Monitoring a Pseudouridine 5’-Monophosphate Synthesis Process Using an Interdigitated MEMS Sensor and Electrochemical Impedance Spectroscopy (EIS)

Abstract This work presents a new method to monitor a biochemical enzymatic reaction, the synthesis of pseudouridine 5’-monophosphate (ΨMP) from uracil and ribose 5’-phosphate (R5P). Pseudouridine is a precursor of an important component, N1-methyl pseudouridine in mRNA-based vaccines. Conventional methods of monitoring the process such as thin-layered chromatography (TLC) and high-performance liquid chromatography (HPLC) are expensive and cumbersome. Here, we propose the use of an interdigitated MEMS sensor and electrochemical impedance spectroscopy (EIS) to monitor the progression of the synthesis process. First, we investigate the electrochemical properties of uracil, R5P, and ΨMP. The measurement results show that R5P and ΨMP have relatively similar Nyquist responses, while uracil shows much higher impedance values. Then, we prepared five samples that mimic the actual process where the concentrations of uracil and R5P gradually decrease in the samples and the concentration of ΨMP increases. The EIS test results show that the MEMS sensor and test setup can capture the change in the composition of the samples as the electrochemical properties of the sample solution changes. The method presented in this work can be used in a microfluidic system that is integrated with the synthesis process to monitor the progression and completion of the process in real time.