Cationically modified poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles have recently been introduced as novel carriers for DNA/RNA delivery. The colloidal characteristics of the nanoparticles--particle size and surface charge--are considered the most significant determinants in the cellular uptake and trafficking of the nanoparticles. Therefore, our aim was to introduce chitosan-coated PLGA nanoparticles, whose size and charge are tunable to adapt for a specific task. The results showed that biodegradable nanoparticles as small as 130 nm and adjustable surface charge can be tailored controlling the process parameters. As a proof of concept, the overall potential of these particulate carriers to bind the antisense oligonucleotides, 2'-O-methyl-RNA, and improve their cellular uptake was demonstrated. The study proved the efficacy of chitosan-coated PLGA nanoparticles as a flexible and efficient delivery system for antisense oligonucleotides to lung cancer cells.