OBJECTIVES To investigate whether silver chelates or silver ions are more effective as therapeutic agents, and to examine their mode of action so that safer and stable compounds that have a broad spectrum of therapeutic activities can be developed. METHODS Efficacy was investigated against Pseudomonas aeruginosa (ATCC 15442) by determining MIC via a broth macrodilution procedure using NCCLS m...

Chelation of iron to iron-binding proteins is a strategy of host defense. Some pathogens counter this via the secretion of low-molecular-weight iron-chelating agents (siderophores). Human phagocytes possess a high-capacity mechanism for iron acquisition from low-molecular-weight iron chelates. Efficient acquisition and sequestration of iron bound to bacterial siderophores by host phagocytes cou...

The effect of ligand structure on the magnetic resonance (MR) imaging and biodistribution of six gadolinium (Gd) chelates based on a hydroxypyridonate-terephthalimide (HOPO-TAM) ligand design was investigated. Modifications to the molecular structure of the Gd-HOPO-TAM chelates (hydrophilicity and aromatic group substitution) significantly influence the efficacy of imaging and biodistribution. ...

A bioactive ligand, 2,5-diamino-1,3,4-thiadiazole (L), derived from semicarbazide hydrochloride, and its metal complexes were prepared and characterized. The complexes were characterized using elemental, infra-red, ultraviolet/visible, magnetic moment, atomic absorption, thin layer chromatography and molar conductance measurements. The IR data revealed that the ligand (L) behaved as a tridentat...

The blood-brain barrier (BBB) remains a formidable obstacle in medicine, preventing efficient penetration of chemotherapeutic and diagnostic agents to malignant gliomas. Here, a transactivator of transcription (TAT) peptide-modified gold nanoparticle platform (TAT-Au NP) with a 5 nm core size is demonstrated to be capable of crossing the BBB efficiently and delivering cargoes such as the antica...

Luminescent gold nanocrystals (AuNCs) are a recently-developed material with potential optic, electronic and biological applications. They also demonstrate energy transfer (ET) acceptor/sensitization properties which have been ascribed to Förster resonance energy transfer (FRET) and, to a lesser extent, nanosurface energy transfer (NSET). Here, we investigate AuNC acceptor interactions with thr...

Luminescent lanthanide complexes have unusual spectroscopic characteristics, including millisecond excited-state lifetime and sharply spiked emission spectra. These characteristics make them valuable alternatives to conventional organic fluorescent probes in detection applications and for measuring nanometer-scale conformational changes in biomolecules via resonance energy transfer. Our group h...

Isoxazole ring formation was examined as a potential Cu-free alternative click reaction to Cu(I)-catalyzed alkyne/azide cycloaddition. The isoxazole reaction was explored at macroscopic and radiotracer concentrations with the fac-[M(I)(CO)3](+) (M = Re, (99m)Tc) core for use as a noncoordinating linker strategy between covalently linked molecules. Two click assembly methods (click, then chelate...

The lithium diisopropylamide-mediated 1,2-elimination of 1-bromocyclooctene to provide cyclooctyne is investigated using approximately 50 potentially hemilabile polyethers and amino ethers. Rate laws for selected ligands reveal chelated monomer-based pathways. The dependence of the rates on ligand structure shows that anticipated rate accelerations based on the gem-dimethyl effect are nonexiste...