Herein, we demonstrate the first continuous measurements of affinity-based aptamer sensors in human subjects. We achieved this by coupling ex vivo sensors to ISF via minimally-invasive, fluid-filled microneedles. In parallel, we report several advances in the manufacturing and storage of such devices. Although we faced multiple limitations in the design of this device, the results presented here demonstrates the feasibility of electrochemical aptamer-based sensors as a continuous sensing modality able to work directly on the human body. To move beyond feasibility studies, continued research into the circuitry through the microneedles and dermis to improve the range of square-wave frequencies that can be employed to interrogate this and similar aptamer sensor devices, which could unlock the ability to correct for sensor drift through kinetic differential measurement and to achieve quantitative in vivo measurements.