Direct Screening of Glycan Patterns from Human Sera: A Selective Glycoprotein Microarray Strategy

Lectin-Based Protein Microarray for the Glycan Analysis of Colorectal Cancer Biomarkers: The Insulin-Like Growth Factor System

Lectin-based protein microarrays are used for glycoprofiling of various kinds of biological samples. Here we describe lectin-based microarray assay in the reverse-phase format where glycoprotein samples are spotted onto microarray slide and then are incubated with set of lectins. This configuration allows high-throughput screening of a large cohort of samples by a set of lectins without need of separation of glycans from glycoproteins. We applied the described method for glycan analysis of glycoprotein biomarkers of colorectal cancer associated with the insulin-like growth factor system.

Regioselective SN2-Type Reaction for the Oriented and Irreversible Immobilization of Antibodies to a Glass Surface Assisted by Boronate Formation

Antibodies have exquisite specificities for molecular recognition, which have led to their incorporation into array sensors that are crucial for research, diagnostic, and therapeutic applications. Many of these platforms rely heavily on surface-bound reactive groups to covalently tether antibodies to solid substrates; however, this strategy is hindered by a lack of orientation control over antibody immobilization. Here, we report a mild electrophilic phenylsulfonate (tosylate) ester-containing boronic acid affinity ligand for attaching antibodies to glass slides. A high level of antibody coupling located near the Fc region of the boronated antibody complex could be achieved by the proximal nucleophilic amino acid driven substitution reaction at the phenylsulfonate center. This enabled the full-length antibodies to be permanently tethered onto surfaces in an oriented manner. The advantages of this strategy were demonstrated through the individual and multiplex detection of protein and serum biomarkers. This strategy not only confers stability to the immobilized antibodies but also presents a different direction for the irreversible attachment of antibodies to solid supports in an orientation-controlled way.

The challenges of glycan recognition with natural and artificial receptors

Glycans - simple or complex carbohydrates - play key roles as recognition determinants and modulators of numerous physiological and pathological processes. Thus, many biotechnological, diagnostic and therapeutic opportunities abound for molecular recognition entities that can bind glycans with high selectivity and affinity. This review begins with an overview of the current biologically and synthetically derived glycan-binding scaffolds that include antibodies, lectins, aptamers and boronic acid-based entities. It is followed by a more detailed discussion on various aspects of their generation, structure and recognition properties. It serves as the basis for highlighting recent key developments and technical challenges that must be overcome in order to fully deal with the specific recognition of a highly diverse and complex range of glycan structures.