Direct Electrochemiluminescence Imaging of a Single Cell on a Chitosan Film Modified Electrode

Abstract

Single-cell imaging is essential for elucidating the biological mechanism of cell function because it accurately reveals the heterogeneity among cells. The electrochemiluminescence (ECL) microscopy technique has been considered a powerful tool to study cells because of its high throughput and zero cellular background light. However, since cells are immobilized on the electrode surface, the steric hindrance and the insulation from the cells make it difficult to obtain a luminous cell ECL image. To solve this problem, direct ECL imaging of a single cell was investigated and achieved on chitosan and nano-TiO modified fluoride-doped tin oxide conductive glass (FTO/TiO/CS). The permeable chitosan film is not only favorable for cell immobilization but also increases the space between the bottom of cells and the electrode; thus, more ECL reagent can exist below the cells compared with the cells on a bare electrode, which guarantees the high sensitivity of quantitative analysis. The modification of nano-TiO strengthens the ECL visual signal in luminol solution and effectively improves the signal-to-noise ratio. The light intensity is correlated with the HO concentration on FTO/TiO/CS, which can be applied to analyze the HO released from cells at the single-cell level. As far as we know, this is the first work to achieve cell ECL imaging without the steric hindrance effect of the cell, and it expands the applications of a modified electrode in visualization study.

Imaging Cell‐Matrix Adhesions and Collective Migration of Living Cells by Electrochemiluminescence Microscopy

“…We think it is the SNM that makes the difference. And unlike the chitosan‐film‐modified electrodes where three dimensional pores decrease the spatial differences, SNM, consisting of vertically aligned channels, could distinguish cellular domains with and without adhesions.…”

Electrochemiluminescence Single‐Cell Analysis: Intensity‐ and Imaging‐Based Methods

“…To solve this problem, Liu et al incubated cells on a chitosan modified electrode. [58] The porous chitosan layer increased the distance between cells and electrode, and thus increased the amount of luminophores. After the optimization of the concentration of chitosan, the ECL intensity under cell became the same as the background.…”

Intracellular Electrochemical Sensing

“…When a cell is analyzed by ECL, steric hindrance and cell insulation become problematic. As a solution to this problem, direct ECL imaging of a single cell using chitosan and fluoride‐doped tin oxide conductive glass modified with nano‐TiO 2 (FTO/TiO 2 /CS) was developed . A cell immobilized on chitosan and FTO/TiO 2 /CS was first stimulated by N ‐formylmethionyl‐leucyl‐phenylalanine; H 2 O 2 was consequently released by individual cells, resulting in ECL of luminol (Figure C).…”