Real-time electrochemical quantification of H2O2 in living cancer cells using Bismuth based MOF

Metal-organic frameworks (MOFs) are receiving significant attention as supporting materials to load or encapsulate metal nanoparticles for electrochemical sensing applications owing to their porous structure and large surface area. In this work, Ag nanoparticles were incorporated upon Bi- terephthalic acid MOF (Bi-BDC) support and used as a viable electrochemical probe for hydrogen peroxide (H2O2) detection for the first time. Interestingly, the Ag-Bi-BDC (s) MOF modified GCE surface revealed remarkable electrocatalytic activity towards H2O2 detection as compared to its individual constituents. The enhanced current response towards the reduction of H2O2 is due to the synergistic combination of the strong binding interaction of the analyte on Ag-Bi-BDC (s) MOF surface through Bi3+ sites and the increased local availability of adsorbed H2O2 molecules, assisted by the high porosity of the MOF, and excellent catalytic activity of Ag particles. The fabricated sensor exhibited two linear ranges covering over four orders of magnitude with sensitivities of 886 and 13.9 mu A mM(-1)cm(-2). Besides, the proposed sensor also displayed a shorter response time (t < 1.8 s) and a lower detection limit of 20.1 nM which surpasses the previously reported similar works. Furthermore, the effect of interfering species on the reduction peak current response were studied and showed excellent selectivity for H2O2. The developed sensor also possesses good repeatability, reproducibility, and stability. Finally, the fabricated sensor exhibited good real time application in detecting H2O2 secreted from THP-1 and AtT-20 cancer cells. Hence, Ag incorporated Bi-BDC (s) MOF/GCE may be used as an alternative potential sensor material for enhanced electrochemical detection of hydrogen peroxide and other similar molecules.

Automated summary

Metal-organic frameworks (MOFs) are widely used as supporting materials for electrochemical sensing applications. In this study, Ag nanoparticles were incorporated into a Bi-BDC MOF and used for the detection of hydrogen peroxide (H2O2). The Ag-Bi-BDC MOF showed excellent electrocatalytic activity towards H2O2 detection, thanks to the strong binding interaction of Bi3+ with H2O2, the high porosity of the MOF, and the catalytic activity of Ag particles. The fabricated sensor exhibited a wide linear range, high sensitivity, short response time, and low detection limit for H2O2, as well as good selectivity, stability, and reproducibility. The sensor also showed promising real-time application in detecting H2O2 secreted from cancer cells.