This manuscript reports on a novel substrate for the amperometric detection of cellular apoptosis, Asp-Glu-Val-Asp-p-methoxyaniline (DEVD-pMA). This substrate showed electrochemical inertia from −0.2 to 0.7 V versus Ag/AgCl in phosphate-buffered saline (PBS), but was cleaved by caspase-3, releasing pMA, which was detected with cyclic voltammetry and chronoamperometry. Compared with p-aminophenol (pAP), pMA showed lower toxicity to the human hepatocellular carcinoma cell line (HepG2) and higher stability in PBS. By using this substrate, we successfully detected caspase-3 in the range of 0.31–2.5×10−2 units/mL and cellular apoptosis in HepG2 cells by using simple amperometry without cell lysis. This work will help to develop a simple method for the electrochemical monitoring of apoptosis, which can be applied in biological research and drug development.
- amperometric detection
- peptide substrate