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Plasmonic biosensors fabricated by galvanic displacement reactions for monitoring biomolecular interactions in real time
摘要： Optical sensors are prepared by reduction of gold ions using freshly etched hydride-terminated porous silicon, and their ability to specifically detect binding between protein A/rabbit IgG and asialofetuin/Erythrina cristagalli lectin is studied. The fabrication process is simple, fast, and reproducible, and does not require complicated lab equipment. The resulting nanostructured gold layer on silicon shows an optical response in the visible range based on the excitation of localized surface plasmon resonance. Variations in the refractive index of the surrounding medium result in a color change of the sensor which can be observed by the naked eye. By monitoring the spectral position of the localized surface plasmon resonance using reflectance spectroscopy, a bulk sensitivity of 296 nm ± 3 nm/RIU is determined. Furthermore, selectivity to target analytes is conferred to the sensor through functionalization of its surface with appropriate capture probes. For this purpose, biomolecules are deposited either by physical adsorption or by covalent coupling. Both strategies are successfully tested, i.e., the optical response of the sensor is dependent on the concentration of respective target analyte in the solution facilitating the determination of equilibrium dissociation constants for protein A/rabbit IgG as well as asialofetuin/Erythrina cristagalli lectin which are in accordance with reported values in literature. These results demonstrate the potential of the developed optical sensor for cost-efficient biosensor applications.
关键词： Surface functionalization,Optical sensor,Lectin,Localized surface plasmon resonance,Biomolecular interactions,Gold nanostructure
更新于2025-09-23 15:19:57
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Photoactivable elimination of tumorigenic human induced pluripotent stem cells using a lectin-doxorubicin prodrug conjugate
摘要： Human pluripotent stem cells (hPSCs) are attractive resources for regenerative medicine but medical applications are hindered by their tumorigenic potential. Previously, we identified a hPSC-specific lectin probe, rBC2LCN, through comprehensive glycome analysis using high-density lectin microarrays. Here, we developed a lectin-doxorubicin (DOX) prodrug conjugate with controllable photolysis activation for the elimination of tumorigenic human induced pluripotent stem cells. rBC2LCN was fused with a biotin-binding protein, Tamavidin (BC2Tama), and the fusion protein was expressed in Escherichia coli and purified using affinity chromatography. BC2Tama was then conjugated with doxorubicin-photocleavable biotin (DOXPCB). The BC2Tama-DOXPCB conjugates were observed to bind to the hPSCs followed by internalization. Upon ultraviolet light exposure, doxorubicin was released inside the cells, which allowed specific killing of the hPSCs. Thus, BC2Tama-DOXPCB should be useful for the targeted elimination of hPSCs contained in hPSC-derived cell therapy products. This is the first report of the generation of lectin-prodrug conjugates. BC2Tama should be applicable for the targeted delivery of various types of biotinylated compounds into hPSCs.
关键词： prodrugs,pluripotent stem cells,tumorigenicity,lectin
更新于2025-09-19 17:15:36
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Evaluating glucose and mannose profiles in Candida species using quantum dots conjugated with Cramoll lectin as fluorescent nanoprobes
摘要： Glycoconjugates found on cell walls of Candida species are fundamental for their pathogenicity. Laborious techniques have been employed to investigate the sugar composition of these microorganisms. Herein, we prepared a nanotool, based on the fluorescence of quantum dots (QDs) combined with the specificity of Cramoll lectin, to evaluate glucose/mannose profiles on three Candida species. The QDs-Cramoll conjugates presented specificity and bright fluorescence emission. The lectin preserved its biological activity after the conjugation process mediated by adsorption interactions. The labeling of Candida species was analyzed by fluorescence microscopy and quantified by flow cytometry. Morphological analyses of yeasts labeled with QDs-Cramoll conjugates indicated that C. glabrata (2.7 μm) was smaller when compared to C. albicans (4.0 μm) and C. parapsilosis sensu stricto (3.8 μm). Also, C. parapsilosis population was heterogeneous, presenting rod-shaped blastoconidia. More than 90% of cells of the three species were labeled by conjugates. Inhibition and saturation assays indicated that C. parapsilosis had a higher content of exposed glucose/mannose than the other two species. Therefore, QDs-Cramoll conjugates demonstrated to be effective fluorescent nanoprobes for evaluation of glucose/mannose constitution on the cell walls of fungal species frequently involved in candidiasis.
关键词： Candida,Cratylia mollis,Bioconjugation,Semiconductor nanocrystals,Lectin
更新于2025-09-11 14:15:04
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Fluorescent Neoglycoprotein Gold Nanoclusters: Synthesis and Applications in Plant Lectin Sensing and Cell Imaging
摘要： Carbohydrate-protein interactions mediate fundamental biological processes, such as fertilization, cell signaling, or host-pathogen communication. However, because of the enormous complexity of glycan recognition events, new tools enabling their analysis or applications emerge in recent years. Here, we describe the first preparation of neoglycoprotein functionalized fluorescent gold nanoclusters, containing a biantennary N-glycan G0 as targeting molecule, ovalbumin as carrier/model antigen, and a fluorescent gold core as imaging probe (G0-OVA-AuNCs). Subsequently, we demonstrate the utility of generated G0-OVA-AuNCs for specific sensing of plant lectins and in vitro imaging of dendritic cells.
关键词： Gold nanoclusters,Dendritic cells,Targeting,Neoglycoproteins,Lectin sensing,Carbohydrate-protein interactions
更新于2025-09-10 09:29:36
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Lectins at Interfaces—An Atomic Force Microscopy and Multi-Parameter-Surface Plasmon Resonance Study
摘要： Lectins are a diverse class of carbohydrate binding proteins with pivotal roles in cell communication and signaling in many (patho)physiologic processes in the human body, making them promising targets in drug development, for instance, in cancer or infectious diseases. Other applications of lectins employ their ability to recognize specific glycan epitopes in biosensors and glycan microarrays. While a lot of research has focused on lectin interaction with specific carbohydrates, the interaction potential of lectins with different types of surfaces has not been addressed extensively. Here, we screen the interaction of two specific plant lectins, Concanavalin A and Ulex Europaeus Agglutinin-I with different nanoscopic thin films. As a control, the same experiments were performed with Bovine Serum Albumin, a widely used marker for non-specific protein adsorption. In order to test the preferred type of interaction during adsorption, hydrophobic, hydrophilic and charged polymer films were explored, such as polystyrene, cellulose, N,-N,-N-trimethylchitosan chloride and gold, and characterized in terms of wettability, surface free energy, zeta potential and morphology. Atomic force microscopy images of surfaces after protein adsorption correlated very well with the observed mass of adsorbed protein. Surface plasmon resonance spectroscopy studies revealed low adsorbed amounts and slow kinetics for all of the investigated proteins for hydrophilic surfaces, making those resistant to non-specific interactions. As a consequence, they may serve as favorable supports for biosensors, since the use of blocking agents is not necessary.
关键词： lectin,gold,adsorption,bovine serum albumin,polystyrene,surface plasmon resonance spectroscopy,cellulose thin film
更新于2025-09-10 09:29:36
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Carbohydrate Functionalization of Few-Layer Graphene through Microwave-Assisted Reaction of Perfluorophenyl Azide
摘要： The excellent physical and chemical properties of graphene make it an attractive nanomaterial and a component in high-performance nanocomposite materials. To prepare graphene-based nanocomposite materials, the chemical functionalization is often necessary. Water-soluble ligands such as carbohydrates not only make the functionalized graphene compatible with aqueous media, but also introduce bio-recognition which is important for graphene to be used in biotechnology. In this study, we report the derivatization of few-layer graphene (FLG) with carbohydrates through microwave-assisted reaction of perfluorophenyl azide (PFPA). FLG was first treated with PFPA under microwave radiation. Subsequent conjugation with glycosyl amine gave carbohydrate-presenting FLG. Thermogravimetric analysis showed that microwave radiation gave a higher degree of functionalization compared to conventional heating, with higher weight losses for both PFPA and Man ligands. The carbohydrates (mannose and galactose) retained their bioactivity, as demonstrated by the lectin binding assays. Higher degree of binding towards lectins was obtained for the carbohydrate-functionalized FLG prepared by microwave radiation than the conventional heating.
关键词： microwave radiation,perfluorophenyl azide,graphene,carbohydrate,lectin
更新于2025-09-04 15:30:14