Nonviral delivery of large gene constructs to human tissues combines physical, chemical, and genetic-engineering strategies to move beyond viral-vector limits while addressing safety and manufacturability concerns. Clinical and preclinical work shows multiple viable avenues, each with tradeoffs for efficiency, persistence, and tissue targeting.
Physical and chemical methods
Electroporation and nucleofection apply transient electric fields to open cell membranes, enabling plasmid-sized DNA to enter cells. David B. Weiner at the University of Pennsylvania has long contributed to electroporation-enhanced DNA vaccination, demonstrating clinical-grade delivery to muscle and skin with acceptable safety. Lipid nanoparticles adapted for larger cargos and polymeric carriers such as polyethylenimine can encapsulate big constructs, though formulation chemistry determines delivery efficiency and toxicity. Ultrasound-mediated microbubble methods and focused ultrasound have been used to increase local permeability in tissues such as muscle and brain; Kullervo Hynynen at Sunnybrook Research Institute and the University of Toronto has shown blood–brain barrier modulation enabling macromolecular delivery in animal models.Transposons and genome integration
Nonviral integration systems like the Sleeping Beauty transposon enable stable insertion of large transgenes when co-delivered with a transposase. Zoltán Ivics at the Max Delbrück Center for Molecular Medicine developed and characterized this system, and clinical translation has been pursued for cell therapies. Laurence Cooper at MD Anderson Cancer Center has advanced Sleeping Beauty-based manufacturing for CAR T cells, demonstrating a pathway to clinical-scale nonviral gene addition. These approaches reduce reliance on viral production but raise integration-site and long-term safety questions that require careful monitoring.Physical accessibility of the target tissue shapes method choice. Skin and skeletal muscle are relatively amenable to direct injection plus electroporation or biolistics, while hematopoietic and immune cells are typically modified ex vivo and reintroduced, allowing higher-efficiency electroporation or transposon-based editing. The blood–brain barrier and poorly vascularized tissues present persistent challenges that may favor focused ultrasound or implantable devices.
Consequences for patients and health systems include potentially lower manufacturing cost and simpler regulatory paths compared with viral vectors, but also the need for longitudinal surveillance for insertional mutagenesis and immune responses. Cultural and territorial factors influence adoption because the required devices and formulation expertise concentrate in well-resourced centers, shaping access to nonviral gene therapies across regions. Strategic selection of method must balance tissue biology, construct size, durability of expression, and societal priorities for safety and equity.