Scaling diagnostics in times of COVID-19: Rapid prototyping of 3D-printed water circulators for Loop-mediated Isothermal Amplification (LAMP) and detection of SARS-CoV-2 virus

Gonzalez-Gonzalez, Everardo; Lara-Mayorga, Itzel Montserrat; Rodriguez-Sanchez, Iram Pablo; Leon, Felipe Yee-de; Garcia-Rubio, Andres; Garciamendez-Mijares, Carlos Ezio; Guerra-Alvarez, Gilberto Emilio; Garcia-Martinez, German; Aguayo-Hernandez, Juan Andres; Marquez-Garcia, Eduardo; Zhang, Yu-Shrike; Martinez-Chapa, Sergio Omar; Zuñiga, Joaquin; Santiago, Grissel Trujillo-de; Alvarez, Mario Moises

By the first week of April 2020, more than 1,500,000 positive cases of COVID-19 and more than 50,000 deaths had been officially reported worldwide. While developed countries such as the USA, Italy, England, France, Spain, and Germany struggle to mitigate the propagation of SARS-CoV-2, the COVID-19 pandemic arrived in Latin America, India, and Africa--territories in which the mounted infrastructure for diagnosis is greatly underdeveloped. An actual epidemic emergency does not provide the required timeframe for testing new diagnostic strategies; therefore, the first line of response must be based on commercially and readily available resources. Here, we demonstrate the combined use of a three-dimensional (3D)-printed incubation chamber for commercial Eppendorf PCR tubes, and a colorimetric embodiment of a loop-mediated isothermal amplification (LAMP) reaction scheme for the detection of SARS-CoV-2 nucleic acids. We used this strategy to detect and amplify SARS-CoV-2 DNA sequences using a set of in-house designed initiators that target regions encoding the N protein. We were able to detect and amplify SARS-CoV-2 nucleic acids in the range of [~]625 to 2 x 105 DNA copies by this straightforward method. The accuracy and simplicity of this diagnostics strategy may provide a cost-efficient and reliable alternative for use during the COVID-19 pandemics, particularly in underdeveloped regions were the availability of RT-qPCR instruments may be limited. Moreover, the portability, ease of use, and reproducibility of this strategy make it a reliable alternative for deployment of point-of-care SARS-CoV-2 detection efforts during the pandemics.