This paper presents a wireless, fully-integrated, miniature “BioMote” sensor node that can be injected through a 16-gauge syringe for continuous, long-term alcohol monitoring. A microelectrode electrochemical sensor array that measures alcohol, background, and pH was implemented to differentially measure ethanol while removing interference and motion artifacts. The low-power multi-technique potentiostat supports both amperometric and potentiometric techniques achieving 2.5 nA sensitivity with 30.1 dB dynamic range and 0.5 mV sensitivity with 43 dB dynamic range, respectively. The measurements are transmitted to a wearable device through backscatter using a self-oscillating current-to-frequency (I-to-F) converter. The system is wirelessly powered via the coupling between an on-chip 4-turn coil and a wearable device at 985 MHz. The self-contained 0.85×1.5 mm ² chip is implemented in 65 nm CMOS and consumes 970 nW.