All biological surfaces are coated with complex carbohydrates known as glycans. This glycan layer transforms biological surfaces into highly selective interfaces that mediate molecular recognition, cell signaling, adhesion, and host-pathogen interactions. These natural recognition mechanisms can be adapted for both analytical and therapeutic applications, enabled through surface engineering of synthetic materials.

In glycan-based analysis, defined carbohydrates are immobilized on sensing surfaces to identify glycan-binding specificities, investigate host susceptibility to pathogens, and characterize the kinetics of host-pathogen interactions. Glycan microarrays enable high-throughput screening, while techniques such as biolayer interferometry provide real-time measurements of binding affinity and kinetics. Such methods often require glycans to be chemically attached to a surface through chemical linker, making linker design as a critical component. A recently introduced trifunctional Fmoc-amino-azido linker provides a versatile strategy for preparing glycan probes which can be used across multiple platforms. This linker enables on-array quality control and comparisons between platforms.

Glycan-modified surfaces also have considerable therapeutic potential. Cellular nanosponges, i.e. polymeric nanoparticles coated with natural cell membranes, can act as biomimetic decoys that capture pathogenic agents before they reach their intended cellular targets. Recent studies by Ai and colleagues show that enriching these nanosponges with specific glycans can enhance the sequestration and neutralization of both SARS-CoV-2 and botulinum neurotoxin.

In this seminar I will examine these two complementary faces of glycan surface engineering: the use of glycans to study biological recognition and their use to intercept harmful biological agents. In both cases, the methods used to modify and present glycans on the surface are central to the performance, reliability, and biological relevance of the resulting platform.