Besides retaining the enzymatic activity, it is critical to consider that dyes and small molecules can easily penetrate into (or scape from) the alginate beads due to their inherent porous structure. Therefore, the ability of the beads to retain the selected redox dyes was evaluated over time, considering the color development within the beads (functionality) as well as in the area surrounding the beads (leaching), upon exposure to the solution containing the analyte. For these experiments, 1% ALG, 5% ALG, and ALGPODES beads were prepared with GOx/HRP (as a model reporter) but containing each of the selected chromogenic indicators (ODI, AAP/DHBS, or TMB). Again, three beads of each composition were placed into the cell (Figure ) containing 1 mL of a 0.1 mM glucose solution and their color development followed capturing pictures every 5 seconds for 600 seconds. The results, summarized in Figure SI 5, showed that the behavior is dominated by the water solubility of the dyes, more so than the composition of the beads; leading to the retention of the majority of ODI (25 mg/mL) and TMB (< 1 mg/mL), but enabling a small fraction AAP/DHBS (50 mg/mL, soluble) to leach out of the beads while in contact with the solution containing the analytes (10 min). As expected, beads fabricated with 1% ALG showed the lowest retention capacity, while the ALGPODES beads were superior at retaining the selected chromogenic agents, leading to the highest color intensities, and therefore supporting their use towards the development of the proposed biosensors.