Choi, MyunghwanChoi, Jin WooKim, SeonghoonNizamoglu, SedatHahn, Sei KwangYun, Seok Hyun2014-11-032013Choi, Myunghwan, Jin Woo Choi, Seonghoon Kim, Sedat Nizamoglu, Sei Kwang Hahn, and Seok Hyun Yun. 2013. “Light-guiding hydrogels for cell-based sensing and optogenetic synthesis in vivo.” Nature photonics 7 (1): 987-994. doi:10.1038/nphoton.2013.278. http://dx.doi.org/10.1038/nphoton.2013.278.1749-4885http://nrs.harvard.edu/urn-3:HUL.InstRepos:13347588Polymer hydrogels are widely used as cell scaffolds for biomedical applications. While the biochemical and biophysical properties of hydrogels have been extensively investigated, little attention has been paid to their potential photonic functionalities. Here, we report cell-integrated polyethylene glycol-based hydrogels for in-vivo optical sensing and therapy applications. Hydrogel patches containing cells were implanted in awake, freely moving mice for several days and shown to offer long-term transparency, biocompatibility, cell-viability, and light-guiding properties (loss: <1 dB/cm). Using optogenetic, glucagon-like peptide-1 (GLP-1) secreting cells, we conducted light-controlled therapy using the hydrogel in a mouse model with type-2 diabetes and attained improved glucose homeostasis. Furthermore, real-time optical readout of encapsulated heat-shock-protein-coupled fluorescent reporter cells made it possible to measure the nanotoxicity of cadmium-based bare and shelled quantum dots (CdTe; CdSe/ZnS) in vivo.en-USOptical waveguideHydrogelBiosensorOptogeneticsSynthetic biologyPhotomedicineJournal Article2014-11-0310.1038/nphoton.2013.278