scholarly journals Rapid Fabrication of Superhydrophobic Virtual Walls for Microfluidic Gas Extraction and Sensing

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 514
Author(s):  
Wojciech Raj ◽  
Daisy Yang ◽  
Craig Priest
Keyword(s):  
Low Cost ◽  
Onset Time ◽  
Ammonium Hydroxide ◽  
Human Saliva ◽  
Adhesive Tape ◽  
Ph Indicator ◽  
Ph Change ◽  
Glass Slides ◽  
Rapid Fabrication ◽  
Volatile Analyte

Based on the virtual walls concept, where fluids are guided by wettability, we demonstrate the application of a gas phase extraction microfluidic chip. Unlike in previous work, the chip is prepared using a simple, rapid, and low-cost fabrication method. Channels were cut into double-sided adhesive tape (280 µm thick) and bonded to hydrophilic glass slides. The tape was selectively made superhydrophobic by ‘dusting’ with hydrophobic silica gel to enhance the wettability contrast at the virtual walls. Finally, the two glass slides were bonded using tape, which acts as a spacer for gas transport from/to the guided liquids. In our example, the virtual walls create a stable liquid–vapor–liquid flow configuration for the extraction of a volatile analyte (ammonia), from one liquid stream to the other through the intermediate vapor phase. The collector stream contained a pH indicator to visualize the mass transport. Quantitative analysis of ammonium hydroxide in the sample stream (<1 mM) was possible using a characteristic onset time, where the first pH change in the collector stream was detected. The effect of gap length, flow rates, and pH of the collector stream on the onset time is demonstrated. Finally, we demonstrate the analysis of ammonium hydroxide in artificial human saliva to show that the virtual walls chip is suitable for extracting volatile analytes from biofluids.

scholarly journals New Single-Layered Paper-Based Microfluidic Devices for the Analysis of Nitrite and Glucose Built via Deposition of Adhesive Tape

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4082 ◽  
Author(s):  
Peng Yu ◽  
Muhan Deng ◽  
Yi Yang
Keyword(s):  
Filter Paper ◽  
Low Cost ◽  
Detection Limits ◽  
Microfluidic Devices ◽  
Adhesive Tape ◽  
Rapid Fabrication ◽  
Artificial Urine ◽  
First Time ◽  
Successful Transfer ◽  
Multiplexed Analysis

A simple, low-cost technique has been developed for the rapid fabrication of single-layered paper-based microfluidic devices (μPADs). This technique, for the first time, made use of the deposition of patterned adhesive tape into the filter paper to construct hydrophobic barriers, with the help of toluene. Unlike other reported multi-layered μPADs that merely made use of adhesive tape as a separate layer for sealing or fluid flow controlling, the patterned adhesive tape was simultaneously dissolved and penetrated into the filter paper, which resulted in the successful transfer of the pattern from the tape to the filter paper. To demonstrate the effectiveness of this approach, nitrite and glucose were individually measured; detection limits as low as 0.015 ± 0.004 mM and 0.022 ± 0.006 mM were reported for nitrite and glucose, respectively. Multiplexed analysis of both analytes was also carried out with respective detection limits of 0.048 ± 0.005 mM and 0.025 ± 0.006 mM for nitrite and glucose. The application of the method was demonstrated by measuring nitrite and glucose in spiked artificial urine samples and satisfied recovery results were obtained.

scholarly journals Electrochemical treatment of ex vivo human abdominal skin and potential use in scar management: A pilot study

2021 ◽  
Vol 7 ◽  
pp. 205951312098853
Author(s):  
Dana M Hutchison ◽  
Amir A Hakimi ◽  
Avin Wijayaweera ◽  
Soohong Seo ◽  
Ellen M Hong ◽  
...  
Keyword(s):  
Color Change ◽  
Ex Vivo ◽  
Low Cost ◽  
Histological Evaluation ◽  
Ph Change ◽  
Level Of Evidence ◽  
Abdominal Skin ◽  
Electrochemical Therapy ◽  
Mean Width ◽  
Scar Management

Introduction: Scar treatments aim to address pathologic collagen deposition; however, they can be expensive or difficult to control. Electrochemical therapy (ECT) offers a simple alternative treatment. The purpose of this study is to examine the acid-base and histological changes in ex vivo human abdominal skin following ECT. Methods: Forty-two ex vivo human panniculus tissue sections collected from six individuals were tumesced with normal saline. ECT was performed by inserting two platinum needle electrodes connected to a DC power supply into each specimen. Voltage was varied (3–6 V) and applied for 5 minutes. Each specimen was sectioned across both electrode insertion sites and immediately stained with pH sensitive dye. The width of dye color change for each dosimetry pair was calculated. Hematoxylin and eosin staining was used to evaluate samples. Results and Discussion: ECT caused a spatially localised and dose-dependent increased area of acidic and basic pH around the anode and cathode, respectively. A significantly greater mean width of pH change was generated at the cathode compared to the anode in all treatment groups. Histological evaluation displayed broad condensation and hyalinisation of dermal collagen. Conclusion: ECT triggered dermal pH alterations and changed the underlying structural framework of the specimen. This technology may serve as a low-cost, minimally invasive local soft-tissue remodeling technique with potential application in scar management. Level of Evidence: 5 Lay Summary Electrochemical therapy is a novel treatment that causes spatially selective dermal injury in areas of interest. This study measures the effects of electrochemical therapy when applied to abdominal skin. Electrochemical therapy appears to have beneficial effects by causing a highly localised reduction in collagen content or local softening of tissue, which is consistent with other studies on scar therapies, including chemexfoliation, radiofrequency technologies, and lasers. However, electrochemical therapy can be performed at a fraction of the costs of these aforementioned modalities.

scholarly journals Low-Cost, Large-Area, Facile, and Rapid Fabrication of Aligned ZnO Nanowire Device Arrays

2016 ◽  
Vol 8 (21) ◽  
pp. 13466-13471 ◽  
Author(s):  
Gerard Cadafalch Gazquez ◽  
Sidong Lei ◽  
Antony George ◽  
Hemtej Gullapalli ◽  
Bernard A. Boukamp ◽  
...  
Keyword(s):  
Low Cost ◽  
Zno Nanowire ◽  
Large Area ◽  
Rapid Fabrication ◽  
Nanowire Device

On-Chip Fabrication of None-Dead-Volume Microtips for ESI-MS Applications

2007 ◽  
Vol 121-123 ◽  
pp. 611-614
Author(s):  
Che Hsin Lin ◽  
Jen Taie Shiea ◽  
Yen Lieng Lin
Keyword(s):  
Surface Tension ◽  
Low Cost ◽  
Microfluidic Channel ◽  
Dead Volume ◽  
Esi Ms ◽  
Rapid Fabrication ◽  
Chip Fabrication ◽  
Novel Method ◽  
On Chip ◽  
Highly Uniform

This paper proposes a novel method to on-chip fabricate a none-dead-volume microtip for ESI-MS applications. The microfluidic chip and ESI tip are fabricated in low-cost plastic based materials using a simple and rapid fabrication process. A constant-speed-pulling method is developed to fabricate the ESI tip by pulling mixed PMMA glue using a 30-μm stainless wire through the pre-formed microfluidic channel. The equilibrium of surface tension of PMMA glue will result in a sharp tip after curing. A highly uniform micro-tip can be formed directly at the outlet of the microfluidic channel with minimum dead-volume zone. Detection of caffeine, myoglobin, lysozyme and cytochrome C biosamples confirms the microchip device can be used for high resolution ESI-MS applications.

scholarly journals A Theoretical and Experimental Study of Electrochemical pH Control at Gold Interdigitated Microband Arrays

2021 ◽  
Author(s):  
Bernardo Patella ◽  
Robert Daly ◽  
Ian Seymour ◽  
Pierre Lovera ◽  
James Rohan ◽  
...  
Keyword(s):  
Electrode Array ◽  
Ph Control ◽  
Reduction Peak ◽  
Solution Ph ◽  
Ph Indicator ◽  
Ph Change ◽  
Initial Ph ◽  
The Impact ◽  
Strong Acids

In electroanalysis, solution pH is a critical parameter that often needs to be adjusted and controlled for the detection of particular analytes. This is most commonly performed by the addition of chemicals, such as strong acids or bases. Electrochemical in-situ pH control offers the possibility for the local adjustment of pH at the point of detection, without additional reagents. FEA simulations have been performed to guide experimental design for both electroanalysis and in-situ control of solution pH. No previous model exists that describes the generation of protons at an interdigitated electrode array in buffered solution with one comb acting as a protonator, and the other as the sensor. In this work, FEA models are developed to provide insight into the optimum conditions necessary for electrochemical pH control. The magnitude of applied galvanostatic current has a direct relation to the flux of protons generated and subsequent change in pH. Increasing the separation between the electrodes increases the time taken for protons to diffuse across the gap. The final pH achieved at both, protonators and sensor electrodes, after 1 second, was shown to be largely uninfluenced by the initial pH of the solution. The impact of buffer concentration was modelled and investigated. In practice, the pH at the electrode surface was probed by means of cyclic voltammetry, i.e., by cycling a gold electrode in solution and identifying the potential of the gold oxide reduction peak. A pH indicator, methyl red, was used to visualise the solution pH change at the electrodes, comparing well with the model’s prediction

scholarly journals An Innovative Three-in-One Face Protective Gear (FPG): A Feasibility Study in a Neonatal Unit in Times of Pandemic!

2021 ◽  
Vol 35 (3) ◽  
pp. 113-115
Author(s):  
Astha Panghal ◽  
Ashok Kumar Gupta ◽  
Girish Gupta ◽  
Kirti M. Naranje ◽  
Anita Singh
Keyword(s):  
Low Cost ◽  
Tertiary Care ◽  
Neonatal Unit ◽  
Protective Equipment ◽  
Adhesive Tape ◽  
Protective Gear ◽  
Northern India ◽  
Global Pandemic ◽  
Feasible Alternative ◽  
Test Feasibility

Background: Healthcare workers (HCWs) are at greatest risk of acquiring infection in times of global pandemic of COVID-19 disease. There is an unprecedented demand of several forms of personal protective equipment (PPE) for HCWs leading to possible acute shortage of these equipment. This has paved way for development of local innovative PPEs. Objective: To test feasibility of a low cost, indigenous three-in-one face protective gear (FPG) in HCWs of a neonatal unit of a tertiary care institute in northern India. Methodology: A three-in-one FPG was developed using the commonly available items in a ward or intensive care and few trash items. Items used were sterile surgical sheet, cling wrap piece/transparency sheet, cover of umbilical catheter/any sterile hollow plastic pipe, or straw and adhesive tape. The FPG was tested in 17 HCWs regarding its ease to use, comfort, and feasibility with the help of questionnaire. Results: A total of 17 HCWs participated in this study. Majority (10, 58.8%) were doctors. Eight (47%) participants have never used any form of PPE previously. Thirteen (76.4%) participants found the FPG comfortable to wear; 12 (70.5%) found it comfortable to wear up to 8 h. Three HCWs found it difficult to work when wear the FPG; 1 out of 3 found it suffocating. Conclusion: Three-in-one FPG is an indigenous, low cost, and may be a feasible alternative in low-risk situations when there is scarcity of conventional protective equipment.

scholarly journals Tunable laser induced periodic surface structures in Ge2Sb2Te5 thin films

2021 ◽  
Vol 2086 (1) ◽  
pp. 012170
Author(s):  
Irina G Bessonova ◽  
Pavel I Trofimov ◽  
Petr I Lazarenko ◽  
Demid A Kirilenko ◽  
Nikolay A Bert ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Change ◽  
Low Cost ◽  
Beam Steering ◽  
Tunable Laser ◽  
Surface Structures ◽  
Periodic Surface ◽  
Light Localization ◽  
Rapid Fabrication ◽  
Direct Laser

Abstract Planar photonic structures, such as gratings and metasurfaces, are routinely used for beam steering, waveguide coupling, and light localization. However, conventional fabrication techniques that involve lithography are demanding in terms of time and cost. Much cheaper and simpler methods for surface patterning and formation of periodic surface structures are enabled by direct laser processing. Here, we demonstrate low-cost rapid fabrication of high-quality phase gratings based on the formation of laser induced periodic surface structures (LIPSS, or ripples) in Ge2Sb2Te5 (GST) thin films. Due to unique phase change properties of GST, the structures demonstrate strong modulation of refractive index with period controlled by the wavelength of laser irradiation. We study the formation of phase change LIPSS in a broad range of excitation wavelengths and observe transition between regimes with different orientations of generated ripples with respect to laser polarization.

Rapid fabrication of versatile omni-directional and long-distance three-dimensional flow paper-fluidic analytical devices using a cut-and-insert method for biomedical applications

2018 ◽  
Vol 10 (38) ◽  
pp. 4648-4654 ◽  
Author(s):  
Tae Joon Kwak ◽  
Wookkun Kwon ◽  
Jiang Yang ◽  
Sang Woo Lee ◽  
Woo-Jin Chang
Keyword(s):  
Liquid Flow ◽  
Biomedical Applications ◽  
Low Cost ◽  
Three Dimensional ◽  
Long Distance ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Rapid Fabrication ◽  
Paper Fluidics ◽  
Cost Regime

Paper fluidics has recently offered an approach to precisely guide liquid flow in analytical devices with a low-cost regime.

An Efficient Method for Rapid Fabrication Using Low Cost 3D Printer

2021 ◽  
pp. 537-544
Author(s):  
Mohammed Balfaqih ◽  
Soltan A. Alharbi ◽  
Fahad Alfarsi ◽  
Osama Alharbi ◽  
Faisal Alsalmi
Keyword(s):  
Efficient Method ◽  
Low Cost ◽  
3D Printer ◽  
Rapid Fabrication

scholarly journals The-Proof-of-Concept of Biochar Floating Cover Influence on Water pH

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1802 ◽  
Author(s):  
Zhanibek Meiirkhanuly ◽  
Jacek A. Koziel ◽  
Andrzej Białowiec ◽  
Chumki Banik ◽  
Robert C. Brown
Keyword(s):  
Buffer Capacity ◽  
Corn Starch ◽  
Tap Water ◽  
Spatial And Temporal Variation ◽  
Gaseous Emissions ◽  
Inorganic Contaminants ◽  
Ph Indicator ◽  
Ph Change ◽  
Air Interface ◽  
Water Ph

Studies have shown that biochar has the potential to remove organic and inorganic contaminants from wastewater. pH is known to have a crucial role in the transformation of pollutants. In this research, we explore the feasibility of using biochars properties to control the pH near the water–air interface, so the gaseous emissions from water (or wastewater) could be mitigated. This study aimed to test the effects of a thin layer biochar addition on the spatial and temporal variation of water pH. Two types of biochar and water were tested. Highly alkaline porous (HAP; pH 9.2) biochars made of corn stover and red oak (RO; pH 7.5) were applied surficially to tap (pH 9.5) and deionized water (DI) (pH 5.4). The spatial pH of solutions was measured every 1 mm of depth on days 0, 2, and 4 after biochar application. The results showed that HAP biochar increased the pH of both tap and DI water, while RO decreased tap water pH and increased DI water pH. On day 0, there was no effect on tap water pH, while a pH change in DI water was observed due to its lower buffer capacity. In addition, the pH (temporal) migration from topically applied biochar into an aqueous solution was visualized using a colorimetric pH indicator and corn starch to increase viscosity (to prevent biochars from sinking). The results prove that the surficial application of biochar to water was able to change both the pH near the water–air interface and the pH of the solution with time. The pH change was dependent on the biochar pH and water buffer capacity. These results warrant further research into the floatability of biochars and into designing biochars with specific pH, which could be a factor influencing gaseous emissions from liquids that are sensitive to pH.

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