The goal of the project is to construct an optical pH sensor which would enable non-invasive pH measurements in vivo with high spatial and temporal resolution. The sensor will be applied for real-time monitoring of pH alterations in the brain in response to stimulation. In a long-term perspective the sensor should help to unravel the mechanisms of function and/or malfunction of pH-sensitive receptors and ion channels, and associated with them disorders, such as anxiety, panic disorder, pain, ischemic stroke, neurodegenerative diseases, seizures and respiratory control. The sensor is composed of 3 fragments: a pH-sensitive receptor, a fluorescent reporter, and a rigid bridge. The pKa of the pH-sensitive receptor is tunable, and should lie in the physiological pH range (5.5-8.0) to allow in vivo measurements. The photophysical properties of the fluorescent reporter (excitation and emission wavelengths, quantum yield, fluorescence lifetime) can be tuned due to the structural modifications. Porphyrins are known to be brightly emissive and have a key feature that is usually high two photon absorption cross section (2A). Due to this property the porphyrins can be utilized as contrast agents for two-photon excitation microscopy. In addition to high 2PA and bright luminescence, the porphyrins possess relatively long fluorescence lifetime, on average 3-4 times longer compared to existing fluorescent dyes. If the fluorescence lifetime of the porphyrin can be modulated by changing pH, it is possible to construct a lifetime-based fluorescent sensor for pH. To ensure aqueous solubility, biocompatibility and prevent binding of the sensor to the cell membranes, the sensor is encapsulated within a water-soluble dendrimer. Therefore, we will develop an optical pH sensor that would be able to measure pH measurement in vivo with high spatial and temporal resolution.

Development of pH sensor for<i> in vivo</i> applications

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Development of pH sensor for in vivo applications