Continuous and non-invasive monitoring of metabolites, biological markers and drugs exploiting wearable sensors is even more an important instrument to monitor the evolution of diseases and to optimize athletes training. These kind of applications require innovative electrochemical sensors with extremely small dimensions, low cost and ultra-low power consumption. Acquisition systems based on standard operational amplifiers designed with conventional analog techniques are not able to satisfy ultra-low power, low dimensions and low-cost requirements of wearable biosensors, motivating an increasing interest in alternative solutions. The aim of this thesis is to design, optimize, implement on silicon in a 130nm CMOS technology and test on chip a digital-based acquisition system for electrochemical sensors (Digital-based potentiostat) with very low power consumption based on innovative digital techniques..