Calu-3 cells (human lung adenocarcinoma, ATCC HTB-55) were maintained in growth medium (MEM 10% FCS, 100 U/mL penicillin G and 100 µg/mL streptomycine, 1% nonessential amino acids (NEA), 1 mM pyruvate, 2 mM glutamine and 2.88 g/L glucose) at 37 °C and 5 % CO 2 . The experiments were performed as described previously. For the measurement of the cytotoxicity of the polymer, 5000 cells/well of both Calu-3 and HEK cells were seeded in 96-well plates in growth medium and incubated at 37 °C and 5 % CO 2 for 24 h and 48 h, respectively. Final polymer concentrations of 10, 5, 1 and 0.1wt.% were prepared from a stock solution (20 wt.%) in growth medium on ice and added to the cells. After 24 h of cell growth, the medium was removed and replaced by fresh cell culture medium. Cells were incubated with WST-1 reagent for 1-4 h at 37 °C according to manufacturer's manual. The formation of formazan was monitored at 450 and 630 nm using a Spectramax 250 microplate reader from Molecular Devices (Sunny-vale, CA, US).