Before use, we must prime our devices to create the required fluidic connection between the ISF and our sensors. Due to the hydrophobic nature of the needle lumen, we employ vacuum to perform this priming. Unfortunately, however, electrochemical aptamer sensors lose functionality after exposure to vacuum (figure ). We speculate that this is due to physical desorption of the sensor surface chemistries, removing both aptamers and portions of the mercaptohexanol monolayer. To circumvent this, we deposited 10% trehalose solution onto the sensing surface and dry the sensors under vacuum, an approach similar to those often used to preserve DNA . Such treatment not only preserves the aptamer, but also impedes desorption of the gold-thiol bonds at the sensor surface (figure ). Critically, phenylalanine-detecting sensors dried in trehalose solution under vacuum and later rehydrated respond to their target with the same affinity and gain as we observed before drying (figure ). In addition to protecting sensors during priming, trehalose treatment also preserves sensors for dry, long-term, room temperature storage, an important consideration for clinical devices. To show this we tested trehalose preservation using two sensors: one targeting phenylalanine and a second targeting cortisol . We deposited trehalose solution on these sensors, dried them under vacuum, and stored them in dry nitrogen at room temperature for up to 90 days. After such storage, both sensors maintained their ability to respond to their targets after rehydrating in solution to remove the trehalose preservation layer (figure &). Specifically, at a square-wave frequency of 10 Hz, stored phenylalanine sensors exhibit signal gain (relative signal change at a given target concentration) within error of that seen in pre-storage controls. At higher frequencies (120 Hz for phenylalanine and 300 Hz for cortisol) the gain even increased slightly. This may be due to loss of non-specifically adsorbed aptamer, which would raise the background signal and thus reduce gain. Consistent with this, we see mild reductions in peak current after storage (figure &). This minor signal loss, is independent of the length of storage, furthering the argument it is not outright sensor degradation and suggests that dry storage under trehalose may be extendable to well beyond 90 days.