A Very Low-Cost, Labor-Efficient, and Simple Method to Block Scattered Ultraviolet Light in PDMS Microfluidic Devices by Inserting Aluminum Foil Strips

2018 ◽  
Vol 11 (1) ◽  
Author(s):  
Shuo Wang ◽  
Peter Shankles ◽  
Scott Retterer ◽  
Yong Tae Kang ◽  
Chang Kyoung Choi
Keyword(s):  
Soft Lithography ◽  
Uv Light ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Aluminum Foil ◽  
Material Synthesis ◽  
Simple Method ◽  
Micro Particles ◽  
Complex Shapes ◽  
The Cost

Abstract Opto-microfluidic methods have advantages for manufacturing complex shapes or structures of micro particles/hydrogels. Most of these microfluidic devices are made of polydimethylsiloxane (PDMS) by soft lithography because of its flexibility of designing and manufacturing. However, PDMS scatters ultraviolet (UV) light, which polymerizes the photocrosslinkable materials at undesirable locations and clogs the microfluidic devices. A fluorescent dye has previously been employed to absorb the scattered UV light and shift its wavelength to effectively solve this issue. However, this method is limited due to the cost of the materials (tens of dollars per microchip), the time consumed on synthesizing the fluorescent material and verifying its quality (two to three days). More importantly, significant expertise on material synthesis and characterization is required for users of the opto-microfluidic technique. The cost of preliminary testing on multiple iterations of different microfluidic chip designs would also be excessive. Alternatively, with a delicate microchannel design, we simply inserted aluminum foil strips (AFS) inside the PDMS device to block the scattered UV light. By using this method, the UV light was limited to the exposure region so that the opto-microfluidic device could consistently generate microgels longer than 6 h. This is a nearly cost- and labor-free method to solve this issue.

scholarly journals Micropipette-Based Microfluidic Device for Monodisperse Microbubbles Generation

Micromachines ◽  
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.

scholarly journals Applicability of using the 3D concrete printing technology in Sudan

2021 ◽  
Vol 9 (2) ◽  
pp. 64-70
Author(s):  
Ruaa Elnaeem ◽  
Mohammed Taglsir
Keyword(s):  
Low Cost ◽  
Three Dimensional ◽  
Sand Mixture ◽  
Housing Projects ◽  
Construction Methods ◽  
Concrete Mixtures ◽  
Complex Shapes ◽  
Low Cost Housing ◽  
Materials Used ◽  
The Cost

Three-dimensional (3D) Printing is an advanced manufacturing process that has been applied to many fields. Recently, the 3D Concrete Printing (3DCP) has been employed for construction due to its ability to produce complex shapes easily, with less human intervention and with minimum material wastage. However, there are challenging issues regarding the cost of construction and the components of concrete mixture which are not fully explored. The aim of this paper is to review the 3DCP technology and investigate the possibility of applying it in Sudan, specifically for low-cost housing. In order to meet this aim, a comprehensive review has been done to study the projects implemented worldwide using 3DCP technique. Then, some concrete mixtures have been reviewed analyze the amount of materials used in each mix. The necessary tests to ensure the, workability, Extrudability and buildability have also been specified. Then the 3DCP technique has been compared with three common construction methods in Sudan for low-cost housing those were 40 square meters area in plan. These methods are the cement blocks, the Ferrocement and the graded sand mixture.. The comparison has been made in terms of construction cost, construction duration and the man-force required. The results have shown that the 3DCP model needed the least number of construction days. However, it was the highest in terms of the cost and the second best in terms of the used labors. It has been concluded that applying 3DCP technology in Sudan is possible and could be effective in the low-cost housing projects.  

scholarly journals Low-cost photolithography system for cell biology labs

2021 ◽  
Vol 7 (2) ◽  
pp. 550-553
Author(s):  
Benjamin K. Naggay ◽  
Kerstin Frey ◽  
Markus Schneider ◽  
Kiriaki Athanasopulu ◽  
Günter Lorenz ◽  
...  
Keyword(s):  
Light Source ◽  
Cell Biology ◽  
Soft Lithography ◽  
Uv Light ◽  
Low Cost ◽  
Cost Effective ◽  
Working Environment ◽  
Light Emitting ◽  
Set Up ◽  
High Level

Abstract Soft lithography, a tool widely applied in biology and life sciences with numerous applications, uses the soft molding of photolithography-generated master structures by polymers. The central part of a photolithography set-up is a mask-aligner mostly based on a high-pressure mercury lamp as an ultraviolet (UV) light source. This type of light source requires a high level of maintenance and shows a decreasing intensity over its lifetime, influencing the lithography outcome. In this paper, we present a low-cost, bench-top photolithography tool based on ninety-eight 375 nm light-emitting diodes (LEDs). With approx. 10 W, our presented lithography set-up requires only a fraction of the energy of a conventional lamp, the LEDs have a guaranteed lifetime of 1000 h, which becomes noticeable by at least 2.5 to 15 times more exposure cycles compared to a standard light source and with costs less than 850 C it is very affordable. Such a set-up is not only attractive to small academic and industrial fabrication facilities who want to enable work with the technology of photolithography and cannot afford a conventional set-up, but also microfluidic teaching laboratories and microfluidic research and development laboratories, in general, could benefit from this cost-effective alternative. With our self-built photolithography system, we were able to produce structures from 6 μm to 50 μm in height and 10 μm to 200 μm in width. As an optional feature, we present a scaled-down laminar flow hood to enable a dust-free working environment for the photolithography process.

Simulation of conductivity made by inkjet-printed silver tracks in E-textiles with different weave patterns

2016 ◽  
Vol 47 (2) ◽  
pp. 173-196 ◽  
Author(s):  
Mozhdeh Ghahremani ◽  
Masoud Latifi ◽  
Mohammadreza Babaei
Keyword(s):  
Electrical Conductivity ◽  
Surface Roughness ◽  
Low Cost ◽  
Electric Circuit ◽  
Contact Method ◽  
Large Area ◽  
Simple Method ◽  
Micro Particles ◽  
Flexible Polymer ◽  
Circuit Fabrication

The development of electric circuit fabrication on flexible polymer substrates has attracted a significant interest as a pathway to low-cost, comfortable movement, and large-area electronics among direct printing techniques. In this study, the inkjet printing technique was used as a simple method to chemically deposit silver nano and micro-particles (85–500 nm) to the polyester fabrics. It is done by the ejection of silver nitrate and ascorbic acid as a reducing agent to attain nano metals on the different weave patterns with different surface roughness to measure the conductivity variations. A four-contact method was used to measure the electrical conductivity of the deposited samples which is usually employed in the electrical assessment of films. COMSOL Multiphysics® modeling software is used in order to simulate the conductivity of printed silver tracks and finally the results of simulation and experimental works have been compared. The main purpose of this study is to evaluate the effect of surface roughness on the electrical conductivity of printed silver tracks.

scholarly journals Mail-order microfluidics: evaluation of stereolithography for the production of microfluidic devices

Lab on a Chip ◽  
2014 ◽  
Vol 14 (7) ◽  
pp. 1294-1301 ◽  
Author(s):  
Anthony K. Au ◽  
Wonjae Lee ◽  
Albert Folch
Keyword(s):  
Soft Lithography ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Mail Order ◽  
The Cost

We explore the three-dimensional capabilities, resolution, and optical clarity of microfluidic devices fabricated by stereolithography using a mail-order service, and we compare the cost and prototyping speed of soft lithography with those of stereolithography.

scholarly journals A rapid-prototyped moulding system towards optimised scalable fabrication of elastomeric microfluidic devices

2021 ◽  
Author(s):  
Christine Poon ◽  
Albert Fahrenbach
Keyword(s):  
3D Printing ◽  
Microfluidic Device ◽  
Lean Manufacturing ◽  
Soft Lithography ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Petri Dish ◽  
Device Fabrication ◽  
Alternative Techniques ◽  
Optimisation Techniques

3D printing and makerspace technologies are increasingly explored as alternative techniques to soft lithography for making microfluidic devices, and for their potential to segue towards scalable commercial fabrication. Here we considered the optimal application of current benchtop 3D printing for microfluidic device fabrication through the lens of lean manufacturing and present a straightforward but robust rapid prototyped moulding system that enables easy estimation of more precise quantities of polydimethylsiloxane (PDMS) required per device to reduce waste and importantly, making devices with better defined depths and volumes for (i) modelling gas exchange and (ii) fabrication consistency as required for quality-controlled production. We demonstrate that this low-cost moulding step can enable a 40 – 300% reduction in the amount of PDMS required for making individual devices compared to the established method of curing approximately 30 grams of PDMS prepolymer overlaid on a 4” silicon wafer master in a standard plastic petri dish. Other process optimisation techniques were also investigated and are recommended as readily implementable changes to current laboratory and foundry-level microfluidic device fabrication protocols for making devices either out of PDMS or other elastomers. Simple calculators are provided as a step towards more streamlined, software controlled and automated design-to-fabrication workflows for both custom and scalable lean manufacturing of microfluidic devices.

scholarly journals Polycarbonate Masters for Soft Lithography

Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1392
Author(s):  
Filippo Amadeo ◽  
Prithviraj Mukherjee ◽  
Hua Gao ◽  
Jian Zhou ◽  
Ian Papautsky
Keyword(s):  
Soft Lithography ◽  
Low Cost ◽  
Microfluidic Devices ◽  
Silicon Substrates ◽  
Large Area ◽  
Aspect Ratios ◽  
Rectangular Channels ◽  
Wide Range ◽  
Long Term Preservation

Fabrication of microfluidic devices by soft lithography is by far the most popular approach due to its simplicity and low cost. The approach relies on casting of elastomers, such as polydimethylsiloxane (PDMS), on masters fabricated from photoresists on silicon substrates. These masters, however, can be expensive, complicated to fabricate, and fragile. Here we describe an optimized replica molding approach to preserve the original masters by heat molding of polycarbonate (PC) sheets on PDMS molds. The process is faster and simpler than previously reported methods and does not result in a loss of resolution or aspect ratio for the features. The generated PC masters were used to successfully replicate a wide range of microfluidic devices, including rectangular channels with aspect ratios from 0.025 to 7.3, large area spiral channels, and micropost arrays with 5 µm spacing. Moreover, fabrication of rounded features, such as semi-spherical microwells, was possible and easy. Quantitative analysis of the replicated features showed variability of <2%. The approach is low cost, does not require cleanroom setting or hazardous chemicals, and is rapid and simple. The fabricated masters are rigid and survive numerous replication cycles. Moreover, damaged or missing masters can be easily replaced by reproduction from previously cast PDMS replicas. All of these advantages make the PC masters highly desirable for long-term preservation of soft lithography masters for microfluidic devices.

scholarly journals Rapid Prototyping of Soft Lithography Masters for Microfluidic Devices Using Dry Film Photoresist in a Non-Cleanroom Setting

Micromachines ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 192 ◽  
Author(s):  
Prithviraj Mukherjee ◽  
Federico Nebuloni ◽  
Hua Gao ◽  
Jian Zhou ◽  
Ian Papautsky
Keyword(s):  
Soft Lithography ◽  
State Of The Art ◽  
Low Cost ◽  
Pharmaceutical Research ◽  
Microfluidic Devices ◽  
Ambient Light ◽  
Glass Slides ◽  
Edge Bead ◽  
Time Savings ◽  
Dry Film

Fabrication of microfluidic devices by soft lithography is by far the most popular approach due to simplicity and low cost. In this approach PDMS (polydimethylsiloxane) is cast on a photoresist master to generate replicas that are then sealed against glass slides using oxygen plasma. In this work, we demonstrated fabrication of soft photolithography masters using lamination of ADEX dry film as an alternative to the now classic SU-8 resist masters formed by spin coating. Advantages of using ADEX dry film include the easily-achievable uniform thickness without edge bead; simplicity of the process with significant time savings due to non-sticky nature of the film; and fewer health concerns due to less toxic developing solution and antimony-free composition. As we demonstrate, the process can be performed in a low-cost improvised fabrication room in ambient light, in place of a conventional yellow-light cleanroom environment. We believe this approach holds the promise of delivering state-of-the-art microfluidic techniques to the broad field of biomedical and pharmaceutical research.

scholarly journals Study of Microchannels Fabricated Using Desktop Fused Deposition Modeling Systems

Micromachines ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 14
Author(s):  
Muhammad Asif Ali Rehmani ◽  
Swapna A. Jaywant ◽  
Khalid Mahmood Arif
Keyword(s):  
Soft Lithography ◽  
Fused Deposition Modeling ◽  
Complex Geometry ◽  
Low Cost ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Fused Deposition Modelling ◽  
Fused Deposition ◽  
Micro Features ◽  
Helical Microchannel

Microfluidic devices are used to transfer small quantities of liquid through micro-scale channels. Conventionally, these devices are fabricated using techniques such as soft-lithography, paper microfluidics, micromachining, injection moulding, etc. The advancement in modern additive manufacturing methods is making three dimensional printing (3DP) a promising platform for the fabrication of microfluidic devices. Particularly, the availability of low-cost desktop 3D printers can produce inexpensive microfluidic devices in fast turnaround times. In this paper, we explore fused deposition modelling (FDM) to print non-transparent and closed internal micro features of in-plane microchannels (i.e., linear, curved and spiral channel profiles) and varying cross-section microchannels in the build direction (i.e., helical microchannel). The study provides a comparison of the minimum possible diameter size, the maximum possible fluid flow-rate without leakage, and absorption through the straight, curved, spiral and helical microchannels along with the printing accuracy of the FDM process for two low-cost desktop printers. Moreover, we highlight the geometry dependent printing issues of microchannels, pressure developed in the microchannels for complex geometry and establish that the profiles in which flowrate generates 4000 Pa are susceptible to leakages when no pre or post processing in the FDM printed parts is employed.

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