Imaging through skin and tissue is something of a unifying theme in the group. Much of our work developing new dyes and chromophores is motivated by what infrared light can do in the body: it scatters and is absorbed less than visible light, so it can show structures deep beneath the skin. We work on both sides of light at the skin, seeing through it and blocking it.

Imaging in the shortwave infrared. With the Sletten and Bruns groups, we have helped develop bright polymethine dyes for in vivo SWIR imaging, and shown that indocyanine green, a dye already used in clinics, can be imaged in the SWIR.

Sunscreens. Mineral sunscreens protect by absorbing and scattering UV light, but the same scattering causes white cast on skin. With Paul Weiss’s group, we have made flame-synthesized ZnO tetrapods as UV filters and developed a way to measure sunscreen reflectance and white cast across skin tones.

Collaborators: Ellen Sletten (Dartmouth) and Paul Weiss (UCLA).