A sandwich electrogenerated chemiluminescence (ECL) biosensor was fabricated based on concanavalin A (Con A)-integrating gold-nanoparticle-modified Ru(bpy)3(2+)-doped silica nanoprobe (Au-RuSiO2 NPs) for in situ and dynamically evaluating cell surface N-glycan expression. Owing to the specific recognition of Con A with mannose and the core trimannoside fragment of N-glycan and the effective ECL amplification of Au-RuSiO2 NPs, the as-proposed biosensor exhibited excellent analytical performance toward the cytosensing of K562 cells with a wide detection linear range from 1.0 × 10(3) to 1.0 × 10(7) cells mL(-1) and a detection limit of 600 cells mL(-1). More importantly, the strategy was successfully applied to evaluate cell surface N-glycan expression under different external stimuli of inhibitors and enzyme. This biosensor is endowed with feasibility and reliability of generating sensitive insight into the majority of N-glycan expression on the cell surface. Furthermore, the biosensor was employed to dynamically profile cell surface N-glycan expression at different phases of cell growth in vitro. This biosensor is promising in studying and elucidating the N-glycan function in biological and physiological processes.

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.

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Mg 3 Sb 2 shows poor comprehensive thermoelectric properties mainly because its conductivity is very poor, despite it has very low thermal conductivity. Excess Mg combined with small amount of Te doping can control carrier type and carrier concentration. The semiconductor and metallic transport mechanism coordinate to control the electrical transport characteristics and improve the electrical transport performance. The lattice thermal conductivity of Mg 3 Sb 2 decreases after Te doping. The maximum ZT value is 0.78 for Mg 3.2 Sb 1.99 Te 0.01 at 773 K.

A simple and sensitive carbohydrate biosensor has been suggested as a potential tool for accurate analysis of cell surface carbohydrate expression as well as carbohydrate-based therapeutics for a variety of diseases and infections. In this work, a sensitive biosensor for carbohydrate-lectin profiling and in situ cell surface carbohydrate expression was designed by taking advantage of a functional glycoprotein of glucose oxidase acting as both a multivalent recognition unit and a signal amplification probe. Combining the gold nanoparticle catalyzed luminol electrogenerated chemiluminescence and nanocarrier for active biomolecules, the number of cell surface carbohydrate groups could be conveniently read out. The apparent dissociation constant between GOx@Au probes and Con A was detected to be 1.64 nM and was approximately 5 orders of magnitude smaller than that of mannose and Con A, which would arise from the multivalent effect between the probe and Con A. Both glycoproteins and gold nanoparticles contribute to the high affinity between carbohydrates and lectin. The as-proposed biosensor exhibits excellent analytical performance towards the cytosensing of K562 cells with a detection limit of 18 cells, and the mannose moieties on a single K562 cell were determined to be 1.8 × 10(10). The biosensor can also act as a useful tool for antibacterial drug screening and mechanism investigation. This strategy integrates the excellent biocompatibility and multivalent recognition of glycoproteins as well as the significant enzymatic catalysis and gold nanoparticle signal amplification, and avoids the cell pretreatment and labelling process. This would contribute to the glycomic analysis and the understanding of complex native glycan-related biological processes.

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