UNC-CH Physics and Astronomy Colloquium

Giuliano Scarcelli, University of Maryland

“Biophysical contrast mechanisms for biomedical imaging”

The interaction between photons and acoustic phonons within materials, first described by Leon Brillouin, has been widely investigated to characterize mechanical and physical properties of samples. To translate this technology to biomedical applications where mechanical properties are often critical, our lab has developed high-resolution spectrometers at high throughput and combined them with optical microscopes to yield 3D imaging modalities that use label-free biophysical properties as contrast mechanisms for imaging. Our first area of application has been in ophthalmology as the loss of corneal strength leads to ectasia and is a major risk factor for refractive surgery complications. To address this issue, we have developed an in vivo Brillouin ophthalmoscope and encouraging data show we can differentiate ectatic corneas as well as characterize outcome of emerging treatments. Recently we have demonstrated increased Brillouin microscopy resolution to characterize intracellular modulus and we developed a flow cytometry platform to rapidly characterize cells based on their mechanical properties. Finally, we will discuss the physics behind the interpretation of Brillouin spectral signatures in the context of soft matter such as cells and tissues.