Sealants are used to prevent prolonged pulmonary air leakage (PAL) after lung resections (incidence 5.6-30%). However, clinical evidence to support sealant use is insufficient, with an unmet need for a more effective product. We compared a novel gelatin patch impregnated with functionalized polyoxazolines (NHS-POx) (GATT-Patch) to commercially available sealant products.GATT-Patch Single/Double layers were compared to Progel®, Coseal®, Hemopatch® and TachoSil® in an ex vivo porcine lung model (first experiment). Based on these results, a second head-to-head comparison between GATT-Patch Single and Hemopatch® was performed. Air leakage (AL) was assessed in three settings using increasing ventilatory pressures (max =70 cmH2O): (I) baseline, (II) with 25 mm × 25 mm superficial pleural defect, and (III) after sealant application. Lungs floating on saline (37 ℃) were video recorded for visual AL assessment. Pressure and tidal volumes were collected from the ventilator, and bursting pressure (BP), AL and AL-reduction were determined.Per sealant 10 measurements were performed (both experiments). In the first experiment, BP was superior for GATT-Patch Double (60±24 cmH2O) compared to TachoSil® (30±11 cmH2O, P<0.001), Hemopatch® (33±6 cmH2O, P=0.006), Coseal® (25±13 cmH2O, P=0.001) and Progel® (33±11 cmH2O, P=0.005). AL-reduction was superior for GATT-Patch Double (100%±1%) compared to Hemopatch® (46%±50%, P=0.010) and TachoSil® (31%±29%, P<0.001), and also for GATT-Patch Single (100%±14%, P=0.004) and Progel (89%±40%, P=0.027) compared to TachoSil®. In the second experiment, GATT-Patch Single was superior regarding BP (45±10 vs. 40±6 cmH2O, P=0.043) and AL-reduction (100%±11% vs. 68%±40%, P=0.043) when compared to Hemopatch®.The novel NHS-POx patch shows promise as a lung sealant, demonstrating elevated BP, good adhesive strength and a superior AL-reduction.