Fig. 1: Schematic illustrations and rheological analysis of flexible drug delivery system with valveless micropump.

a Schematic illustration of valveless micropump implanted into the brain to generate directional airflow for drug delivery b Exploded view of the device architecture, consisting of a drug reservoir, microfluidic layer, pumping layer, microheaters, and a flexible substrate. c Working principle of the micropump showing airflow generation in supply (S, top) and pump (P, bottom) modes via diaphragm deformation controlled by microheater heating and cooling. d Top and Cross-sectional views of the micropump with three chambers for peristaltic motion. Fluid intake through the supply mode (S) and fluid pumping for drug delivery through the pump mode (P). e Finite element analysis (FEA) showing directional airflow induced during the supply mode. f Sequence of peristaltic pumping actuation. Velocity profiles during pump mode (g) and supply mode (h). Flow rate comparison during pump (i) and supply mode (j), illustrating forward flow (solid line), reverse flow (dotted line), and differential volume changes (colored in red or blue line).