A Novel Method for the Preparation of Nanoaggregates of Methoxy Polyethyleneglycol Linked Chitosan

In the study, methoxy polyethyleneglycol (MPEG) linked chitosan (PLC) with a different degrees of substitution were prepared using a novel yet simple method in the presence of formaldehyde in a solvent of formic acid and dimethylsulfoxide (DMSO). The obtained PLC was verified by the Fourier transformed infrared (FT-IR) and carbon nuclear magnetic resonance (13C-NMR) spectroscopy and by the gel permeation chromatography (GPC). The aqueous solubility of chitosan increased after chemically linking with MPEG and was found to depend on its degree of substitution. With a proper degree of substitution of MPEG on chitosan, PLC may undergo inter- and/or intra-molecular entanglements to produce nanoaggregates. The critical aggregation concentration (CAC) of PLC was determined by the fluorescence emission spectra of pyrene and was found to be 0.003 mg/ml. Measurements of the size distribution and zeta potential of the prepared nanoaggregates were carried out using a Zetasizer. The results suggested that as the degree of MPEG substitution increased, the size and polydispersity index of the prepared nanoaggregates decreased. The prepared nanoaggregates showed a pH-sensitive property and thus may be suitable for the development of drug delivery devices for tumors.

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Characterization of spilled oils by measuring fluorescence emission spectra of fractions separated by high-speed gel-permeation chromatography

Fresenius Zeitschrift für Analytische Chemie ◽

10.1007/bf00694512 ◽

1980 ◽

Vol 302 (4) ◽

pp. 281-285 ◽

Cited By ~ 1

Author(s):

K. Higashi ◽

K. Hagiwara

Keyword(s):

High Speed ◽

Fluorescence Emission ◽

Emission Spectra ◽

Gel Permeation Chromatography ◽

Fluorescence Emission Spectra ◽

Gel Permeation

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A New Schiff’s Base Fluorescent Sensor for the Selective Detection of Mercury Ion

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.239-242.1105 ◽

2011 ◽

Vol 239-242 ◽

pp. 1105-1108 ◽

Cited By ~ 1

Author(s):

Xue Mei Wang ◽

Hua Yan ◽

Yong Chen ◽

He Bin Bao

Keyword(s):

Fluorescent Sensor ◽

Fluorescence Emission ◽

Emission Spectra ◽

Mercury Ion ◽

Fluorescence Measurement ◽

Fluorescence Emission Spectra ◽

H Nmr ◽

Complex Process ◽

Characteristic Wavelength ◽

Ft Ir

A new Hg2+-sensing and selective fluorescent sensor, 1-(1-pyrenecarboxaldehyd e)-thiocarbohydrazone, was synthesized and characterized by elemental analysis, FT-IR and 1H NMR spectra. Its fluorescence and recognition properties to the mercury ion were studied by the fluorescence emission spectra. With adding mercury ion into solution, the fluorescence emission intensities at different characteristic wavelength changed continually. Hence the ratiometric fluorescence measurement was used for detecting the complex process. It was found that a 1:1 stoichiometry complex is formed between the mercury ion and the compound with the association constants were 2.04×105 L/mol, respectively. And the detection limits of the mercury ion were 2.52×10-8 mol/L.

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Solid state fluorescence of proteins in high throughput mode and its applications

F1000Research ◽

10.12688/f1000research.2-82.v2 ◽

2019 ◽

Vol 2 ◽

pp. 82

Author(s):

Saurabh Gautam ◽

Munishwar N Gupta

Keyword(s):

Solid State ◽

High Throughput ◽

Fluorescence Spectra ◽

Fluorescent Protein ◽

Resonance Energy Transfer ◽

Fluorescence Emission ◽

Resonance Energy ◽

Emission Spectra ◽

Fluorescence Emission Spectra ◽

Simple Method

Direct comparison between fluorescence spectra of a sample in solution and solid state form is valuable to monitor the changes in protein structure when it is “dried” or immobilized on a solid surface (for biocatalysis or sensor applications). We describe here a simple method for recording fluorescence emission spectra of protein powders without using any dedicated accessory for solid samples in a high-throughput format. The 96-well plate used in our studies, was coated black from all the sides and the excitation and emission paths are identical and are from the top of the well. These two features minimize scatter and provide fairly noise free spectra. Even then the fluorescence intensity may be dependent upon many factors such as the extent of protein aggregation, morphology and sizes of the protein particles. Hence, (changes in) λmax emission may be a more reliable metric in the case of fluorescence spectra of proteins in the solid state. However, any large changes in the intensity could indicate changes in the microenvironment of the fluorophore. The fluorescence emission spectra were blue-shifted (4 to 9 nm), showed an increase in the intensity for different proteins studied upon lyophilization, and were similar to what has been reported by others using available commercial accessories for solid state samples. After validating that our method worked just as well as the dedicated accessories, we applied the method to compare the fluorescence emission spectra of α-chymotrypsin in solution, precipitated form, and the lyophilized powder form. We further examined the fluorescence emission spectra of green fluorescent protein (GFP) in solution and solid form. We also analyzed fluorescence resonance energy transfer (FRET) between tryptophan (Trp57) and the cyclic chromophore of GFP. These findings pointed towards the change in the microenvironment around the cyclic chromophore in GFP upon lyophilization.

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Solid state fluorescence of proteins in high throughput mode and its applications

F1000Research ◽

10.12688/f1000research.2-82.v1 ◽

2013 ◽

Vol 2 ◽

pp. 82

Author(s):

Saurabh Gautam ◽

Munishwar N Gupta

Keyword(s):

Solid State ◽

High Throughput ◽

Fluorescence Spectra ◽

Tertiary Structure ◽

Fluorescence Emission ◽

Emission Spectra ◽

Red Shift ◽

Solid Samples ◽

Fluorescence Emission Spectra ◽

Simple Method

A simple method to determine fluorescence emission spectra of proteins in solid state is described. The available commercial accessories can only accommodate solid samples and hence do not allow a direct comparison between fluorescence spectra of a sample in solution and solid state form. Such comparisons are valuable to monitor the changes in protein structure when it is “dried” or immobilized on a solid surface (for biocatalysis or sensor applications). The commercially available accessories also do not allow working in a high throughput mode. We describe here a simple method for recording fluorescence emission spectra of protein powders without using any dedicated accessory for solid samples. This method works with a 96-well plate format. It enables the comparison of fluorescence spectra of a sample in a solid state with solution spectra, using comparable quantities of protein. The fluorescence emission spectra were blue-shifted (4 to 9 nm), showed an increase in the intensity for different proteins studied upon lyophilization, and were similar to what has been reported by others using available commercial accessories for solid state samples. After validating that our method worked just as well as the dedicated accessories, we applied the method to compare the fluorescence emission spectra of α-chymotrypsin in solution, precipitated form and the lyophilized powder form. α-Chymotrypsin in solution showed a λmax of 335 nm while a high-activity preparation of the same enzyme for non-aqueous media, known as enzyme precipitated and rinsed with propanol (EPRP), showed an increase in the intensity of the fluorescence emission spectra. However, there was a small red shift of 2 nm (λmax of 337 nm) in contrast to lyophilized powder which showed a λmax of 328 nm. This is due to a difference in the tertiary structure of the protein as well as the microenvironment of aromatic residues between the two preparations. We further examined the fluorescence emission spectra of green fluorescent protein (GFP) in solution and solid form. The relative fluorescence intensity of lyophilized GFP powder was decreased significantly to 17% as compared to GFP in solution, and showed a red shift of 4 nm in the emission λmax. It was found that fluorescence resonance energy transfer (FRET) between tryptophan (Trp57) and the cyclic chromophore of GFP was significantly diminished. This indicated the change in the microenvironment around the cyclic chromophore in GFP upon lyophilization.

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Influence of trimethoxy-substituted positions on fluorescence of heteroaryl chalcone derivatives

Chemical Papers ◽

10.2478/s11696-011-0084-4 ◽

2011 ◽

Vol 65 (6) ◽

Cited By ~ 10

Author(s):

Thitipone Suwunwong ◽

Suchada Chantrapromma ◽

Hoong-Kun Fun

Keyword(s):

Aldol Condensation ◽

Fluorescence Emission ◽

Emission Spectra ◽

Fluorescent Properties ◽

Fluorescence Emission Spectra ◽

Strong Emission ◽

X Ray ◽

Methoxy Groups ◽

Phenyl Rings ◽

Ft Ir

AbstractThree series of heteroaryl chalcones, (E)-1-(2-pyridyl)-3-(X)prop-2-en-1-one (Ia-Ic), (E)-1-(2-thienyl)-3-(X)prop-2-en-1-one (IIa-IIc), and (E)-1-(2-furyl)-3-(X)prop-2-en-1-one (IIIa-IIIc), where X = 2,4,5-trimethoxyphenyl (for series a), X = 2,4,6-trimethoxyphenyl (for series b), and X = 3,4,5-trimethoxyphenyl (for series c) were synthesised using basic catalysed aldol condensation and characterised using 1H NMR and FT-IR spectroscopies. Compound IIa was also characterised by single crystal X-ray analysis. The absorption and fluorescence emission spectra of these compounds revealed that the absorption and fluorescence depended on the heterocycle rings and trimethoxysubstituted phenyl rings linked to the enone system. The position of methoxy groups substantially affected the fluorescent properties. Compounds Ia-IIIa containing the 2,4,5-trimethoxyphenyl moiety exhibited the red-shift phenomenon and strong emission fluorescence.

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CdTe Quantum Dots Embedded in Multidentate Biopolymer Based on Salep: Characterization and Optical Properties

Journal of Chemistry ◽

10.1155/2013/202061 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Ghasem Rezanejade Bardajee ◽

Zari Hooshyar

Keyword(s):

Quantum Dots ◽

Optical Properties ◽

Fluorescence Emission ◽

Emission Spectra ◽

Water Soluble ◽

Cdte Quantum Dots ◽

Fluorescence Emission Spectra ◽

Cdte Qds ◽

Transmission Electron ◽

Ft Ir

This paper describes a novel method for surface modification of water soluble CdTe quantum dots (QDs) by using poly(acrylic acid) grafted onto salep (salep-g-PAA) as a biopolymer. As-prepared CdTe-salep-g-PAA QDs were characterized by Fourier transform infrared (FT-IR) spectrum, thermogravimetric (TG) analysis, and transmission electron microscopy (TEM). The absorption and fluorescence emission spectra were measured to investigate the effect of salep-g-PAA biopolymer on the optical properties of CdTe QDs. The results showed that the optical properties of CdTe QDs were significantly enhanced by using salep-g-PAA-based biopolymer.

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Optical Properties and Zinc Nitride Thin Films Prepared Using Magnetron Reactive Sputtering

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.940.11 ◽

2014 ◽

Vol 940 ◽

pp. 11-15

Author(s):

Jun Qin Feng ◽

Jun Fang Chen

Keyword(s):

Thin Films ◽

Band Gap ◽

Near Infrared ◽

Fluorescence Emission ◽

Emission Spectra ◽

Sem Images ◽

Fluorescence Emission Spectra ◽

Glass Substrates ◽

Zinc Nitride ◽

Direct Band

Zinc nitride films were deposited by ion sources-assisted magnetron sputtering with the use of Zn target (99.99% purity) on 7059 glass substrates. The films were characterized by XRD, SEM and EDS, the results of which show that the polycrystalline zinc nitride thin film can be grown on the glass substrates, the EDS spectrum confirmed the chemical composition of the films and the SEM images revealed that the zinc nitride thin films have a dense structure. Ultraviolet-visible-near infrared spectrophotometer was used to study the transmittance behaviors of zinc nitride thin films, which calculated the optical band gap by Davis Mott model. The results of the fluorescence emission spectra show the zinc nitride would be a direct band gap semiconductor material.

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Stress and Phase Transformation Phenomena in Oxide Films: Real-Time Spectroscopic Measurements

MRS Proceedings ◽

10.1557/proc-271-319 ◽

1992 ◽

Vol 271 ◽

Cited By ~ 3

Author(s):

Gregory J. Exarhos ◽

Nancy J. Hess

Keyword(s):

Phase Transformation ◽

Applied Pressure ◽

Oxide Films ◽

Fluorescence Emission ◽

Emission Spectra ◽

Film Deposition ◽

Optical Methods ◽

Fluorescence Emission Spectra ◽

Line Intensities ◽

Deposition Parameters

ABSTRACTIn situ optical methods are reviewed for characterization of phase transformation processes and evaluation of residual stress in solution-deposited metastable oxide films. Such low density films most often are deposited as disordered phases making them prone to crystallization and attendant densification when subjected to increased temperature and/or applied pressure. Inherent stress imparted during film deposition and its evolution during the transformation are evaluated from phonon frequency shifts seen in Raman spectra (TiO2) or from changes in the laser-induced fluorescence emission spectra for films containing rare earth (Sm+3:Y3Al5O12) or transition metal (Cr+3 :Al2O3) dopants. The data in combination with measured increases in line intensities intrinsic to the evolving phase are used to follow crystallization processes in thin films. In general, film deposition parameters are found to influence the crystallite ingrowth kinetics and the magnitude of stress and stress relaxation in the film during the transformation. The utility of these methods to probe crystallization phenomena in oxide films will be addressed.

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