Gene therapeutic applications, including ex vivo and in vivo gene replacement and editing, often require a long, single-stranded template or donor DNA. Conventional solid-phase DNA synthesis is limited to short oligonucleotides, and enzymatic synthesis is challenging to scale for quantities needed in pre-clinical and clinical studies. In the first part of the talk, the speakers will show how DNA can be used to fabricate virus-like particles for early stage, in vitro studies of prophylactic vaccine candidates in HIV and SARS-CoV-2, and then give an outlook on therapeutic, cancer vaccines. In the second part of this talk, they will present a scalable, biotechnological process developed to achieve production of grams and larger quantities of single-stranded DNA of custom sequence with lengths up to ten kilobases, and will then highlight important milestones for pharmaceutical-grade manufacturing on an industrial scale.