Figure 3.

(A) Schematic presentation of the cascaded oxidation of dopamine to aminochrome by the aptamer-modified pA-AuNPs, i.e., the aptananozyme bioreactor system, using the catalyzed aerobic oxidation of glucose as the source of the intermediate H₂O₂ oxidant. The set of aptananozymes I–V was used to catalyze the cascaded process. (B) Rates of dopamine oxidation to aminochrome in the presence of glucose by (a–e) the aptananozyme in configurations I–V, (f) the pA-AuNPs functionalized with scrambled DBA (2a), and (g) the pA-AuNPs separated with DBA (2). All systems consist of a 5 mM MES buffer solution, pH = 5.5, 5 mM MgCl₂, 100 mM NaCl, that includes the 5 nM aptananozyme and 50 mM glucose. Error bars derived from N = 3 experiments.