“…Since chitosan is positively charged, it can interact with the negative charge of cell membranes through electrostatic interactions, resulting in increased cellular uptake, an important feature for drug delivery systems [ 136 ]. Thanks to its promising properties, chitosan has already been used as a matrix polymer for NBs (CS NBs) to achieve two different goals: NBs for the delivery of nucleic acids, such as DNA, antisense oligonucleotides (AON), or siRNA, or NBs for cancer treatment [ 128 , 129 , 137 , 138 , 139 , 140 , 141 ]. In the first case, CS NBs were used as transfection agents in conjunction with US or external shock waves (ESW), which resulted in the enhanced transfer of DNA and siRNA into cells, whereas they showed impairment in AON delivery [ 138 , 139 , 140 ].…”