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While serology represents the forefront technique for cancer diagnosis, current clinical methods for the detection of serum biomarkers have flaws in terms of the need of complicated manipulations, long analytical time, and high cost. Here, we develop a supramolecular glycoprobe for the quick serological detection of a cancer biomarker. The probe formed by agglutination between self-assembled glyco-gold nanoparticles and a lectin shows subtle optical variations upon the competitive recognition of a glycoprotein biomarker secreted by cancer cells, tumor-bearing mice, as well as clinical cancer patients, with no response to a series of controls including the serum of hepatitis patients. This research provides an insight into the development of effective tools for serological diagnosis of cancer. [ABSTRACT FROM AUTHOR]

Bacterial evolution, particularly in hospital settings, is leading to an increase in multidrug resistance. Understanding the basis for this resistance is critical as it can drive discovery of new antibiotics while allowing the clinical use of known antibiotics to be optimized. Here, we report a photoactive chemical probe for superresolution microscopy that allows for the in situ probing of antibiotic-induced structural disruption of bacteria. Conjugation between a spiropyran (SP) and galactose via click chemistry produces an amphiphilic photochromic glycoprobe, which self-assembles into glycomicelles in water. The hydrophobic inner core of the glycomicelles allows encapsulation of antibiotics. Photoirradiation then serves to convert the SP to the corresponding merocyanine (MR) form. This results in micellar disassembly allowing for release of the antibiotic in an on-demand fashion. The glycomicelles of this study adhere selectively to the surface of a Gram-negative bacterium through multivalent sugar-lectin interaction. Antibiotic release from the glycomicelles then induces membrane collapse. This dynamic process can be imaged in situ by superresolution spectroscopy owing to the "fluorescence blinking" of the SP/MR photochromic pair. This research provides a high-precision imaging tool that may be used to visualize how antibiotics disrupt the structural integrity of bacteria in real time. [ABSTRACT FROM AUTHOR]

Fluorogenic supramolecular complexes formed between tubular-shaped pyrenyl-β-cyclodextrins and glyco-rhodamine are determined to respond to a selective lectin with 'turn-on' fluorescence with excellent selectivity over a range of competing species. [ABSTRACT FROM AUTHOR]

The synthesis of diversely functionalized carbohydrate building blocks is of great interest towards the generation of new carbohydrate mimetics. Glycoaminoxy acids are recently developed glycoamino acid analogues with both an aminoxy and a carboxyl group connected to the sugar scaffold. These molecules could be readily used for the synthesis of various glycoconjugates through N-oxy amide or oxime bond, thus providing a potent tool for the design of novel functional carbohydrate mimetics. Here, the efficient synthesis of 2,6-functionalized pyranoid glycoaminoxy acid from commercially available methyl glucopyranoside is reported. The subsequent assembly of this glycoaminoxy acid building unit via N-acylation led successfully to the novel 2,6-linked oligosaccharide mimetics. [ABSTRACT FROM AUTHOR]

O-GlcNAcase (OGA) is implicated in several important biological and disease-relevant processes. Here, we synthesized fluorogenic probes for OGA by grafting GlcNAc directly or using a self-immolative linker to the hydroxyl position of 4-hydroxylisoindoline (BHID), a typical excited-state intramolecular proton transfer (ESIPT) probe. The probe was used for a fluorogenic assay to determine the half maximal inhibitory concentration of a known OGA inhibitor and differentiate between OGA and hexosaminidase when GlcNAc is replaced by GlcNPr,where a propionyl group is used instead of an acetyl group. [ABSTRACT FROM AUTHOR]

Here, we describe a novel "switch-on" biosensor based on quinonyl glycosides functionalized quantum dots (QDs) for the specific targeting and imaging of transmembrane glycoprotein receptors on the surface of cancer cells. The design of the quinonyl glycosides lies in that the quinone moiety serves as a quencher of QDs and the glycoside moiety as a biospecific ligand for targeting a receptor. We observed that the quenched photoluminescence of the quinone glycosides functionalized QDs could be significantly recovered by a specific lectin that selectively binds to the glycosides clustering the QDs but was not affected by a panel of nonspecific lectins. Moreover, we determined that quinonyl galactoside functionalized QDs could optically image the asialoglycoprotein receptors of a hepatoma cell line in a target-specific manner. This system might provide new insights into the fabrication of photoluminogenic biosensors for the analysis of the universal ligand-receptor recognitions in nature. [ABSTRACT FROM AUTHOR]

This study depicts the 'click' construction of a water-soluble galactosyl rhodamine that can selectively probe mercury ions internalized by hepatoma cells over other cancer cells. [ABSTRACT FROM AUTHOR]

A tetrameric N-acetyl galactosaminyl (GalNAc) peptidomimetic was constructed by N-acetylation of repeating proline-based hydroxamic acid units, followed by a convergent 'click chemistry' coupling. This novel glycopeptidomimetic was determined to effectively antagonize the interaction between a transmembrane hepatic lectin and GalNAc on the cellular level. [ABSTRACT FROM AUTHOR]

Development of sugar-based fluorescence (FL) chemo-probes is of much interest since sugars are biocompatible, water-soluble and structurally rigid natural starting materials. We report here that fluorescent glycoligands with two triazolyl coumarin moieties installed onto the different positions of an identical glucosyl nucleus exert completely reversed optical response to a metal ion. C3,4-, C2,3- and C4,6-di-substituted coumarin glucosides synthesized by a click reaction similarly showed a selective FL variation in the presence of silver (I) among a range of metal cations in an aqueous solution. However, the variation was determined to be converse: the FL of the C3,4-ligand was quenched whereas that of the C2,3/ C4,6-ligand tangibly enhanced. FL andNMRtitrations suggested that this divergence was due to the distinct complexation modes of the conformationally constrained ligands with the ion. The optimal motifs of the ligand-ion complexation were predicted by a computational simulation. Finally, the C2,3-ligand was determined to be of low cytotoxicity and applicable in the FL imaging of silver ions internalized by live cells. [ABSTRACT FROM AUTHOR]

Intercellular ligand-receptor recognitions are crucial natural interactions that initiate a number of biological and pathological events. We present here the simple construction of a unique class of biomimetic interfaces based on a graphene-mediated self-assembly of glycosyl anthraquinones to a screen-printed electrode for the detection of transmembrane glycoprotein receptors expressed on a hepatoma cell line. We show that an electroactive interface confined with densely clustered galactosyl ligands is able to ingeniously recognize the asialoglycoprotein receptors on live Hep-G2 cells employing simple electrochemical techniques. The only facility used is a personal laptop in connection with a cheap and portable electrochemical workstation. [ABSTRACT FROM AUTHOR]

Autologous vein grafts is still commonly used for arterial reconstructive procedures. Their success is limited by the development of neointimal hyperplasia. Clinical and experimental evidence suggest that the bone marrowderived mesenchymal stem cells (MSCs) participate in the neovascularization. The current study used a direct approach to test the hypothesis that, after vein grafting in a rat model, MSCs have potential effects on reendothelialization and neointimal formation. MSCs were isolated by bone marrow cell adherence. Autologously interpositioning left external jugular vein (LEJV) to left common carotid artery-induced vein grafting model of rat was utilized. Vascular lesion formation after transplantation of MSCs labeled with 4′,6-diamidino-2-phenylindole (DAPI) was investigated. Two weeks after implantation, immunofluorescence studies revealed that engrafted cells acquired an endothelial phenotype, and some expressed endothelial nitric oxide synthase (eNOS). Furthermore, proliferation of cells and neointimal formation decreased signiB cantly after MSC implantation. Real-time reverse transcription-PCR and western blotting analysis showed a rise of eNOS expression in the MSC group compared with the vein grafting group. Therefore, engrafted MSCs appeared to differentiate into endothelial cells, diminish the neointima formation and contribute to the improvement on endothelial function, which indicates that MSCs may exert an important function as repair mechanism in vascular injury after vein grafting. [ABSTRACT FROM AUTHOR]