NeuO for Neuronal Labeling in Zebrafish

10.18383/j.tom.2015.00127Tomography1130-3

Synthesis and systematic evaluation of dark resonance energy transfer (DRET)-based library and its application in cell imaging

10.1002/asia.201403257Chemistry - An Asian Chemistry103581-58

The development of a highly photostable and chemically stable zwitterionic near-infrared dye for imaging applications

Chemical Communications51193989-399

High-efficiency in vitro and in vivo detection of Zn2+ by dye-assembled upconversion nanoparticles

10.1021/ja5115248Journal of the American Chemical Society13762336-234

Seeing Elastin: A Near-Infrared Zwitterionic Fluorescent Probe for In Vivo Elastin Imaging

Elastic fibers are present in a variety of tissues and are responsible for their resilience. Until now, no optical contrast agent in the near-infrared (NIR) wavelength range of 700-900 nm has been reported for the imaging of elastic fibers. Here, we report the discovery of a NIR zwitterionic elastin probe ElaNIR (elastin NIR) through fluorescent-image-based screening. The probe was successfully applied for in vitro, ex vivo, and in vivo imaging by various imaging modalities. Age-related elastin differences shown by in vivo fluorescent and photoacoustic imaging indicated that ElaNIR can be a potentially convenient tool for uncovering changes of elastin in live models.11Ysciescopu

The structure and assembly of apolipoprotein C-II amyloid fibrils

© 2011 Dr. Chai Lean TeohThe self-assembly of specific proteins to form insoluble amyloid fibrils is a characteristic feature of a number of age-related and debilitating diseases. Lipid-free human apolipoprotein (apo) C-II forms characteristic amyloid fibrils and is one of several apolipoproteins that accumulate in amyloid deposits located within atherosclerotic plaques. This project examines the formation of apoC-II amyloid fibrils, with a focus on its structure and assembly. X-ray diffraction analysis of aligned apoC-II fibrils indicated a simple cross-β structure, composed of two β-sheets. Examination of apoC-II fibrils using transmission electron microscopy, scanning transmission electron microscopy and atomic force microscopy revealed that the fibrils are flat ribbons composed of one molecule per 4.7 Å rise of the cross-β structure. The ability of single cysteine substitution mutants to form cross-links is consistent with a parallel, in-register structural model for apoC-II fibrils, while fluorescence resonance energy transfer analysis of apoC-II fibrils provided distance constraints within the fibrils. On the basis of these studies, a simple structural model composed of stacked apoC-II subunits in a ‘letter G-like’ β-strand-loop-β-strand conformation was proposed. The time course of the molecular dynamics simulations revealed that charge clusters in the fibril rearrange to minimize the effects of same-charge interactions inherent in parallel-in-register models. The development of this model for apoC-II amyloid fibrils provided a basis for investigations into the factors that control the properties and stabilities of amyloid fibrils. The effects of amino acid substitutions, seeding, shear-flow and lipids on fibril assembly and morphology were examined. ApoC-II forms amyloid fibrils in a lipid-dependent manner via an initial nucleation step, where lipid induced rapid formation of a tetrameric species, which is followed by a slow isomerisation that precedes monomer addition and fibril growth. The ability of apoC-II pre-formed dimers to self-assemble into amyloid fibrils and act as seeds for apoC-II amyloid fibril formation, led to the proposal of an alternate fibril assembly pathway, which incorporates isomerization of monomers into a configuration that favours rapid self-assembly into mature fibrils. Studies on the effects of shear-flow on apoC-II amyloid fibril formation showed that shear induced an irreversible structural change in apoC-II monomers, which subsequently form an on-pathway pre-fibrillar oligomeric species. Lastly, the final chapter demonstrates the application of total internal reflection fluorescence microscopy to visualize the polymorphism in apoC-II amyloid fibrils, where low concentrations of micellar phospholipids and lipid bilayers induced a novel, straight rod-like morphology for apoC-II fibrils, which is distinct from the twisted-ribbon morphology observed for apoC-II fibrils formed in the absence of lipids. Overall, these studies shed light on the molecular organization of apoC-II in the amyloid form and add to an understanding of the molecular basis of amyloid formation and deposition by apolipoproteins. They also raise a number of potential areas for further investigation which will lead to an improved understanding of the interactions that stabilize amyloid structures, the commonalities and differences among amyloid structures, the mechanisms by which amyloid fibrils form, and potential practical uses of amyloid structures

NeuO for Neuronal Labeling in Zebrafish

We report the application of our newly developed fluorescent probe 3-(benzylamino)-4,4-difluoro-5-(4-propyl-1H-1,2,3-triazol-1-yl)-8-(4-(2-hydroxyacetamido)phen-yl)-4-bora-3a,4a-diaza-s-indacene (NeuO) to label and image live neurons in zebrafish. Immersing zebrafish embryos in NeuO or injecting NeuO into zebrafish brain ventricles results in nontoxic in vivo neuronal labeling. We demonstrate the applicability of NeuO and envisage the potential of this compound as a rapid and simple labeling reagent for studying neuron development and degeneration11Nothe

Motion-induced change in emission (MICE) for developing fluorescent probes

The need for detecting and labelling environmentally and biologically important analytes has driven considerable research efforts in developing fluorescent probes. During the sensing process, molecular motions (i.e., molecular rotations or vibrations) of a flexible fluorescent probe can be significantly altered by its embedding micro-environment or analyte, thereby leading to substantial changes in readout signals. Motion-induced change in emission (MICE) can be utilized as an effective sensing mechanism. However, in comparison to the well-understood sensing mechanisms, such as photo-induced electron transfer (PET), intramolecular charge transfer (ICT), aggregation-induced emission (AIE) and disaggregation-induced emission (DIE), MICE has not been systematically discussed to date. In this tutorial review, we will summarize the concept and mechanisms of MICE for developing single-molecular fluorescent probes, present unique advantages of MICE based sensors, demonstrate their various applications, and discuss technical challenges in this field. We expect that this review will promote a deeper understanding of MICE and facilitate the development of novel MICE based probes.1120sciescopu

A Simple BODIPY-Based Viscosity Probe for Imaging of Cellular Viscosity in Live Cells

Intracellular viscosity is a fundamental physical parameter that indicates the functioning of cells. In this work, we developed a simple boron-dipyrromethene (BODIPY)-based probe, BTV, for cellular mitochondria viscosity imaging by coupling a simple BODIPY rotor with a mitochondria-targeting unit. The BTV exhibited a significant fluorescence intensity enhancement of more than 100-fold as the solvent viscosity increased. Also, the probe showed a direct linear relationship between the fluorescence lifetime and the media viscosity, which makes it possible to trace the change of the medium viscosity. Furthermore, it was demonstrated that BTV could achieve practical applicability in the monitoring of mitochondrial viscosity changes in live cells through fluorescence lifetime imaging microscopy (FLIM)

Live cells imaging using a turn-on FRET-based BODIPY probe for biothiols

10.1016/j.biomaterials.2014.04.035Biomaterials35236078-608