Nanopipette-Based Nanosensor for Label-Free Electrochemical Monitoring of Cell Membrane Rupture under H₂O₂ Treatment

Abstract

H 2 O 2 is an essential signaling molecule in living cells that can cause direct damage to lipids, proteins, and DNA, resulting in cell membrane rupture. However, current studies mostly focus on probe-based sensing of intracellular H 2 O 2 , and these methods usually require sophisticated probe synthesis and instruments. In particular, local H 2 O 2 treatment induces cell membrane rupture, but the level of cell membrane destruction is unknown because the mechanical properties of the cell membrane are difficult to accurately determine. Therefore, highly sensitive and label-free methods are required to measure and reflect mechanical changes in the cell membrane. Here, using an ultrasmall quartz nanopipette with a tip diameter less than 90 nm as a nanosensor, label-free and noninvasive electrochemical single-cell measurement is achieved for real-time monitoring of cell membrane rupture under H 2 O 2 treatment. By spatially controlling the nanopipette tip to precisely approach a specific location on the membrane of a single living cell, stable cyclic membrane oscillations are observed under a constant direct current voltage. Specifically, upon nanopipette advancement, the mechanical status of the cell membrane can be sensibly displayed by continuous current versus time traces. The electrical signals are collected and processed, ultimately revealing the mechanical properties of the cell membrane and the degree of cell apoptosis. This nanopipette-based nanosensor paves the way for developing a facile, label-free, and noninvasive strategy to assay the mechanical properties of the cell membrane during external stimulation at the single-cell level.

The Modification and Applications of Nanopipettes in Electrochemical Analysis

“…They speculated that the periodic signals came from the oscillation of the membrane driven by electroosmosis. Afterwards, the rupture process of a single living cell membrane was monitored in situ under the treatment of hydrogen peroxide (H 2 O 2 ) [10b] . To further improve the selectivity and sensitivity, many researchers are devoted to modifying some functional materials on the inner wall of the nanopipette.…”

Amperometric Identification of Single Exosomes and Their Dopamine Contents Secreted by Living Cells

“…By contrast, electrochemical nanosensors, such as nanoelectrodes and nanopipettes, provide valuable tools for single-entity analysis because of their nanometer-scale structures, high biocompatibility, and good conductivity, which is highly favorable for trace DA detection. − For example, Ewing’s group utilized the nanopipettes to measure the size of chromaffin vesicles and the amount of electroactive molecules in individual chromaffin vesicles. Jiang’s group described a carbon nanopipette to achieve electrochemical quantification of DA contained in a single liposome .…”

Label-Free Imaging of Cell Apoptosis by a Light-Addressable Electrochemical Sensor

“…In light of the above concerns, label-free technologies that allow timely single-cell analysis are highly in demand for an insightful investigation of cellular activities. , For example, spontaneous Raman microscopy was reported for mapping dynamic changes in cytochrome c released from mitochondria, which is a highly specific event in apoptotic signaling . Plasmonic-based electrochemical impedance microscopy (P-EIM) has been used to investigate apoptosis processes and intracellular calcium signaling with high spatial and temporal resolution.…”