Fabrication of PAMAM antimicrobial monolayer via UV induced grafting on the surface of polyethylene terephthalate.

Poly (amidoamine) (PAMAM) with 3rd and 5th generation was covalently grafted as the contact active biocidal agent on the surface of polyethylene terephthalate (PET) with the help of UV induced carbene chemistry (PAMAM-g-PET). The graft density and the surface roughness were controlled by turning UV irradiation time and the PAMAM generation. The PAMAM graft monolayer was characterized via the contact angle, XPS, nanoIR, SEM and AFM. The antibacterial ability of PAMAM-g-PET was evaluated ex-vivo with the help of laser scanning confocal microscope (CLSM), and the results indicated that the decorated PET was able to kill both S. aureus and E. coli in the aqueous environment. Increasing the surface graft concentration and using the dendrimer with higher generation enhanced the lethality towards the bacterial. The decorated film was still able to kill the contact bacterial strain when the cationic primary amine groups were shielded by acetyl chloride, however, the bacterial in the suspension was hardly affected in this case. The un-selectivity and instantaneity of carbene chemistry endowed this grafting strategy the potential to be extended to other organic substances.