Assessing Nucleic Acid: Cationic Nanoparticle Interaction for Gene Delivery.

The assessment of the efficient binding between a nucleic acid and its associated nanoparticle is crucial for gene delivery. Emerging from the extensive search for versatile gene carriers, are complexes formed between nucleic acids and nonviral nanocarriers that promise to be viable alternatives to the predominantly viral-based gene delivery vehicles. However, much is still to be known about the exact structure and physico-chemical properties of such nanocomplexes. This chapter will concentrate on cationic lipid, polymer, and functionalized metal nanoparticles and their interaction with nucleic acids by direct conjugation or electrostatic interaction. Methods commonly employed to evaluate the nature and extent of nucleic acid interactions with cationic nanocarriers, such a nucleic acid binding, nuclease protection, and dye displacement assays will be described. In addition, the ultrastructural morphology, size, and zeta potential of these nanocomplexes, which are crucial for their cellular uptake and intracellular trafficking, will be assessed using electron microscopy, fluorescent detection, and nanoparticle tracking analysis (NTA). These assays have the ability to visualize and quantify the interaction and can also be used to complement each other, in addition to providing confirmation of the formation of the relevant nanocomplexes.