In recent years, we have observed spectacular advancements in the area of nano-circuits and systems at several levels, from the fabrication material and device levels to the system and application levels. New emerging materials provide us with a wealth of new devices such as (silicon) nanowires, graphene, and carbon nanotubes fabricated in various technologies. Applications of these devices are vast and include, but are not limited to, new computing and memory structures, super-capacitors, as well as nano-bio-sensors based on the molecular combination of molecular probes to electronic devices. This special issue of the Journal on Emerging and Selected Topics in Circuits and Systems (JETCAS) has the purpose to collect some selected contributions to the workshop as well as other works in this domain, all subject to peer review. In particular, this issue focuses on two specific topics: biomedical circuits and systems, and 3-D integrated circuits and systems. This choice is motivated by a synergy of the spontaneous contributions in these areas as well as by the importance of these fields. We will review these two areas at large before briefly summarizing the contributions.