Imaging for physiologically relevant 3D micro-environment

Optical imaging enables fast and minimally invasive observation of biological processes within living cells and organisms. However, current state-of-the-art imaging instruments have limitations in acquisition speed, spatial resolution and light-penetration depth that restrict the types of biological questions that can be addressed. This is particularly problematic for biological samples that span several orders of magnitude in spatiotemporal scale. For example, cell-cell interactions within the tumor microenvironment and their response to treatment can occur over seconds to days and be heterogeneous throughout an entire tissue volume. Coupling these physiological outcomes to the underlying molecular mechanisms (and potential therapeutic targets) requires a transformation in not only the technologies we use, but also the combination of methods to cross the spatiotemporal scales from cells to tissues. Recent developments in emerging techniques like cleared-tissue-imaging coupled with lightsheet microscopy (LSM) has enabled researchers to probe deeper into the tissue without needing to section them. Illumination with lightsheet offers a much faster and less phototoxic alternative in comparison to point scanning microscopes. However, all LSM struggle with a number of fundamental limitations: (a) poor axial spatial resolution, (b) a limited refractive-index range that the objectives can be employed and thus the LSM can operate on, and, (c) the size of the samples that they can handle. In this presentation we will explore how efforts in my laboratory are trying to circumvent these problems and to develop new technologies that vastly extend the imaging capabilities and reach of optical microscopy such that research related to basic biology and to human diseases can be performed in more physiologically relevant, 3D environments, ex vivo and in vivo.