FIG. 2.

Microneedle-based insulin delivery at 1, 3.5, and 5 mm insertion depths in comparison to 9-mm catheter control (Phase 1). (a) Plasma free insulin level and (b) corresponding plasma glucose level response. Microneedle-based insulin delivery at 1 mm led to high insulin absorption and rapid glucose level reduction. (c) AUIC for 0–1 h and (d) change in plasma glucose levels from 0 to 1 h. Within 1 h of insulin bolus, the 1-mm microneedle (MN) delivery case led to an AUIC more than twice that of the catheter control and produced a higher change in plasma glucose levels.