Search results for "Nile Red"
showing 10 items of 11 documents
Luminescent TOP Nanosensors for Simultaneously Measuring Temperature, Oxygen, and pH at a Single Excitation Wavelength
2019
Two nanosensors for simultaneous optical measurements of the bioanalytically and biologically relevant analytes temperature (“T”), oxygen (“O”), and pH (“P”) have been designed. These “TOP” nanosensors are based on 100 nm-sized silica-coated polystyrene nanoparticles (PS-NPs) doped with a near-infrared emissive oxygen- and temperature-sensitive chromium(III) complex ([Cr(ddpd)2][BPh4]3, CrBPh4) and an inert reference dye (Nile Red, NR or 5,10,15,20-tetrakis(pentafluorophenyl) porphyrin, TFPP) and are covalently labeled with pH-sensitive fluorescein isothiocyanate (FITC). These emitters can be excited at the same wavelength and reveal spectrally distinguishable emission bands, allowing for r…
Extraction of lipids from wet microalga Auxenochlorella protothecoides using pulsed electric field treatment and ethanol-hexane blends
2017
Abstract Pulsed Electric Field (PEF) treatment was used as pre-treatment on the microalgae strain Auxenochlorella protothecoides (A.p.) prior to organic solvent extraction of lipids. Experiments were performed on fresh biomass from mixotrophic or autotrophic culture which both had an evaluated lipid content of 30–35% of cell dry weight. Lipid yield was determined gravimetrically and compared to the reference lipid content assessed by bead-milling and subsequent Soxhlet extraction. The biomass was concentrated at 10% w/w solids prior to PEF-treatment and further dewatered afterwards to approximately 25% w/w before extraction. PEF-treatment with an energy input of 1.5 MJ per kilogram of dry m…
Deconvolution procedure of the UV-vis spectra. A powerful tool for the estimation of the binding of a model drug to specific solubilisation loci of b…
2015
UV-vis-spectra evolution of Nile Red loaded into Tween 20 micelles with pH and [Tween 20] have been analysed in a non-conventional manner by exploiting the deconvolution method. The number of buried sub-bands has been found to depend on both pH and bio-surfactant concentration, whose positions have been associated to Nile Red confined in aqueous solution and in the three micellar solubilisation sites. For the first time, by using an extended classical two-pseudo-phases-model, the robust treatment of the spectrophotometric data allows the estimation of Nile Red binding constant to the available loci. Hosting capability towards Nile Red is exalted by the pH enhancement. Comparison between bin…
“AD HOC” MODIFIED CLAYS FOR BIOTECHNOLOGICAL APPLICATIONS
Nowadays, the scientific community has to face with cogent problems strictly linked to the improvement of quality of live. Among the different tasks to achieve the prefixed objective the focus has been put on the drug administration, i.e., attention has been paid to propose an appropriate solution to improve the performance of a drug delivery system and to eliminate both the side effect and drawbacks. With the aim to achieve the design, synthesis, and characterization of versatile systems, with peculiar characteristics, based on clays and clays modified with a biocompatible surfactant, able to adsorb and release organic substances of pharmaceutical interest the present PhD thesis has been u…
Effects of caspase inhibitors (z-VAD-fmk, z-VDVAD-fmk) on Nile Red fluorescence pattern in 7-ketocholesterol-treated cells: Investigation by flow cyt…
2007
Background: The 7-ketocholesterol (7KC)-induced cell death has some characteristics of apoptosis and is associated with polar lipid accumulation. So, we investigated the effects of the broad-spectrum caspase inhibitor z-VAD-fmk and of the caspase-2 inhibitor z-VDVAD-fmk on lipid profile evaluated by staining with Nile Red (NR). Methods: The 7KC-treated human monocytic U937 cells were cultured in the absence or in the presence of the caspase inhibitors z-VAD-fmk or z-VDVAD-fmk. When staining with NR is performed, neutral and polar lipids have yellow and orange/red emission, respectively, and fluorescence was then analyzed by flow cytometry (FCM) and by confocal laser scanning microscopy (CLS…
Nile Red lifetime reveals microplastic identity
2020
Microplastic pollution is recognized as a worldwide environmental problem. The increasing daily use and release of plastics into the environment have led to the accumulation of fragmented microplastics, with potentially awful consequences for the environment, and animal and human health. The detection and identification of microplastics are of utmost importance, but available methods are still limited. In this work, a new approach is presented for the analysis of microplastics based on hydrophobic fluorescence staining with Nile Red, using spectrally resolved confocal fluorescence microscopy and fluorescence lifetime imaging microscopy (FLIM). Significant differences were observed in the em…
Polarity study of ionic liquids with the solvatochromic dye Nile Red: a QSPR approach using in silico VolSurf+ descriptors
2016
The in silico VolSurfþ descriptors, accounting for both cationic and anionic structural features of ionic liquids (ILs) were used to develop a Partial Least Squares (PLS) model able to establish a Quantitative Structure Property Relationship (QSPR) correlation with their solvatochromic dye Nile Red polarity. The PLS model allowed prediction of ENR values for 116 ILs providing an in silico ILs polarity database.
Increased electron donor and electron acceptor characters enhance the adhesion between oil droplets and cells of Yarrowia lipolytica as evaluated by …
2003
International audience; The adhesion of methyl ricinoleate droplets to cells of the yeast Yarrowia lipolytica was investigated. A new cytometric method, relying on the double staining of fatty globules with Nile Red and of cells with Calcofluor, enabled us to quantify methyl ricinoleate droplet adhesion to cells precultured on a hydrophilic or on a hydrophobic carbon source. In this last case, droplet adsorption was enhanced and a MATS (microbial adhesion to solvents) test revealed that this increase was due to Lewis acid-base interactions and not to an increase in the hydrophobic properties of the cell surface. These preliminary results demonstrate that the developed cytometric method is p…
Transportan 10 Induces Perturbation and Pores Formation in Giant Plasma Membrane Vesicles Derived from Cancer Liver Cells
2023
Continuous progress has been made in the development of new molecules for therapeutic purposes. This is driven by the need to address several challenges such as molecular instability and biocompatibility, difficulties in crossing the plasma membrane, and the development of host resistance. In this context, cell-penetrating peptides (CPPs) constitute a promising tool for the development of new therapies due to their intrinsic ability to deliver therapeutic molecules to cells and tissues. These short peptides have gained increasing attention for applications in drug delivery as well as for their antimicrobial and anticancer activity but the general rules regulating the events involved in cell…
Use of fluorescent dyes for developing latent lip prints
2004
Advances in the sensitivity of techniques used to examine latent prints (finger or labial) make it necessary to find more effective methods of locating prints on different surfaces. The most difficult surfaces are those which are porous or multicoloured, in which case the developed print may not be easily seen. This study analyses the effectiveness of two fluorescent dyes, Nile Blue and Nile Red, in developing both recent and older latent lip prints on porous and multicoloured surfaces. The results indicate that Nile Red is a very effective reagent for the development of latent lip prints on difficult surfaces of this type.