RNA interference (RNAi) is the process where the introduction of double stranded RNA into a cell inhibits gene expression in a sequence dependent fashion. However, advanced drug delivery, systemic distribution and long-term silencing of genes are necessary before gene therapy can enter the clinical phase and eventually benefit patients. It is essential that the drug carrier system be capable of delivering these nucleic acid-based drugs to the target cells. One emerging and promising technique is to use biodegradable polymeric micelle drug delivery system. Polymeric (e.g. block copolymer) micelles are amphiphilic molecules that will self-assemble in aqueous solutions. The goals of this project are to fabricate, optimize and characterize a nano self-assembled micelle system for drug delivery of siRNA. The siRNA drug delivery is a new, exciting and yet very challenging area in pharmaceutical research. The long-term objective is to achieve enhanced and targeted delivery of siRNA to cells using the proposed polymeric micelle system.
The nano self-assembled DSPE-PEG micelle delivery system of siRNA will be prepared and characterized in terms of particle size, size distribution, formulation stability and surface morphology using quasi-elastic light scattering particle sizer, differential scanning calorimetry and cryo scanning electron microscopy (SEM). The drug loading efficiency, drug stability and in vitro evaluation of the micelle delivery system will be studied using liquid-liquid extraction, solid-phase extraction, UV, HPLC and dissolution testing. Transfection studies of dsGFP siRNA loaded micelle drug delivery system will be done in cell culture to test the efficiency of silencing. RNase protection assay will be used to determine the efficient of siRNA loading. The RNA silencing effort will be determined by northern blot. At the protein level, the green fluorescent intensity will be monitored through a Fluorescent microscope. The cyto-toxicity of the siRNA loaded micelle delivery system on targeted cells will be monitored by MTT assay.