Nanopolyplexes - Responsive Multipurpose Delivery Vehicles

Our body presents several mechanisms that prevent delivery systems from reaching their target. Overcoming these hurdles requires the development of intelligent delivery vehicles that could respond to the each of the mechanisms. We envision a novel self-assembly based technique for synthesizing nano-polyplex delivery systems that could help towards this goal. This technique involves assembly of polycationic (negatively-charged) polymers by multivalent anions (positively-charged) to form polymer-salt complexes. By this method, size and composition of the delivery system is altered easily and, cargos as varied as siRNA, flurochromes and drugs can be encapsulated. These nano-polyplexes can be fabricated to be responsive to specific stimulus, which enables them to deliver the cargo at desired sites. Here we present two examples of nano-polyplexes for: (i) delivery of siRNA and (ii) development of protease-responsive nanoprobes for imaging.