Advantageous antibody microarray fabrication through DNA-directed immobilization: A step toward use of extracellular vesicles in diagnostics

Microarrays were introduced to run multiple assays on a single platform. Since then, researchers developed DNA and protein microarrays to study both transcription and expression of genes. Protein microarray technology represents a powerful tool to get an insight into living systems. However, despite their enormous potential, the fabrication of protein arrays is affected by technological hurdles that limit their application. One of the significant challenges is the immobilization of proteins on solid surfaces. To overcome this limitation, DNA-directed immobilization (DDI) of proteins, an approach that exploits DNA-protein conjugates to transform DNA microarrays into a protein array, has been developed. The adoption of DDI is limited, as this approach requires the synthesis of DNA-protein conjugates. Herein, we introduce an optimized general protocol for DNA-protein ligation, and demonstrate the use of conjugates to convert DNA arrays into antibody microarrays. Arrays obtained through DDI were used to capture and characterize extracellular vesicles (EVs), an emerging class of biomarkers. The proposed platform was tested against commercially available antibody microarrays, showing good performance combined with ease of fabrication.