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Development and comparison of the first electrochemical bioplatforms for determining anti-centromere B antibodies (CENPB-Abs) developed in magnetic microbead-assisted or integrated formats using His-tag chemistry.

This work reports the first amperometric biosensor for the simultaneous determination of the single or total content of the most relevant human immunoglobulin isotypes (hIgs) of anti-dsDNA antibodies, dsDNA-hIgG, dsDNA-hIgM, dsDNA-hIgA and dsDNA-three hIgs, which are considered relevant biomarkers in prevalent autoimmune diseases such as systemic lupus erythematosus (SLE) as well as of interest in neurodegenerative diseases such as Alzheimer's disease (AD). The bioplatform involves the use of neutravidin-functionalized magnetic microparticles (NA-MBs) modified with a laboratory-prepared biotinylated human double-stranded DNA (b-dsDNA) for the efficient capture of specific autoantibodies that are enzymatically labeled with horseradish peroxidase (HRP) enzyme using specific secondary antibodies for each isotype or a mixture of secondary antibodies for the total content of the three isotypes. Transduction was performed by amperometry (-0.20 V vs. the Ag pseudo-reference electrode) using the H2O2/hydroquinone (HQ) system after trapping the resulting magnetic bioconjugates on each of the four working electrodes of a disposable quadruple transduction platform (SP4CEs). The bioplatform demonstrated attractive operational characteristics for clinical application and was employed to determine the individual or total hIgs classes in serum from healthy individuals and from patients diagnosed with SLE and AD. The target concentrations in AD patients are provided for the first time in this work. In addition, the results for SLE patients and control individuals agree with those obtained by applying ELISA tests as well as with the clinical ranges reported by other authors, using individual detection methodologies restricted to centralized settings or clinical laboratories. The financial support of PID2019-103899RB-I00 and PID2021-122457OB-I00 (Spanish Ministerio de Ciencia e Innovación) Research Projects, PI17CIII/00045 and PI20CIII/00019 Grants from the AESISCIII Program co-founded by FEDER funds and the TRANSNANOAVANSENS-CM Program from the Comunidad de Madrid (Grant S2018/NMT-4349) are gratefully acknowledged. B.A. acknowledges predoctoral contracts from the Spanish Ministerio de Ciencia, Innovación y Universidades (PRE2019-087596). M.G-A. acknowledges the postdoctoral contract Margarita Salas for the requalification of the Spanish University System. A.M-C. was supported by a FPU predoctoral contract supported by the Spanish Ministerio de Educación, Cultura y Deporte. Sí

A dual immunosensor is reported for the simultaneous determination of two important immunity-related cytokines: BAFF (B cell activation factor) and APRIL (a proliferation-induced signal). Sandwich-type immunoassays with specific antibodies (cAbs) and a strategy for signal amplification based on labelling the detection antibodies (dAbs) with binary MoS2/MWCNTs nanostructures and using horseradish peroxidase (HRP) were implemented. Amperometric detection was carried out at screen-printed dual carbon electrodes (SPdCEs) through the hydroquinone HQ/H2O2 system. The developed dual immunosensor provided limit of detection (LOD) of 0.08 and 0.06 ng mL-1 for BAFF and APRIL, respectively, and proved to be useful for the determination of both cytokines in cancer cell lysates and serum samples from patients diagnosed with autoimmune diseases and cancer. The obtained results agreed with those found using ELISA methodologies. Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. Financial support was provided by Spanish Ministerio de Ciencia, Innovacion y Universidades (RTI2018-096,135-B-I00), Spanish Ministerio de Ciencia e Innovación (PID2019-103899RB-I00) Research Project, and the TRANSNANOAVANSENS-CM Program from the Comunidad de Madrid (Grant S2018/NMT-4349). Financial support of the PI17CIII/00045 and PI20CIII/00019 grants from the AES-ISCIII program was also provided to R. B. A predoctoral contract from the Spanish Ministerio de Ciencia, Innovacion y Universidades (PRE2019-087,596) was provided to B. Arévalo. A FPU predoctoral contract supported by the Spanish Ministerio de Educación, Cultura y Deporte was provided to A. M.-C. G. S.-F. is recipient of a predoctoral contract (grant number 1193818 N) supported by The Flanders Research Foundation (FWO). Sí