Neuraminidase Resistant Sialosides for the Detection of Influenza Viruses

We report the synthesis of influenza virus neuraminidase (NA) resistant sialosides that include different glycoside linkages (<i>C</i>-, <i>S</i>-, and triazole). These unnatural sialosides were printed onto glass slides to generate a small focused microarray. We evaluated the binding affinity of multiple lectins and compared the stability of these sialosides with <i>O</i>-linked sialosides toward influenza virus neuraminidase and intact virus. We demonstrated the ability of these molecules to capture eight different strains of influenza virus at ambient temperature without the addition of NA inhibitors. The glycans capture extremely low, clinically relevant concentrations of viruses and each strain gives rise to a specific “fingerprint” binding pattern, which could potentially be used in rapid diagnostic tests

Indirect Detection of Glycosidases Using Amperometry

Glycosidases are essential enzymes that cleave glycoside bonds. The presence of glycosidases have been widely used to detect pathogens, label cells/tissues, and report specific diseases. We have developed a rapid electrochemical assay to detect glycosidases. Exposure of electrochemically inactive substrates to glycosidases releases glucose, which can be measured easily using an electrochemical cell. Five different glycosidases were detected rapidly within 1 h using disposable electrodes. This assay could readily be incorporated into repurposed glucose meters to rapidly detect glycosidases, which in turn could be useful to report the presence of a pathogen or illness

Synthesis and Evaluation of Biotinylated Bivalent HistoBlood Group Antigens for Capturing Human Noroviruses

A panel of biotinylated bivalent H-type glycans that have been reported as binding ligands for human noroviruses were synthesized using a modular synthetic strategy. These glycoconjugates were attached to streptavidin-coated magnetic beads and used to recover human norovirus from fecal samples using a magnetic bead-based assay. The biotinylated bivalent glycans synthesized for this study exhibited similar or better capturing ability when compared to commercial biotinylated glycopolymers

Toward the Development of the Next Generation of a Rapid Diagnostic Test: Synthesis of Glycophosphatidylinositol (GPI) Analogues of Plasmodium falciparum and Immunological Characterization

A large number of proteins in malaria parasites are anchored using glycophosphatidylinositols (GPIs) with lipid tails. These GPIs are structurally distinct from human GPIs. Plasmodium falciparum GPIs have been considered as potential vaccine candidates because these molecules are involved in inducing inflammatory responses in human hosts, and natural anti-GPI antibody responses have been shown to be associated with protection against severe disease. GPIs can also be considered as targets for rapid diagnostic tests. Because isolation of native GPIs in large quantities is challenging, development of synthetic GPI molecules can facilitate further exploration of GPI molecules for diagnostics. Here, we report synthesis and immunological characterization of a panel of malaria-specific GPI analogues. A total of three GPI analogues were chemically synthesized and conjugated to a carrier protein to immunize and generate antibodies in rabbits. The rabbit immune sera showed reactivity with synthetic GPIs and native GPIs extracted from P. falciparum parasite, as determined by Luminex and ELISA methods

Fluorescent Neomannosyl Bovine Serum Albumin as Efficient Probe for Mannose Receptor Imaging and MCF‑7 Cancer Cell Targeting

Robust carbohydrate conjugated fluorescent bovine serum albumin (BSA) as useful tool to study carbohydrate–receptor interactions and in vivo targeting is reported. Amine terminated α-mannoside was attached to fluorescein labeled BSA via diethyl squarate strategy. The surface functionalization and lectin binding specific to fluorescent neomannosyl glycoprotein were confirmed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), surface plasmon resonance (SPR), and microarray imaging. The glycoconjugate was further used to image concanavalin A (ConA), pili of <i>E. coli</i> K12, and lysosomes in MCF-7 cancerous cells successfully, suggesting that this neomannosyl glycoprotein can be used as suitable probe to elucidate carbohydrate–protein interactions, image cancers, and target drug specifically toward tumors