Biosensor-based Binding Assay for Platelet-Derived Growth Factor Receptor-α Autoantibodies in Human Serum

Biosensors are versatile tools for monitoring molecular interactions. Herein, we report a novel assay designed to detect anti-platelet-derived growth factor receptor α (PDGFRα) autoantibodies in the serum of patients affected by systemic sclerosis (SSc), an autoimmune disease of the connective tissue. The assay was based on resonant mirror sensing, and used recombinant PDGFRα as molecular “bait” for anti-PDGFRα autoantibodies (IgG class). The selection and optimization of the analytical procedure required a preliminary investigation on the preservation of the native-like conformation of the receptor following the immobilization procedure. The PDGFRα-based biosensor was used to test IgG purified from sera of SSc patients and healthy controls (HC). The specificity and the reversibility of the interaction permitted a rapid analysis, a single detection test requiring only a few minutes. Remarkably, this assay could discriminate between SSc patients and HC. This receptor-based biosensor, based on the reversible interaction between a blocked macromolecule and soluble ligands, and with major advantages such as the rapidity, the reusability of the capturing surface and the low cost per single test, could represent a promising approach for the diagnosis of SSc and other diseases characterized by anti-receptor autoantibodies or other bioactive ligands to cellular receptors.