Frederik Brondsted

Frederik’s dissertation, “Listening to Light: Leveraging a New Class of Near-Infrared Dyes to Transform Biological Imaging,” examines the use of Nebraska Red dyes to increase PA signal and construct acoustogenic probes. Optical methods have provided invaluable insight into the structure, organization, and function of molecules in biological systems. However, purely optical methods have largely been limited to living cells and shallow imaging applications in small animals. Alternatively, photoacoustic tomography (PAT) relies on chromophores that excite in the far-red to near-infrared region (NIR, > 650 nm) and a phenomenon known as the photoacoustic (PA) effect, in which absorbed NIR excitation is converted to sound waves. Given the ability of sound waves to travel through biological tissues, PAT can yield imaging depths up to ~10 cms. We seek to address this issue by leveraging a new class of phosphinate-containing xanthene derivatives described in our laboratory, termed Nebraska Red (NR) dyes (Fig. 1).8 Importantly, NR dyes display the highest extinction coefficient among red-shifted xanthenes described in the literature, indicating their potential as robust PA imaging probes.