AUTHOR=Zhai Jiali , Wang Wenting , Wu Shuang , Yu Tianxi , Xiang Chongjun , Li Yue , Lin Chunhua , Zhao Guangtao TITLE=Real-time calcium uptake monitoring of a single renal cancer cell based on an all-solid-state potentiometric microsensor JOURNAL=Frontiers in Bioengineering and Biotechnology VOLUME=11 YEAR=2023 URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2023.1159498 DOI=10.3389/fbioe.2023.1159498 ISSN=2296-4185 ABSTRACT=

Introduction: In addition to many cellular processes, Ca²⁺ is also involved in tumor initiation, progression, angiogenesis, and metastasis. The development of new tools for single-cell Ca²⁺ measurement could open a new avenue for cancer therapy.

Methods: The all-solid-state calcium ion-selective microelectrode (Ca²⁺-ISμE) based on carbon fiber modified with PEDOT (PSS) as solid-contact was developed in this work, and the characteristics of the Ca²⁺-ISμE have also been investigated.

Results: The Ca²⁺-ISμE exhibits a stable Nernstian response in CaCl₂ solutions in the active range of 1.0 × 10⁻⁸ - 3.1 × 10⁻³ M with a low detection limit of 8.9 × 10⁻⁹ M. The Ca²⁺-ISμE can be connected to a patch clamp to fabricate a single-cell analysis platform for in vivo calcium monitoring of a single renal carcinoma cell. The calcium signal decreased significantly (8.6 ± 3.2 mV, n = 3) with severe fluctuations of 5.9 ± 1.8 mV when the concentration of K⁺ in the tumor microenvironment is up to 20 mM.

Discussion: The results indicate a severe cell response of a single renal carcinoma cell under high K⁺ stimuli. The detection system could also be used for single-cell analysis of other ions by changing different ion-selective membranes with high temporal resolution.