Hydrogel optical fibers: Bringing light to brain, nerves, and bioreactors
Light is a powerful tool for regulating biological activity, sensing physiological signals, and driving photosynthetic processes. However, delivering light within biological environments remains challenging because conventional optical fibers are fabricated from rigid materials that are mechanically incompatible with soft tissues and difficult to integrate into complex living systems. In this webinar, I will discuss our efforts to develop hydrogel optical fibers based on nanoparticle-polymer composites that combine tissue-like mechanical properties with programmable optical functions. By engineering nanoparticle composition, polymer network architecture, and fiber geometry, we establish design principles governing light transmission and scattering in soft photonic materials. These principles have enabled hydrogel optical fibers for applications spanning biomedicine and biomanufacturing. In the nervous system, we developed mechanically compliant optical interfaces for light delivery and signal collection in the brain, nerves, and muscles of freely moving animals, minimizing tissue damage and improving long-term optical coupling. In bioreactors, we engineered scattering hydrogel fibers that redistribute light throughout dense algal cultures, overcoming the severe light attenuation that limits conventional photobioreactors. The above two examples demonstrate how hydrogel fibers can bridge optics and biology and create new opportunities for human-machine interface and sustainable biomanufacturing.
Bio: Xinyue Liu is an assistant professor in the Department of Chemical Engineering and Materials Science at Michigan State University. She earned her B.S. in polymer science from Sichuan University in 2015 and her Ph.D. in mechanical engineering from the Massachusetts Institute of Technology (MIT) in 2021, followed by postdoctoral training at MIT. Her research seeks to establish network topology as a design principle for soft materials, enabling programmable control over phase separation, fracture, optical transport, and molecular transport. Her lab integrates polymer physics, biomaterials, and nanocomposites to develop hydrogel optical fibers, mechanoresponsive biomaterials, and living-cell-laden matrices for applications spanning neural interfaces, regenerative medicine, biosensing, and sustainable biomanufacturing. Liu has been recognized with the NSF CAREER Award, the ACS Petroleum Research Fund Doctoral New Investigator Award, Journal of Materials Chemistry B Emerging Investigator, and Forbes 30 Under 30 Asia.