Automated ELISA on-chip for the detection of an-ti-SARS-CoV-2 antibodies

Gonzalez-Gonzalez, E.; Garcia-Ramirez, R.; Diaz Armas, G. G.; Esparza, M.; Aguilar-Avelar, C.; Flores-Contreras, E. A.; Rodriguez-Sanchez, I. P.; Delgado-Balderas, J. R.; Soto-Garcia, B.; Araiz-Hernandez, D.; Abarca-Blanco, M.; Yee-de Leon, J. R.; Velarde-Calvillo, L. P.; Abarca-Blanco, A.; Yee-de Leon, J. F.

The COVID-19 pandemic has been the most critical public health issue in modern history due to its highly infectious and deathly potential; and the limited access to massive, low-cost, and relia-ble testing has significantly worsened the crisis. The recovery and the vaccination of millions of people against COVID-19, have made serological tests highly relevant to identify the presence and levels of SARS-CoV-2 antibodies. Due to its advantages, microfluidic-based technologies repre-sent an attractive alternative to the conventional testing methodologies used for these purposes. In this work, we describe the development of an automated ELISA on-chip capable of detecting an-ti-SARS-CoV-2 antibodies in serum samples from COVID-19 patients and vaccinated individu-als. The colorimetric reactions were analyzed with a microplate reader. No statistically signifi-cant differences were observed when comparing the results of our automated ELISA on-chip against the ones obtained from a traditional ELISA on a microplate. Moreover, we demonstrated that it is possible to carry out the analysis of the colorimetric reaction by performing basic image analysis of photos taken with a smartphone, which constitutes a useful alternative when lacking specialized equipment or a laboratory setting. Our automated ELISA on-chip has the potential to be used in a clinical setting and mitigate some of the burden caused by testing deficiencies