Simple fabrication of antibody microarrays on nonfouling polymer brushes with femtomolar sensitivity for protein analytes in serum and blood

The fabrication of antibody (Ab) arrays on Poly(oligo(ethylene glycol) methacrylate) POEGMA brushes with several significant features has been reported. Ellipsometry in air of POEGMA brushes grown on oxidized silicon wafers under identical conditions indicated a polymer brush thickness of (105±2) nm. The non covalent adsorption of antibodies provides a simple and robust procedure for the stable immobilization of the capture antibody, which avoids the need for chemical activation and deactivation of the surface. Antibody arrays spotted on the POEGMA brushes require only minimal washing steps, and do not require blocking steps during interrogation, which simplifies the assay and reduces the time required to perform the assay. The femtomolar Limit-Of-Detection (LOD) in serum and blood and the wide dynamic range of antibody arrays spotted on POEGMA brushes suggest that these microarrays will be useful for the quantification of low-abundance protein biomarkers directly from complex mixtures with minimal sample pre-processing, with application in proteomics and clinical diagnostics.