Automated ELISA On-Chip for the Detection of Anti-SARS-CoV-2 Antibodies

Abstract

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 reliable 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 represent an attractive alternative to the conventional testing methodologies used for these purposes. In this work, we described the development of an automated ELISA on-chip capable of detecting anti-SARS-CoV-2 antibodies in serum samples from COVID-19 patients and vaccinated individuals. The colorimetric reactions were analyzed with a microplate reader. No statistically significant 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 mitigates some of the burden caused by testing deficiencies.

Ultra-Fast and Sensitive Screening for Antibodies against the SARS-CoV-2 S1 Spike Antigen with a Portable Bioelectric Biosensor

“…Advanced optical sensor technologies (Table 3) such as photonic [27] and surface plasmon resonance sensors [28,29] are able to provide results within 10 min, whereas more traditional approaches require more time (LFA, ELISA, 15-60 min) [30,31].On the other hand, electrochemical sensors require a mean response time of approximately 30 min [32][33][34][35][36]. Taking into account the above-mentioned, our biosensor is able to detect SARS-CoV-2 antibodies in an ultra-rapid manner (3 min) and at quite low concentrations (5 ng/mL).…”

Microfluidics Technology in SARS-CoV-2 Diagnosis and Beyond: A Systematic Review

“…The automated enzyme-linked immunosorbent assay (ELISA) on-chip microfluidic platform developed by Gonzalez-Gonzalez et al, the Opto microfluidic sensing platform based on localizes surface plasmon resonance (LSPR) developed by Funari et al, paper-based pulling force spinning top microfluidic devices designed by Gong et al, microfluidic chemiluminescent ELISA technique by Tan et al, and the reciprocating flowing immunobinding strategy by Liu et al detect anti-SARS-CoV-2 antibodies by spectrometer-based detection techniques ( Table 1 ) [ 26 , 27 , 28 , 29 , 30 ].…”

“…Gonzalez-Gonzalez et al, Liu et al, and Gong et al reported the use of commercial smartphone cameras to take photographs of the resulting colorimetric reactions and analyze the images with ImageJ software to detect and quantify the antibody concentrations with a high limit of detections. In contrast, the Opto microfluidic sensing platform developed by Funari et al and the microfluidic chemiluminescent ELISA-based platform designed by Tan et al require comparatively complex and extensive analyzing equipment NanoDrop One UV-Vis spectrometer (Thermo Fisher’s, USA) and CMOS camera along with ImageJ software (NIH, Bethesda, MD, USA) [ 26 , 27 , 28 , 29 , 30 ].…”

“…All the spectrometer based microfluidic platforms that function on the principles of the ELISA technique are capable of detecting SARS-CoV-2 specific antibodies in serum or plasma samples with minimum sample requirements, reduced reagent usage, shortened sample processing time, and without extensive equipment and expert technicians as needed for the traditional ELISA technique [ 28 ].…”

Microfluidic particle dam for direct visualization of SARS-CoV-2 antibody levels in COVID-19 vaccinees

“…To achieve quantitative measurement while maintaining a simple and user-friendly interface, attempts have been made to conduct immunoassays in miniaturized devices (28) using principles such as ELISA (29)(30)(31), electrochemistry (32,33), surface plasmon resonance (34), and fluorescence (35)(36)(37)(38). However, signal quantification requires additional detection modules, e.g., optical fibers, light source, amperemeters, or photodetectors, for measuring optical absorbance or fluorescence intensity.…”