title: Quantum dot nanometal surface energy transfer based biosensing of sialic acid compositions and linkages in biological samples.
abstract: Current methods for analyzing sialic acid diversity in modifications and linkages require multistep processing, derivatization, and chromatographic analyses. We here report a single-step optical method for identification and quantification of different compositions of sialoglycans on glycoproteins and in serum. This was achieved by measuring and quantifying nanometal surface energy transfer (NSET) signals between quantum dots and gold nanoparticles bound to specific sialic acid binding proteins (SBPs) and sialic acid moieties, respectively. The biosensing process is based on the NSET turn-on by external sialic acid species that compete for binding to the SBPs. Selectivity of the biosensor toward sialoglycans can be designed to detect the total amount, glycosylation linkages (α2-6 vs α2-3), and modifications (9-O-acetyl and N-glycolyl groups) in the samples. This nanobiosensor is a prototype expected to achieve limits of the detection down to the micromolar range for high-throughput quantification and analysis of different compositions of sialoglycans present in biological or biomedical samples.
authors.affiliation: Glycobiology Research and Training Center, Department of Medicine, University of California, San Diego, La Jolla, California, United States.
authors.forename: Raghavendra
authors.initials: R
authors.lastname: Kikkeri
authors.forename: Vered
authors.initials: V
authors.lastname: Padler-Karavani
authors.forename: Sandra
authors.initials: S
authors.lastname: Diaz
authors.forename: Andrea
authors.initials: A
authors.lastname: Verhagen
authors.forename: Hai
authors.initials: H
authors.lastname: Yu
authors.forename: Hongzhi
authors.initials: H
authors.lastname: Cao
authors.forename: Martijn A
authors.initials: MA
authors.lastname: Langereis
authors.forename: Raoul J
authors.initials: RJ
authors.lastname: De Groot
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.forename: Ajit
authors.initials: A
authors.lastname: Varki
mesh_terms: D000906:Antibodies / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002240:Carbohydrate Sequence; D004735:Energy Transfer; D006023:Glycoproteins / Q000097:blood*; D006046:Gold / Q000737:chemistry; D006801:Humans; D055767:Immobilized Proteins / Q000737:chemistry; D007700:Kinetics; D037102:Lectins / Q000737:chemistry; D057230:Limit of Detection; D008969:Molecular Sequence Data; D053758:Nanoparticles / Q000737:chemistry*; D045663:Quantum Dots; D012794:Sialic Acids / Q000032:analysis*; D013816:Thermodynamics
chemical_list: D000906:Antibodies; D006023:Glycoproteins; D055767:Immobilized Proteins; D037102:Lectins; D012794:Sialic Acids; D006046:Gold