A DNA-based nano-immunoassay for the label-free detection of glial fibrillary acidic protein in multicell lysates

We have developed a quantitative approach to eventually enable precise and multiplexing protein analysis of very small systems, down to a single or a few cells. As a proof of concept we realized a nano-immunoassay for glial fibrillary acidic protein (GFAP), a biomarker for glioma, the most common of primary malignant brain tumors. DNA nanoarrays were fabricated by means of AFM-based nanografting. Antibodies were then immobilized on the DNA nanostructures using DNA-directed immobilization of DNA-protein conjugates. We tested the efficiency of our assay in standard solution and in cellular lysate and we compared it with conventional ELISA assay.221