A photo-triggered layered surface coating producing reactive oxygen species

We report a photoactive surface coating which produces cytotoxic reactive oxygen species (ROS) upon irradiation with near infrared (NIR) light. The coating is assembled layer-by-layer, and consists of cross-linked hyaluronic acid (HA) and poly-l-lysine (PLL) modified with the photoactive molecule pheophorbide a. Pheophorbide a loading can be fine-tuned by varying the number of bilayers, yielding stable materials with the capacity to generate repeated and/or prolonged light-triggered ROS release. Light irradiation of the photoactive surface coatings provides a versatile platform for the spatiotemporal control of events at the material-tissue interface, such as bacterial colonization, platelet adhesion, and mammalian cell attachment.