506 research outputs found
-
No full textTwo-photon probes for biothiols are developed based on arylsulfonyl azides for the first time. Thus, 6-(dimethylamino)naphthalene-2-sulfonyl azide and its triphenylphosphonium derivative undergo a fast reduction with turn-on fluorescence change by typical biothiols such as hydrogen sulfide, glutathione, cysteine, and homocysteine to produce the corresponding sulfonamides that is two-photon excitable. The cationic probe enables the selective imaging of the biothiols in mitochondria by two-photon fluorescence microscopy.11
-
No full textA two-photon excitable molecular probe for fluoride, developed based on a fluoride-specific desilylation reaction, is demonstrated to be useful for fluorescent imaging of fluoride ions in live zebrafish by one-photon as well as two-photon microscopy for the first time.17
-
No full textFluorescence imaging of tissues offer an essential means for studying biological systems. Autofluorescence becomes a serious issue in tissue imaging under excitation at UV−vis wavelengths where biological molecules compete with the fluorophore. To address this critical issue, a novel class of fluorophores that can be excited at ∼900 nm under two-photon excitation conditions and emits in the red wavelength region (≥600 nm) has been disclosed. The new π-extended dipolar dye system shows several advantageous features including minimal autofluorescence in tissue imaging and pronounced solvent-sensitive emission behavior, compared with a widely used two-photon absorbing dye, acedan. As an important application of the new dye system, one of the dyes was developed into a fluorescent probe foramyloid-β plaques, a key biomarker of Alzheimer’s disease. The probe enabled in vivo imaging of amyloid-β plaques in a disease-model mouse, with negligible background signal. The new dye system has great potential for the development of other types of two-photon fluorescent probes and tags for imaging of tissues with minimal autofluorescence.16
A Dipolar Anthracene Dye: Synthesis, Optical Properties and Two-photon Tissue Imaging
No full textTwo-photon microscopy is a powerful tool for studying biological systems. In search of novel two-photon absorbing dyes for bioimaging, we synthesized a new anthracene-based dipolar dye (anthradan) and evaluated its two-photon absorbing and imaging properties. The new anthradan, 9,10-bis(o-dimethoxy-phenyl)-anthradan, absorbs and emits at longer wavelengths than acedan, a well-known two-photon absorbing dye. It is also stable under two-photon excitation conditions and biocompatible, and thus used for two-photon imaging of mouse organ tissues to show bright, near-red fluorescence along with negligible autofluorescence. Such an anthradan thus holds promise as a new class of two-photon absorbing dyes for the development of fluorescent probes and tags for biological systems.
Two-Photon Absorbing Dyes with Minimal Autofluorescence in Tissue Imaging: Application to in Vivo Imaging of Amyloid-beta Plaques with a Negligible Background Signal
No full textFluorescence imaging of tissues offer an essential means for studying biological systems. Autofluorescence becomes a serious issue in tissue imaging under excitation at UV-vis wavelengths where biological molecules compete with the fluorophore. To address this critical issue, a novel class of fluorophores that can :be excited at, similar to 900 nm under two-photon excitation conditions and emits in the red wavelength region (>= 600 nm) has been disclosed. The new pi-extended dipolar dye system, shows several advantageous features including minimal antofluorescence in tissue imaging and pronounced solvent-sensitive emission behavior, compared with a widely used two-photon absorbing dye, acedan. As an important application of the new dye system, one of the dyes was developed into a fluorescent probe for amyloicl-beta plaques, a key biomarker of Alzheimer's disease. The probe enabled in Vivo imaging of amyloid-beta plaques in a disease-model mouse, with negligible background signal. The new dye system has great potential for the development of other types of two-photon fluorescent probes and tags for imaging of tissues with minimal autofluorescence.
-
No full textThe donor–acceptor (D–A) type dipolar fluorophores, an important class of luminescent dyes with two photon absorption behaviour, generally emit strongly in organic solvents but poorly in aqueous media. To understand and enhance the poor emission behaviour of dipolar dyes in aqueous media, we undertake a rational approach that includes a systematic structure variation of the donor, amino substituent of acedan, an important two-photon dye. We identify several factors that influence the emission behaviour of the dipolar dyes in aqueous media through computational and photophysical studies on new acedan derivatives. As a result, we can make acedan dyes emit bright fluorescence underone- and two-photon excitation in aqueous media by suppressing the liable factors for poor emission: 1,3-allylic strain, rotational freedom, and hydrogen bonding with water. We also validate that these findings can be generally extended to other dipolar fluorophores, as demonstrated for naphthalimide, coumarin and (4-nitro-2,1,3-benzoxadiazol-7-yl)amine (NBD) dyes. The new acedan and naphthalimide dyes thus allow us to obtain much brighter two-photon fluorescent images in cells and tissues than in their conventional forms. As an application of these findings, a thiol probe is synthesized based on a new naphthalimide dye, which shows greatly enhanced fluorescence from the widely used N,N-dimethyl analogue. The results disclosed here provide essential guidelines for the development of efficient dipolardyes and fluorescence probes for studying biological systems, particularly by two-photon microscopy.14
Selective Recovery of Lithium Hydroxide from Spent NCA (LiNiCoAlO2) Powder
No full textThis research was conducted on the method of recovering the lithium hydroxide and valuable metal from the NCA-based cathode active materials in the spent lithium-ion batteries. The recovery rate of lithium depends on the reaction temperature, retention time, reaction time during H2 reduction and solid-liquid ratio. Lithium hydroxide and valuable metals were recovered under each experimental condition, and the following optimal process conditions were determined based on the results of experiment. Based on the charging of 10g of NCA powder, the optimal process conditions were determined as follows: the reaction temperature of 700?; the retention time of 3hrs; and the H2 gas flowrate of 300cc/min; the leaching time of 1hr for water leaching; the solid-liquid ratio of the sample and distilled water at 1:30; the stirring speed of 300rpm at room temperature, and the recovery rate of 92.30% was achieved
Multiphoton tissue imaging by using moxifloxacin
No full textMultiphoton microscopy has been widely used for in-vivo tissue imaging of various biological studies. However, its application to clinical studies has been limited due to either lack of clinically compatible exogenous contrast agents or weak autofluorescence of tissues. We investigated moxifloxacin as a contrast agent of cells for multiphoton tissue imaging. Moxifloxacin is an FDA approved antibiotic with relatively good pharmacokinetic properties for tissue penetration and intrinsic fluorescence. Two-photon microscopy (TPM) of moxifloxacin treated mouse corneas showed good tissue penetration and high concentration inside the corneal cells [1]. Cell labeling of moxifloxacin was tested in both cultured cells and isolated immune cells. Moxifloxacin tissue applications were tested in various mouse organs such as the skin, small intestine, and brain. Most of tissues were labeled well via topical administration, and only the skin required additional gentle removal of the outermost stratum corneum by tape stripping. TPM of these tissues showed non-specific cell labeling of moxifloxacin and fluorescence enhancement [2]. Although most of experimental results were from mouse tissues, its clinical application would be possible. Clinical application is promising since imaging based on moxifloxacin labeling could be 10 times faster than imaging based on endogenous fluorescence. Moxifloxacin labeling of cultured cells was demonstrated by comparing TPM images with and without moxifloxacin treatment. Bright fluorescence inside cells were observed only with moxifloxacin at the same imaging condition. TPM of the skin dermis visualized many dermal cells with increased fluorescence, and TPM of the villus in the small intestine showed the covering epithelial cells and cells inside the villus clearly.
Please click Additional Files below to see the full abstract
Case studies on public policy in Korea for knowledge sharing
No full text노트 : Please send an email to the following address to contact the author M. Jae Moon : [email protected]
- …
