Track Membranes Research Articles

A microfluidic biosensor based on finger-driven mixing and nuclear track membrane filtration for fast and sensitive detection of Salmonella

A novel colorimetric biosensor was explored for fast, sensitive, and on-site detection of Salmonella on a microfluidic chip employing immune gold@platinum nanoparticles (Au@Pt NPs) for specific bacterial labeling, a finger-driven mixer with two serial air chambers for efficient immunoreaction and a nuclear track membrane as specific-size microfilter for effective bacterial isolation from excessive immune Au@Pt NPs. First, the bacterial sample and immune Au@Pt NPs were pipetted into the mixing chamber and mixed sufficiently through repeated press-release actions on the small air chamber which could precisely control the air volume, leading to the formation of bacteria-immune Au@Pt NP conjugates. Then, the small and large air chambers were pressed simultaneously to push all the solution in the mixing chamber to flow through the microfilter for trap of the formed larger-size conjugates on the membrane and removal of the unbound smaller-size immune Au@Pt NPs. After the H2O2-TMB substrate was pipetted into the microfilter and catalyzed by the conjugates, ImageJ was used to analyze the color change for bacterial determination. This simple biosensor enabled Salmonella detection as low as 168 CFU/mL in 25 min.

Method for the Certification of Track Membranes Using Computer Vision

Method for the Certification of Track Membranes Using Computer Vision

Effect of electron irradiation on polyimide composites based on track membranes for space systems

The paper presents data on the resistance to electron irradiation of polyimide (PI) composite with nano-sized lead filler. PI composite with nano-filler were obtained on the basis of PI track membranes by electrochemical deposition of nano lead into the pores of track membranes. SEM-images, physical–mechanical and dielectric characteristics of PI composite with 70 wt% content of lead filler were examined. The composite was irradiated with 1–5 MeV electrons, and the maximum cumulative dose was 10 MGy. The effective range of an electron in a PI is greater than in a composite based on track membranes at the same initial electron energy: at E = 2 MeV - by 2.08 times, and at E = 5 MeV by 2.33 times.

Use of Spectroscopic Methods to Study the Morphology of Polymeric Track Membranes

Use of Spectroscopic Methods to Study the Morphology of Polymeric Track Membranes

Angular Characteristics of Soft X-Ray Transmission by Track Membranes with Large Pores

Angular Characteristics of Soft X-Ray Transmission by Track Membranes with Large Pores

Composite Track Membrane Produced by Roll Technology of Magnetron Sputtering of Titanium Nanolayer

Composite Track Membrane Produced by Roll Technology of Magnetron Sputtering of Titanium Nanolayer

USE OF SPECTROSCOPIC METHODS FOR STUDYING MORPHOLOGY OF POLYMER TRACK MEMBRANES

The morphology of track membranes based on polyethylene terephthalate and polypropylene with different track diameters and their surface densities were studied by UV, IR, Raman spectroscopy, and scanning electron microscopy (SEM). The SEM method was used to plot the distribution curves of the number of tracks depending on their average size (diameter). Similar distribution curves were obtained using UV and IR spectroscopy. Good agreement was found between the data of independent methods of optical spectroscopy
 and SEM. It is shown that with an increase in the surface density of tracks, the background elastic scattering in the Raman spectra increases linearly. It is proposed to use the observed effect in the Raman spectra to estimate the surface track density of polymer track membranes.

Electrical properties arrays of intersecting of nanowires obtained in the pores of track membranes

In the following work by means of matrix synthesis the nanowire arrays of Fe–Ni alloy with elemental composition close to permalloy (Fe0·20Ni0.80) were obtained. In capacity of matrix the polyethylene terephthalate (PET) track membranes with angular distribution of pores within the range of ±30° and the diameter of pores in 100 nm were used. As a result, via electrochemical deposition method the metal-polymer composite in the form of nanowire arrays in the polymeric matrix were obtained. The distribution of pores over the surface of track membranes and the average amount of nanowire intersections under a variety of lengths of the grown nanowires were calculated. The resistivity of metal-polymer composite arrays, formed with nanowires of varying length, was measured. The growth boundary conditions and the lengths of nanowire arrays that are essential for obtaining of conducting metal-polymer composite were determined.

Formation of Island SERS Films on Surfaces of Track Membranes and Silicon Substrates

It is shown that metallic nano-island SERS-active layers can be created on the surfaces of porous track membranes made of polyethylene terephthalate and silicon substrates optimized for exciting laser radiation with wavelengths of 532 and 785 nm. Characteristic patterns of changes in the optical properties of SERS structures upon altering the morphology of metal nanoparticles on a substrate’s surface are established. Such structures can be used as SERS chips and highly sensitive filtering SERS elements in optical biosensors.

Research and Design of Etching Line about Nuclear Track Membrane

Nuclear track membrane is a new type of membrane material with uniform pore size distribution. It can be used as a high-precision filtration membrane and there is a wide range of applications in sewage treatment, cell filtration, and biomedicine. The main production processes of nuclear track membrane include heavy ion irradiation and chemical etching, so there is a great significance about the research and design of etching lines. The main contents studied in this paper include the physical design principle of the etched line, the basic engineering structure, the basic control system architecture, and a complete HMI. The research plays an important role in the development and large-scale application of nuclear track membrane in this paper.

Formation of Nanowires of Various Types in the Process of Galvanic Deposition of Iron Group Metals into the Pores of a Track Membrane.

The processes of formation of one-dimensional nanostructures by the method of matrix synthesis was studied in this work. Nanowires (NWs) from magnetic metals of iron-group and copper (3-d metals) were synthesized in the pores of matrix-track membranes by galvanic deposition. NWs with both homogeneous elemental distribution (alloys) and with periodically alternating parts with different composition (layers) were obtained in matrices with different pore diameters and under different parameters of the galvanic process. The transport of ions, which determined the growth of wires, in pores of different sizes was analyzed. The influence of the size of pore channels on the features of NWs growth, the correlation between the elemental composition of the NWs and the growth electrolyte, as well as the influence of the growth conditions (voltage and pore diameter) were investigated. Approaches to formation of thin layers in layered NWs were studied. This included the choice of methods for controlling the pulse duration, slowing down the growth rate by the dilution of the solution, the use of additives and the work with reference electrode. The study of NWs was carried out using visualization and analysis of their structure using transmission and scanning electron microscopy, electron diffraction, energy dispersive analysis, and elemental mapping. For the studied types of samples, a relationship was established between the growth conditions and the structure. This data raises the possibility of varying the magnetic properties of NWs.

Two- and three-component alloys nanowires: correlation of structural and magnetic properties

Several types of nanowires (NWs) made of alloys of various compositions obtained by the method of matrix synthesis based on track membranes have been studied. Electrolytes were selected to obtain NWs of the desired composition. The control of electrodeposition by chronoamperograms made it possible to systematically change the geometric parameters and morphology. The topographies of the resulting NW arrays and their elemental composition were studied using electron microscopy with an X-ray spectral analyzer. The magnetic properties of the samples were studied on a vibrating magnetometer. The structures of binary alloys were studied: for NWs of FeCo alloys, the dependence of the coercive force on the composition was studied. The obtained dependence has two maxima --- at an equiatomic composition and at a cobalt content of about 90%. For Fe0.3Co0.7 NWs, a sharp increase in the coercive force with decreasing diameter is shown. It is assumed that this effect is due to the formation of single-domain crystallites, the processes of magnetization reversal of which are associated with a uniform rotation of the magnetization. For NWs made of FeNi alloys, the influence of the aspect ratio on the coercive force has been proved. Ternary alloys of the FeCoCu system have been studied: it has been shown that the addition of copper significantly increases the coercive force, which reaches a maximum at a copper content of about 5%. The obtained X-ray data suggest that the effect of an increase in the coercive force is associated with the formation of fine-grained inclusions based on copper, which lead to effective deceleration of the domain walls. The data obtained expand the range of possibilities for controlling the magnetic properties of NW arrays obtained by the method of matrix synthesis. Keywords: nanowires, matrix synthesis, microscopy, elemental analysis, magnetic properties, coercive force. Keywords: nanowires, matrix synthesis, microscopy, elemental analysis, magnetic properties, coercive force.

Нанопроволоки из двух- и трехкомпонентных сплавов: корреляция структурных и магнитных свойств

Several types of nanowires (NWs) made of alloys of various compositions obtained by the method of matrix synthesis based on track membranes have been studied. Electrolytes were selected to obtain NWs of the desired composition. The control of electrodeposition by chronoamperograms made it possible to systematically change the geometric parameters and morphology. The topographies of the resulting NW arrays and their elemental composition were studied using electron microscopy with an X-ray spectral analyzer. The magnetic properties of the samples were studied on a vibrating magnetometer. The structures of binary alloys were studied: for NWs of FeCo alloys, the dependence of the coercive force on the composition was studied. The obtained dependence has two maxima - at an equiatomic composition and at a cobalt content of about 90%. For Fe0.3Co0.7 NWs, a sharp increase in the coercive force with decreasing diameter is shown. It is assumed that this effect is due to the formation of single-domain crystallites, the processes of magnetization reversal of which are associated with a uniform rotation of the magnetization. For NWs made of FeNi alloys, the influence of the aspect ratio on the coercive force has been proved. Ternary alloys of the FeCoCu system have been studied: it has been shown that the addition of copper significantly increases the coercive force, which reaches a maximum at a copper content of about 5%. The obtained X-ray data suggest that the effect of an increase in the coercive force is associated with the formation of fine-grained inclusions based on copper, which lead to effective deceleration of the domain walls. The data obtained expand the range of possibilities for controlling the magnetic properties of NW arrays obtained by the method of matrix synthesis. Keywords: nanowires, matrix synthesis, microscopy, elemental analysis, magnetic properties, coercive force.

Measurements of the ohmic voltage drop by the current interruption method in the course of the electrodeposition of nickel in the pores of track membranes

Measurements of the ohmic voltage drop by the current interruption method in the course of the electrodeposition of nickel in the pores of track membranes

Effect of a Deposited Silver Film on the Deformation Strength Properties of Track Membranes

Effect of a Deposited Silver Film on the Deformation Strength Properties of Track Membranes

Raman spectroscopy and optical microscopy of medical infusion solutions for parenteral nutrition

Usage of Raman spectroscopy, optical microscopy, and retaining track membranes to find 20% SMOFlipid microparticles with a diameter of 5 to 10 μm and to prevent complications that arise during parenteral nutrition.

Point Agglomeration of Nickel and Iron Nanowires Synthesized in the Pores of Track Membranes

Point Agglomeration of Nickel and Iron Nanowires Synthesized in the Pores of Track Membranes

Thermo-activation spectroscopy of track-etched membranes based on polyethylene terephthalate films irradiated by swift Xe ions

In this work, thermally stimulated spectroscopy methods are applied to PET films to analyse the electret state. The thermally stimulated discharge currents, or thermally stimulated depolarization of track-etched like membrane samples obtained at different technological stages of their manufacture, have been investigated. The analysis of thermally stimulated depolarization currents indicates a significant change in the spectra of energy states of the electric charge accumulated during PET films' polarization after irradiation with accelerated swift Xe ions, ultraviolet treatment, and alkaline etching of the latent tracks. The Eyring method was used to calculate the parameters of the relaxation processes occurring in irradiated PET, such as the activation energy and the effective frequency factor. The significant change in the spectra of energy states of the electric charge accumulated during polarization in PET films due to ion-track processes indicates the possibility of creating an electret state in irradiated PET films and track membranes.

Biological method based on track membranes to form controlled gaseous media for fruit cold storage

The article proposes a biological method based on the use of gas-selective track membranes to form a modified gas atmosphere, considering the respiration rate of fruit. The work aims to study the change in the respiration rate of apples depending on the variety and storage time to substantiate the formation of the gas medium composition depending on the respiration rate of the fruit and the area of track membranes, and to study the kinetics of oxidation reactions of biologically active substances during cold storage of apples. The research is based on autumn apple varieties: Grushovka Yudicheva, Kordonovka and Pepin Shafranny. We have obtained the kinetic curves of changes in the content of mono- and disaccharides, ascorbic and organic acids in autumn apple varieties depending on the gas composition in terms of oxygen and carbon dioxide content, as well as the duration of fruit storage using track membranes. For maximum quality preservation, nutritional and biological value of the studied apple varieties at t = (3 ± 1) °C, we have determined a recommended composition of the controlled gas atmosphere: oxygen concentration - (5.2 ± 0.1%), carbon dioxide - (3.6 ± 0.1%). Controlled atmosphere is created using a gas-selective composite membrane with an area of 14-22 cm2/kg, depending on the variety and respiration rate.

Gamma radiation attenuation characteristics of composites based on polyimide track membranes filled with nanodispersed Pb

The paper presents data on the effect of γ-radiation on polymer composites based on polyimide track membranes filled with nanodispersed lead. The radiation-protective properties of the composites were studied by theoretical and experimental methods. To carry out experimental studies on the effect of γ-radiation on the composite, radioactive sources cesium-137 and cobalt- 60 were used. The calculated data of the linear attenuation coefficient of γ-radiation in the composite, depending on the initial energy of γ-quanta in the range from 0.5 to 5 MeV, are presented. The contribution of the photoelectric effect, the Compton effect, and the formation of electron-positron pairs to the total linear attenuation coefficient of the gamma radiation of the composite is estimated. When γ-radiation passes through 2.5 mm of the composite, the intensity of γ-radiation absorption decreases by 17.7 and 4.4% at radiation energies of 0.5 and 5 MeV, respectively. It was experimentally established that the introduction of nanodispersed filler Pb into a polyimide track membrane made it possible to increase the linear attenuation coefficient of γ-radiation by more than 6 times at an energy of 0.662 MeV, and by a factor of 3.7 at an energy of 1.252 MeV as compared to pure polymeric material.