Interstitial fluid (ISF) is the fluid that occupies the space between blood capillaries and cells. ISF consists mainly of water, salts, sugars, hormones, neurotransmitters, CO2 and fatty acids. It is particularly interesting as it is described as a filtrate of plasma, but more accessible than blood for continuous monitoring. Continuous monitoring of ISF is targeted, for example, for cortisol (a marker of stress, whose circadian rhythm makes continuous monitoring very interesting), sex hormones (PMA) and other biomarkers for monitoring a patient's state of health. The aim of this thesis is to develop a wearable device for ISF sampling, which co-integrates biocompatible or even resorbable hollow microneedles and a capillary microfluidic part. Eventually, this type of system will be combinable with various types of sensors at the fluidic outlet for various applications such as circadian cortisol monitoring for stress and post-traumatic stress. Three main issues will need to be addressed in this thesis: (a) One is the management of very low flow rates in passive microfluidics (flow rates in the nL/min range). (b) Technologically, the manufacturing process for resorbable hollow microneedles with fine management of the surface finish of the channel interior (to promote capillarity) will also be an important focus of the study. (c) Finally, the process will be evaluated and improved in terms of eco-circularity.