Metastasis is responsible for the vast majority of cancer deaths. As the first step of metastasis, migration of tumor cells through the extracellular matrix (ECM) to the surrounding tissue is regulated by a variety of biochemical and biophysical signals in the ECM, which may even couple with each other to impose a combined effect. For example, interstitial flow—the slow convection of fluid occurring in the interstitial space of ECM—not only conjoins matrix permeability (or specific hydraulic conductivity) to provide direct mechanical cues to the resident cells through shear and normal stress, but also couples with biomolecular diffusion to induce chemotactic signals (e.g. CCR7-mediated autologous chemotaxis). Therefore, a mechanistic and quantitative understanding of the dependence of cancer cell migration on interstitial flow would require an ability to manipulate interstitial flow, matrix permeability, and bioactive molecules in the ECM without affecting other contributing factors such as stiffness and physical confinement.

We apply microfluidic technology to develop a variety of functional materials at the micrometer-scale, which are useful for targeted delivery of drugs and active materials, optical display, sensing, enhanced oil recovery, and environmental bioremediation. For example, we developed uniform-sized giant unilamellar vesicles (GUVs) encapsulating a combination of drugs and nutrients for treating mitochondrial dysfunction, which correlates with chronic fatigue syndrome; we fabricated photo-responsive liquid crystal micro-shells and drops for lasing, display and sensing; we created hydrogel microparticles with various 3D shapes, from hexagonal disks and prisms to Kelvin and Weaire-Phelan structures; we developed temperature-switchable nanoparticle colloidosomes for targeted drug delivery; we developed smart, deformable microcapsules that can release surfactant in the reservoir condition for enhanced oil recovery.