dsRNA) was found to cause gene silencing in a sequence-specific way. Researchers had long thought that RNA would be the perfect way to control gene expression, because the right sequence of RNA should bind to DNA and interfere with its transcription. The greatest difficulty of RNA interference Mechanism[5] is penetration of cell membrane. To overcome this problem, we design a complex made up of polyethylene glycol (PEG), photocleavable linker (PL), and thiolated siRNA(Scheme 2). In this work we report, compare and discuss the results obtained from agarose gel electrophoresis (Figure 3) , the result of in vitro test and the data from Dynamic Light Scattering(DLS). To simulate the penetrant mechanism, we design a mimic experiment that use larger PEG (MW=20000) to detect its particle properties by Dynamic Light Scattering (DLS). DLS data (Table 3) suggested that it might accumulate into micelles (Figure 4) and negatively charged surface imply outer layer might consist of siRNA. These evidence shows that the penetration of siRNA might be assisted by PEG micelle. Finally, acroding to the in vitro test we find out that various length of siRNA will have different extent of gene silencing (Figure. 5-7).
