Development and Characterization of Zein-Sodium Caseinate Nanoparticles-Hydrogel Composite for Localized and Sustained Sirna Delivery(3/3)

The use of RNA interference (RNAi) to silence the expression of specific genes associated with disease is one of the most promising new therapeutic paradigms in medicine. Although RNAi, and specifically small interfering RNA (siRNA), has shown much promise for the treatment of cancer and a broad spectrum of other diseases, delivery of RNAi is a challenge due to the vulnerability of RNA to serum nucleases, the propensity to cause off- target effects, and the requirement for delivery into the cytosol of target cells. Thus, new methods and vectors are needed to effectively deliver RNAi to target tissue. The objective of this proposal is to engineer a localized and sustaining release siRNA delivery system which containing biopolymer nanoparticles hydrogel, permitting long-term inhibition of gene expression at a specific site and convenient for clinical use (simple, effective, and safe). Biocompatible, biodegradable, and nontoxic zein is selected to from a complex with siRNA in low pH environment by liquid-liquid dispersion method. Sodium caseinate will be used a stabilizer in optimum concentration (forming zein/caseinate nanoparticle; ZN) to maintaining the structure and prevent zein particles form aggregation under stronger ion strength environment. Furthermore, a thermosensitive hydrogel, containing poloxamer 407 and chitosan, is designed to complex with zein/caseinate siRNA nanoparticle (ZN-siRNA) for the purpose of slow, sustained release in vivo. Three Aims are proposed: (1) To optimization and physiochemical characterizations of zein/caseinate nanoparticles as novel delivery system and understand the effect of sodium caseinate on the physiochemical properties of ZN-siRNA. (2) To study the in vitro release of ZN-siRNA and evaluate the transfection efficiency of ZN-siRNA. (3) To develop and characterize e of chitosan- and the poloxamer-based thermosensitive hydrogel and fabricate ZN-siRNA hydrogel for sustained release. Further evaluate their gene silencing ability in vitro. Accordingly, we will test the overall hypothesis that siRNA delivery with respect to gelation, degradation, ZN-siRNA release, and gene silencing efficiencies in vitro with single injections. It is hoping the injectable hydrogel stimuli-dependent sol gel transition can provide a new concept for localized and long-term delivery of siRNA with high transfection efficiencies.