Consequently, our technology can greatly accelerate and improve the on-site testing process of potential convalescent serum donors. assay, we were able to identify certified donors for convalescent serum therapy with only one fixed dilution element (200?). Finally, we shown that our technology can sensitively detect SARS-CoV-2 antigens (S1 and N proteins) with pg/mL level sensitivities in 40?min. Overall, our technology can greatly facilitate quick, sensitive, and quantitative analysis of COVID-19 related markers for restorative, diagnostic, epidemiologic, and prognostic purposes. Keywords: COVID-19, Antibody detection, Immunoassay, Microfluidics Shows ? Identified a calibrator antibody for anti-SARS-CoV-2 S1 IgG quantification. ? Quick (15?min) and sensitive detection of anti-SARS-CoV-2S1 IgG in serum. ? Quantitative evaluation of COVID-19 convalescent serum Dll4 with a single dilution element (200X). ? Sensitive detection of SARS-CoV-2 N- and S-protein in serum down to ~10?pg/mL with 3-4 orders of magnitude dynamic range. ? 8?L sample/reagent volume. 1.?Intro The disease (COVID-19) related to novel coronavirus (SARS-CoV-2) has caused more than half a million of deaths and remains a severe threat to global health (Who also, 2020c). The World Health Organization offers indicated the mortality rate for the essential care COVID-19 instances may be higher than 50% (WHO, 2020a, b). Regrettably, to date there is no standardized therapy for treating COVID-19 patients, especially those in the essential stage (WHO, 2020a). Recent clinical researches possess shown the convalescent serum therapy is definitely a promising approach to improve the survival rate in the severe instances (Bloch et al., 2020; Casadevall and Pirofski, 2020; Chen et al., 2020; Duan et al., 2020; Shen et al., 2020). SARS-CoV-2 neutralizing IgG (S1-specific IgG), the major active component in the convalescent serum is definitely developed by the adaptive immune system approximately 7C10 days after SARS-CoV-2 illness (Padoan et al., 2020; Sun et al., 2020). Due to its high affinity and high large quantity, neutralizing IgG can bind and block the binding epitopes, (e.g., receptor binding domains (RBDs) and additional related domains, within the S1 protein on SARS-CoV-2), avoiding it from invading human being cells (Very long et al., 2020; Shen et al., 2020). Due to the variations in the strength of the adaptive immune response, the large quantity of SARS-CoV-2 S1 specific IgG varies significantly from patient to patient (Amanat et al., 2020; Ju et al., 2020). To ensure a high restorative efficacy, only the convalescent serum from recovered donors with a high level of SARS-CoV-2 S1-specific IgG should LYPLAL1-IN-1 be LYPLAL1-IN-1 selected as the restorative agent. Thus, knowing the concentration of SARS-CoV-2 S1-specific IgG is essential for selecting appropriate convalescent serum donors. Yet, existing antibody detection methods are still far from adequate. The gold nanoparticle-based lateral circulation assay (e.g., paper-based test strips) is popular for rapid detection of IgG/IgM antibodies (especially for point-of-care diagnostics). Although fast (5C20?min), it provides only binary (i.e., yes/no) info with very limited sensitivities. Consequently, it cannot be utilized for the quantitative evaluation of the convalescent serum. Conventional ELISA (enzyme-linked immunosorbent assay), on the other hand, can provide accurate and sensitive results, but it entails complicated and expensive instruments and long assay time (~3?h) (Amanat et al., 2020; Wang et al., 2020). Given the narrow dynamic range (<2 orders of magnitude), multiple dilution factors are required for carrying out the serological analysis of SARS-CoV-2 S1-specific IgG, which increases the cost and decreases the assay throughput. Moreover, due to the lack of an internal calibration standard, standard ELISA cannot measure the effective concentration of the circulating anti-S1 IgG, making quality control of the convalescent serum harder (Ju et al., 2020). In this work, we present a portable microfluidic chemiluminescent ELISA technology for quick (15?min), quantitative, and sensitive detection of SARS-CoV-2 S1 specific IgG. We 1st characterized four humanized (chimeric) monoclonal IgG and recognized a suitable candidate (D006) with a high binding affinity and specificity towards SARS-CoV-2 S1 protein that can consequently serve as the calibration standard of anti-SARS-CoV-2 S1 IgG in serological analyses. To evaluate medical applicability of our technology, we carried out measurements with the serum samples collected from 16 recovered COVID-19 individuals LYPLAL1-IN-1 and 3 healthy donors. Because of the availability of a calibration standard and large dynamic range of our assay, we successfully converted the measured results into effective D006 concentrations and recognized the best donor candidates for the convalescent serum therapy with only one fixed serum dilution element (200?). Consequently, our technology can greatly accelerate and improve the on-site screening process of potential convalescent serum donors. To further extend the ability of the portable microfluidic technology, we also shown sensitive detection of SARS-CoV-2 antigens (S1 and N proteins) with LYPLAL1-IN-1 a lower limit of detection (LLOD) of ~10?pg/mL in 40?min using spiked serum.