title: Sensitive electrochemical aptamer biosensor for dynamic cell surface N-glycan evaluation featuring multivalent recognition and signal amplification on a dendrimer-graphene electrode interface.
abstract: We demonstrate a multivalent recognition and highly selective aptamer signal amplification strategy for electrochemical cytosensing and dynamic cell surface N-glycan expression evaluation by the combination of concanavalin A (Con A), a mannose binding protein, as a model, conjugated poly(amidoamine) dendrimer on a chemically reduced graphene oxide (rGO-DEN) interface, and aptamer- and horseradish peroxidase-modified gold nanoparticles (HRP-aptamer-AuNPs) as nanoprobes. In this strategy, the rGO-DEN can not only enhance the electron transfer ability but also provide a multivalent recognition interface for the conjugation of Con A that avoids the weak carbohydrate-protein interaction and dramatically improves the cell capture efficiency and the sensitivity of the biosensor for cell surface glycan. The high-affinity aptamer- and HRP-modified gold nanoparticles provide an ultrasensitive electrochemical probe with excellent specificity. As proof-of-concept, the detection of CCRF-CEM cell (human acute lymphoblastic leukemia) and its surface N-glycan was developed. It has demonstrated that the as-designed biosensor can be used for highly sensitive and selective cell detection and dynamic evaluation of cell surface N-glycan expression. A detection limit as low as 10 cells mL(-1) was obtained with excellent selectivity. Moreover, this strategy was also successfully applied for N-glycan expression inhibitor screening. These results imply that this biosensor has potential in clinical diagnostic and drug screening applications and endows a feasibility tool for insight into the N-glycan function in biological processes and related diseases.
authors.affiliation: Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and Chemical Engineering, Hunan Normal University , Changsha 410081, China.
authors.forename: Xiaojiao
authors.initials: X
authors.lastname: Chen
authors.forename: Yangzhong
authors.initials: Y
authors.lastname: Wang
authors.forename: Youyu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zhuhai
authors.initials: Z
authors.lastname: Chen
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Zhaolong
authors.initials: Z
authors.lastname: Li
authors.forename: Jinghong
authors.initials: J
authors.lastname: Li
mesh_terms: D052157:Aptamers, Nucleotide; D001483:Base Sequence; D015374:Biosensing Techniques; D002462:Cell Membrane / Q000737:chemistry; D017931:DNA Primers; D050091:Dendrimers; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D011134:Polysaccharides / Q000032:analysis*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D052157:Aptamers, Nucleotide; D017931:DNA Primers; D050091:Dendrimers; D011134:Polysaccharides; D006108:Graphite