A Prussian Blue ZnO Carbon Nanotube Composite for Chronoamperometrically Assaying H2O2 in BT20 and 4T1 Breast Cancer Cells.

A Prussian Blue (PB) zinc oxide carbon nanotube sensing composite was developed for the rapid assaying of H₂O₂ generated from BT20 and 4T1 breast cancer cells, important for elucidating mechanisms governing apoptosis of these cell lines. The combination of H₂O₂'s transient nature along with matrix effects makes monitoring this molecule in biological samples a challenge. The standard addition method (SAM) was coupled with chronoamperometric sensing (CA) to overcome these obstacles. An electrocatalyst composite consisting of refluxed zinc oxide nanoparticles (NPs) tethered to carboxylic acid-functionalized multiwalled carbon nanotubes (ZnO/COOH-MWNTs) was electrostatically attached to PB for signal enhancement. Optimization of the sensor was achieved via adjusting solution pH and stirring time to optimize PB electrostatic attachment to ZnO/COOH-MWNTs prior to its deposition onto the working glassy carbon electrode (GCE) surface. CA SAM showed the ability to accurately measure H₂O₂ within the 1-21 μM range, suitable for monitoring cancer cell line apoptosis resistance scenarios and offering analytical advantages over standard enzyme-linked immunosorbent assays (ELISA) for rapid, matrix-effect-free analysis.