Label‐Free Electrochemiluminescence Imaging of Single‐Cell Adhesions by Using Bipolar Nanoelectrode Array

• Published in: Chemistry : a European journal 2022-01, Vol.28 (3), p.e202103964-n/a
• Main Authors: Qin, Xiang, Jin, Hua‐Jiang, Li, Xiuxiu, Li, Jian, Pan, Jian‐Bin, Wang, Kang, Liu, Songqin, Xu, Jing‐Juan, Xia, Xing‐Hua
• Format: Article
• Language: English
• Subjects: Adhesion; Adhesive strength; Anodizing; Arrays; Biosensing Techniques; bipolar nanoelectrodes; Cell Adhesion; Cell morphology; Chemistry; Confined spaces; Cytology; Electrochemical Techniques; Electrochemiluminescence; Electrochemistry; Electrodes; Humans; Image acquisition; label-free imaging; Luminescent Measurements; Oxygen; oxygen concentration gradient; Reduction; single cells; Steric hindrance
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202103964

A label‐free and fast approach for positive electrochemiluminescence (ECL) imaging of single cells by bipolar nanoelectrode array is proposed. The reduction of oxygen at a platinized gold nanoelectrode array in a closed bipolar electrochemical system is coupled with an oxidative ECL process at the anodic side. For elevating the ECL imaging contrast of single cells, a driving voltage of −2.0 V is applied to in situ generate oxygen confined beneath cells that is subsequently used for ECL imaging at 1.1 V. High oxygen concentration in the confined space resulting from steric hindrance generates prominent oxygen reduction current at the cathodic side and higher ECL intensity at the anodic side, allowing positive ECL imaging of the cells adhesion region with excellent contrast. Cell morphology and adhesion strength can be successfully imaged with high image acquisition rate. This approach opens a new avenue for label‐free imaging of single cells. A label‐free method for fast and positive electrochemiluminescence (ECL) imaging of single cells by bipolar nanoelectrode array is proposed using oxygen as the electrochemical probe. The successful imaging is achieved by transient generation of difference in oxygen concentration over the nanoelectrodes covered with or without cells. Thus, cell morphology and adhesion strength can be imaged.