Iron Probe Project

Below is a video of my research during my time in graduate school. The video was sponsored by the University of New Hampshire College of Engineering and Physical Sciences. 

The focus of my current work is on Fe(III) recognition-based ratiometric fluorescent probes. These probes are designed based on peptides with relevant chelators and fluorophores attached. The iron probes will target the mitochondria to monitor ferroptosis, a form of iron-related cell death. Iron probes are notoriously difficult to synthesize and test due to iron's redox activity & selective coordination chemistry. 

Current work includes optimization of the chelator design to be a tripod, therefore 1 chelator will bind to 1 iron atom. Additionally, the selectivity of the chelator is currently undergoing thorough selectivity testing to ensure the probe will not bind to other metals, such as Zn(II) found in cells. This selectivity testing is being conducted with Jobs plots, fluorescence studies and titration experiments.

Future work includes localization targeting to the mitochondria over other organelles in the cell. Two possibilities are available to target the mitochondria. First the amino acids that makeup the peptide will be varied to determine the best localization effect from alternating hydrophobic and cationic hydrophilic groups. The cationic groups target the negatively charged phospholipid membrane layer and the hydrophobic groups pull the entire probe through the bilayer to the inside of the cell. A second choice for improved localization is a mitochondria localizing fluorophore, similar to the results we found experimentally with a thiazole orange fluorophore targeting an iron probe to the nucleus in OVCAR cells.

Finally, since this work is focused on designing a ratiometric fluorophore, it is thereby necessary that fluorophores are chosen which do not undergo the inner filtering effect or non-radiative decay pathways, such as intersystem crossing. Current fluorophore choices include BODIPY variations previously published in the literature or available commercially to purchase.