Drug-Porous Silicon Dual Luminescent System for Monitoring and Inhibition of Wound Infection.

Wound monitoring and curing is of great importance in biomedical research. This work created a smart bandage that can simultaneously monitor and inhibit wound infection. The main components of the smart bandage are luminescent porous silicon (LuPSi) particles loaded with ciprofloxacin (CIP). This dual luminescent system can undergo accelerated fluorescent color change from red to blue upon the stimulation of reactive oxygen species (ROS) and elevated pH, which are main biomarkers in the infected wound. The mechanism behind the chemical-triggered fluorescent color change was studied in detail. In vitro experiment showed that the ratiometric fluorescent intensity (IRed/IBlue) of CIP-LuPSi particles decreased from 10 to 0.03 at pH 7.5 after 24 h, while the value deceased from 10 to 2.15 at pH 7.0. Strong correlation can be also found between the IRed/IBlue value and ROS concentration ranging from 0.1 to 10 mM. In addition, the oxidation of LuPSi also simultaneously triggered the release of CIP molecules, which exhibited bacterial inhibition activity. Therefore, the ratiometric fluorescent intensity change at red and blue channels can indicate not only the wound infection status but also the release of antibiotics. In vivo test proved that the smart bandage could distinguish infected wounds from acute wounds, just relying on the naked eyes or a cell phone camera. On the basis of the Si nanotechnology established in this work, theranostic wound care will be realized in future.