Stacked graphdiyne nano-Iontronic device enables selective pH detection in single cells

Graphdiyne, as an emerging two-dimensional carbon material, has attracted considerable attention in recent years due to its unique molecular architecture and outstanding physicochemical properties. This 2D network formed by benzene rings connected through carbon–carbon triple bonds feature high conjugation, excellent electrical conductivity, and uniformly distributed nanopores that provide an ideal platform for ion transport and sieving. however, translating graphdiyne’s distinctive attributes into practical tools for analytical biochemistry, enabling precise measurement of key intracellular physiological parameters, remains a frontier challenge.

Recently, Prof. Ping Yu (Institute of Chemistry, Chinese Academy of Sciences) has recently reported an innovative study in National Science Review: “Stacked-overlapped graphdiyne nano-iontronics enabling enhanced monovalent/divalent cation selectivity for single-cell pH detection”. The work exploited the nanoporous architecture and surface charge properties of graphdiyne to develop a nano-iontronic sensor capable of real‑time monitoring of pH dynamics at the single‑cell level, opening a new avenue for the application of graphdiyne in biosensing.

In this work, graphdiyne was directly grown on confined nanotip structures to construct a miniature iontronic sensor. The graphdiyne surface bears negative charge, and upon immersion in electrolyte, electrostatic attraction concentrates cations while excluding anions, rendering the graphdiyne nanopores cation‑selective channels. When the solution pH changes, protons associate with or dissociate from oxygen-containing functional groups on the graphdiyne surface, modulating the surface charge density and thereby altering cation transport through the nanopores. By precisely measuring the resulting changes in ionic current, the device effectively transduces local pH variations into a quantitative electrical readout, providing a sensitive means to “interpret” microenvironmental pH. The sensor exhibits fast and reversible responses to pH shifts, and critically retains accurate proton sensing in the presence of interferents such as Li⁺, Na⁺, Ca²⁺, and Mg²⁺, demonstrating outstanding resistance to divalent‑cation interference. Fluorescent staining experiments confirmed minimal cellular damage and good biocompatibility of the sensor. Leveraging these features, the authors achieved pH measurements at single‑cell and even single‑organelle resolution. They further used the iontronic probe to monitor, in real time, the intracellular pH response of a single PC12 cell to the drug cariporide. Under drug treatment, intracellular pH exhibited significant changes within minutes, a dynamic process that was clearly recorded by the sensor and found to be consistent with previous reports, validating the device’s accuracy. This study not only showcases the unique advantages of graphdiyne for nano‑iontronic devices but also provides a novel approach for real‑time intracellular pH detection at the single‑cell level.

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