Abstract: The invention is based on the discovery of a method for scalable, continuous flow production of a nucleic acid-containing microparticle that maintains the structural integrity of the associated nucleic acid and results in a microparticle having a purity suitable for introduction into an animal (e.g., human) host. Microparticles prepared according to the continuous flow processes described herein can be used for delivery of a nucleic acid for gene therapy, antisense therapy, vaccination, treatment of autoimmune disease, and either specific or non-specific modulation of an immune response (e.g., via cytokine regulation). The microparticles can additionally be used to deliver nucleic acid encoding a protein or peptide useful in any type of therapy.