Major

Chemistry

Research Abstract

Surgical intervention is often necessary in the management of cancer; however, sufficient tumor resection is reliant on adequate discrimination between malignant and healthy tissues. A dual-modality imaging agent with Magnetic Resonance Imaging (MRI) and Optical Imaging capabilities has the potential to improve tumor visualization before and during surgery. Administration of the agent would provide preoperative MR images that localize the bulk of the tumor and intraoperative fluorescence imaging would elucidate tumor margins. Macrocyclic lanthanide complexes possess long-lived luminescent lifetimes, making them ideal candidates for this class of imaging probe; however, the use of high energy lasers to directly excite these ions could potentially be damaging to biological tissue. To address this issue, organic chromophores such as quinolines can be used to absorb the incident light and transfer it to a nearby lanthanide ion. This intramolecular energy transfer results in the indirect sensitization of the lanthanide ion luminescence. The goal of this project is to investigate the effect of different quinoline amide substituents on lanthanide sensitization and the resulting optical imaging and MRI properties of bimodal europium (III) complexes. To date, a library of europium (III) complexes comprised of an octadentate chelating ligand with an appended quinoline antenna has been synthesized. Upon spectroscopic analysis of these complexes, indirect sensitization of the europium (III) luminescence by the quinoline pendant arm was observed for all complexes in the library, the magnitude of which was found to be dependent on the position of the amide substituent. Using phosphorescence lifetime measurements in D2O and H2O, the majority of complexes have been estimated to possess one bound water molecule, which is necessary for MR agents to produce a contrast signal. Future work will include evaluation of the MRI properties of these complexes to better understand the effect of the different quinoline substituents on water exchange rates.

Faculty Mentor/Advisor

Osasere M. Evbuomwan

Available for download on Sunday, May 01, 2022

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Chemistry Commons

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May 1st, 12:00 AM

Effect of Quinoline Amide Substituents on the Luminescence and Magnetic Resonance Imaging (MRI) Properties of Bimodal Europium (III) Complexes

Surgical intervention is often necessary in the management of cancer; however, sufficient tumor resection is reliant on adequate discrimination between malignant and healthy tissues. A dual-modality imaging agent with Magnetic Resonance Imaging (MRI) and Optical Imaging capabilities has the potential to improve tumor visualization before and during surgery. Administration of the agent would provide preoperative MR images that localize the bulk of the tumor and intraoperative fluorescence imaging would elucidate tumor margins. Macrocyclic lanthanide complexes possess long-lived luminescent lifetimes, making them ideal candidates for this class of imaging probe; however, the use of high energy lasers to directly excite these ions could potentially be damaging to biological tissue. To address this issue, organic chromophores such as quinolines can be used to absorb the incident light and transfer it to a nearby lanthanide ion. This intramolecular energy transfer results in the indirect sensitization of the lanthanide ion luminescence. The goal of this project is to investigate the effect of different quinoline amide substituents on lanthanide sensitization and the resulting optical imaging and MRI properties of bimodal europium (III) complexes. To date, a library of europium (III) complexes comprised of an octadentate chelating ligand with an appended quinoline antenna has been synthesized. Upon spectroscopic analysis of these complexes, indirect sensitization of the europium (III) luminescence by the quinoline pendant arm was observed for all complexes in the library, the magnitude of which was found to be dependent on the position of the amide substituent. Using phosphorescence lifetime measurements in D2O and H2O, the majority of complexes have been estimated to possess one bound water molecule, which is necessary for MR agents to produce a contrast signal. Future work will include evaluation of the MRI properties of these complexes to better understand the effect of the different quinoline substituents on water exchange rates.