Preparation of Polymeric Nanoparticles for Gene Delivery

Gene delivery strategies include two main approaches: viral and nonviral systems to deliver the genetic material to target cells. Although viral vectors have high transfection efficacy, their clinical usage has been limited due to the risks of immunogenicity and mutagenesis. Therefore, nonviral delivery strategies such as polymeric nanoparticles gained considerable interest, since they are safer and more flexible. In this chapter, we comprehensively explained the protocols for preparing chitosan, a natural polymer, as well as poly(beta-amino esters) and poly(lactic-co-glycolic acid) nanoparticles, which are synthetic biodegradable polymers, and discussed their characterization. Within the scope of the chapter, we reviewed the ionic gelation method for chitosan, the nanoprecipitation and self-assembly methods for poly(beta-amino esters) systems, and the emulsion-solvent evaporation method for poly(lactic-co-glycolic acid). Particularly, the pH sensitivity and high transfection efficacy of poly(beta-amino esters) and the FDA-approved bioavailability and controlled-release characteristics of poly(lactic-co-glycolic acid) are discussed. Moreover, we explained the efficiency of these systems in gene delivery, basic physicochemical characterization methods such as particle size and polydispersity analysis with dynamic light scattering, and surface charge assessment with zeta potential, in addition to the biological performance criteria such as nucleic acid binding capacity, enzymatic protection, and serum stability. This section aims to provide a holistic guide to design and evaluate polymeric gene delivery systems.