scholarly journals Chemical modification of TiO2 by H2PO4−/HPO42− anions using the sol-gel route with controlled precipitation and hydrolysis: enhancing thermal stability

2014 ◽  
Vol 32 (4) ◽  
pp. 617-625 ◽  
Author(s):  
Kais Elghniji ◽  
Mohamed Saad ◽  
Manel Araissi ◽  
Elimame Elaloui ◽  
Younes Moussaoui
Keyword(s):  
31P Nmr ◽  
Sol Gel ◽  
Phosphate Buffer Solution ◽  
Rutile Phase ◽  
Titanium Phosphate ◽  
Buffer Solution ◽  
Raman Analysis ◽  
Phosphate Species ◽  
Ft Ir ◽  
Controlled Precipitation

AbstractTwo titanium phosphate materials (TpP and ThP) have been successfully synthesized by sol-gel route with controlled precipitation and hydrolysis. The TpP material was obtained from the reaction between precipitated titania and phosphate buffer solution H2PO4− /HPO42− (pH = 7.3). The TpP material was prepared through hydrolysis of titanium in the presence of H2PO4−/HPO42. The probable state of the phosphate anions in titania framework and their effect on the anatase-to-rutile transformation were characterized by ICP-AES, DTA-TG, 31P NMR, FT-IR, and Raman analysis HRTEM/SEM. FT-IR and 31P NMR analyses of titanium phosphate TpP calcined at low temperature showed that the phosphate species existed not only as Ti-O-P in the bulk TiO2 but also as amorphous titanium phosphates, including bidentate Ti(HPO4)2 and monodentate Ti(H2PO4)4. Increased calcination temperature only gave an enrichment of bidentate structure on the titania surface. For the TpP material, H2PO4−/HPO42− anions were introduced into the initial solution, before precipitation, what promoted their lattice localization. At high temperatures, all the phosphorus inside the bulk of TiO2 migrated to the surface. The Raman analysis of both samples showed that the bidentate phosphates increased the temperature of the anatase-to-rutile phase transformation to more than 1000 °C with the formation of well crystalline TiP2O7 phase. This phenomenon was more evident for TpP sample.

Fabrication of an Electrochemical Sensor for Glucose Detection using ZnO Nanorods

MRS Advances ◽  
2016 ◽  
Vol 1 (13) ◽  
pp. 861-867 ◽  
Author(s):  
Sanghamitra Mandal ◽  
Mohammed Marie ◽  
Omar Manasreh
Keyword(s):  
Response Time ◽  
Glass Substrate ◽  
Glucose Sensor ◽  
Limit Of Detection ◽  
Sol Gel ◽  
Zno Nanorods ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Coated Glass Substrate ◽  
Coated Glass

ABSTRACTAn electrochemical glucose sensor based on zinc oxide (ZnO) nanorods is fabricated, characterized and tested. The ZnO nanorods are synthesized on indium titanium oxide (ITO) coated glass substrate, using the hydrothermal sol-gel technique. The working principle of the sensor under investigation is based on the electrochemical reaction taking place between cathode and anode, in the presence of an electrolyte. A platinum plate, used as the cathode and Nafion/Glucose Oxidase/ZnO nanorods/ITO-coated glass substrate used as anode, is immersed in pH 7.0 phosphate buffer solution electrolyte to test for the presence of glucose. Several amperometric tests are performed on the fabricated sensor to determine the response time, sensitivity and limit of detection of the sensor. A fast response time less than 3 s with a high sensitivity of 1.151 mA cm-2mM-1 and low limit of detection of 0.089 mM is reported. The glucose sensor is characterized using the cyclic voltammetry method in the range from -0.8 – 0.8 V with a voltage scan rate of 100 mV/s.

In Vivo Biological Behavior of Calcium Phosphate Cements with Different Ca/P Ratio

2008 ◽  
Vol 396-398 ◽  
pp. 237-240
Author(s):  
Sybele Saska ◽  
N.S. Nunes ◽  
Emelly Aveiro ◽  
Cristina A.C. Pavan ◽  
S.H. Santagneli ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
31P Nmr ◽  
Phosphate Buffer Solution ◽  
Biological Behavior ◽  
X Ray Diffraction ◽  
Buffer Solution ◽  
X Ray ◽  
Calcium Phosphate Cements ◽  
Subcutaneous Tissues

Bioceramics with different Ca/P ratio were prepared from a mechanical mixture of NaPO3, CaCO3, Ca(OH)2 and phosphate buffer solution and implanted in rats subcutaneous tissues. The cements were characterized by Thermogravimetric analysis (TG-TDA), X-ray diffraction and 31P-NMR. The implant sites were excised after 1, 4 and 16 weeks, fixed, dehydrated, included in paraffin wax for serial cutting and examined under the light transmitted microscope. They were biocompatible and biodegradable when implanted in rat subcutaneous. None of the materials induced ectopic osteogenesis. According to the results, the studied materials seem to be able for manufacturing reabsorbable bone implants.

Synthesis, characterization, and drug delivery property of 2-N-carboxymethyl-6-O-diethylaminoethyl-chitosan

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Aidi Zhang ◽  
Derun Ding ◽  
Jicun Ren ◽  
Xiangli Zhu ◽  
Youhong Yao
Keyword(s):  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Controlled Delivery ◽  
Protective Agent ◽  
Buffer Solution ◽  
Solution Ph ◽  
H Nmr ◽  
Structure Morphology ◽  
Ft Ir ◽  
Model Drug

Abstract A novel route is demonstrated for the synthesis of 2-N-carboxymethyl-6- O-diethylaminoethyl-chitosan (DEAE-CMC) by incorporation of carboxymethyl groups as hydrophilic moieties to the C2-NH2, and diethylaminoethyl groups as hydrophobic moieties to the C6-CH2OH of the structural unit of chitosan, via a protection-graft-deprotection procedure with benzaldehyde as protective agent. The structure, morphology, and thermal properties of the chitosan graft copolymers were characterized by means of FT-IR, 1H NMR, SEM, TGA and DSC. Chitosan and its derivatives were used as carrier of model drug-Vitamin B12 (VB12), and their controlled delivery behaviour in phosphate buffer solution (pH 7.4) were studied. The results show that the release rate of VB12 from the carrier of DEAE-CMC copolymer becomes much slower than that of chitosan in phosphate buffer solution.

Encapsulation of Urease in Molybdenum Trioxide Sol-Gel

2004 ◽  
Vol 828 ◽  
Author(s):  
Prashant K. Jha ◽  
P. I. Gouma
Keyword(s):  
Gas Sensing ◽  
Molybdenum Trioxide ◽  
Ph Value ◽  
Sol Gel ◽  
Microstructural Analysis ◽  
Phosphate Buffer Solution ◽  
Gaseous Ammonia ◽  
Buffer Solution ◽  
Transmission Electron ◽  
The Matrix

ABSTRACTMolybdenum trioxide sol-gel matrices were tested for their ability to host biomaterials in their structures without adversely affecting the activity of the encapsulated biomolecules. The sol-gel composites were prepared at room temperature; the urease was added during the hydrolysis step to ensure proper encapsulation in the pore structure of the sol. Phosphate buffer solution was added during this stage to maintain the pH value of the sol in the bio-compatible range. The activity of incorporated urease was tested by exposing composite sol-gel material to standard urea test solutions and measuring the amount of gaseous ammonia (released by the reaction of urea with water in the presence of urease) using an ammonia electrode. The concentration of urea solutions ranged from 1mM to 10mM. An electronic olfactory system (EOS 835) was also employed to detect the presence of gaseous ammonia. Gas sensing tests were done to verify the sensitivity of the matrix to ammonia. Microstructural analysis was carried out by means of scanning and transmission electron microscopy. It was found that urease retained its activity inside molybdenum trioxide sol-gels that are sensitive to ammonia. These hybrid nanoporous composites are useful in the field of biosensors and fuel cells.

Deposition of organic−inorganic hybrid coatings over 316L surgical stainless steel and evaluation on vascular cells

2014 ◽  
Vol 92 (10) ◽  
pp. 987-995 ◽  
Author(s):  
F.G. Doro ◽  
A.P. Ramos ◽  
J.F. Schneider ◽  
U.P. Rodrigues-Filho ◽  
M.A.M.S. Veiga ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Hybrid Materials ◽  
Sol Gel ◽  
Phosphate Buffer Solution ◽  
Hybrid Coatings ◽  
Stainless Steel Surface ◽  
Buffer Solution ◽  
Migration Assay ◽  
Mechanical Adhesion ◽  
Drug Eluting

Surface coating of metallic materials using the sol-gel technique is a suitable approach to obtain hybrid materials with improved properties for biomedical applications. In this study, an AISI 316L stainless steel surface was coated with ormosils prepared from tetraethylsiloxane and 3-glycidoxypropyltrimethoxysilane or polydimethylsiloxane. The characterization of structural and surface properties was performed by several techniques. Surface microstructure, morphology, and energy are dependent on organosilane type and content. Chemical stability of coatings was investigated by static immersion tests in phosphate buffer solution at 37 °C, and silicon leaching after 21 days was found to be in the range of ∼200−300 μg L−1. Mechanical adhesion was found to be within 1.0 and 3.7 N cm−1. The interaction of the samples and materials in the cardiovascular environment was investigated through cellular behavior. Biological assays were performed with slides to avoid any cytotoxic effects on human endothelial cells (HUVEC) and rabbit arterial smooth muscle cells (RASM). No significant alterations were observed after 24 h in the viability of RASM and HUVEC cells exposed to different coatings. No increase of HUVEC or RASM migration was observed after 24 h as evaluated by transwell migration assay. The hybrid materials showed suitable properties for potential application as biomaterials in cardiovascular environment as well as for incorporation of bioactive species with the aim to prepare drug-eluting stents.

Synthesis and Antimicrobial Activity of Fe:TiO2 Particles

2019 ◽  
Vol 56 ◽  
pp. 28-38 ◽  
Author(s):  
Uraiwan Werapun ◽  
Jaraslak Pechwang
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Rutile Phase ◽  
Antibacterial Activities ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ft Ir ◽  
Xrd Patterns ◽  
Increasing Temperature ◽  
Scanning Electron

TiO2 and iron-doped TiO2 were synthesized by sol-gel method. TiO2 and 0.5 %mol Fe:TiO2 were calcined at 500 and 800 °C for 3 h. The synthesized particles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV-VIS diffuse reflectance spectrophotometry (UV/DRS), scanning electron microscopy (SEM) and scanning electron microscope-energy dispersive X-Ray analysis (SEM-EDX). The XRD patterns of all samples that were calcined at 500 °C showed only anatase phase. On increasing temperature from 500 to 800 °C, the anatase phase transformed to rutile phase. For 0.5 %mol Fe:TiO2, pseudobrookite (Fe2TiO5) phase was observed at 800 °C. The particles that contained rutile showed higher antibacterial activities against E.coli, B. subtilis, and S. aureus than anatase phase, under fluorescent irradiation.

scholarly journals Photocatalytic Degradation of Herbicide Orthosulfamuron using Zinc Oxide Nanoparticles in Water

2020 ◽  
Author(s):  
Gaggara Naveetha ◽  
Atmakuru Ramesh ◽  
Chirukuri Rajasekharam
Keyword(s):  
Degradation Products ◽  
Sol Gel ◽  
Amic Acid ◽  
Optimum Concentration ◽  
Nano Particles ◽  
Buffer Solution ◽  
Initial Concentration ◽  
Sol Gel Process ◽  
Rate Of Reaction ◽  
Ft Ir

In the present study, the Photocatalysis of Orthosulfamuron, a new class of sulfonyl urea herbicide was investigated using ZnO nano particles in different buffer solutions of pH ranging from 4 to 9. In this study, optimum concentration of the catalyst, initial concentration of the orthosulfamuron and effect of pH of the buffer solution were studied under direct sunlight. The ZnO nano particles were synthesized by sol-gel process and characterized by using SEM, XRD and FT-IR. A commercial formulation of the herbicide having the active strength of 50% was used for the experiment. The rate of reaction followed pseudo first-order kinetics in water. The rate of reaction was 12 folds higher when compared to photolysis. The DT50 values of orthosulfamuron with ZnO nano particles in different buffer solution were 6. 42, 21.68 and 35.22 hours, respectively. The optimum concentration of nano particles to decontamination of orthosulfamuron was observed at 100 mg L-1 and the initial concentration of the orthosulfamuron used in the photocatalysis is 10 mg L-1. The fastest degradation of herbicide orthosulafamuron was observed in pH 4 buffer solution. The degradation products formed during the photocatalysis were identified by using LC-MS/MS which were N-(4,6-dimethoxypyrimidin-2-yl) urea, 2- dimet hyl carbamoyl phenyl sulf amic acid and 1-(4-hydroxy-6-methoxypyrimidin-2-yl)-3-[2-(dimethylcarbamoyl) pheny lsulfamoyl] urea.

scholarly journals Development of Methanol Sensor Based on Sol-Gel Drop-Coating Co3O4·CdO·ZnO Nanoparticles Modified Gold-Coated µ-Chip by Electro-Oxidation Process

Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 235
Author(s):  
Mohammed M. Rahman ◽  
Jahir Ahmed ◽  
Abdullah M. Asiri ◽  
Sulaiman Y.M. Alfaifi ◽  
Hadi. M. Marwani
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metallic Nanoparticles ◽  
Dynamic Range ◽  
Sol Gel ◽  
Phosphate Buffer Solution ◽  
Fast Response ◽  
Buffer Solution ◽  
Metallic Oxide ◽  
X Ray ◽  
Methanol Sensor

Herein, novel Co3O4·CdO·ZnO-based tri-metallic oxide nanoparticles (CCZ) were synthesized by a simple solution method in basic phase. We have used Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Field Emission Scanning Electron Microscope (FESEM), Dynamic Light Scattering (DLS), Tunneling Electron Microscopy (TEM), and Energy-Dispersive Spectroscopy (EDS) techniques to characterize the CCZ nanoparticles. XRD, TEM, DLS, and FESEM investigations have confirmed the tri-metallic nanoparticles’ structure, while XPS and EDS analyses have shown the elemental compositions of the CCZ nanoparticles. Later, a Au/μ-Chip was modified with the CCZ nanoparticles using a conducting binder, PEDOT: PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) in a sol-gel system, and dried completely in air. Then, the CCZ/Au/μ-Chip sensor was used to detect methanol (MeOH) in phosphate buffer solution (PBS). Outstanding sensing performance was achieved for the CCZ/Au/μ-Chip sensor, such as excellent sensitivity (1.3842 µAµM−1cm−2), a wide linear dynamic range of 1.0 nM–2.0 mM (R2 = 0.9992), an ultra-low detection limit (32.8 ± 0.1 pM at S/N = 3), a fast response time (~11 s), and excellent reproducibility and repeatability. This CCZ/Au/μ-Chip sensor was further applied with appropriate quantification results in real environmental sample analyses.

A Study of the Amide III Band by FT-IR Spectrometry of the Secondary Structure of Albumin, Myoglobin, and γ-Globulin

1987 ◽  
Vol 41 (2) ◽  
pp. 180-184 ◽  
Author(s):  
Koichi Kaiden ◽  
Tomoko Matsui ◽  
Shigeyuki Tanaka
Keyword(s):  
Secondary Structure ◽  
Conformational Changes ◽  
Phosphate Buffer Solution ◽  
Heat Denaturation ◽  
Buffer Solution ◽  
Ir Spectrometry ◽  
Ft Ir ◽  
Α Helix ◽  
Β Lactoglobulin ◽  
Β Sheet

FT-IR spectrometry was applied to the identification of the secondary structure species of a living protein. The spectra of native myoglobin and albumin were obtained with methods using either KBr pellet or film formed on a KBr window from an aqueous solution. Pellet preparation of myoglobin and albumin caused the structure to change from α-helix to β-structure. The conformational changes that arise from heat denaturation of myoglobin, albumin, and γ-globulin were observed by the changes in the amide I, II, and III bands. The bands of the 1300, 1260, and 1235 cm−1 regions were respectively assigned to α-helix, disordered, and β-sheet structures. These band positions were substantiated by the spectra of β-lactoglobulin and α-casein. α-Helix structure probably changes to β-structure in the presence of alkali halide, and changes to disordered structure with heat denaturation in phosphate buffer solution. The secondary structure of a protein is further identified by use of the information obtained from the amide I, II, and III bands; the amide III band is especially important. Furthermore, it may be possible to characterize the species of secondary structures of proteins adsorbed on material surfaces.

scholarly journals Mesoporous silica nanoparticles equipped with surface nanovalves for pH-controlled liberation of doxorubicin

2016 ◽  
Vol 6 (6) ◽  
pp. 20160041 ◽  
Author(s):  
N. V. Roik ◽  
L. A. Belyakova
Keyword(s):  
Phosphate Buffer ◽  
Uv Spectroscopy ◽  
Mesoporous Silica Nanoparticles ◽  
Sol Gel ◽  
Phosphate Buffer Solution ◽  
Mesoporous Structure ◽  
Drug Carriers ◽  
Buffer Solution ◽  
Synthesized Materials ◽  
Ph Controlled

Silica carriers equipped with molecular and supramolecular pH-sensitive nanovalves were designed by combination of sol–gel synthesis and selective postsynthetic modification. Mesoporous structure of synthesized materials was characterized by low-temperature nitrogen adsorption–desorption, small-angle X-ray diffraction and transmission electron microscopy. Chemical immobilization of N -[ N ′-( N ′-phenyl)-2-aminophenyl]aminoalkyl groups was confirmed by IR spectral and chemical analyses of surface layer. Loading and release behaviour of synthesized drug carriers was studied in phosphate buffer solutions with pH 5.0 and pH 7.0 using doxorubicin (Dox) as a test molecule. It was found that the loading efficiency of synthesized materials determined by UV spectroscopy measurements reached 59–76%, whereas cumulative value of Dox released from silica materials equipped with molecular and supramolecular nanovalves into the phosphate buffer solution with pH 5.0 reached up to 48% and 51%, respectively. It was proved that aromatic amino groups and surface supramolecular structures localized near pore openings play an essential role in pH-controlled Dox release.

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