Longitudinal, quantitative monitoring of therapeutic response in 3D in vitro tumor models with OCT for high-content therapeutic screening

In vitro three-dimensional models of cancer have the ability to recapitulate many features of tumors found in vivo, including cell-cell and cell-matrix interactions, microenvironments that become hypoxic and acidic, and other barriers to effective therapy. These model tumors can be large, highly complex, heterogeneous, and undergo time-dependent growth and treatment response processes that are difficult to track and quantify using standard imaging tools. Optical coherence tomography is an optical ranging technique that is ideally suited for visualizing, monitoring, and quantifying the growth and treatment response dynamics occurring in these informative model systems. By optimizing both optical coherence tomography and 3D culture systems, it is possible to continuously and non-perturbatively monitor advanced in vitro models without the use of labels over the course of hours and days. In this chapter, we describe approaches and methods for creating and carrying out quantitative therapeutic screens with in vitro 3D cultures using optical coherence tomography to gain insights into therapeutic mechanisms and build more effective treatment regimens.