Project Summary Annually, over 1.2 million CT-guided lung biopsies are performed worldwide for lung cancer diagnosis (~400,000 in the US). Pneumothorax (PTX), a collapsed lung, is the most common complication of this procedure, occurring in 20-40% of all CT-guided lung biopsies. In 10-15% of lung biopsies, the patient becomes symptomatic due to PTX and requires an invasive chest tube insertion, the definitive treatment for PTX. This complication costs, on an average, $15k per chest tube insertion and $1.3 billion worldwide to treat. This turns a same-day diagnostic procedure into a multi-day hospitalization. In addition to extreme respiratory distress to patients, it is inconvenient for radiologists to manage. PTX arises when air from the lungs or external environment enters the area between the chest wall and lungs during or after needle insertion due to a pressure difference. A recent time dependent analysis of 3,251 patients undergoing CT-guided lung biopsy demonstrated that ~75% of PTX occur while the needle is inserted (meaning air is actively leaking during the procedure). Several methods are used for preventing PTX due to biopsy, including the only FDA approved device, blood/saline patch and air aspiration. All of these methods, however, are for application to the puncture site once the biopsy is complete and are therefore relatively ineffective (<50%). Additionally, they add time (>10mins) and steps (>5) to the procedure. The development of a novel biopsy needle track biosealant that will reduce or eliminate PTX would be most valuable. The focus of the current investigation is to evaluate and demonstrate the possibility of using a biosealant and delivery device to seal needle tracks and prevent PTX during transthoracic lung biopsy. Further, in-vitro and in-vivo biocompatibility of the material as well as efficacy of the delivery device as compared to the current standard of care will be assessed. Data from the Phase 1 program supports that an injectable hydrogel formulation can successfully prevent PTX in animal studies, and that candidate formulations show no adverse biological activity. In this Phase 2 proposal, we intend to refine the formulation for improved surgical performance and validate it with an animal model to demonstrate both efficacy and safety.