There is an increasing demand for rapid and sensitive methods for the quantification of bacterial pathogen in very diverse areas, such as clinical diagnosis, environmental monitoring and food safety. Molecular methods, based on the amplification of a specific sequence of the bacterium genome by the polymerase chain reaction (PCR) are widely used. Unfortunately, these methods are usually limited to centralized laboratories. To meet the ASSURED criteria outlined by the WHO [1] for the design of a test useful in point-of-need detection, the use of isothermal nucleic acid amplification methods could be an excellent alternative to PCR.
Here, we present two different electrochemical platforms for Salmonella genome quantification. Both platforms integrate an isothermal amplification process with chronoamperometric detection. Specifically, we compare the signaling and analytical performance of two miniaturized DNA sensing devices fabricated using either indium-tin oxide surfaces in combination with helicase dependent amplification (HDA) [2] or gold surfaces and recombinase polymerase amplification (RPA) [3]. These devices support efficient detection of small amounts of the Salmonella genome on the same platform without thermal cycling while using simple equipment.
References
[1] Wu, G.; Zaman, M.H. Bulletin of the World Health Organization. 2012, 90, 914-920.
[2] Barreda-García S., Miranda-Castro R., de-los-Santos-Álvarez N., Miranda-Ordieres A.J., Lobo-Castañón M. J. Chem. Commun 2017, 53, 9721-9724.
[3] Sánchez-Salcedo R., Miranda-Castro R., de-los-Santos-Álvarez N., Lobo-Castañón M.J. ChemElectroChem 2019, 6, 793-800.
Acknowledgments: This research was funded by the Spanish Government (project RTI-2018-095756-B-I00) and Principado de Asturias Government (IDI2018-000217), co-financed by FEDER funds.