To simulate the mechanical properties of human skin, a skin-mimicking phantom gel was prepared and used to evaluate the electrochemical performance of the sensor . A 1.4% agarose gel was prepared by mixing 140 mg of agarose into 10 mL of the aforementioned artificial ISF. The mixture was continuously stirred at 120 °C until it became completely clear. Subsequently, the solution was poured into round-shape molds to solidify at room temperature. To further mimic skin, a layer of parafilm was placed over the prepared gel . During the "in vivo" phantom hydrogel experiments, the HMNs of the sensor were penetrated through the parafilm into the phantom gel, The HMNs remained in contact with the gel for 1 minute before the electrochemical detection of the glucose . This setup verified the ISF sampling ability and the electrochemical sensitivity of the integrated sensor. The same method used for glucose detection in ISF was applied to detect glucose concentration in skin-mimicking phantom gel. The signal from connector was analyzed using amperometry in the EIWP110 software. Once the current stabilized, the gel with a certain concentration of glucose was replaced with the gel containing a different glucose concentration.