Preparation of Chitosan-based Nanoparticles for Gene Delivery Applications in Nerve Tissue

Introduction: In central nervous system (CNS) injuries, neurons and glial cells activate leading to change their morphology and molecular expression. On the other hand, activated glial cells prevent axonal regeneration by producing inhibitors and forming glial scar in the site of injury. One approach to prevent formation of glial scar is to release specific genes into the activated glial cells to differentiate them most probably into the neurons. Significance: Up to date, researchers have used viral vectors as a gene carrier to promote axonal regrowth after neural injury. But, the main detrimental effects of viral vectors are their cytotoxicity and immunogenic response. From this point of view, biocompatible polymeric nanoparticles (NPs) are most desired candidates to efficiently carry and release bioactive agents in drug delivery and gene therapy applications.Methods: In current study, chitosan (CS) and polyacrylic acid (PAA) as biocompatible polymers were used to prepare NPs by ionic gelation method. The green fluorescent protein (GFP)-loaded NPs were prepared to detect cell uptake of NPs. GFP could also be a favorable candidate for further gene delivery into the injured cells. To determine average hydrodynamic diameter, size distribution and surface charge of NPs, dynamic light scattering (DLS) and zeta potential analysis were used. Fourier transform infrared spectroscopy (FTIR) was employed to characterize functional groups of NPs after electrostatic interactions. Results and discussion: GFP loaded CS/PAA NPs with 140 nm mean size and +26 mV surface charges were prepared and successfully transfected into the activated cells of rat cerebral cortex in vitro. Biological assays showed that CS based NPs efficiently transfected into reactive astrocytes more than neurons.Conclusion: This study offered CS/PAA NPs as effective carriers to transfect into activated cells in neural injuries for gene delivery applications.

Keywords:

Neural injury , Glial scar , Polymeric nanoparticles , Chitosan , Cell uptake , Gene delivery