Microfabricated platforms can be used to study a heterogeneous panel of biosamples in a realistic in vivo setting. The platform can be formed of a polymer (e.g., a hydrogel) and can be constructed for implantation into an animal host for in vivo testing. The platform can have a plurality of testing regions therein that are constructed to allow exposure of the testing region to the host stroma when implanted in vivo. For example, the microfabricated platform can be used for screening different cancer cell-lines (e.g., to identify which cell line responds to an anti-cancer drug) or for screening different biomaterials (e.g., to identify a composition with ideal host response for a specific implantable device).
