The coated porous membrane was used to mimic the enteric coating of the GI tract. In this experiment, it contained fluorescent dye to more easily evaluate the selective opening of the coated pores in gastric and intestinal model fluids. Figure 4a shows images of the porous membrane in the following conditions, i) without coating, ii) filled with an enteric coating containing a fluorescent dye, iii) filled with fluorescent enteric coating after one-hour incubation in gastric simulant (pH 2.0) and, iv) filled with fluorescent enteric coating after one-hour incubation in buffer (pH 7.4). The coated membrane immersed in gastric simulant (low pH) maintained the polymeric coating blocking the pores, while the enteric-coated membrane submerged in buffer solution (neutral pH) dissolved, Figure 4b. The ability to delay the sampling of the robotic pill was evaluated by incubating the coated pill in a fluorescent solution. In this case, the enteric coating was not loaded with the fluorescent dye; thus, the signal obtained was related to the captured solution. Figure 4c displays photographs under fluorescent light of i) a robotic pill with no coating and ii) a coated robotic pill after one-hour incubation in gastric simulant with fluorescent dye and after the subsequent incubation of the same pill in buffer media. The non-coated porous membrane pill absorbed the media during incubation in the acidic solution. Conversely, the coated porous membrane presented limited absorption after incubation in acidic medium and full absorption at physiological pH, as shown in Figure 4d. These results indicate the potential of the robotic pill to selectively open its collection chamber in the intestine rather than in the stomach, thus avoiding contamination with stomach biomarkers.