Off-Grid Electrical Cell Lysis Microfluidic Device Utilizing Thermoelectricity and Thermal Radiation

Microfluidic devices have enormous potential and a wide range of applications. However, most applications end up as chip-in-a-lab systems because of power source constraints. This work focuses on reducing the reliance on the power network and expanding on the concept of a lab-on-a-chip for microfluidic devices. A cellulose-based radiator to reflect infrared (IR) radiation with wavelengths within the atmospheric window (8–13 µm) into outer space was fabricated. This process lowered the temperature inside the insulated environment. The difference in temperature was used to power a thermoelectric generator (TEG) and generate an electric current. This electric current was run through a DC-DC transformer to increase the voltage before being used to perform electrical cell lysis with a microfluidic device. This experimental setup successfully achieved 90% and 50% cell lysis efficiencies in ideal conditions and in field tests, respectively. This work demonstrated the possibility of utilizing the unique characteristics of a microfluidic device to perform an energy-intensive assay with minimal energy generated from a TEG and no initial power input for the system. The TEG system also required less maintenance than solar, wind, or hydroelectricity. The IR radiation process naturally allows for more dynamic working conditions for the entire system.

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Control of Winged Waterprimrose (Jussiaea decurrens) and Northern Jointvetch (Aeschynomene virginica) with Fungal Pathogens

Weed Science ◽

10.1017/s0043174500044477 ◽

1979 ◽

Vol 27 (5) ◽

pp. 497-501 ◽

Cited By ~ 46

Author(s):

C. D. Boyette ◽

G. E. Templeton ◽

R. J. Smith

Keyword(s):

Oryza Sativa ◽

Glycine Max ◽

Fungal Pathogens ◽

Liquid Culture ◽

Field Experiments ◽

Colletotrichum Gloeosporioides ◽

Pathogenic Fungus ◽

Field Tests ◽

Wide Range ◽

Growing Region

An indigenous, host-specific, pathogenic fungus that parasitizes winged waterprimrose [Jussiaea decurrens(Walt.) DC.] is endemic in the rice growing region of Arkansas. The fungus was isolated and identified asColletotrichum gloeosporioides(Penz.) Sacc. f.sp. jussiaeae(CGJ). It is highly specific for parasitism of winged waterprimrose and not parasitic on creeping waterprimrose (J. repensL. var.glabrescensKtze.), rice (Oryza sativaL.), soybeans [Glycine max(L.) Merr.], cotton (Gossypium hirsutumL.), or 4 other crops and 13 other weeds. The fungus was physiologically distinct from C.gloeosporioides(Penz.) Sacc. f. sp.aeschynomene(CGA), an endemic anthracnose pathogen of northern jointvetch[Aeschynomene virginica(L.) B.S.P.], as indicated by cross inoculations of both weeds. Culture in the laboratory and inoculation of winged waterprimrose in greenhouse, growth chamber and field experiments indicated that the pathogen was stable, specific, and virulent in a wide range of environments. The pathogen yielded large quantities of spores in liquid culture. It is suitable for control of winged waterprimrose. Winged waterprimrose and northern jointvetch were controlled in greenhouse and field tests by application of spore mixtures of CGJ and CGA at concentrations of 1 to 2 million spores/ml of each fungus in 94 L/ha of water; the fungi did not damage rice or nontarget crops.

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Conventional and Conservation Seedbed Preparation Systems for Wheat Planting in Silty-Clay Soil

Sustainability ◽

10.3390/su13116506 ◽

2021 ◽

Vol 13 (11) ◽

pp. 6506

Author(s):

Roberto Fanigliulo ◽

Daniele Pochi ◽

Pieranna Servadio

Keyword(s):

Clay Soil ◽

Conservation Tillage ◽

Field Tests ◽

Superficial Layer ◽

Soil Tillage ◽

Energy Requirements ◽

Silty Clay ◽

Wide Range ◽

Seedbed Preparation ◽

Silty Clay Soil

Conventional seedbed preparation is based on deep ploughing followed by lighter and finer secondary tillage of the superficial layer, normally performed by machines powered by the tractor’s Power Take-Off (PTO), which prepares the seedbed in a single pass. Conservation methods are based on a wide range of interventions, such as minimum or no-tillage, by means of machines with passive action working tools which require two or more passes The aim of this study was to assess both the power-energy requirements of conventional (power harrows and rotary tillers with different working width) and conservation implements (disks harrow and combined cultivator) and the soil tillage quality parameters, with reference to the capability of preparing an optimal seedbed for wheat planting. Field tests were carried out on flat, silty-clay soil, using instrumented tractors. The test results showed significant differences among the operative performances of the two typologies of machines powered by the tractor’s PTO: the fuel consumption, the power and the energy requirements of the rotary tillers are strongly higher than power harrows. However, the results also showed a decrease of these parameters proceeding from conventional to more conservation tillage implements. The better quality of seedbed was provided by the rotary tillers.

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Negative Pressure Provides Simple and Stable Droplet Generation in a Flow-Focusing Microfluidic Device

Micromachines ◽

10.3390/mi12060662 ◽

2021 ◽

Vol 12 (6) ◽

pp. 662

Author(s):

Nikita A. Filatov ◽

Anatoly A. Evstrapov ◽

Anton S. Bukatin

Keyword(s):

Microfluidic Device ◽

Negative Pressure ◽

Low Cost ◽

Control Valve ◽

Droplet Microfluidics ◽

Droplet Generation ◽

Electric Signal ◽

Absolute Pressure ◽

Flow Focusing ◽

Wide Range

Droplet microfluidics is an extremely useful and powerful tool for industrial, environmental, and biotechnological applications, due to advantages such as the small volume of reagents required, ultrahigh-throughput, precise control, and independent manipulations of each droplet. For the generation of monodisperse water-in-oil droplets, usually T-junction and flow-focusing microfluidic devices connected to syringe pumps or pressure controllers are used. Here, we investigated droplet-generation regimes in a flow-focusing microfluidic device induced by the negative pressure in the outlet reservoir, generated by a low-cost mini diaphragm vacuum pump. During the study, we compared two ways of adjusting the negative pressure using a compact electro-pneumatic regulator and a manual airflow control valve. The results showed that both types of regulators are suitable for the stable generation of monodisperse droplets for at least 4 h, with variations in diameter less than 1 µm. Droplet diameters at high levels of negative pressure were mainly determined by the hydrodynamic resistances of the inlet microchannels, although the absolute pressure value defined the generation frequency; however, the electro-pneumatic regulator is preferable and convenient for the accurate control of the pressure by an external electric signal, providing more stable pressure, and a wide range of droplet diameters and generation frequencies. The method of droplet generation suggested here is a simple, stable, reliable, and portable way of high-throughput production of relatively large volumes of monodisperse emulsions for biomedical applications.

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Application areas of the angle reflector

10.33920/pro-2-2104-05 ◽

2021 ◽

pp. 54-59

Author(s):

L. R. Yurenkova ◽

O. A. Yakovuk ◽

I. V. Morozov

Keyword(s):

Radio Wave ◽

Outer Space ◽

Road Transport ◽

Optical Systems ◽

Design Parameters ◽

Design Activity ◽

Primary Role ◽

Beam Laser ◽

Wide Range ◽

Graphical Calculation

The article provides examples of how the device known as the «angle reflector» a few decades ago has been increasingly used in various fields of science and technology in recent years. Angle reflectors are designed to change (reflect) optical and radar rays in the direction, opposite to the original direction. At present, angle reflectors are widely used to ensure the safety of road transport on dangerous road sections. Radio wave reflectors have the same design as optical ones; therefore, in radio detection and location, angle reflectors are used to send warning signals to ship radars on bridge supports, beacons and buoys. Modern angle reflectors attached to meteorological probes allow determining the direction and speed of the wind at high altitude, which is especially important in the study of the outer space. In recent years, devices have been developed to improve the accuracy of radar stations calibration. The examples of graphical calculation of angle reflectors presented in the article clearly demonstrate the primary role of geometry in the design activity of an engineer. The graphical calculation is based on the theoretical positions of projective geometry. The design and calculation of optical systems is carried out by the graphoanalytic method, since only with a combination of graphical and analytical methods it is possible to accurately calculate the course of a light beam, laser, or radio wave and thereby determine the design parameters of the devices. The article focuses on a graphical method for calculating two types of angle reflectors using orthogonal projection, due to which modern engineers will be able to create more up-to-date designs of optical systems with a wide range of applications.

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Micropipette-Based Microfluidic Device for Monodisperse Microbubbles Generation

Micromachines ◽

10.3390/mi9080387 ◽

2018 ◽

Vol 9 (8) ◽

pp. 387

Author(s):

Carlos Toshiyuki Matsumi ◽

Wilson José da Silva ◽

Fábio Kurt Schneider ◽

Joaquim Miguel Maia ◽

Rigoberto E. M. Morales ◽

...

Keyword(s):

Electric Fields ◽

Microfluidic Device ◽

Soft Lithography ◽

Low Cost ◽

Characteristic Curve ◽

Microfluidic Devices ◽

Average Diameter ◽

Internal Diameter ◽

Medical Diagnostic ◽

Average Size

Microbubbles have various applications including their use as carrier agents for localized delivery of genes and drugs and in medical diagnostic imagery. Various techniques are used for the production of monodisperse microbubbles including the Gyratory, the coaxial electro-hydrodynamic atomization (CEHDA), the sonication methods, and the use of microfluidic devices. Some of these techniques require safety procedures during the application of intense electric fields (e.g., CEHDA) or soft lithography equipment for the production of microfluidic devices. This study presents a hybrid manufacturing process using micropipettes and 3D printing for the construction of a T-Junction microfluidic device resulting in simple and low cost generation of monodisperse microbubbles. In this work, microbubbles with an average size of 16.6 to 57.7 μm and a polydispersity index (PDI) between 0.47% and 1.06% were generated. When the device is used at higher bubble production rate, the average diameter was 42.8 μm with increased PDI of 3.13%. In addition, a second-order polynomial characteristic curve useful to estimate micropipette internal diameter necessary to generate a desired microbubble size is presented and a linear relationship between the ratio of gaseous and liquid phases flows and the ratio of microbubble and micropipette diameters (i.e., Qg/Ql and Db/Dp) was found.

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Manufacturing of Microfluidic Devices with Interchangeable Commercial Fiber Optic Sensors

Sensors ◽

10.3390/s21227493 ◽

2021 ◽

Vol 21 (22) ◽

pp. 7493

Author(s):

Krystian L. Wlodarczyk ◽

William N. MacPherson ◽

Duncan P. Hand ◽

M. Mercedes Maroto-Valer

Keyword(s):

Porous Structure ◽

Steady Flow ◽

Microfluidic Device ◽

Fiber Optic ◽

Dynamic Pressure ◽

Pressure Sensors ◽

Microfluidic Devices ◽

Fiber Optic Sensors ◽

Valuable Insight ◽

Local Pressure

In situ measurements are highly desirable in many microfluidic applications because they enable real-time, local monitoring of physical and chemical parameters, providing valuable insight into microscopic events and processes that occur in microfluidic devices. Unfortunately, the manufacturing of microfluidic devices with integrated sensors can be time-consuming, expensive, and “know-how” demanding. In this article, we describe an easy-to-implement method developed to integrate various “off-the-shelf” fiber optic sensors within microfluidic devices. To demonstrate this, we used commercial pH and pressure sensors (“pH SensorPlugs” and “FOP-MIV”, respectively), which were “reversibly” attached to a glass microfluidic device using custom 3D-printed connectors. The microfluidic device, which serves here as a demonstrator, incorporates a uniform porous structure and was manufactured using a picosecond pulsed laser. The sensors were attached to the inlet and outlet channels of the microfluidic pattern to perform simple experiments, the aim of which was to evaluate the performance of both the connectors and the sensors in a practical microfluidic environment. The bespoke connectors ensured robust and watertight connection, allowing the sensors to be safely disconnected if necessary, without damaging the microfluidic device. The pH SensorPlugs were tested with a pH 7.01 buffer solution. They measured the correct pH values with an accuracy of ±0.05 pH once sufficient contact between the injected fluid and the measuring element (optode) was established. In turn, the FOP-MIV sensors were used to measure local pressure in the inlet and outlet channels during injection and the steady flow of deionized water at different rates. These sensors were calibrated up to 140 mbar and provided pressure measurements with an uncertainty that was less than ±1.5 mbar. Readouts at a rate of 4 Hz allowed us to observe dynamic pressure changes in the device during the displacement of air by water. In the case of steady flow of water, the pressure difference between the two measuring points increased linearly with increasing flow rate, complying with Darcy’s law for incompressible fluids. These data can be used to determine the permeability of the porous structure within the device.

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Reversible Protein Capture and Release by Redox-Responsive Hydrogel in Microfluidics

Polymers ◽

10.3390/polym14020267 ◽

2022 ◽

Vol 14 (2) ◽

pp. 267

Author(s):

Chen Jiao ◽

Franziska Obst ◽

Martin Geisler ◽

Yunjiao Che ◽

Andreas Richter ◽

...

Keyword(s):

Microfluidic Device ◽

Disulfide Bonds ◽

Stimuli Responsive ◽

Disulfide Exchange ◽

Protein Capture ◽

Wide Range ◽

Redox Responsive ◽

Potential Applications ◽

Capture And Release ◽

Cross Linker

Stimuli-responsive hydrogels have a wide range of potential applications in microfluidics, which has drawn great attention. Double cross-linked hydrogels are very well suited for this application as they offer both stability and the required responsive behavior. Here, we report the integration of poly(N-isopropylacrylamide) (PNiPAAm) hydrogel with a permanent cross-linker (N,N′-methylenebisacrylamide, BIS) and a redox responsive reversible cross-linker (N,N′-bis(acryloyl)cystamine, BAC) into a microfluidic device through photopolymerization. Cleavage and re-formation of disulfide bonds introduced by BAC changed the cross-linking densities of the hydrogel dots, making them swell or shrink. Rheological measurements allowed for selecting hydrogels that withstand long-term shear forces present in microfluidic devices under continuous flow. Once implemented, the thiol-disulfide exchange allowed the hydrogel dots to successfully capture and release the protein bovine serum albumin (BSA). BSA was labeled with rhodamine B and functionalized with 2-(2-pyridyldithio)-ethylamine (PDA) to introduce disulfide bonds. The reversible capture and release of the protein reached an efficiency of 83.6% in release rate and could be repeated over 3 cycles within the microfluidic device. These results demonstrate that our redox-responsive hydrogel dots enable the dynamic capture and release of various different functionalized (macro)molecules (e.g., proteins and drugs) and have a great potential to be integrated into a lab-on-a-chip device for detection and/or delivery.

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A Multifunctional Microfluidic Device Based on Bifurcation Geometry

ASME 2010 8th International Conference on Nanochannels, Microchannels, and Minichannels: Parts A and B ◽

10.1115/fedsm-icnmm2010-30950 ◽

2010 ◽

Author(s):

Ahmed Fadl ◽

Stefanie Demming ◽

Zongqin Zhang ◽

Bjo¨rn Hoxhold ◽

Stephanus Bu¨ttgenbach ◽

...

Keyword(s):

Microfluidic Device ◽

Microfluidic Devices ◽

Optical Lithography ◽

Working Fluid ◽

The Novel ◽

Flow Rates ◽

Single Function ◽

Fluidic Device ◽

Bifurcation Structures ◽

Novel Design

Developing multifunctional devices are essential to realize more efficient Microsystems. With miniaturization processes taking place in many different applications, the rooms for single function microfluidic devices are limited. In this study, we introduce a multifunctional micro fluidic device based on bifurcation geometry which is capable of performing pumping and mixing at the same time. Optical lithography is used to fabricate the designed microfluidic device. The microfluidic device is tested at low actuator frequencies, and ethanol is employed as a working fluid. The operational principles are based on rectifying the oscillatory flows by using bifurcation structures for flow rectification. The results prove the feasibility of the novel design, and results are presented in terms of flow rates and maximum back pressures.

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Programmable Paper-Based Microfluidic Devices for Biomarker Detections

Micromachines ◽

10.3390/mi10080516 ◽

2019 ◽

Vol 10 (8) ◽

pp. 516 ◽

Cited By ~ 13

Author(s):

Veasna Soum ◽

Sooyong Park ◽

Albertus Ivan Brilian ◽

Oh-Sun Kwon ◽

Kwanwoo Shin

Keyword(s):

Point Of Care ◽

High Sensitivity ◽

Microfluidic Devices ◽

Portable Devices ◽

Biomarker Detection ◽

Fluid Delivery ◽

Wide Range ◽

Paper Based Microfluidics ◽

Digital Microfluidic ◽

Detection Of Biomarkers

Recent advanced paper-based microfluidic devices provide an alternative technology for the detection of biomarkers by using affordable and portable devices for point-of-care testing (POCT). Programmable paper-based microfluidic devices enable a wide range of biomarker detection with high sensitivity and automation for single- and multi-step assays because they provide better control for manipulating fluid samples. In this review, we examine the advances in programmable microfluidics, i.e., paper-based continuous-flow microfluidic (p-CMF) devices and paper-based digital microfluidic (p-DMF) devices, for biomarker detection. First, we discuss the methods used to fabricate these two types of paper-based microfluidic devices and the strategies for programming fluid delivery and for droplet manipulation. Next, we discuss the use of these programmable paper-based devices for the single- and multi-step detection of biomarkers. Finally, we present the current limitations of paper-based microfluidics for biomarker detection and the outlook for their development.

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Creation of New Analogues of Natural Phytogormons for Increasing the Yield of Agricultural Crops

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i3.32.18393 ◽

2018 ◽

Vol 7 (3.32) ◽

pp. 59

Author(s):

Zhylkybaev Oral ◽

Alimzhanova Mereke ◽

Ashimuly Kazhybek ◽

Shoinbekova Sabina ◽

Tukenova Zulfia

Keyword(s):

Biological Activity ◽

Growth Regulator ◽

High Efficiency ◽

Field Tests ◽

Dry Mass ◽

Water Soluble ◽

High Yield ◽

Small Scale ◽

Wide Range ◽

Reference Preparation

Synthesis of new potential plant growth regulators (analogues of natural phytohormones) is accomplished by mixing an equimolar mixture of aryloxypropin and 1-methylpiperidin-4-one under the conditions of Favorsky's reactions. New derivatives of acetylene aminoalcohols - the ZhOT series - have been obtained. The structure of the synthesized compounds was established by IR and NMR 1H spectroscopy. Screening of their water-soluble forms, on wheat and barley seeds, two preparations (ZhOT-4 and ZhOT-7) were selected, which exceed both the control and standards of known phytohormones, such as heteroauxin (indolyl-3-acetic acid), 6-BAP (6-benzylaminopurine) for further testing. Conducted in-depth laboratory and demonstration field tests on cereals (wheat and barley) showed high efficiency of ZhOT-4 and ZhOT-7, the indicators of which exceeded the well-known reference preparation - Agrostimulin (Ukraine). The growth regulating activity of synthesized compounds was determined. Processing of wheat seeds ZhOT-4 and ZhOT-7 increased the field germination of seeds, plant height, leaf area, the mass of the aerial part and the total area. The conducted studies showed that the biological activity of the tested compounds largely depends on the concentration and the best growth regulator is ZhOT-4. The activity of the synthesized growth regulatory compounds has been determined. Treatment of seeds of with ZhOT-4 and ZhOT-7 increased seed germination, height of plants, leave areas, weight of an elevated part and the total area, weight of an elevated part and the total area. Studies have shown that the biological activity of tested compounds is largely dependent on the concentration and the best growth regulator is ZhОТ-4. Thus, the advanced laboratory and demonstration (small-scale) comparative tests of ZhOT-4 and ZhOT-7 and the well-known reference preparation "Agrostimulin" (Ukraine) for cereals (wheat and barley) showed high efficiency of new synthesized preparations. The use of ZhOT preparations increases the germination and germination energy, the number of spikelets, the mass of grains, the bushiness and the yield of wheat and barley, leads to the accumulation of dry mass in both the ground and underground parts of plants. The advantages of ZhOT-4 and ZhOT-7 are: high efficiency, a wide range of cultures, good solubility in water, low application dose of 0.0001% by active ingredient (1g per 1t of water) or 13-50 mg per hectare, comparable to natural phytohormones, long shelf life, safety, high yield of target products, sequential 3-stage reaction in one reactor.

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