Abstract: The present invention relates to methods and devices for non-invasive and non-disturbing measurements of metabolizing rates of substantially spherical metabolizing particles, such as an embryo, and to a method and device for controlling oxygen partial pressure at the level of the embryo. Furthermore, the invention relates to a method for regulating supply of metabolites to a substantially spherical metabolizing particle, as well as a method for selecting substantially spherical metabolizing particles of a predetermined quality. The invention is carried out in a device capable of establishing a diffusion gradient of metabolites between the substantially spherical metabolizing particle inside a compartment in the device and the environment outside the compartment. The metabolizing rate is determined based on information of the metabolite diffusion gradient.

Abstract: The present invention relates to a sensor for measuring tissue perfusion comprising a diffusionally permeable reservoir and at least two diffusionally permeable detector chambers, in which sensor at least two diffusionally permeable detector chambers are located in different distances from the reservoir and that the at least two detector chambers are also located in different distances from any additional diffusionally permeable reservoir. Furthermore the present invention relates to a method for measuring tissue perfusion in which method a tracer gas is measured in separate detection chambers located in increasing distance from a reservoir comprising at least one tracer gas.