Multiplex label-free biosensor for detection of autoantibodies in human serum: Tool for new kinetics-based diagnostics of autoimmune diseases.

A multiplex label-free biosensor is developed for diagnostics of autoimmune diseases by highly sensitive measuring in human serum both critical characteristics of autoantibody: concentration and native kinetic parameters that reflect autoantibody aggressiveness to the organism's tissues. The biosensor is based on the spectral-correlation interferometry and image processing of a microarray glass biochip, affordable to be single-used in medical applications. Simultaneous 25-min detection and activity characterization of several autoantibodies in the same serum sample have been demonstrated for anti-thyroglobulin (anti-TG) and anti-thyroid peroxidase (anti-TPO) as models. The biosensor offers extremely high sensitivity: limits of detection in serum are 1.7 IU/mL and 6 IU/mL for anti-TPO and anti-TG, respectively. The dynamic range covers the whole range of clinically relevant concentrations of the autoantibodies up to 1000 IU/mL. The developed method of characterization of autoantibody activity by recording the kinetics of their binding with free native antigens is based on autoantibody polyvalency. The measurements in clinical serum samples have shown that the native kinetic parameters are independent of concentration. The proposed biosensor and method of native kinetic registration can be used to develop new criteria for comprehensive diagnostics of autoimmune diseases, based not only on traditional measurements of concentration but also on quantitative evaluation of autoantibody aggressiveness. The developed method can be adapted to other label-free sensors such as those based on the surface plasmon resonance, optical waveguides, etc.

Data on characterization of glass biochips and validation of the label-free biosensor for detection of autoantibodies in human serum.

The data represent in-depth characterization of a novel method for highly sensitive simultaneous measuring in human serum of both critical parameters of autoantibodies: concentration and native kinetics. The latter refers to autoantibody interaction with free, not immobilized, antigen. The method and related biosensors are based on the spectral-correlation and spectral-phase interferometry. The data cover: multi-factor optimization and quantitative characterization of the developed affordable single-used biochips, including X-ray photoelectron spectroscopy (XPS) control of chemical modifications of the surface during fabrication; antibody screening; optimization and verification of protocols for label-free biosensing in human serum; mathematical model for fitting experimental data and calculation of kinetic constants of interaction of autoantibodies with free antigen; comprehensive verification of the method specificity; correlation between the data obtained with the developed biosensor and with enzyme linked immunosorbent assay (ELISA); comparison of analytical characteristics of the developed biosensor with the most advanced label-based methods. The data importance is confirmed by a companion paper (DOI 10.1016/j.bios.2020.112187), which shows that the combination of mentioned autoantibody parameters is promising for more accurate criteria for early diagnostics and efficient therapy of autoimmune disorders. The obtained data can be used in development of a wide range of biosensors, both label-free and based on various labels.