On-chip on-demand delivery of K+ for in vitro bioelectronics.

Bioelectronic devices that interface electronics with biological systems can actuate and control biological processes. The potassium ion plays a vital role in cell membrane physiology, maintaining the cell membrane potential (V_mem) and generating action potentials. In this work, we present two bioelectronic ion pumps that use an electronic signal to modulate the potassium ion concentration in solution. The first ion pump is designed to integrate directly with six-well cell culture plates for optimal ease of integration with in vitro cell culture, and the second on-chip ion pump provides high spatial resolution. These pumps offer increased ease of integration with in vitro systems and demonstrate K⁺ concentration distribution with high spatial resolution. We systematically investigate the ion pump's performance using electrical characterization and computational modeling, and we explore closed-loop control of K⁺ concentration using fluorescent dyes as indicators. As a proof-of-concept, we study the effects of modulating K⁺ concentration on V_mem of THP-1 macrophages. [ABSTRACT FROM AUTHOR]