Enhancing Optical Transparency in Biological Tissues Using Photonics Engineering

Dynamic imaging is a pivotal tool for answering complex scientific questions across physics and biology. However, traditional optical imaging platforms are hampered by the inadequate penetration depth in biological tissues, which restricts our understanding of dynamic behaviors. The complex structure of biological matter, while enabling a tremendous diversity of functions, also causes opacity due to unwanted scattering and absorption of light, which limits the penetration depth of optical imaging. In this talk, I will discuss the utilization of photonics engineering to achieve optical transparency in biological tissues. The turbid of the tissue originates from the microscale refractive index heterogeneity of the biological tissue and light scattering originates from the difference between low refractive index aqueous-based components and high refractive index lipid- and protein-based components. Leveraging Kramers-Kronig relations in the visible region, we integrate molecules that significantly absorb light into a scattering medium and transform an opaque sample into a transparent window, allowing deep investigation into embedded anatomical features. Utilizing this innovation, we have developed non-invasive imaging techniques to analyze the dynamic bheaviors (e.g., internal organ, vascular flow, neural network) inside living animals. These innovations highlight the potential of photonic engineering to revolutionize our understanding of biological systems.