  There has been a recent tremendous interest in label-free detection of
biomarkers which is a critical enabler of point-of-need diagnostics. A
low-power, small form factor, multiplexed wearable system is proposed for
continuous detection of glucose in passively expressed sweat using
electrochemical impedance spectroscopy (EIS) measurement. The wearable EIS
system consists of a sensing analog front end integrated with low-volume (1-5
$\mu$L) ultra-sensitive flexible biosensors. A passive sweat sensor was
designed to integrate a glucose oxidase electrochemical system on active
semiconducting material. The non-faradaic EIS response of the biosensor was
used to calibrate the analog front end response using ratiometric Discrete
Fourier Transform (DFT) for a shorter measurement time. In this work, a
stringent assessment of a continuous glucose sensing platform is performed in a
bottom-up approach, going from the biosensor to the system to the interaction
with a human subject. The active semiconductor-based biosensors are dosed with
glucose concentrations ranging from 5-200 mg/dL and detection is performed
using the analog front end. In addition, a detailed analysis of battery life
and performance of a wearable EIS system is discussed to define a figure of
merit for an optimally integrated design. Moreover, a continuous glucose
detection test is performed on a healthy human subject cohort to investigate
the stability of the sensor-system mechanism for an 8-hour period, and a
time-series-based, auto-regressive (AR) model was created for the system.
