Red Fluorescent Dye Research Articles

Metformin reverses cardiac SR/ER-mitochondria remodeling and mitochondrial complex I dysfunction in Dystrophin-deficient mice

Besides skeletal and diaphragmatic muscle dysfunction, Duchenne muscular dystrophy (DMD) exhibit a progressive cardiomyopathy with an altered Ca2 + handling and a defect in mitochondrial respiration capacity. The aim of the present study was to determine if the sarco-endoplasmic reticulum (SR/ER)-mitochondria interaction and mitochondrial Ca2 + homeostasis contribute to the progression of the cardiomyopathy. Ventricular myocytes were isolated from 3-month old Dystrophin-deficient mice (mdx mice). Using proximity ligation assay, we observed an increase interaction between the SR/ER Ca2 + release channels, IP3R1, and the porine of the mitochondria, VDAC1, associated with an increase expression levels of IP3R1 and SIGMA1R. Similarly, the mitochondrial Ca2 + uniporter (MCU) and its regulated subunit, MICU1, expressions levels were enhanced in mdx heart. Furthermore the mitochondrial Ca2 + uptake kinetics and the mitochondrial Ca2 + content were significantly increased. Using oxygraphy experiment, we observed a severe decrease in respiration driven by the complex I with a stimulation in anion superoxide production measured with Mitosox red fluorescent dye. Finally, mdx mice were treated with the complex I modulator metformin at 200 mg/kg/day during one month. Metformin normalize the SR/ER-mitochondria interaction, decreases MICU1 expression and mitochondrial Ca2 + content and tends to restore complex I alteration in cardiomyocytes. In summary, our data demonstrate for the first time that in the DMD heart the mitochondrial dysfunction is linked to an excessive SR/ER-mitochondria coupling with an increase in mitochondrial Ca2 + uptake and complex I dysfunction. Such remodeling could be reversed by metformin providing a novel therapeutic perspective in DMD.

Organic light-emitting devices based on 4,4’-bis(2,2’-diphenyl vinyl)-1,1’-biphenyl as a spacer between dual ultrathin layers

White organic light-emitting devices (WOLEDs) were fabricated by using a highly blue fluorescent dye of 4,4’-bis(2,2’-diphenyl vinyl)-1,1’-biphenyl (DPVBi) and a red fluorescent dye of 5H-benzo[ij] quinolizin-9-yl) ethenyl]-4H-pyran-4-ylidene] propane-dinitrile (DCM2), together with a green fluorescent dye of 10-(2-benzothiazolyl)-2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H,5H,11H-(1)-benzopyroyran-o(6,7-8-i,j) quinolizin-11-one (C545T). The multilayer WOLEDs does not involve the doping process. The structure of the device is indium tin oxide (ITO)/4,4’,4”-tris{N,-(3-methylphenyl)-N-phenylamin}triphenylamine (m-MTDATA) (55 nm)/ N,N’-bis-(1-naphthyl)-N,N’-diphenyl-1,1’-biph-enyl-4,4’-diamine (NPB) (10 nm)/ DPVBi (8 nm)/ C545T (x nm)/ DPVBi (5 nm)/ DCM2 (y nm)/ tris- (8-hydroxyquinoline) aluminum (Alq3) (60nm)/ LiF (1 nm)/ Al, where the DPVBi is introduced as a spacer. By changing the thicknesses of dual ultrathin layers of C545T and DCM2, the WOLED is obtained. When x=y=0.05, the Commission Internationale de 1’Eclairage (CIE) coordinates of the device change from (0.262 6, 0.351 4) at 4 V to (0.214 7, 0.269 3) at 12 V that are well in the white region. Its maximum luminance is 41400 cd/m2 at 13 V, and the maximum current efficiency and the maximum power efficiency are 7.95 cd/A at 6 V and 5.37 lm/W at 5 V, respectively.

Molecular basis of the inhibition and disaggregation of thermally-induced amyloid fibrils of human serum albumin by an anti-Parkinson's drug, benserazide hydrochloride

This study summarises the results of multifactorial analysis of the inhibition/destabilization of human serum albumin (HSA) amyloid fibrils by an anti-Parkinson's drug, benserazide hydrochloride (BH). Different biophysical techniques have been utilized for this purpose. Rayleigh light scattering (RLS) and dynamic light scattering (DLS) confirmed the formation of aggregates, that were identified as amyloid fibrils by the thioflavin T (ThT) and Congo Red (CR) fluorescent dye binding assays. Formation of amyloid fibrils and their inhibition/disaggregation was further characterized by transmission electron microscopy (TEM). The cytoprotective role of BH was examined by cytotoxicity assay performed on the SH-SY5Y neuronal cells. The deviation from linearity in the Stern Volmer plot indicated the presence of static and dynamic quenching of the HSA intrinsic fluorescence by BH. The value of Kd obtained by Scatchard plot was 4.5 × 10−4 M. The changes in the Trp microenvironment caused by the BH binding were further characterized by the synchronous fluorescence spectroscopy. Circular dichroism (CD) and differential scanning calorimetry (DSC) indicated increased HSA stability when bound to BH. Multiple binding sites in human serum albumin (HSA) for BH were found by binding and docking analysis, which revealed the involvement of hydrophobic and hydrogen bonding in the HSA-BH complex formation. Further, the negativity of the binding free energy suggested the spontaneity of the BH-HSA interaction. Overall, our study indicated that BH can serve as an efficient inhibitor/destabilizer of amyloid fibrils and the possible mechanism of this efficiency includes stabilization of HSA in the presence of BH. Therefore, BH can be used in treatment of systemic amyloidoses, since this drug cannot cross blood brain barrier (BBB).

Optimizing a Gravid Mosquito Resting Box to Enhance Auto-dissemination of Larvicides under Semi-field Conditions in Western Kenya

Malaria control strategies are challenged by emergence of insecticide resistance and behavioral changes of the vector. New vector management tools are required to avert control failure. The aim of this study was to optimize a mosquito resting box that act as contamination station for auto-dissemination of novel chemicals by female Anopheles gambiae to their oviposition sites. In this study, cotton fabrics (red, black, blue, white), circular & rectangular boxes of different sizes were tested for resting preference. Optimal box size and shape, aligned with most attractive colour, was dusted with red fluorescent dye (larvicide proxy). Two artificial oviposition sites were set up in a screen house, one of which was treated with Cedrol, the other had tap water only. Two to three days old bloodfed mosquitoes were used for resting preference whereas gravid females were used for auto-dissemination experiments. A high resting preference was observed in red and black fabrics (28.08 ± 3.211), (28.00 ±3.922) respectively, compared to white (4.67±0.890). Choice of colour was found to influence mosquito landing (P=0.000<0.05). With the choice of most preferred colour, the rectangular black box (45m×30m×45m) attracted high proportion (60%) of mosquitoes. The box effectively transferred dye to the resting mosquitoes and to the oviposition site, with 67% visited oviposition site, having dye on their body. These results reveal that the black rectangular box attracted adult blood-fed and gravid mosquitoes high enough showing great potential as future malaria vector control and/or sampling tool, and is recommended for further field-based evaluation.&nbsp

Regenerative activity of Hericium erinaceus on axonal injury model using in vitro laser microdissection technique

ABSTRACTObjective: Peripheral nerve injury (PNI) is an important global health problem. Nerve Growth Factor (NGF) plays crucial role in the survival, growth, and maintenance of various neurons in the mammalian nervous system, human included. Hericium erinaceus (HE), an edible and medicinal mushroom, has been extensively studied for its neuroprotective properties. In this study, the neuroprotective and neurotogenic effects of HE and NGF were compared on mouse PNI model by using a laser microdissection technique.Methods: Neuronal cultures were prepared from dorsal root ganglia (DRG) of 6–8 week aged mice, pretreated them with phosphate-buffered saline (PBS), NGF, HE, or the combination of NGF and HE. To model axonal injury in vitro, axons were cut (axotomy) with a microscope-controlled laser beam. Axotomized neurons were imaged under the microscope. Axotomized neurons’ survival ratios were calculated using the propidium iodide (PI), which is a red-fluorescent nuclear dye. Their axon lengths were measured using the AxioVision 4.8 software.Results: Although both HE and NGF have neuroprotective and regenerative effects on axotomized peripheral sensory neurons, HE exhibits a higher neuroprotective activity compared to the NGF. The combination of HE and NGF maximizes axonal regeneration ability of axotomized neurons.Conclusion: HE has capabilities of preventing the death of neurons and regenerating their axons in the experimental axonal injury model. Our findings provide experimental evidence that HE may serve as a neuroprotective and regenerative candidate for treating peripheral nerve injuries. Present study warrants further investigation of HE as a potential natural compound to remedy PNI.

Influence of Anion Variations on Morphological, Spectral, and Physical Properties of the Propidium Luminophore.

Propidium iodide (3,8-diamino-5-[3-(diethylmethylammonio)propyl]-6-phenylphenanthridinium diiodide, [P][I]), is a well-known red fluorescent dye that is widely used for biological applications such as staining. In this study, we have replaced the iodide counteranion of [P][I] with three hydrophobic and bulky organic anions, trifluoromethanesulfonate/[TfO], bis(trifluoromethanesulfonyl)imide/[NTf2], and bis(perfluoroethylsulfonyl)imide/[BETI], and have thus obtained a propidium-derived group of uniform materials based on organic salts (PGUMBOS). The morphological, spectral, and physical properties of these materials were investigated in order to understand the impact of anion variations. While [P][I] is a crystalline solid, propidium salts with [BETI] or [NTf2] counteranions, i.e., [P][BETI] and [P][NTf2], have significantly lower crystallinity as reflected in powder X-ray diffraction data. In addition, [P][BETI] and [P][NTf2] exhibited improved photothermal stability as compared to [P][I] when examined using thermogravimetric analysis and time-dependent kinetic fluorescence experiments under the given experimental conditions. Spectral and electronic properties of the propidium luminophore were not significantly changed upon anion variations, although fluorescence lifetimes and quantum yields showed a systematic increase with decreasing solvent polarity. The experimental HOMO-LUMO energy gaps of these compounds were ∼2 eV with energies of HOMO and LUMO orbitals obtained as -5.15 (±0.08) and -3.19 (±0.08) eV.

A Quantitative and Reliable Calibration Standard for Dual-Color Fluorescence Cross-Correlation Spectroscopy.

Dual-color Fluorescence Cross-Correlation Spectroscopy (dcFCCS) allows binding analysis of biomolecules. Combining cross- and autocorrelation amplitudes yields binding degrees and concentrations of bound and unbound species. However, non-ideal detection volume overlap reduces the cross-correlation, causing overestimation of the Kd . The overlap quality factor that relates measured and true cross-correlation amplitudes has been difficult to determine, because neither a perfect 1 : 1 labeled sample nor perfectly overlapping volumes are readily accomplished. Here, we describe how a stochastically labeled sample can be used for quantitative calibration. Lipid vesicles doped with green and red fluorescent dyes yield highly reproducible relative cross-correlations and allow determination of the setup-dependent overlap quality factor. This reliable, affordable and quick-to-prepare calibration standard expedites any quantitative co-localization or binding analysis by dcFCCS.

Mesoporous silica nanoparticles capped with graphene quantum dots as multifunctional drug carriers for photo-thermal and redox-responsive release

Abstract A novel photo-thermal and redox-responsive drug delivery carrier was developed by capping mesoporous silica nanoparticles (MSNs) with graphene quantum dots (GQDs). The disulfide bonds were introduced by amidation reaction between cystine and amino functionalized MSNs. Rhodamine B (RhB), a red fluorescent dye, was loaded into the mesopores of MSNs as the model drug and GQDs capped on MSNs as gatekeepers could prevent the release of RhB. Transmission electron microscopy (TEM), nitrogen adsorption and desorption analysis, X-ray diffraction (XRD), thermogravimetric (TG) analysis and Fourier transform infrared spectroscopy (FTIR) proved that the nanocomposites MSNs capped with GODs were achieved successfully. The nanocomposites with the size of about 100 nm have excellent photo-thermal property originated from GQDs. Moreover, the nanocomposites were endowed with remarkable redox-responsion to glutathione (GSH) from disulfide bonds, and hence the loaded drugs could release controlably. In this work, we provided an exploration of photo-thermal and redox-responsive drug delivery system and the results proved that this drug delivery system can be considered as a promising candidate for drug delivery and stimuli-responsive release.

Dipsticks and sensor microtiterplate for determination of copper (II) in drinking water using reflectometric RGB readout of digital images, fluorescence or eye-vision

A dipstick and a sensor microtiterplate were developed for fast determination of Cu(II) in drinking water with good sensitivity. The dipsticks are based on filter paper that contains a chromogenic probe (cuprizone) along with a red fluorescent dye (sulforhodamine 101) incorporated inside a hydrogel. Upon reaction with Cu(II), the visible color of the spots shifts from pink over blue to green. This enables determination of the WHO threshold level of Cu(II) in drinking water by eye-vision or using the reflectometric RGB readout of digital images of the dipsticks. Visually, 1–2000.0 μg L−1 of Cu(II) can be determined and 1–1000.0 μg L−1 from the evaluation of the digital images. The sensor microtiterplate was fabricated by fixing the sensor cocktail of the dipsticks on the bottom of the wells of a standard microtiterplate. Luminescence determination of Cu(II) in the microtiterplate is based on the inner-filter effect (increasing absorbance) of the Cu-cuprizone complex on the emission of sulforhodamine 101. Hence, the rhodamine emission is increasingly quenched with increasing concentrations of Cu(II). The calibration plot for quantitation of Cu(II) by utilizing a microtiterplate reader spans over more than 3 orders of magnitude from 0.1 to 300.0 μg L−1. The limit of detection is 0.1 μg L−1 which is the lowest for sensor microplates for determination of Cu(II) so far. The method is hardly affected in a pH range from 4.0 to 7.0 and only 5 min of incubation time are required. The selectivity for Cu(II) is high, even in presence of various heavy metals. The dipsticks and the sensor microtiterplate were successfully applied to real samples and the accuracy of both tools was validated by ICP-atomic emission spectrometry.

Platelets isolated from an Alzheimer mouse damage healthy cortical vessels and cause inflammation in an organotypic ex vivo brain slice model

Platelets are anuclear blood cells and play a major role in hemostasis and thrombosis. Platelets express amyloid-precursor protein (APP), release beta-amyloid (Aβ) and are stimulated (pre-activated) in Alzheimer’s disease (AD). We hypothesize that such stimulated platelets severely damage brain vessels which subsequently leads to cerebrovascular damage in AD. In order to study this issue we isolated platelets from AD mice (expressing APP with the Swedish-Dutch-Iowa mutations), labeled them with the red fluorescent dye PKH26 and transcardially infused these freshly isolated platelets into the brains of anesthetized healthy C57BL6 wildtype mice. Brains were immediately taken, 110 µm thick organotypic brain slices prepared and cultured for 1 or 14 days. We observed that red PKH26+ fluorescent platelets were localized in collagen IV and Lectin-649 counterstained cortical brain vessels and that platelets from AD mice severely damaged cortical brain vessels in wildtype mice and entered the brain parenchyma. Confocal microscopy showed immunoreactivity for matrix metalloproteinases (MMP-2 and MMP-9) and beta-amyloid around these platelets. The effect was completely inhibited with an MMP inhibitor. Furthermore, isolated AD platelets caused inflammation and activated microglia around the site where platelets damaged cortical brain vessels. We conclude that AD-derived platelets more aggressively damage healthy vessels which may consequently play a role in the progression of cerebral amyloid angiopathy in AD.

Self-Assembled Nanostructures of Red Fluorescent Amphiphilic Block Copolymers as Both Imaging Probes and Drug Carriers.

We report a red-fluorescent drug delivery system formed by biodegradable and biocompatible amphiphilic A-B-A block copolymers. Each polymer consists of a red fluorescent dye covalently bonded in the middle of hydrophobic block (B) of polylactone, tethered at both ends with poly[(oligo ethylene glycol) methyl ether methacrylate] (POEGMA) as the hydrophilic block. Two types of polylactones, i.e., semicrystalline poly(ε-caprolactone) (PCL) and amorphous poly(δ-decalactone) (PDL), respectively, were incorporated as the hydrophobic segment in the block copolymers. Using transmission electron microscopy, we characterized the self-assembled nanostructures formed by these amphiphilic block copolymers in mixtures of water/tetrahydrofuran or water/dimethylformamide. All of these polymers remained highly fluorescent in water, although some extent of aggregation-induced fluorescence quenching was still observed. Among the three types of polymers presented here, the polymer (RPO-3) containing an amorphous block of PDL showed the highest drug-loading capacity and the largest extent of drug release in acidic media. RPO-3 micelles loaded with doxorubicin as a model of anticancer drug showed sustainable intracellular release and cytotoxicity against HeLa cells.

Observing and tracking single small ribosomal subunits in vivo.

Ribosomes are formed of a small and a large subunit (SSU/LSU), both consisting of rRNA and a plethora of accessory proteins. While biochemical and genetic studies identified most of the involved proteins and deciphered the ribosomal synthesis steps, our knowledge of the molecular dynamics of the different ribosomal subunits and also of the kinetics of their intracellular trafficking is still limited. Adopting a labelling strategy initially used to study mRNA export we were able to fluorescently stain the SSU in vivo. We chose DIM2/PNO1 (Defective In DNA Methylation 2/Partner of NOb1) as labelling target and created a stable cell line carrying an inducible SNAP-DIM2 fusion protein. After bulk labelling with a green fluorescent dye combined with very sparse labelling with a red fluorescent dye the nucleoli and single SSU could be visualized simultaneously in the green and red channel, respectively. We used single molecule microscopy to track single SSU in the nucleolus and nucleoplasm. Resulting trajectory data were analyzed by jump-distance analysis and the variational Bayes single-particle tracking approach. Both methods allowed identifying the number of diffusive states and the corresponding diffusion coefficients. For both nucleoli and nucleoplasm we could identify mobile (D = 2.3-2.8 µm2/s), retarded (D = 0.18-0.31 µm2/s) and immobilized (D = 0.04-0.05 µm2/s) SSU fractions and, as expected, the size of the fractions differed in the two compartments. While the fast mobility fraction matches perfectly the expected nuclear mobility of the SSU (D = 2.45 µm2/s), we were surprised to find a substantial fraction (33%) of immobile SSU in the nucleoplasm, something not observed for inert control molecules.

Laser-induced fluorescence quenching of red fluorescent dyes with green excitation: Avoiding artifacts in PIE-FRET and FCCS analysis

Multicolor excitation is at the core of many fluorescence spectroscopy techniques such as PIE-FRET, ALEX-FRET, or FCCS. However, the influence of the multiple laser excitations on the dye photophysics is often overlooked. Here, we show that green laser pulses can surprisingly quench the fluorescence of common red dyes Alexa Fluor 647 and Atto 647N, even when the conditions leading to photobleaching are avoided. The physical origin of this phenomenon is discussed via a long-lived dark state and/or photorefractive effects. These observations are important to avoid measurement artifacts as both the fluorophore concentration and the fluorescence brightness are affected.

Rapid and Sensitive Detection of Cardiac Troponin I for Point-of-Care Tests Based on Red Fluorescent Microspheres.

A reliable lateral flow immunoassay (LFIA) based on a facile one-step synthesis of single microspheres in combining with immunochromatography technique was developed to establish a new point-of-care test (POCT) for the rapid and early detection of cardiac troponin I (cTnI), a kind of cardiac specific biomarker for acute myocardial infarction (AMI). The double layered microspheres with clear core-shell structures were produced using soap-free emulsion polymerization method with inexpensive compounds (styrene and acrylic acid). The synthetic process was simple, rapid and easy to control due to one-step synthesis without any complicated procedures. The microspheres are nanostructure with high surface area, which have numerous carboxyl groups on the out layer, resulting in high-efficiency coupling between the carrier and antibody via amide bond. Meanwhile, the red fluorescent dye, Nile-red (NR), was wrapped inside the microspheres to improve its stability, as well to reduce the background noise, because of its higher emission wavelength than interference from real plasma samples. The core-shell structures provided different functional areas to separate antibody and dyes, so the immunoassay has highly sensitive, wide working curves in the range of 0–40 ng/mL, low limits of detection (LOD) at 0.016 ng/mL, and limits of quantification (LOQ) at 0.087 ng/mL with coefficient of variations (CV) of 10%. This strategy suggested an outstanding platform for LFIA, with good reproducibility and stability to straightforwardly analyze the plasma samples without washing steps, thereby reducing the operating procedures for non-professionals and promoting detection efficiency. The whole detection process can be completed in less than 15 min. This novel immunoassay offers a reliable and favorable analytical result by detecting the real samples, indicating that it holds great potential as a new alternative for biomolecule detection in complex samples, for the early detection of cardiac specific biomarkers.

β2 Integrins Regulate Migratory Properties of M1 and M2 Macrophages during Inflammation

BackgroundThe development of chronic inflammation depends on the balance between accumulation of pro‐inflammatory, classically activated (M1) and alternatively activated (M2) macrophages within the injured tissue. The mesenchymal migration and accumulation of macrophages in the inflamed sites largely depend on myeloid‐specific αMβ2 and αDβ2 integrins, which share similar ligands but have different densities on different subsets of macrophages. The level of integrin expression regulates cell migration. Namely, a low‐intermediate expression supports cell motility, while a high expression generates strong adhesion that prevents cell migration. In this project, we tested how αMβ2 and αDβ2 integrins are involved in the migration and retention of M1 and M2 macrophages at the site of inflammation.Method and ResultsTo test our hypothesis, wild type (WT), αD−/− and αM−/− mice were intraperitoneally injected with thioglycollate to generate macrophages. Isolated macrophages were treated with IFN‐γ and IL‐4 for 4 days to activate M1 and M2 phenotypes, respectively. Integrin levels on macrophages were evaluated by qPCR and FACS. We found that the expression of αD was strongly upregulated on M1 macrophages, but not on M2 macrophages, while the level of αM remained unchanged on both subsets. To test the effect of integrins on the migration of M1 and M2 macrophages, we labeled cells with red and green fluorescent dyes and applied in vitro migration assay in 3D fibrin matrix.Our results showed that WT M2 macrophages possess significantly stronger migratory properties compared to WT M1 macrophages. To understand the contribution of individual integrins we used αD−/− and αM−/− macrophages. The results demonstrated that while αM‐deficiency had no significant effect, αD‐deficiency improved the migration of M1 macrophages. In contrast, both αD‐ and αM‐deficiency reduced the migration of M2 macrophages. To verify these results, we tested in vivo macrophage migration using the model of resolution of peritoneal inflammation. M1 and M2 macrophages, labeled with red and green fluorescent dyes respectively, were injected into the peritoneal cavity of mice with induced peritoneal inflammation. After 3 days, we evaluated the ability of macrophages to emigrate from the peritoneal cavity to lymphatics. Our results corresponded to our in vitro migratory assay. M2 macrophages emigrate significantly faster, αD‐deficiency improves the efflux of M1 macrophages and αD‐ and αM‐deficiency reduced the emigration of M2 macrophages.ConclusionTaken together, these data suggest that integrin αM, which has an intermediate expression on M1 and M2 macrophages, supports macrophage migration. In contrast, integrin αD, which has a high expression on M1 macrophages, prevents the migration of these cells and can promote the retention of M1 macrophages in the inflamed sites. Therefore, integrin αD is a potential therapeutic target to prevent pro‐inflammatory macrophage accumulation and development of chronic inflammation.Support or Funding InformationThis project is funded by NIH and the project number is 5R01DK102020‐05This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Magnetic polymer microcapsules loaded with Nile Red fluorescent dye

Fabrication of multifunctional smart vehicles for drug delivery is a fascinating challenge of multidisciplinary research at the crossroads of materials science, physics and biology. We demonstrate a prototypical microcapsule system that is capable of encapsulating hydrophobic molecules and at the same time reveals magnetic properties.The microcapsules are prepared using a templated synthesis approach where the molecules to be encapsulated (Nile Red) are present in the organic droplets that are suspended in the polymerization solution which also contains magnetic nanoparticles. The polymer (polypyrrole) grows on the surface of organic droplets encapsulating the fluorescent dye in the core of the formed microcapsule which incorporates the nanoparticles into its wall.For characterization of the resulting structures a range of complementary physicochemical methodology is used including optical and electron microscopy, magnetometry, 1H NMR and spectroscopy in the visible and X-ray spectral ranges. Moreover, the microcapsules have been examined in biological environment in in vitro and in vivo studies.

Bright and two-photon active red fluorescent dyes that selectively move back and forth between the mitochondria and nucleus upon changing the mitochondrial membrane potential.

Since mitochondrial dysfunction was discovered to be the underlying cause of several severe diseases, fluorescent probes with excellent optical properties for visualising and monitoring the mitochondrial membrane potential (MMP) (a parameter of mitochondrial vitality) have been in high demand. Herein, we present novel pyrene-based dyes exhibiting remarkably large two-photon absorption around 900 nm and bright red emission around 620 nm (two-photon brightness (Φσ2) = 425-525 GM), with selective localisation to the mitochondria or nucleus in response to changes in the MMP, providing several advantages over traditional MMP-monitoring probes such as Rhodamine 123 (Φσ2 = 64 GM). The intracellular behavior of the new dyes was investigated in detail. The driving forces for the dyes to dissociate from the mitochondria and migrate toward the nucleus upon decreasing the MMP were two key molecular characteristics: the dyes' permeability to mitochondrial membranes and their affinity to nuclear DNA. The results provide significant insights into improving the molecular design of the dyes.

Biochemical and Molecular Studies on Bone Marrow Derived Stromal Stem Cells on Liver Injuries in Rats

Liver is a remarkable vital organ, it is responsible for metabolizing the different food elements, filtering and detoxifying poisons in the blood to remove numerous toxic compounds. Liver affections are essentially caused by harmful chemicals (certain anti-infection, paracetamol, carbon tetrachloride, aflatoxins, per oxidized oil and so on.), overabundance utilization of liquor, immune system issue and disease. Up till now, orthotropic liver transplantation is the most powerful treatment of liver infections. Because of the deficiency of donors, high costs, the number of patients who can profit by this methodology is extremely constrained. Recently, cell based treatments have been explored as other option to entire liver transplantation. Thirty rats were separated into three equivalent groups (n=10, each). Group 1: control; Group 2: was infused peritoneally with acetaminophen (300 mg/kg); Group 3: was injected intra peritoneal with acetaminophen (300 mg/kg), then injected intra-venous with mesenchymal stromal stem cells (1 million BM-MSCs/kg). Blood samples for estimation of liver functions, and liver samples for detection of homing labeled MSCs with red fluorescent cell linker dye (PKH26), gene expression of matrix metalopeptidase (MMP2), tissue inhibitor metalopeptidase (TIMP) and histopathological examination were collected . The infusion of BM-MSCs enhanced liver capacities test, MMP2 and TIMP. Histopathological examination of liver tissue demonstrated critical antifibrotic impact, improvement in the hepatic structure as compared to the second group. It could be concluded that BM-MSC is effective in treatment of liver damage by upgrading hepatocyte recovery through enhancing the liver stress and inflammatory signaling by improving MMP2 and TIMP, besides it has a significant antifibrotic effect. The MSCs stem cell is an attractive cell source for regenerative medicine.

Green and Red Fluorescent Dyes for Translational Applications in Imaging and Sensing Analytes: A Dual-Color Flag.

Invited for this month's cover picture is the BIOSCOPE group of Professors Carlos Lodeiro and José Luis Capelo at the REQUIMTE/UCIBIO‐LAQv‐FCT University NOVA of Lisbon (Portugal), and their collaborators. The cover picture is devoted to Translational Research, and shows the Portuguese Flag represented by the interaction between cells and Janus gold/silver nanoparticles functionalized with rhodamine (red) and Fluorescein (green) dyes as tools for biomedical translational research. Read the full text of their Review at 10.1002/open.201700135.

Synthesis of [18F]2B-SRF101: A Sulfonamide Derivative of the Fluorescent Dye Sulforhodamine 101.

Background: The red fluorescent dye Sulforhodamine 101 (SR101) has been used in neuroscience research as a useful tool for staining of astrocytes, since it has been reported as a marker of astroglia in the neocortex of rodents in vivo. The aim of this work is to label SR101 with positron emission radionuclides, in order to provide a radiotracer to study its biological behavior. This is the first attempt to label SR101 by [18F], using a chem-ical derivatization via a sulfonamide-linker and a commercially available platform.Methods: The synthesis of SR101 N-(3-Bromopropyl) sulfonamide and SR101 N-(3-Fluoropropyl) sulfonamide (2B-SRF101) was carried out. The radiosynthesis of SR101 N-(3-[18F]Fluoropropyl) sulfonamide ([18F]2B-SRF101) was performed in a TRACERlab® FX-FN. Different labeling conditions were tested. Three pilot batches were produced and quality control was performed. Lipophilicity, plasma protein binding and radiochemical sta-bility of [18F]2B-SRF101 in final formulation and in plasma were determined.Results: SR101 N-(3-Bromopropyl) sulfonamide was synthetized as a precursor for radio-labeling with [18F]. 2B-SRF101 was prepared for analytical purpose. [18F]2B-SRF101 was obtained with radiochemical purity of (97.0 ± 0.6%). The yield of the whole synthesis was (11.9 ± 1.7%), non-decay corrected. [18F]2B-SRF101 was found to be stable in final for-mulation and in plasma. The octanol-water partition coefficient was (Log POCT = 1.88 ± 0.14). The product showed a high percentage of plasma protein binding.Conclusions: The derivatization of SR101 via sulfonamide-linker and the first radiosyn-thesis of [18F]2B-SRF101 were performed. It was obtained in accordance with quality con-trol specifications. In vitro stability studies verified that [18F]2B-SRF101 was suitable for preclinical evaluations.