distance from the solution/gel boundary, although the detailed variation suggests
heterogeneity in the diffusion within the agarose gel. Significantly, the ability to
map the diffusion of molecular and biomolecular species in 3D hybrid systems
Fig. 3.4 3D macroporous chemical sensors.ax-z views of 3D reconstructed image of the 3D
macroporous nanoelectronic network in gel. Red (rhodamine 6G): SU-8 mesh network and blue
(DAPI): agrose gel. Dimensions: x = 317lm; y = 317lm; and z = 144lm.bSchematics of the
experimental set-up.cThe projection of four nanowire devices in the y-z plane. Red dashed line
corresponds to the approximate gel boundary, and the red and blue areas correspond to aqueous
solution and agrose gel, respectively.dRepresentative change in calibrated voltage over time with
pH change for 3D macroporous nanowire chemical sensors in solution (I) and embedded in agrose
gel (II).eCalibrated voltage with one pH value change in solution for 4 different devices located
in 3D space. (I) 4 devices without gel and (II) 4 devices embedded in agrose gel
3.3 Results and Discussion 33