St. Luke's-Roosevelt Medical Center View Institution's Website 1 article published in JoVE Biology Protein Transfection of Mouse Lung Patrick Geraghty1, Robert Foronjy1 1Department of Medicine, St. Luke's Roosevelt Medical Center Transgenic mice or viral vectors have been used to increase protein expression within the lung. However, these techniques are time-consuming, technically challenging and have off-target effects that can confound results. Our protein transfection protocol uses a lipid based transfection reagent and an ultrafine microsprayer to uniformly deliver active protein to lung cells.