Simulations of the time required to reach 90% of the "dermal" (i.e., applied) analyte concentration at the sensor surface suggest that, for low molecular weight (<3 kDa) analytes, the lag times associated with our ex-vivo sensor placement would be on the order of tens of minutes (Figure &). To perform these simulations, we construct a model dermis, microneedle lumen, and sensor space and set a homogenous concentration throughout the entire model (figure ). Then we spike simulated dermis with 5 mM of the target and monitor the concentration seen at the furthest point from the microneedle lumen. Doing so we found that, with glucose (180 Da) as the target, the sensor surface reaches 90% of its final concentration within 20 min, a time scale that compares well with the previously demonstrated 11 min lag times of a similar, on-body, microneedle-based continuous glucose monitor . Using the amino acid phenylalanine (165 Da) as the target this lag time decreases to 17 min, and for the antibiotic vancomycin (1449 Da) times it increases to 50 min. Not surprisingly, our device performs more poorly for higher molecular weight analytes. For inflammatory marker IL-6 (21 kDa), for example, the concentration at the distal site reaches only 31% of the dermal analyte concentration even after 2h.