A groove (500-μm width and 200-μm depth) on a Teflon surface was purposely created by scraping the substrate using a blade. To repair the damage, syringes containing DOPA-modified TLC-M solution containing liquid-like droplets (2 mg/ml) and fluorescent PS microspheres (10 μm in diameter) solution (10 mg/ml) 1:1 were simultaneously coinjected around the damage sites along the groove. The repaired samples were then incubated overnight at 4°C to ensure full curing and were later on inspected under SEM after drying in air. Data are presented in Fig. 4F.