Next generation glycan microarray enabled by DNA-coded glycan library and next-generation sequencing (NGS) technology.

Interactions of glycans with proteins, cells, and microorganisms play important roles in cell cell adhesion and host pathogen interaction. Glycan microarray technology, in which multiple glycan structures are immobilized on a single glass slide and interrogated with glycan-binding proteins (GBPs), has become an indispensable tool in the study of protein glycan interactions. Despite its great success, the current format of the glycan microarray requires expensive, specialized instrumentation and labor-intensive assay and image processing procedures, which limit automation and possibilities for high-throughput analyses. Furthermore, the current microarray is not suitable for assaying interaction with intact cells due to their large size compared to the two-dimensional microarray surface. To address these limitations, we developed the next generation glycan microarray (NGGM) based on artificial DNA coding of glycan structures. In this novel approach, a glycan library is presented as a mixture of glycans and glycoconjugates, each of which is coded with a unique oligonucleotide sequence (code). The glycan mixture is interrogated by GBPs followed by the separation of unbound coded glycans. The DNA sequences that identify individual bound glycans are quantitatively sequenced (decoded) by powerful next-generation sequencing (NGS) technology, and copied numbers of the DNA codes represent relative binding specificities of corresponding glycan structures to GBPs. We demonstrate that NGGM generates glycan GBP binding data that are consistent with that generated in a slide-based glycan microarray. More importantly, the solution phase binding assay is directly applicable to identifying glycan binding to intact cells, which is often challenging using glass slide-based glycan microarrays.