A poly-N-acetylglucosamine nanoparticle/nucleic acid composition comprises poly-N-acetylglucosamine and a nucleic acid, wherein the nanoparticles are between about 5 nm and 500 nm in size, and wherein 60% to 70% of the poly-N-acetylglucosamine is deacetylated. The composition is used to deliver a nucleic acid to a subject.