CMOS electrochemical pH localizer-imager

• Published in: Science advances 2022-07, Vol.8 (30), p.eabm6815-eabm6815
• Main Authors: Jung, Han Sae, Jung, Woo-Bin, Wang, Jun, Abbott, Jeffrey, Horgan, Adrian, Fournier, Maxime, Hinton, Henry, Hwang, Young-Ha, Godron, Xavier, Nicol, Robert, Park, Hongkun, Ham, Donhee
• Format: Article
• Language: English
• Subjects: Applied Sciences and Engineering; Electrochemistry; Physical and Materials Sciences; SciAdv r-articles
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.abm6815

pH controls a large repertoire of chemical and biochemical processes in water. Densely arrayed pH microenvironments would parallelize these processes, enabling their high-throughput studies and applications. However, pH localization, let alone its arrayed realization, remains challenging because of fast diffusion of protons in water. Here, we demonstrate arrayed localizations of picoliter-scale aqueous acids, using a 256-electrochemical cell array defined on and operated by a complementary metal oxide semiconductor (CMOS)-integrated circuit. Each cell, comprising a concentric pair of cathode and anode with their current injections controlled with a sub-nanoampere resolution by the CMOS electronics, creates a local pH environment, or a pH "voxel," via confined electrochemistry. The system also monitors the spatiotemporal pH profile across the array in real time for precision pH control. We highlight the utility of this CMOS pH localizer-imager for high-throughput tasks by parallelizing pH-gated molecular state encoding and pH-regulated enzymatic DNA elongation at any selected set of cells.