Development of Sphere-Polymer Brush Hierarchical Nanostructure Substrates for Fabricating Microarrays with High Performance.

In this work, a sphere-polymer brush hierarchical nanostructure-modified glass slide has been developed for fabricating high-performance microarrays. The substrate consists of a uniform 160 nm silica particle-self-assembled monolayer on a glass slide with a postcoated poly(glycidyl methacrylate) (PGMA) brush layer (termed PGMA@3D(160) substrate), which can provide three-dimensional (3D) polymer brushes containing abundant epoxy groups for directly immobilizing various biomolecules. As a typical example, the interactions of three monosaccharides (4-aminophenyl β-d-galactopyranoside, 4-aminophenyl β-d-glucopyranoside, and 4-aminophenyl α-d-mannopyranoside) with two lectins (biotinylated ricinus communis agglutinin 120 and biotinylated concanavalin A from Canavalia ensiformis) have been assessed by PGMA@3D(160) substrate-based carbohydrate microarrays. The carbohydrate microarrays show good selectivity, strong multivalent interaction, and low limit of detection (LOD) in the picomolar range without any signal amplification. Furthermore, the proposed sphere-polymer brush hierarchical nanostructure substrates can be easily extended to fabricate other types of microarrays for DNA and protein detection. PGMA@3D(160) substrate-based microarrays exhibit higher reaction efficiencies and lower LODs (by at least 1 order of magnitude) in comparison to those of two-dimensional microarrays, which are fabricated on planar epoxy substrates, making it a promising platform for bioanalytical and biomedical applications.