In tissue engineering, cells are grown on biomaterials in vitro and subsequently implanted. A critical parameter in effective proliferation and differentiation is the availability of nutrients. Few tools are currently available to monitor the nutritional status of cells. In this study, we have employed A4-4 cells [1], a Chinese hamster ovary cell line stably transfected with a luciferase gene driven by the hypoxia responsive element (HRE) from the promoter region of the VEGF gene [2, 3]. HRE activity, and thus luciferase activity, directly correlates with decreasing cellular O2 levels.The aim of this study is to investigate whether the HREluciferase construct can be used for non-invasive imaging of hypoxia in tissue engineering