In-vivo cancer cells create a unique microenvironment which enables their spread to other organs. To understand the tumor microenvironment, special tools and devices are required to monitor the interaction among different cell types as well as the effects of particular chemical gradients. We are reporting on the status of a new device (the NANIVID: NANoIntraVItal Device) that will collect chemotactic cells from the tumor environment. Due to the transparency of this implantable device, direct in-vivo cell imaging both inside and outside the device is possible. The cell collection chamber of the device consists of a micro-electrode system based on patterning of transparent, conducting films that deliver real time data including cell density and dynamics. The current development and testing status of the device will be presented. This will include the modeling of ligand gradient profile results produced from the device and the cell migration in the EGF (epidermal growth factor) gradient created by the device. Further, prototype electrode arrays were designed, fabricated and cells were cultured on the arrays at selected degrees of confluence to measure the device sensitivity. The development path of the NANIVID will be integrated with an existing animal model protocol for in-vivo testing. This will result in a clearer understanding of the dynamics of a tumor's metastatic progression.