Search

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 (Vmem) 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 Vmem of THP-1 macrophages. [ABSTRACT FROM AUTHOR]

Ions and biomolecules are signal carriers in biological systems and transfer information for intracellular communication and organism function. As such, bioelectronic devices that conduct ions rather than electrons and holes provide an interface to monitor and control physiological processes. These processes often are affected by multiple distinct ionic species. Here, we develop an ion pump that can control the delivery of multiple ionic species on the same chip. We demonstrate on-chip delivery of H+, Na+, and Cl− by monitoring the dynamic concentration change using fluorescent dyes. We integrate the multi-ion pump with machine-learning driven closed-loop control of delivery to ensure precise dose control. The ability to deliver multiple ions with tight control of their concentrations has the potential to finely regulate the extracellular environment and precisely control physiological processes. [ABSTRACT FROM AUTHOR]

Ions and biomolecules are the languages that biological systems use to transfer signals in intracellular communication and organism function. As such, bioelectronic devices that conduct ions and biomolecules rather than electrons and holes are particularly suited for biological integration. Among these ions, protons (H+) are important in many biochemical reactions including neuronal excitability and oxidative phosphorylation of adenosine triphosphate (ATP). In this Research Update, we describe our efforts in measuring and controlling the concentration of H+ ions in biological systems using bioelectronic devices with contacts that are made of palladium and palladium hydride (Pd/PdHx). Pd/PdHx contacts act as an electron to proton transducer and can be used in artificial membranes containing ion channels, biohybrid photodetectors, the delivery of biochemical stimuli, pH sensitive glucose sensing, and precise control of pH using machine learning. [ABSTRACT FROM AUTHOR]

Translation between ionic currents and measurable electronic signals is essential for the integration of natural systems and artificial bioelectronic devices. Chloride ions (Cl−) play a pivotal role in bioelectricity, and they are involved in several brain pathologies, including epilepsy and disorders of the autistic spectra, as well as cancer and birth defects. As such, controlling [Cl−] in solution can actively influence biochemical processes and can be used in bioelectronic therapies. Here, we demonstrate a bioelectronic device that uses Ag/AgCl contacts to control [Cl−] in solution by electronic means. We do so by exploiting the potential dependence of the reversible reaction, Ag + Cl− ↔ AgCl + e−, at the contact/solution interface, which is at the basis of the well-known Ag/AgCl reference electrode. In short, a negative potential on the Ag/AgCl contact transfers Cl− from the contact to the solution with increasing [Cl−] and vice versa. With this strategy, we demonstrate precise spatiotemporal control of [Cl−] in solution that can be used to affect physiological processes that are dependent on [Cl−]. As proof-of-concept, we use [Cl−] control to influence the membrane voltage on human pluripotent stem cells. [ABSTRACT FROM AUTHOR]

San Roman I et al. i [4] review the use of graphene nanostructures and discuss the fundamental relationships between device geometries, materials properties, and performance of the next generation bioelectronic devices. Jia I et al. i [5] demonstrate an electrochemical device that uses Ag/AgCl contacts to achieve precise spatiotemporal control of chloride ion concentration in solution and review their recent progress on using bioelectronics to control pH. Modern electronics and materials science are bringing revolutionary advances to biointerface design and are shattering the limits of what is possible in the areas of biomedical diagnostics and sensing, neuroscience, and prosthetics. [Extracted from the article]

Translating ionic currents into measureable electronic signals is essential for the integration of bioelectronic devices with biological systems.We demonstrate the use of a Pd/PdHx electrode as a bioprotonic transducer that connects H+ currents in solution into an electronic signal. This transducer exploits the reversible formation of PdHx in solution according to PdH ← Pd + H+ + e-, and the dependence of this formation on solution pH and applied potential. We integrate the protonic transducer with glucose dehydrogenase as an enzymatic AND gate for glucose and NAD+. PdHx formation and associated electronic current monitors the output drop in pH, thus transducing a biological function into a measurable electronic output. [ABSTRACT FROM AUTHOR]