Date of Award
Campus Access Dissertation
Doctor of Philosophy (PhD)
Small molecules are attractive for imaging due to their size and ease of modification relative to other imaging counterparts. A new type of imaging modality, with the potential to generate high contrast images at greater depths than previously achieved, called photoacoustic imaging (PAI) has generated interest in recent years. Importantly, PAI requires access to light absorbing materials that have the capacity to convert absorbed light energy to sound energy in the ultrasound frequency (~10 MHz). Dye molecules well suited for this purpose must have a high capacity for light absorption and undergo efficient non-radiative decay for the production of a strong acoustic signal at the probing wavelength of interest. The di-fluoroboron curcumin molecule has been identified here as an inspirational molecular structure with the potential to fulfill these requirements as it possesses a high molar extinction coefficient (ε) and has the potential to undergo significant non-radiative decay through cis-trans isomerization. Furthermore, as discussed in this thesis, curcuminoid dyes have the potential to participate in nonlinear absorption processes to populate upper excited states and amplify the PA response. The scope of this thesis is focused on how synthetic modification at the terminal ends of the difluoroboron β-diketonate backbone influences the dye’s electronic, photophysical and photoacoustic properties. By adapting a variety of π-extended (accepting) aryl and electron-rich (donating) amino substituents the goal of the synthetic design is to not only increase the molar extinction coefficients of these dyes but also to tune their absorption maxima toward the near infrared (NIR) biological imaging window (700 – 900 nm) relative to the reference curcumin molecule.
Bellinger, Stephanie Erin, "Photophysical & Photoacoustic Properties of Electron Rich & π-Extended Quadrupolar Curcuminoid Dyes" (2017). Graduate Doctoral Dissertations. 315.