%0 Journal Article
%T Recent Advances in Electrochemical Glycobiosensing
%A Germarie S¨˘nchez-Pomales
%A Rebecca A. Zangmeister
%J International Journal of Electrochemistry
%D 2011
%I Hindawi Publishing Corporation
%R 10.4061/2011/825790
%X Biosensors based on electrochemical transduction mechanisms have recently made advances into the field of glycan analysis. These glyco-biosensors offer simple, rapid, sensitive, and economical approaches to the measurement need for rapid glycan analysis for biomarker detection, cancer and disease diagnostics, and bioprocess monitoring of therapeutic glycoproteins. Although the prevalent methods of glycan analysis (high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy) provide detailed identification and structural analysis of glycan species, there are significantly few low-cost, rapid glycan assays available for diagnostic and screening applications. Here we review instances in which glyco-biosensors have been used for glycan analysis using a variety of electrochemical transduction mechanisms (e.g., amperometric, potentiometric, impedimetric, and voltammetric), selective binding agents (e.g., lectins and antibodies), and redox species (e.g., enzyme substrates, inorganic, and nanomaterial). 1. Introduction Glycosylation is the process by which a glycan (i.e., saccharide or carbohydrate) is added to a nonglycan moiety (e.g., protein) and is the most common posttranslational modification of proteins [1]. The glycoforms (i.e., diverse molecular forms of a glycoprotein, resulting from variable glycan structure and/or glycan attachment site occupancy) of a protein profoundly influence structure, function, stability, and serum half-life, which in turn affects many biological processes. Glycosylation plays a role in cell-cell interactions and has been linked to several disease states, including infection, genetic disorders, and cancer [2¨C4]. In the case of cancer, abnormal protein glycosylation has been linked to early tumor cell growth and proliferation; therefore, glycan-based biomarkers have been sought for early detection [3, 5¨C9]. Protein glycans are classified as either N-linked or O-linked (Figure 1). N-linked glycans are attached to the peptide at an Asn-X-Ser/Thr sequence site, where X ˇŮ proline, and share a common branched trimannosyl core. There are three N-glycan subtypes: high-mannose N-glycans which have mannose residues attached to the mannose core, complex N-glycans that do not contain terminal mannose residues but have complex branching, and hybrid N-glycans which contain both mannose residues and complex branching. O-linked glycans tend to be less complex (i.e., linear), they do not share a common single core, and they attach through serine or threonine residues (GalNAc¦Á1-O-Ser/Thr). The seven
%U http://www.hindawi.com/journals/ijelc/2011/825790/