Figure 1
Layouts and characteristics of bioresorbable, wirelessly programmable drug delivery devices that exploit thermally activated lipid membranes. (a) Optical image (scale bar: 5 mm) of a device that consists of a 2 × 2 array of inductive coupling coils and serpentine thermal actuators on a bioresorbable substrate (left). Schematic exploded view illustration (right). (b, c) Three-dimensional (3D) Z-stacked confocal microscope images and schematic illustrations of a lipid membrane loaded with drug molecules. (d) Small angle X-ray scattering (SAXS) scans from a lipid membrane at temperatures between 25 and 50 °C (left), with expanded view between 40 and 43 °C (right) showing the transition from an liquid-ordered to a liquid-disordered state. (e) An infrared (IR) image (scale bar: 1 cm) collected during operation of a representative device with a corresponding optical image (inset) showing spatially controlled heating (f) Distribution of temperature determined by finite element analysis (FEA). (g) Experimental (lines) and FEA (dots) results for average temperatures (marked 4 in e, f). The temperature of the wirelessly triggered actuator reaches 45 °C while the other regions (marked 1, 2, 3 in e, f) remain at nearly room temperature. FEA, finite element analysis; Ld, liquid disordered; Lo, liquid ordered; PLGA, poly(lactic-co-glycolic acid).
