Sol-gel entrapment of monoclonal anti-atrazine antibodies

We report the successful doping of a sol-gel matrix with an antibody, retaining its ability to bind free antigen from an aqueous solution. The particular system described is monoclonal anti-atrazine mouse antibody which was entrapped in SiO₂ sol-gel matrices, prepared from tetramethoxysilane by several methods. Atrazine was selected as a model compound for this study, within the framework of the development of immunochemical-based methods for monitoring pesticide residues and other organo-synthetic environmental contaminants. Nanogram quantities of atrazine were applied on SiO₂ sol-gel columns doped with this antibody, and the amount of eluted antigen was determined by Enzyme Linked ImmunoSorbent Assay (ELISA). Under appropriate sol-gel-forming conditions, high amounts of atrazine were bound to the sol-gels, ranging between 60% and 91% of the amount applied to the column. The combination of the properties of the sol-gel matrix (e.g., stability, inertness, high porosity, high surface area and optical clarity), together with the selectivity and sensitivity of the antibodies, enable extension of this feasibility study to development of a novel group of immunosensors which could be used for purification, concentration and monitoring of a variety of residues from different sources.Contribution from the Agricultural Research Organization (ARO), Bet Dagan, Israel. No., 1697-E, 1995 series.     

Characterization and Bioavailability of Vitamin C Nanoliposomes Prepared by Film Evaporation-Dynamic High Pressure Microfluidization

Vitamin C nanoliposomes were prepared by combining a conventional method (film evaporation) with dynamic high pressure microfluidization. Their physicochemical characterizations (antioxidant activity, particle size, entrapment efficiency, morphology, in vitro drug release, and storage stability) and skin permeation behavior were investigated. The results showed that vitamin C nanoliposomes, having equivalent DPPH (2, 2-diphenyl-1-picrylhydrazyl) free radical scavenging capacity of pure vitamin C solution without loss of their biological activity, exhibited better storage stability at 37°C for 24 hours and at 4°C for 60 days, a more excellent sustained drug release as well as higher skin penetration rate than vitamin C liposomes.     

Spectrophotometric Studies of Entrapped Thymol Phtalein pH Indicator into Sol‐Gel Matrix

This research involves the behavior of thymol phtalein pH indicator entrapped into the sol‐gel derived inorganic matrix. The method is based on the physical entrapment of the reagent molecules in the sol‐gel matrix. The immobilized thymol phthalein pH indicator shows behavior similar to its solution counterpart. The UV/vis spectra indicate that the thymol phthalein retains its structure during the sol‐gel reactions in terms of response to pH. Thymol phthalein can be regarded as uniformly distributed in the sol‐gel matrix. This observation has been confirmed using polarized microscopy. This research shows that thymol phtalein can be immobilized in sol‐gel glasses and used as a solid pH sensor.     

Entrapment of pH Universal Indicator into Sol‐Gel Matrix

This study involves the behavior of universal indicator entrapped into the sol‐gel matrix. The encapsulation of universal indicator has been prepared by acid catalyzed sol‐gel reaction of tetraethylorthosilicate (TEOS) in the presence of universal indicator to produce transparent monolithic silica doping with universal indicator. The immobilized universal indicator pH‐indicator shows behavior similar to its solution counterpart. The UV/VIS spectra indicate that the universal indicator retains its structure during the sol‐gel reactions in terms of response to pH. The universal indicator can be regarded as uniformly distributed in the sol‐gel matrix. The use of SDS surfactant has positive effects on the immobilized universal indicator monolithic disk due to homogenizing the polymerizing system. This observation has been confirmed using polarized microscopy.     

Entrapment of organic fluorophores in calcium phosphate nanoparticles with slow release

Two organic fluorophores, fluorescein (F) and rhodamine B (Rd), were entrapped in calcium phosphate nanoparticles. The as-obtained nanoparticles can be used for biological release applications. For this aim, calcium phosphate nanoparticles were synthesized using the precipitation method. Structural analysis of these nanoparticles was performed using XRD, FTIR, and Raman spectroscopy, confirming that the synthesized nanoparticles were hydroxyapatite. TEM and SEM analyses demonstrated that these nanoparticles had a size of 20 nm and a well-defined morphology. F and Rd (about 0.5 wt.%) were entrapped in these nanoparticles and their release, as a function of time, was studied via UV-Vis spectroscopy. The obtained results showed that the release of both fluorophores was progressive over time. The trapping efficiencies of the fluorophores were 67.15% and 90.76% for F and Rd, respectively.     

Percolation theory approach to transport phenomena in porous media

The percolation theory approach to static and dynamic properties of the single- and two-phase fluid flow in porous media is described. Using percolation cluster scaling laws, one can obtain functional relations between the saturation fraction of a given phase and the capillary pressure, the relative permeability, and the dispersion coefficient, in drainage and imbibition processes. In addition, the scale dependency of the transport coefficient is shown to be an outcome of the fractal nature of pore space and of the random flow pattern of the fluids or contaminant.     

A Similarity Solution for Oil Lens Redistribution Including Capillary Forces and Oil Entrapment

Redistribution of a LNAPL lens (oil) at the phreatic surface is described using a multi-phase flow model, with emphasis on the effect of oil entrapment by water. The flow process is analyzed under the assumption that the vertical capillary and gravitational forces balance. Vertical integration leads to explicit functions which approximate the relations between the free oil volume per unit lateral area and the vertically averaged oil relative permeability on the one hand and the vertical position of the interface between zones with either two or three phases on the other hand. A linear relation between the trapped and free oil volume per unit lateral area approximates the vertically integrated nonlinear expression for the trapped oil saturation. The resulting differential equation admits a similarity solution describing the lateral spreading of free oil and the amount and location of trapped oil. Comparison with illustrative numerical computations, which are based on the nonreduced flow model in a two-dimensional planar or axisymmetric domain, shows that the analytical solution provides a good approximation of the free oil distribution at all later times.     

连铸结晶器内部流场及熔渣卷入的数值模拟

针对连铸结晶器内部流场及熔渣卷入过程 ,提出了两方程k -ε湍流模型和充填法数值计算模型 ,并采用硅油 /水模拟体系代替熔渣 /钢液体系 ,进行了模拟试验和数值计算。对充气造成的浸入式水口水流脉动的影响进行分析。计算结果与试验结果符合良好 ,表明本文所采用的数值模拟方法是适用的     

Horse radish peroxidase immobilized polyaniline for hydrogen peroxide sensor

Horse radish peroxidase (HRP) has been electrochemically entrapped into perchlorate (ClO) doped polyaniline (PANI) film deposited onto indium‐tin‐oxide (ITO) coated glass plate. This HRP‐PANI‐ClO/ITO bioelectrode characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), UV‐Visible spectroscopy, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques has been utilized for estimation of hydrogen peroxide (H₂O₂). This H₂O₂ sensor exhibits response time of 5 s, linearity from 3 to 136 mM, sensitivity as 0.5638 µA mM^?1 cm^?2 with linear regression of 0.985. The value of the Michaelis–Menten constant (K_m) has been obtained as 1.984 mM. Copyright © 2009 John Wiley & Sons, Ltd.     

Surface Engineering of Poly(DL‐lactic acid) by Entrapment of Biomacromolecules

Alginate, chitosan and gelatin were deposited on the surface of PDL‐LA films via an entrapment method. ATR‐FT‐IR, XPS and contact‐angle analyses revealed the formation of stable thin biomacromolecule layers on the PDL‐LA film, thus enhancing the hydrophilicity of the films. Confocal laser scanning microscopy showed the existence of entrapment areas of approximately 10–20 μm in depth. This simple surface‐treatment method may have the potential for many biomedical applications.