Phenylboronic acid polymer brush-enabled oriented and high density antibody immobilization for sensitive microarray immunoassay

• Polymer brush with boronic acid is prepared on glass slide.
• High density and oriented antibody immobilization is achieved on boronic acid brush.
• Oriented immobilized antibody renders high bioactivity and signal-to-noise ratio.
• Highly sensitive antibody microarray is demonstrated by sandwich immunoassay.

There still has a big challenge for low-abundance protein detection with antibody microarrays. In this work, phenylboronic acid (PBA) polymer brush-enabled oriented, high density, and covalent antibody immobilization was realized for sensitive antibody microarrays. PBA-enabled oriented antibody attachment via carbohydrate at Fc portion keeps antigen-binding sites fully expose to their corresponding antigens, resulting in higher antibody–antigen (Ab–Ag) binding efficiency. Sandwich immunoassay with rabbit IgG as model analyte was performed on poly(glycidyl methacrylate)-amino-phenylboronic acid-coated glass slide (PGMA-APBA-slide). One order improvement of LOD was achieved as compared with that on poly(glycidyl methacrylate) glass slide (PGMA-slide). The improvement is mainly attributed to PBA-assisted high density and oriented antibody immobilization. This work provides a versatile and effective strategy to develop high sensitive antibody microarrays for low-abundance protein analysis in various proteomic applications.

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