Photoacoustic Nanosensors for Continuous Monitoring of Physiological Chloride Levels for Cystic Fibrosis

Current methods of cystic fibrosis diagnosis are inconsistent and demanding. In patients with cystic fibrosis, defective chloride ion channels lead to a buildup of chloride within the interstitial fluid. Using nanosensors known as optodes, it is possible to achieve continuous monitoring of these chloride levels. In this study we validated the potential of photoacoustic nanosensors for consistent chloride monitoring in the physiological chloride range. These nanosensors take advantage of the increased penetration depth and resolution provided by photoacoustic imaging in order to expand and improve upon previously existing fluorescent chloride nanosensors. We confirmed the assembly of these sensors in the nanometer diameter range and validated their fluorescent response with that of existing fluorescent chloride optodes. We further investigated these nanosensor’s photoacoustic response to chloride levels within the dynamic range and successfully demonstrated a relationship between our sensor’s photoacoustic signal output and the chloride concentration of the surrounding environment. This relationship serves as a potential basis for our sensor's use in vivo for continuous chloride monitoring in cystic fibrosis patients.