Fluorophore-decorated carbon nanotubes with enhanced photothermal activity as antimicrobial nanomaterials

Official URL: http://dx.doi.org/10.1021/acsomega.9b00099

Alternative approaches to inactivate bacteria through physical damage provide an important solution to problems associated with colonization of material surfaces by antibiotic-resistant bacteria. Here, we present the utilization of carbon nanotubes functionalized with near-infrared (NIR)-absorbing fluorophores as effective photothermal agents that can kill bacteria through laser-activated heat generation. The array of 3,3'-diethylthiatricarbocyanine (DTTC) fluorophores self-assembled on the surface of multiwalled carbon nanotubes (MWNTs) acted as a light-harvesting antenna that increased the NIR light absorption and heat generation capacity of the MWNTs. The MWNT/DTTC nanohybrids generated elevated temperatures reaching 92 degrees C upon 15 min NIR laser irradiation, resulting in a 77% killing efficiency on Pseudomonas aeruginosa cells in dispersion. When the MWNT/DTTC nanohybrids were embedded into a waterborne polyurethane matrix, the resulting surface coatings presented temperatures reaching 120 degrees C in only 2 min of laser irradiation, where multiple laser irradiation cycles did not affect the generated temperature elevations. MWNT/DTTC-polyurethane nanocomposite coatings were also demonstrated to kill all P. aeruginosa cells attached to the surface, indicating their strong potential as light-activated antimicrobial and antibiofilm coatings.