Microsystems for express analysis

Zimina, Tatiana M.; Лучинин, В. В.

doi:10.1134/s1061934811100236

Cited by 12 publications

(10 citation statements)

References 19 publications

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“…In addition, macro-mesoporous structures of this kind are interesting as growth platforms, optically inhomogeneous media, biosensors, as implant materials, etc. [ 53 , 54 , 55 ].…”

Section: Resultsmentioning

confidence: 99%

Low-Frequency Dielectric Relaxation in Structures Based on Macroporous Silicon with Meso-Macroporous Skin-Layer

et al. 2021

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The spectra of dielectric relaxation of macroporous silicon with a mesoporous skin layer in the frequency range 1–106 Hz during cooling (up to 293–173 K) and heating (293–333 K) are presented. Macroporous silicon (pore diameter ≈ 2.2–2.7 μm) with a meso-macroporous skin layer was obtained by the method of electrochemical anodic dissolution of monocrystalline silicon in a Unno-Imai cell. A mesoporous skin layer with a thickness of about 100–200 nm in the form of cone-shaped nanostructures with pore diameters near 13–25 nm and sizes of skeletal part about 35–40 nm by ion-electron microscopy was observed. The temperature dependence of the relaxation of the most probable relaxation time is characterized by two linear sections with different slope values; the change in the slope character is observed at T ≈ 250 K. The features of the distribution of relaxation times in meso-macroporous silicon at temperatures of 223, 273, and 293 K are revealed. The Havriliak-Negami approach was used for approximation of the relaxation curves ε″ = f(ν). The existence of a symmetric distribution of relaxers for all temperatures was found (Cole-Cole model). A discussion of results is provided, taking into account the structure of the studied object.

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“…In addition, macro-mesoporous structures of this kind are interesting as growth platforms, optically inhomogeneous media, biosensors, as implant materials, etc. [ 53 , 54 , 55 ].…”

Section: Resultsmentioning

confidence: 99%

Low-Frequency Dielectric Relaxation in Structures Based on Macroporous Silicon with Meso-Macroporous Skin-Layer

et al. 2021

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“…The microacoustic methods of biomedical analysis, implemented on piezoelectric crystals and ceramics are becoming increasingly perspective due to potential of integration, as functional sensor elements, into the hybrid analytical devices and laboratories-on-a-chip [1][2][3]. One of possible applications of such sensor is alternative to identification of bacteria according to Gram method, which enables to discriminate them according to composition of their cell walls [4].…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the method is labor intensive. However, it seems useful as additional indicator in identification of microorganisms, for example in implementing a new generation hybrid device for microbiological analysis [2,3]. This is due to a strong discriminative feature of these two groups of bacteria, i.e., the rigidly of the cell wall, which is a subject of physical methods of measurement.…”

Section: Introductionmentioning

confidence: 99%

Acoustic Biosensor for Discrimination of Pathogens according to the Gram Principle

Lemozerskii

Zimina

Gagarina

2020

The 1st International Electronic Conference on Biosensors

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The microacoustic methods of biomedical analysis, implemented on piezoelectric crystals and ceramics, are becoming increasingly popular due to the fact of their potential for integration into laboratories-on-a-chip, biochips, and biosensors as functional elements of biosensors. An important stage in diagnostics of infectious diseases is the identification of pathogens. One possible applications of such a sensor is an alternative to the time- and labor-consuming Gram method of discriminating bacteria according to the composition of their cell walls. Thus, bacteria, which in a Gram staining procedure do not decolor after application of the dye solution, are classified as Gram-positive (G(+)). They are surrounded with a thick peptidoglycan layer that is pulpy and dampens acoustic waves. While Gram-negative (G(–)) bacteria, which acquire a red color in a Gram procedure, are covered with a thin and springy layer, demonstrating resonance effects when interacting with acoustic fields. Thus, G(+) and G(–), which are differently colored in Gram procedures, also react differently to an external acoustic field: for G(–) bacteria, this was a sharp decrease in the Q-factor of the “resonator–suspension” system and a shift of the resonance curve to lower frequencies. While for G(+) bacteria, although a certain shift of the resonance curve was also observed, the bandwidth of the resonance curve practically did not change. This effect was studied for L. acidophilus (G(+)) and Escherichia coli (G(–)) bacilli with quarts resonators of 4 MHz, 5 MHz, and 10 MHz. The biosensor was tested using Lactobacillus fermentum, E. coli M-17, Bifidobacterium bifidum, Burkholderia cepacian, and Staphylococcus aureus. At this stage, it has been demonstrated that the method is particularly effective for discriminating bacteria of a similar shape, such as, for example, cocci. The discrimination of the Gram factor for cocci and bacilli was less accurate and needs further studies for selection of precise resonance frequencies.

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“…An ultimate goal of this effort is development of portable autonomos device for rapid multi-parametric express diagnostics of microorganisms, based on a bioMEMS system [6], heterogeneously integrating life microorganism processing line, comprising: modules for sample preparation, microcolonies growth on a biologically friendly platform with topologically coded multipores forming growth sites for pathogens and providing nutrient delivery and microhydraulic shock displacement of grown juvenile colonies (JC) [7], identification means based on high density CMOS sensors and physical sensors, microfluidic transport and logic lines for classification and address delivery of pathogens, antibiotic susceptibility testing (AST) module for exposure to a set of antibiotics and quantitative viability determination and other means, necessary for modern portable diagnostic devices (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Image recognition of juvenile colonies of pathogenic microorganisms in the culture based microbiological method implemented in bioMEMS device for express species identification

Gvozdev

Zimina

Краева

et al. 2016

2016 IEEE NW Russia Young Researchers in Electrical and Electronic Engineering Conference (EIConRusNW)

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In this paper an image recognition method for microbiological analysis of species is described. This method is developed for use in bioMEMS hybrid laboratory-on-a-chip for total microbiological analysis and is aimed at recognition of colonies of microorganisms for express species identification and sorting. The described approach is based on the Histograms of Oriented Gradients (HOG) method, developed earlier. A principle of this technique is the computation of intensity gradients directions in local areas of image and determination of objects affinity using special classifier. The method is widely used for people identification, where it proved to be very efficient. In microbiology it appeared to be not as successful, because images of single microorganisms and their colonies are too similar. Here an advanced version of HOG is presented, which enabled a number of microbiological species to be identified. The method comprises the following stages: 1) Initial image acquisition; 2) Search and retrieval of the colony; 3) Simplification of the image, transition to local gradients of the grey; 4) Processing with threshold noise filter; 5) Fourier-transform of local gradients of the grey; 6) Formation of classifier by teaching the expert system by comparison with reference images. The described method is applied for recognizing colonies at earlier stages of growth (juvenile colonies) incorporating about 1000 cells. A sample of investigated microorganisms comprised 18 species from 8 different genera.

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Microsystems for express analysis

Cited by 12 publications

References 19 publications

Low-Frequency Dielectric Relaxation in Structures Based on Macroporous Silicon with Meso-Macroporous Skin-Layer

Low-Frequency Dielectric Relaxation in Structures Based on Macroporous Silicon with Meso-Macroporous Skin-Layer

Acoustic Biosensor for Discrimination of Pathogens according to the Gram Principle

Image recognition of juvenile colonies of pathogenic microorganisms in the culture based microbiological method implemented in bioMEMS device for express species identification

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