ABSTRACT
It was reported previously that monosaccharide-functionalized single-walled carbon nanotubes (SWNTs) could interact with Bacillus anthracis (Sterne) spores with the mediation of a divalent cation such as Ca(2+) to result in significant spore aggregation and reduction in colony forming units. In this work a more systematic investigation was performed on interactions of the SWNTs functionalized with individual mannose and galactose moieties and their various dendritic configurations with B. anthracis and B. subtilis spores in the presence and absence of a divalent cation. Significant differences and selectivity between the Bacillus spores and between different sugars and their configurations were observed. The relevant results are presented, and their mechanistic implications are discussed.
Subject(s)
Bacillus/chemistry , Carbohydrates/chemistry , Nanotechnology/methods , Nanotubes, Carbon/chemistry , Nanotubes, Carbon/ultrastructure , Spores, Bacterial/chemistry , Binding Sites , Crystallization/methods , Macromolecular Substances/chemistry , Materials Testing , Molecular Conformation , Particle Size , Surface PropertiesABSTRACT
Covalent conjugates of fullerene C(60) and the highly effective anticancer drug doxorubicin (DOX) were prepared and studied. The conjugation was through the amide linkage to preserve the intrinsic properties of DOX and fullerene cage. As designed, the conjugates with hydrophilic ethylene glycol spacers exhibited much improved aqueous compatibility, with significant solubility in water-DMSO mixtures. The anti-neoplastic activities of DOX were apparently unaffected in the conjugates according to evaluations in vitro with a human breast cancer cell line.
ABSTRACT
Single-walled carbon nanotube (SWNT) is a pseudo-one-dimensional nanostructure capable of carrying/displaying a large number of bioactive molecules and species in aqueous solution. In this work, a series of dendritic beta-D-galactopyranosides and alpha-D-mannopyranosides with a terminal amino group were synthesized and used for the functionalization of SWNTs, which targeted the defect-derived carboxylic acid moieties on the nanotube surface. The higher-order sugar dendrons were more effective in the solubilization of SWNTs, with the corresponding functionalized nanotube samples of improved aqueous solubility characteristics. Through the functionalization, the nanotube apparently serves as a unique scaffold for displaying multiple copies of the sugar molecules in pairs or quartets. Results on the synthesis and characterization of these sugar-functionalized SWNTs and their biological evaluations in binding assays with pathogenic Escherichia coli and with Bacillus subtilis (a nonvirulent simulant for Bacillus anthracis or anthrax) spores are presented and discussed.
Subject(s)
Galactose/chemistry , Mannose/chemistry , Nanotubes, Carbon/chemistry , Bacillus subtilis/chemistry , Binding Sites , Carboxylic Acids/chemistry , Dendrimers/chemistry , Escherichia coli/chemistry , Galactose/analogs & derivatives , Mannose/analogs & derivatives , Molecular Structure , Particle Size , Solubility , Surface PropertiesABSTRACT
There have been rapid advances in the development and applications of semiconductor quantum dots (QDs) represented by CdSe/ZnS. However, a serious limitation of these QDs is the necessary use of toxic heavy metals. It is reported here that small carbon nanoparticles doped with inorganic salts serve as a highly promising new platform for brightly photoluminescent dots. The photoluminescent carbon dots with the carbon core doped with ZnO (C(ZnO)-Dots) or ZnS (C(ZnS)-Dots) in aqueous solutions are competitive to the commercially available CdSe/ZnS QDs in luminescence brightness.
ABSTRACT
There has been significant interest in the binding of anthrax spores by molecular species, but with only limited success. Proteins and more recently peptides were used. However, despite the known presence of carbohydrates on the spore surface, carbohydrate-carbohydrate interactions have hardly been explored likely because of the lack of required specific platform for synthetic carbohydrates. We report the successful use of single-walled carbon nanotubes as a truly unique scaffold for displaying multivalent monosaccharide ligands that bind effectively to anthrax spores with divalent cation mediation to cause significant spore aggregation. The work should have far-reaching implications in development of countermeasure technologies.
Subject(s)
Bacillus anthracis/isolation & purification , Bacterial Adhesion/physiology , Bacteriological Techniques , Carbohydrates/chemistry , Nanotubes, Carbon/chemistry , Spores, Bacterial/isolation & purification , Animals , Bacillus anthracis/metabolism , Microscopy, Electron, Scanning , Spores, Bacterial/metabolismABSTRACT
Bovine serum albumin-functionalized multiple-walled carbon nanotubes with encapsulated ferromagnetic elements were conjugated with pathogen-specific antibody, and the conjugate was evaluated for immunomagnetic separation of Escherichia coli O157:H7 in pure and mixed (with Salmonella Typhimurium) cultures.
Subject(s)
Escherichia coli O157/isolation & purification , Immunomagnetic Separation/methods , Iron/chemistry , Nanotechnology/methods , Nanotubes, Carbon/chemistry , Nanotubes, Carbon/ultrastructure , Serum Albumin, Bovine/chemistry , Coated Materials, Biocompatible/chemistry , Crystallization/methods , Materials Testing , Particle SizeSubject(s)
Antibodies, Bacterial/chemistry , Bacterial Adhesion/immunology , Escherichia coli O157/immunology , Nanotubes, Carbon/chemistry , Animals , Antibodies, Bacterial/immunology , Cattle , Escherichia coli O157/ultrastructure , Goats , Microscopy, Atomic Force , Microscopy, Electron, Scanning , Microscopy, Fluorescence , Serum Albumin, Bovine/chemistryABSTRACT
A single-walled carbon nanotube was exploited for its semi-flexible pseudo-one-dimensional nanostructure as a unique scaffold to display multivalent carbohydrate ligands, with a specific demonstration showing that galactosylated carbon nanotubes were effective in the capturing of pathogenic Escherichia coli in solution.
Subject(s)
Carbohydrates/chemistry , Escherichia coli/pathogenicity , Nanotubes, Carbon/chemistry , Ligands , Nanostructures/chemistry , Solutions/chemistry , Structure-Activity Relationship , Surface PropertiesABSTRACT
A derivatized porphyrin with long alkyl chains, 5,10,15,20-tetrakis(hexadecyloxyphenyl)-21H,23H-porphine, is selective toward semiconducting single-walled carbon nanotubes (SWNTs) in presumably noncovalent interactions, resulting in significantly enriched semiconducting SWNTs in the solubilized sample and predominantly metallic SWNTs in the residual solid sample according to Raman, near-IR absorption, and bulk conductivity characterizations.
