Ultra-Low-Cost Integrated Silicon-based Transducer for On-Site, Genetic Detection of Pathogens

Estefania Nunez-Bajo; Michael Kasimatis; Yasin Cotur; Tarek Asfour; Alex Collins; Ugur Tanriverdi; Max Grell; Matti Kaisti; Guglielmo Senesi; Karen Stevenson; Firat Guder

The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.23.002931 doi: bioRxiv preprint 11 28 With increasing temperature, however, the error bars also widen, indicating that the precision of the measurement decreases. We speculate that this could be related to thermal and electrical crosstalk between the heater and the electrochemical sensing structures which introduce additional noise to the electroanalytical measurements at higher temperatures. We have also studied the thermal stability of MB over time (Figure 4D) . In this experiment, we added MB to the PCR and RPA mastermix solutions to simulate the conditions during isothermal and cyclic amplification reactions. As illustrated in Figure 4D (and Figure S6) , MB remained relatively stable both at 40 °C over 45 mins (i.e. RPA conditions) and 35 cycles of PCR conditions (30 sec for each step at 94 °C, 63 °C and 72 °C; every 5 th cycle, the temperature is reduced to 40 °C for the measurement to increase precision as illustrated in Figure S7 ) indicated by the small spread of the measurements. The SWV measurements at elevated temperatures produced similar results to the measurements taken at room temperature (25 °C) in terms of repeatability, in agreement with the findings in the literature by other groups although we did observe a slight decrease in stability for the PCR conditions (i.e. higher temperatures). 23 The results of the thermal stability experiments indicate that MB is a sufficiently stable redox-active reporter for use in NA amplification reactions at elevated temperatures.