According to Dr. Sei Kwang Hahn from Pohang University of Science and Technology in South Korea, smart photonic materials have a variety of biomedical applications for biosensing, molecular imaging, surgery and therapies. In a conference organized by the Gordon Center, he discussed his research efforts to develop melanoidin nanoparticles for in vivo noninvasive photoacoustic mapping of sentinel lymph nodes, photoacoustic tomography of gastro-intestinal tracts, and photothermal ablation cancer therapy. Dr. Hahn and his colleagues created biodegradable polymer waveguides and upconversion nanoparticles for photochemical tissue bonding. They also synthesized cell-integrated poly(ethylene glycol) hydrogels for in vivo optogenetic sensing and therapy. Real-time optical readout of encapsulated heat-shock-protein-coupled fluorescent reporter cells made it possible to measure the nanotoxicity of cadmium-based quantum dots in vivo. Using optogenetic cells to produce glucagon-like peptide-1, Dr. Hahn developed smart contact lenses composed of biosensors, drug delivery systems and power sources for the treatment of diabetes as a model disease.