Publications by authors named "El-Zeiny M Ebeid"

16 Publications

  • Page 1 of 1

Laser performance and investigation of the optimal density functional and the dependence of the basis sets for (E, E)-2,5-bis (3,4-dimethoxystyryl) pyrazine (BDP) molecule.

J Mol Model 2021 Aug 20;27(9):256. Epub 2021 Aug 20.

Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt.

This manuscript includes some photophysical parameters and some optical properties such as absorption and emission spectra of the (E, E)-2,5-bis (3,4-dimethoxystyryl) pyrazine (BDP) by applying sol-gel and copolymer matrices. The BDP molecular structure is incorporated in sol-gel matrix and copolymer of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA). In case of sol-gel matrix, the BDP molecular structure has higher quantum yield in addition to photostability maxima. The laser behavior of this molecular structure containing sol-gel matrix is good senior compared to copolymer one via using diode laser (450 nm) as pumping laser of power 160 mW. Also, the fluorescence profile of the BDP molecular structure is sensitized via using cadmium sulfide (CdS) quantum dots (QDs) by applying sol-gel host. The optimized structure of the BDP molecule is obtained via applying B3LYP/6-31G(d) level of theory. The electronic absorption and emission spectra of the BDP molecular structure in ethanol solvent were calculated using time-dependent density functional theory (TDDFT) at CAM-B3LYP/6-31G +  + (d, p) level. The obtained theoretical results were compared to experimental ones.
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http://dx.doi.org/10.1007/s00894-021-04876-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8376731PMC
August 2021

Spectral Behavior and Photophysical Parameters of Dihydrophenanthro[9,10-e][1,2,4]Triazine Derivative Dyes in Sol-Gel and Methyl Methacrylate Polymer Matrices.

J Fluoresc 2021 Sep 30;31(5):1547-1554. Epub 2021 Jul 30.

Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt.

This paper deals with the optical and photophysical properties of dihydrophenanthro[9,10-e][1,2,4]triazine fluorescent dyes doped in Silicate based sol-gel and homo-poly methyl methacrylate (PMMA). Solid hosts were found to effect on the optical and photophysical parameters such as molar absorptivity, cross sections of singlet-singlet electronic absorption and emission spectra, excited state lifetime, quantum yield of fluorescence. The dipole moment of electronic transition, the length of attenuation and oscillator strength of electronic transition from S → S have been calculated. The dyes were pumped with different powers using 3 harmonic Nd:YAG laser of 355 nm and pulse duration 8 ns, with a repetition rate at (10 Hz). Good photostability for compounds 1 and 2 were attained. It was decreased to 49% & 54% and 46% & 40% of the initial ASE of dyes in sol gel and PMMA, respectively, after 55,000 pumping pulses at (10 mJ/pulse). The dyes in sol-gel showed improved photostability compared with those in organic polymeric matrices.
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http://dx.doi.org/10.1007/s10895-021-02781-6DOI Listing
September 2021

Binary coagulation system (graphene oxide/chitosan) for polluted surface water treatment.

J Environ Manage 2021 Jun 7;288:112481. Epub 2021 Apr 7.

Chemistry Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt; Misr University for Science and Technology (MUST), 6th of October City, Egypt.

In this study, chitosan (CS) is used as a natural coagulant aid alongside graphene oxide (GO) to remove turbidity and numerous pollutants from raw and artificially contaminated surface water. The coagulation capability of the system (GO/CS) was assessed with respect to a water sample's turbidity, pH, coagulant dose, settling velocity, and temperature. The presence of CS enhanced the coagulation capacity of GO at varied pH levels and no GO residue was detected in the water after the treatment. The proposed system achieved high turbidity removal efficiency (≥98.3%) for all turbidity levels. A mixture of GO (8 mg/L) and CS (2 mg/L) was ideal to remove algae (99.5%) and bacteria (≥95.0%). Furthermore, it demonstrated a high coagulation capacity to remove dyes, direct brown-2 (DB-2), methylene blue (MB), and Pb(II) ions from artificially contaminated surface water. Interestingly, the sludge exhibited an extraordinary adsorption capacity for DB-2, MB, and Pb(II) ions. The adsorption process followed the pseudo-second-order kinetic model, and was consistent with the Langmuir model, with an adsorption capacity of up to 667.8, 400.7, and 459.1 mg/g for DB-2, MB, and Pb(II) ions, respectively. Therefore, the presented binary coagulation system is of great potential economic value for the treatment of raw surface water and wastewater.
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http://dx.doi.org/10.1016/j.jenvman.2021.112481DOI Listing
June 2021

Novel eco-friendly electrospun nanomagnetic zinc oxide hybridized PVA/alginate/chitosan nanofibers for enhanced phenol decontamination.

Environ Sci Pollut Res Int 2020 Dec 29;27(34):43077-43092. Epub 2020 Jul 29.

Electronic Materials Research Department, Advanced Technology and New Materials Research Institute (ATNMRI), City of Scientific Research and Technological Applications (SRTA-City), New Borg El-Arab City, Alexandria, 21934, Egypt.

In the current study, poly(vinyl alcohol)/alginate/chitosan (PVA/Alg/CS) composite nanofiber was immobilized with six different ratios of nanomagnetic zinc oxide (M-ZnO) (0 wt%, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, and 1 wt%) via the electrospinning technique. The various fabricated composite (M-6) nanofibers were characterized using Fourier transform infrared (FTIR), X-ray diffractometer (XRD), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), atomic force microscope (AFM), thermogravimetric analysis (TGA), mechanical testing machine, and optical contact angle measurement. The fabricated composite nanofibers were applied for the adsorption of phenol from aqueous solutions. The 1.0 wt% M-ZnO/PVA/Alg/CS composite nanofibers were selected as the best phenol adsorbent with removal percentage of 84.22%. The influence of different processing parameter such as contact time, composite nanofiber dosage, pH, initial pollutant concentration, and temperature were examined. Increasing nanofiber dosage and the solution temperature was found to enhance the phenol adsorption onto the prepared nanocomposites. The maximum percentage of phenol removal was achieved at 84.22% after 90 min. Meanwhile, the maximum monolayer adsorption capacity (at pH = 5.0) was estimated to be 10.03 mg g at 25 °C. Kinetic, isotherm, and thermodynamic studies were designated to proof the endothermic, spontaneous, and thermodynamically nature of the phenol adsorption process. These outcomes indicate the effectiveness of the fabricated M-ZnO/PVA/Alg/CS nanofibers as adsorbent materials for phenol from aqueous solutions.
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http://dx.doi.org/10.1007/s11356-020-10247-8DOI Listing
December 2020

Optical, photo physical parameters and photo stability of 6-Substituted-1, 2, 4-Triazine mono glucosyl derivative to act as a laser dye in various solvents.

Spectrochim Acta A Mol Biomol Spectrosc 2020 May 10;232:118145. Epub 2020 Feb 10.

Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt; Misr University for Science and Technology (MUST), 6th of October City, Egypt.

The optical properties of a visible absorption range6-Substituted-1, 2, 4-Triazine mono glucosyl fluorescent derivative dye, such as absorption spectra, emission spectra in different solvents, were experimentally investigated. As well, some important photo physical parameters such as extinction coefficient (ε), cross-sections of the absorption (σ) and the emission (σ), quantum yield (ф), fluorescence lifetime, oscillator strength (f), the dipole moment (μ), decay rate radiative constant (k), energy yield of fluorescence (E) and the length of attenuation Λ (λ) were assessed. The ground-state (μ) and excited-state (μ) dipole moments by solvatochromic correlations method were reported. The dye amplified spontaneous emission (ASE) of 2 × 10M with different input pumping energies of a continuous wave blue diode laser (λ = 450 nm) was studied. Photostability of dye was observed that was decreased to 53% of its initial energy by pumping with 100 mW of diode laser after exposure to 120 min.
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http://dx.doi.org/10.1016/j.saa.2020.118145DOI Listing
May 2020

Synthesis of Hollow Co-Fe Prussian Blue Analogue Cubes by using Silica Spheres as a Sacrificial Template.

ChemistryOpen 2018 Aug 7;7(8):599-603. Epub 2018 Aug 7.

School of Chemical Engineering and Australian Institute for, Bioengineering and Nanotechnology (AIBN) The University of Queensland Brisbane QLD 4072 Australia.

Herein, we report a novel method for the formation of hollow Prussian blue analogue (CoFe-PBA) nanocubes, using spherical silica particles as sacrificial templates. In the first step, silica cores are coated by a CoFe-PBA shell and then removed by etching with hydrofluoric acid (HF). The cubic shape of CoFe-PBA is well-retained even after the removal of the silica cores, resulting in the formation of hollow CoFe-PBA cubes. The specific capacity of the hollow CoFe-PBA nanocubes electrodes is about two times higher than that of solid CoFe-PBA nanocubes as storage materials for sodium ions. Such an improvement in the electrochemical properties can be attributed to their hollow internal nanostructure. The hollow architecture can offer a larger interfacial area between the electrolyte and the electrode, leading to an improvement in the electrochemical activity. This strategy can be applied to develop PBAs with hollow interiors for a wide range of applications.
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http://dx.doi.org/10.1002/open.201800120DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6080567PMC
August 2018

Loading of doxorubicin and thymoquinone with F2 gel nanofibers improves the antitumor activity and ameliorates doxorubicin-associated nephrotoxicity.

Life Sci 2018 Aug 6;207:461-470. Epub 2018 Jun 6.

Biochemistry Department, Faculty of Pharmacy, Menoufia University, Egypt.

Aims: This study aimed to elucidate the benefits of nanoformulation of doxorubicin (DOX) and thymoquinone (TQ) loaded with nanofibers of poly-N-acetyl glucosamine (pGlcNAc), which is known as F2 gel, over their conventional free forms. Moreover, evaluate the role of TQ in improving chemotherapeutic effect and ameliorating nephrotoxicity of DOX.

Main Methods: The drugs were loaded into F2 gel followed by measurement of physicochemical characterization. Next, MCF-7 and HEPG2 cells were treated with the prepared formulations and assessed for apoptosis alongside with cellular proliferation. Furthermore, we experimentally induced Heps liver carcinoma in mice and at the end of the treatment, mice were sacrificed and serum samples were used to assess nephrotoxicity markers; blood urea nitrogen (BUN) and creatinine. Additionally, renal tissue was used for determination of oxidative markers and antioxidant enzymes; whereas, tumor tissue was utilized to measure nuclear factor kappa B (NF-κB) and caspase 3.

Key Findings: Nanoformulation showed dramatic increase in apoptosis, caspase 3, and antioxidant enzymes; in contrast to, dramatic fall in cell viability, tumor volume, oxidative and nephrotoxicity markers, and NF-κB compared to corresponding free therapies. Combined therapy was superior in conserving the measured parameters compared to other treated groups.

Significance: F2 gel loaded with DOX and TQ revealed enhanced antitumor activity with minimal toxicity. Moreover, using TQ as an adjuvant with DOX could augment its cytotoxicity and ameliorate nephrotoxicity.
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http://dx.doi.org/10.1016/j.lfs.2018.06.008DOI Listing
August 2018

Enhanced anticancer effect and reduced toxicity of doxorubicin in combination with thymoquinone released from poly-N-acetyl glucosamine nanomatrix in mice bearing solid Ehrlish carcinoma.

Eur J Pharm Sci 2017 Nov 7;109:525-532. Epub 2017 Sep 7.

Biochemistry Department, Faculty of Pharmacy, Menoufia University, Egypt. Electronic address:

The incidence of breast cancer remarkably increases all over the world. Therefore, there is a great demand to introduce new approaches into cancer treatment field. The current study was designated to evaluate the role of doxorubicin (DOX) and/or thymoquinone (TQ) nanomatrix in potentiating the cytotoxicity of either drug, and to investigate the ability of TQ to reduce cardiotoxicity of DOX in solid Ehrlich carcinoma (SEC)-bearing mice. DOX and TQ were loaded into F2 gel, which is a fully-acetylated poly-N-acetyl glucosamine nanofiber. SEC was induced in female albino mice as a model for experimentally induced breast cancer. Mice were randomly divided into eight groups (n=10): normal control, tumor control, F2 gel, free DOX, DOX+F2 gel, free TQ, TQ+F2 gel, and DOX+TQ+F2 gel. On day 28th from tumor inoculation, mice were sacrificed and blood samples were collected for measurement of the cardiac markers; lactate dehydrogenase (LDH) and creatine kinase (CK-MB). In addition, cardiac tissue was utilized for determination of lipid peroxide, and tumor tissue was used for measurement of anti-apoptotic protein Bcl-2 as well as gene expression of the tumor suppressor gene P53. DOX and/or TQ showed a significant reduction in tumor volume, cardiac markers, tumor Bcl-2, and P53 upregulation compared to free conventional therapies. Co-treatment with DOX+TQ+F2 gel was superior to all other groups in exerting beneficial effects. Use of TQ as an adjuvant therapy with DOX could improve its cytotoxic effects and limit its cardiac toxicity. Furthermore, loading of DOX and/or TQ into F2 gel showed a remarkable anti-cancer activity.
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http://dx.doi.org/10.1016/j.ejps.2017.09.012DOI Listing
November 2017

Coagulation effectiveness of graphene oxide for the removal of turbidity from raw surface water.

Chemosphere 2017 Aug 27;181:738-746. Epub 2017 Apr 27.

Chemistry Department, Faculty of Science, Tanta University, Tanta, 31527, Egypt; Misr University for Science and Technology (MUST), 6th of October City, Egypt.

This study presents the performance of graphene oxide (GO) as a coagulant in turbidity removal from naturally and artificially turbid raw surface water. GO is considered an excellent alternative to alum, the more common coagulant used in water treatment processes, to reduce the environmental release of aluminum. Effects of GO dosage, pH, and temperature on its coagulation ability were studied to determine the ideal turbidity removal conditions. The turbidity removal was ≥95% for all levels of turbid raw surface water (20, 100, and 200 NTU) at optimum conditions. The role of alkalinity in inducing turbidity removal by GO coagulation was much more pronounced upon using raw surface water samples compared with that using artificially turbid deionized water samples. Moreover, GO demonstrated high-performance removal of biological contaminants such as algae, heterotrophic bacteria, and fecal coliform bacteria by 99.0%, 98.8% and 96.0%, respectively, at a dosage of 40 mg/L. Concerning the possible environmental release of GO into the treated water following filtration process, there was no residual GO in a wide range of pH values. The outcomes of the study highlight the excellent coagulation performance of GO for the removal of turbidity and biological contaminants from raw surface water.
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http://dx.doi.org/10.1016/j.chemosphere.2017.04.137DOI Listing
August 2017

Laser Performance of Some Oxazole Laser Dyes in Restricted Matrices.

J Fluoresc 2017 Jul 13;27(4):1267-1275. Epub 2017 Mar 13.

Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt.

This article reports the optical properties such as absorption profile, molar absorptivity, fluorescence profile and photo-physical parameters such as dipole moment, oscillator strength, fluorescence quantum yields, fluorescence lifetimes, laser performance and finally photostability of 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBOT),1,4-Bis(5-phenyl-2-oxazolyl)benzene (POPOB), 5-diphenyel-oxazole (PPO) laser dyes in different restricted hosts. (BBOT), (POPOB) and (PPO) are embedded in transparent silica-based nanoporous sol-gel glass and copolymer matrix of methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA). The absorption and fluorescence properties of these laser dyes in sol-gel glass matrices are compared with their respective properties in copolymer host. In case of sol-gel matrix, all dyes had higher quantum yields as well as lasing wavelength maxima. The laser performances as well as the photostability of these laser dyes in sol-gel glass displayed senior behavior compared with (MMA/ HEMA) copolymer samples upon using nitrogen laser (337.1 nm) as pumping energy.
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http://dx.doi.org/10.1007/s10895-017-2058-6DOI Listing
July 2017

Photo-induced interaction of thioglycolic acid (TGA)-capped CdTe quantum dots with cyanine dyes.

Spectrochim Acta A Mol Biomol Spectrosc 2016 Nov 24;168:1-11. Epub 2016 May 24.

Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt; Misr University for Science and Technology (MUST), 6th of October City, Egypt.

The photo-induced interaction of three different sizes of thioglycolic acid (TGA)-capped CdTe quantum dots (CdTe QDs) with two monomethine cyanine dyes belonging to the thiazole orange (TO) family has been studied. Positively charged cyanines interact with QDs surface which is negatively charged due to capping agent carboxylate ions. The energy transfer parameters including Stern-Volmer constant, Ksv, number of binding sites, n, quenching sphere radius, r, the critical energy transfer distance, R0, and energy transfer efficiencies, E have been calculated. The effect of structure and the number of aggregating molecules have been studied as a function of CdTe QDs particle size. Combining organic and inorganic semiconductors leads to increase of the effective absorption cross section of the QDs which can be utilized in novel nanoscale designs for light-emitting, photovoltaic and sensor applications. A synthesized triplet emission of the studied dyes was observed using CdTe QDs as donors and this is expected to play a potential role in molecular oxygen sensitization and in photodynamic therapy (PDT) applications.
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http://dx.doi.org/10.1016/j.saa.2016.05.029DOI Listing
November 2016

A highly efficient and selective turn-on fluorescent sensor for Hg2+, Ag+ and Ag nanoparticles based on a coumarin dithioate derivative.

Luminescence 2014 Mar 22;29(2):158-67. Epub 2013 May 22.

Chemistry Department, Faculty of Science, El Menoufia University, Sheben ElKoom, Egypt.

Based on chelation-enhanced fluorescence, a new fluorescent coumarin derivative probe 3(1-(7-hydroxy-4-methylcoumarin)ethylidene)hydrazinecarbodithioate for Hg(2+), Ag(+) and Ag nanoparticles is reported. Fluorescent probe acts as a rapid and highly selective "off-on" fluorescent probe and fluorescence enhancement by factors 5 to 12 times was observed upon selective complexation with Hg(2+), Ag(+) and Ag nanoparticles. The molar ratio plots indicated the formation of 1:1 complexes between Hg(2+) and Ag(+) with the probe. The linear response range covers a concentration range 0.1 × 10(-5) -1.9 × 10(-5) mol/L, 0.1 × 10(-5) -2.3 × 10(-5) mol/L and 0.146 × 10(-12) -2.63 × 10(-12) mol/L for Hg(2+), Ag(+) and Ag nanoparticles, respectively. The interference effect of some anions and cations was also tested.
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http://dx.doi.org/10.1002/bio.2521DOI Listing
March 2014

Structural and fluorescence quenching characterization of hematite nanoparticles.

Spectrochim Acta A Mol Biomol Spectrosc 2011 Dec 31;83(1):398-405. Epub 2011 Aug 31.

Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt.

Nanoparticles of the dominant hematite form (α-Fe(2)O(3)) of iron oxide have been prepared by a simple route of dropping FeCl(3) solution into boiling water. The nanoparticles have been characterized by transmission electron microscopy (TEM), UV-visible electronic absorption spectroscopy, chemical stoichiometry, thermal analysis methods (TGA, DSC and DTA), XRD, FTIR and magnetic susceptibility measurements. Kinetic analysis of the DSC calorigram of thermal dehydration of the nanoparticles reveals one stage of the dehydration process of energy of activation of 29.0 kJ mol(-1). The role of iron oxide nanoparticles in fluorescence quenching of coumarin thiourea derivatives (I-IV) was investigated at room temperature (296 K) by means of steady-state fluorescence spectroscopy. The quenching process was characterized by Stern-Volmer (S-V) plots which display a positive deviation from linearity. This could be explained by static and dynamic quenching models. The positive deviation in the S-V plot is interpreted in terms of ground-state complex formation model and sphere of action static quenching model. Various rate parameters for the fluorescence quenching process were determined by using the modified Stern-Volmer equation. The sphere of action static quenching model agrees very well with experimental results. Quenching constants for iron oxide nanoparticles are about four orders of magnitudes higher than quenching by Fe(3+) ions.
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http://dx.doi.org/10.1016/j.saa.2011.08.052DOI Listing
December 2011

Kinetics of catalyzed hydrolysis of 4-methylumbelliferyl caprylate (MUCAP) salmonella reagent.

Spectrochim Acta A Mol Biomol Spectrosc 2011 Sep 6;79(5):1540-5. Epub 2011 Jun 6.

Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt.

The kinetics of chemical hydrolysis including neutral, acid- and base-catalyzed hydrolysis of 4-methylumbelliferyl caprylate (MUCAP) salmonella reagent were studied at different temperatures. The rate constants and activation parameters were determined by following the build-up of fluorescence peak of the hydrolysis product 4-methylumbelliferone (4-MU). The time scale of esterase enzyme hydrolysis caused by salmonella was compared with chemical hydrolysis as a background process.
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http://dx.doi.org/10.1016/j.saa.2011.05.013DOI Listing
September 2011

Nanostructure-loaded mesoporous silica for controlled release of coumarin derivatives: a novel testing of the hyperthermia effect.

Eur J Pharm Biopharm 2011 Jan 23;77(1):66-74. Epub 2010 Oct 23.

Chemistry Department, Tanta University, Tanta, Egypt.

The synthesis of three types of mesoporous materials is reported: pure mesoporous silica (MCM-41), a nanocomposite of mesoporous silica with hydroxyapatite (MCM-41-HA) and mesoporous silica/gold nanorods nanocomposite (MCM-41-GNRs). The mesoporous materials were characterized by X-ray diffraction, N(2) adsorption isotherms, FTIR spectroscopy, transmission electron microscopy, and scanning electron microscopy. The samples were loaded with coumarin thiourea derivatives (I-IV) having functional groups of varying sizes and the in vitro release assays were monitored, and the release behavior was investigated as a function of soaking time in simulated body fluid. Two release stages were obtained in MCM-41, MCM-41-HA and MCM-41-GNRs loaded samples with the early release stages accounting for about 30% of loaded derivatives. These early release stages are characterized by Higuchi rate constant values nearly twice the values associated with the second release stages. The influence of substituent size on the release rate constants was explained in terms of sorption sites and hydrogen bonding with silanol groups on silicates. The release of coumarin derivatives loaded on MCM-41, MCM-41-HA and MCM-41-GNRs occurs over remarkably long time of the order of about 260 h with faster release rates in loaded MCM-41 and MCM-41-GNRs samples compared with MCM-41-HA ones. The role of hyperthermia effect in enhancing release rates was investigated by subjecting loaded MCM-41-GNRs to near infrared (NIR) radiation at 800 nm. This would be of significance in targeted drug release using hyperthermia effect. Unlike hydroxyl apatite, loading MCM-41 with gold nanorods does not affect the release kinetics. Only when these samples are irradiated with NIR photons, does the release occur with enhanced rates. This property could be valuable in selected targeting of drugs.
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http://dx.doi.org/10.1016/j.ejpb.2010.10.007DOI Listing
January 2011

Fluorescence enhancement of coumarin thiourea derivatives by Hg2+, Ag+, and silver nanoparticles.

J Phys Chem A 2009 Aug 31;113(34):9474-84. Epub 2009 Jul 31.

Chemistry Department, Faculty of Science, Tanta University, Tanta, Egypt.

Fluorescence enhancement by factors of 5-12 times 8-alkyl thiourido-7-ethoxy-4-methyl coumarin derivatives was observed upon complexation with Hg(2+), Ag(+), and Ag nanoparticles. The study reveals a chelation-enhanced fluorescence (CHEF) mechanism with the formation of 1:2 complexes in Hg(2+)/coumarin derivatives and 1:1 complexes in Ag(+)/coumarin derivatives. The activation parameters of the complexation processes were evaluated with energy of activation values in the case of Ag(+) being nearly twice those in the case of Hg(2+) complexation. Isokinetic studies indicate an enthalpy-controlled mechanism in the Hg(2+)/coumarin derivatives complex formation. No fluorescence enhancement was observed with Fe(3+), Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+), La(3+), and Ce(3+), making the present coumarin thiourea derivatives selective chemosensors of both Hg(2+) and Ag(+) ions with different complexation time scales between these two ions. Fluorescence enhancement of the studied coumarin thiourea derivatives using silver nanomaterials occurs almost instantaneously and can be induced by silver nanoparticles in the picomolar (pM) concentration ranges.
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http://dx.doi.org/10.1021/jp905566zDOI Listing
August 2009
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