Ratiometric techniques can be used to determine activity levels of reactive oxidation species (“ROS”) in a target area (in vitro or in vivo) to indicate inflammatory responses and/or infection. Target areas may be a tissue surface, a wound, and/or a body cavity. A ROS-sensitive bioluminescent agent and ROS-insensitive fluorescent reference dye are conjugated to surfaces, biocompatible particles, or polymer carriers. The compounds may be constituted as a spray, solution for injection, a wound dressing, medical implants, and/or medical device. The bioluminescent compound and reference fluorescent intensity ratios can be calculated to reflect the extent of localized ROS activities.
