Neonatal respiratory distress syndrome (RDS) is the most common respiratory cause of death and morbidity in infants <1 year of age in the United States. Monogenic mutations in genes regulating surfactant homeostasis, namely surfactant protein B (SFTPB), surfactant protein C (SFTPC), and ATP binding cassette subfamily A member 3 (ABCA3), are causative drivers of RDS in 25% of infants with severe refractory respiratory failure. Standard therapeutic regimens for genetic lung disease are limited to symptomatic treatments and lung transplant, a procedure with poor prognosis for long-term survival and high complication rates. These unsatisfactory outcomes highlight the pressing need for more precise therapies that directly address the genetic aberrations underlying RDS. Herein, we combine highly complementary expertise in neonatal lung disease treatment (Dr. Alapati) and non-viral gene delivery (Dr. Sullivan) necessary to develop a non-surgical approach to genetically correct lung progenitor cells during early postnatal lung development, a widely accessible strategy designed to prevent disease manifestation. We will establish this innovative and translationally-relevant approach via two aims: Aim 1. Design non-viral nanocarriers (‘polyplexes’) that are biocompatible, stable in lung fluids, and capable of cell-selective and efficient gene editing in neonatal AT2 cells. Aim 2. Engineer a partial-liquid ventilation approach for CRISPR-Cas9 delivery to maximize AT2 cell access and gene editing persistence in models of neonatal lung, and demonstrate this approach for durable, widespread, and safe non-viral gene editing in lung epithelium. Our hypothesis is built on our published studies demonstrating that (i) histone polyplex gene transfer hinges upon polyplex uptake via the caveolin-1 transporter, a mechanism that enables highly efficient transfection in caveolin-1- expressing cells and permits precise cell ‘targeting’ based upon differences in caveolin-1 availability; and (ii) airway delivery of CRISPR-Cas9 cargo into fluid filled fetal lungs results in efficient pulmonary epithelial cell gene editing. This work will thus uncover important new information on neonatal pulmonary epithelial gene transfer mechanisms while simultaneously establishing new, more cell-selective gene therapy strategies relevant to a variety of pulmonary genetic disorders. The study outcome will demonstrate a new delivery platform for effective, cell- specific, and safe gene editing in postnatal lung epithelium, a strategy that would enable wide usage even in basic-level NICUs, while simultaneously aligning with the timing of disease diagnosis, and lay groundwork for future translation to fundamentally new, more effective, and one-shot treatment modes for genetic surfactant protein diseases.