Electrochemical biosensor based on NAD(P)H-dependent quinone reductase for rapid and efficient detection of vitamin K3

Vitamin K refers to a group of vitamins that play an important role in blood coagulation and regulation of bone and vascular metabolism. However, vitamin K3 may give severe side effects in animal and humans when improperly added to food and feed due to its toxicity. Here, an electrochemical biosensor, based on the YaiB NADPH-dependent quinone reductase from Lactococcus lactis (YaiB), was developed to achieve rapid and redox probe-free detection of vitamin K3. First, the ability of the carbon electrode to distinguish between 1,4-benzoquinone and hydroquinone was demonstrated. Then, we engineered YaiB to work as a bioreceptor immobilized at the electrode and its sensitivity and specificity to reduce vitamin K3 were demonstrated. Finally, to demonstrate the practical potential of the biosensor, we tested it directly in spiked milk samples, achieving 15-minute quantification of the vitamin K3. The limit of detection was 0.87 mu M and 4.1 mu M in buffer and milk, respectively.