Lanthanide-Based Optical Probes of Biological Systems.
Ontology highlight
ABSTRACT:
SUBMITTER: Cho U
PROVIDER: S-EPMC7484113 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Luminescent lanthanides possess ideal properties for biological imaging, including long luminescent lifetimes and emission within the optical window. Here, we report a novel approach to responsive luminescent Tb(iii) probes that involves direct modulation of the antenna excited triplet state energy. If the triplet energy lies too close to the 5D4 Tb(iii) excited state (20 500 cm-1), energy transfer to 5D4 competes with back energy transfer processes and limits lanthanide-based emission. To validate this approach, a series of pyridyl-functionalized, macrocyclic lanthanide complexes were designed, and the corresponding lowest energy triplet states were calculated using density functional theory (DFT). Subsequently, three novel constructs L3 (nitro-pyridyl), L4 (amino-pyridyl) and L5 (fluoro-pyridyl) were synthesized. Photophysical characterization of the corresponding Gd(iii) complexes revealed antenna triplet energies between 25 800 and 30 400 cm-1 and a 500-fold increase in quantum yield upon conversion of Tb(L3) to Tb(L4) using the biologically relevant analyte H2S. The corresponding turn-on reaction can be monitored using conventional, small-animal optical imaging equipment in presence of a Cherenkov radiation emitting isotope as an in situ excitation source, demonstrating that antenna triplet state energy modulation represents a viable approach to biocompatible, Tb-based optical turn-on probes.
| S-EPMC8278976 | biostudies-literature
Project description:The potent redox activity of copper is required for sustaining life. Mismanagement of its cellular pools, however, can result in oxidative stress and damage connected to aging, neurodegenerative diseases, and metabolic disorders. Therefore, copper homeostasis is tightly regulated by cells and tissues. Whereas copper and other transition metal ions are commonly thought of as static cofactors buried within protein active sites, emerging data points to the presence of additional loosely bound, labile pools that can participate in dynamic signalling pathways. Against this backdrop, we review advances in sensing labile copper pools and understanding their functions using synthetic fluorescent indicators. Following brief introductions to cellular copper homeostasis and considerations in sensor design, we survey available fluorescent copper probes and evaluate their properties in the context of their utility as effective biological screening tools. We emphasize the need for combined chemical and biological evaluation of these reagents, as well as the value of complementing probe data with other techniques for characterizing the different pools of metal ions in biological systems. This holistic approach will maximize the exciting opportunities for these and related chemical technologies in the study and discovery of novel biology of metals.
| S-EPMC4478099 | biostudies-literature
Project description:Oxygen levels in biological systems can be measured by the phosphorescence quenching method using probes with controllable quenching parameters and defined biodistributions. We describe a general approach to the construction of phosphorescent nanosensors with tunable spectral characteristics, variable degrees of quenching, and a high selectivity for oxygen. The probes are based on bright phosphorescent Pt and Pd complexes of porphyrins and symmetrically pi-extended porphyrins (tetrabenzoporphyrins and tetranaphthoporphyrins). pi-Extension of the core macrocycle allows tuning of the spectral parameters of the probes in order to meet the requirements of a particular imaging application (e.g., oxygen tomography versus planar microscopic imaging). Metalloporphyrins are encapsulated into poly(arylglycine) dendrimers, which fold in aqueous environments and create diffusion barriers for oxygen, making it possible to regulate the sensitivity and the dynamic range of the method. The periphery of the dendrimers is modified with poly(ethylene glycol) residues, which enhance the probe's solubility, diminish toxicity, and help prevent interactions of the probes with the biological environment. The probe's parameters were measured under physiological conditions and shown to be unaffected by the presence of biomacromolecules. The performance of the probes was demonstrated in applications, including in vivo microscopy of vascular pO(2) in the rat brain.
| S-EPMC2805241 | biostudies-literature
Project description:A new mixed pyridyl-carboxylate ligand with two picolinate chromophores and a flexible linear spacer, potassium 2,2'-(butane-1,4-diylbis((pyridin-2-ylmethyl)azanediyl))diacetate (K2bpbd), which is obtained in high yield and spectroscopically characterized, has been utilized to make new lanthanide complexes, namely, [Ln(bpbd) (H2O)2(NO3)]·xH2O, where Ln = Tb (1) and x = 6, Ln = Sm (2) and x = 7, and Ln = Dy (3) and x = 7. These complexes have been extensively characterized by various spectroscopic techniques (UV-vis and Fourier transform infrared spectroscopy), elemental analyses, thermogravimetric analysis, field emission scanning electron microscopy, and powder X-ray diffraction. These show very intense characteristic luminescence features that confirm the antenna effect of the ligand on the metal center. These complexes have been utilized for the detection of various nitroaromatic compounds. Among these three complexes, 1 is found to be the best for the selective sensing of 2,4,6-trinitrophenol in water with a detection limit of (0.35 ± 0.05) ppm. Its Stern-Volmer constant, K SV [(5.48 ± 0.1) × 104 M-1], is one of the highest among similar sensors reported so far.
| S-EPMC6648830 | biostudies-literature
Project description:Boron has been employed in materials science as a marker for imaging specific structures by electron energy loss spectroscopy (EELS) or secondary ion mass spectrometry (SIMS). It has a strong potential in biological analyses as well; however, the specific coupling of a sufficient number of boron atoms to a biological structure has proven challenging. Herein, we synthesize tags containing closo-1,2-dicarbadodecaborane, coupled to soluble peptides, which were integrated in specific proteins by click chemistry in mammalian cells and were also coupled to nanobodies for use in immunocytochemistry experiments. The tags were fully functional in biological samples, as demonstrated by nanoSIMS imaging of cell cultures. The boron signal revealed the protein of interest, while other SIMS channels were used for imaging different positive ions, such as the cellular metal ions. This allows, for the first time, the simultaneous imaging of such ions with a protein of interest and will enable new biological applications in the SIMS field.
| S-EPMC6593772 | biostudies-literature
Project description:Secure data encryption relies heavily on one-way functions, and copy protection relies on features that are difficult to reproduce. We present an optical authentication system based on lanthanide luminescence from physical one-way functions or physical unclonable functions (PUFs). They cannot be reproduced and thus enable unbreakable encryption. Further, PUFs will prevent counterfeiting if tags with unique PUFs are grafted onto products. We have developed an authentication system that comprises a hardware reader, image analysis, and authentication software and physical keys that we demonstrate as an anticounterfeiting system. The physical keys are PUFs made from random patterns of taggants in polymer films on glass that can be imaged following selected excitation of particular lanthanide(III) ions doped into the individual taggants. This form of excitation-selected imaging ensures that by using at least two lanthanide(III) ion dopants, the random patterns cannot be copied, because the excitation selection will fail when using any other emitter. With the developed reader and software, the random patterns are read and digitized, which allows a digital pattern to be stored. This digital pattern or digital key can be used to authenticate the physical key in anticounterfeiting or to encrypt any message. The PUF key was produced with a staggering nominal encoding capacity of 73600. Although the encoding capacity of the realized authentication system reduces to 6 × 10104, it is more than sufficient to completely preclude counterfeiting of products.
| S-EPMC5786441 | biostudies-literature
Project description:In principle, the millisecond emission lifetimes of lanthanide chelates should enable their ultrasensitive detection in biological systems by time-resolved optical microscopy. In practice, however, lanthanide imaging techniques have provided no better sensitivity than conventional fluorescence microscopy. Here, we identified three fundamental problems that have impeded lanthanide microscopy: low photon flux, inefficient excitation, and optics-derived background luminescence. We overcame these limitations with a new lanthanide imaging modality, transreflected illumination with luminescence resonance energy transfer (trLRET), which increases the time-integrated signal intensities of lanthanide lumiphores by 170-fold and the signal-to-background ratios by 75-fold. We demonstrate that trLRET provides at least an order-of-magnitude increase in detection sensitivity over that of conventional epifluorescence microscopy when used to visualize endogenous protein expression in zebrafish embryos. We also show that trLRET can be used to optically detect molecular interactions in vivo. trLRET promises to unlock the full potential of lanthanide lumiphores for ultrasensitive, autofluorescence-free biological imaging.
| S-EPMC5726931 | biostudies-literature
Project description:Many bacteria secrete metallophores, low-molecular weight organic compounds that bind ions with high selectivity and affinity, in order to access essential metals from the environment. The biosynthetic machinery to produce metallophores as well as their structures have been elucidated for iron, zinc, nickel, molybdenum, and copper specific molecules. No lanthanide-specific metallophore has been discovered despite the knowledge that lanthanide metals (Ln) have recently been revealed to be essential cofactors for certain alcohol dehydrogenases across a diverse range of phyla. Here, we report the biosynthetic machinery for, the structure of, and the physiological relevance of the first known lanthanophore, methylolanthanin. The structure of methylolanthanin exhibits a unique 4-hydroxybenzoate moiety which has not previously been described in other metallophores. We find that production of methylolanthanin is required for normal levels of Ln accumulation in the methylotrophic bacterium Methylobacterium extorquens AM1, while overexpression of the molecule greatly increases bioaccumulation. Our results provide a clearer understanding of how Ln-utilizing bacteria sense, scavenge, and store Ln; essential processes in the environment where Ln are poorly bioavailable. Beyond Ln, we anticipate our study to be a starting point for understanding how organisms acquire other f-block metals, the actinides. More broadly, the discovery of a lanthanophore opens doors for study of how biosynthetic gene clusters are repurposed for new functions, how metallophores acquire their metal specificity, and the complex relationship between metal homeostasis and fitness.
2023-10-16 | GSE244060 | GEO
Project description:four biological sludge systems Raw sequence reads
| PRJNA532830 | ENA
Project description:The polarity of biological mediums controls a host of physiological processes such as digestion, signaling, transportation, metabolism, and excretion. With the recent widespread use of near-infrared (NIR) fluorescent dyes for biological imaging of cells and living organisms, reporting medium polarity with these dyes would provide invaluable functional information in addition to conventional optical imaging parameters. Here, we report a new approach to determine polarities of macro- and microsystems for in vitro and potential in vivo applications using NIR polymethine molecular probes. Unlike the poor solvatochromic response of NIR dyes in solvents with diverse polarity, their fluorescence lifetimes are highly sensitive, increasing by a factor of up to 8 on moving from polar to nonpolar mediums. We also established a correlation between fluorescence lifetime and solvent orientation polarizability and developed a lifetime polarity index for determining the polarity of complex systems, including micelles and albumin binding sites. Because of the importance of medium polarity in molecular, cellular, and biochemical processes and the significance of reduced autofluorescence and deep tissue penetration of light in the NIR region, the findings reported herein represent an important advance toward using NIR molecular probes to measure the polarity of complex biological systems in vitro and in vivo.
| S-EPMC1989699 | biostudies-literature