Experimental studies of surface-driven capillary flow in pmma microfluidic devices prepared by direct bonding technique and passive separation of microparticles in microfluidic laboratory-on-a-chip systems
15 Jun 2015-Surface Review and Letters (World Scientific Publishing Company)-Vol. 22, Iss: 3, pp 1550050
TL;DR: In this paper, a SU-8-based silicon stamp is fabricated by maskless lithography to achieve leakage-free surface-driven capillary flow in polymethylmethacrylate (PMMA) microfluidic devices.
Abstract: Proper bonding technique is investigated to achieve leakage-free surface-driven capillary flow in polymethylmethacrylate (PMMA) microfluidic devices. SU-8-based silicon stamp is fabricated by maskless lithography. This stamp is used to produce PMMA microchannel structure by hot embossing lithography. A direct bonding technique is mainly employed for leakage-free sealing inside PMMA microfluidic devices. The effect of surface wettability on surface-driven capillary flow is also investigated in PMMA microfluidic devices. The separation of polystyrene microparticles in PMMA laboratory-on-a-chip systems is investigated with the reduction of separation time by air dielectric barrier discharge (DBD) plasma processing of channel surfaces. This study is useful to fabricate the microfluidic laboratory-on-a-chip systems and to understand the surface-driven capillary flow.
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TL;DR: Developments and applications of microfluidics in crystallization research including: crystal nucleation and growth, polymorph and cocrystal screening, preparation of nanocrystals, solubility and metastable zone determination, are summarized and discussed.
Abstract: Microfluidic technology provides a unique environment for the investigation of crystallization processes at the nano or meso scale. The convenient operation and precise control of process parameters, at these scales of operation enabled by microfluidic devices, are attracting significant and increasing attention in the field of crystallization. In this paper, developments and applications of microfluidics in crystallization research including: crystal nucleation and growth, polymorph and cocrystal screening, preparation of nanocrystals, solubility and metastable zone determination, are summarized and discussed. The materials used in the construction and the structure of these microfluidic devices are also summarized and methods for measuring and modelling crystal nucleation and growth process as well as the enabling analytical methods are also briefly introduced. The low material consumption, high efficiency and precision of microfluidic crystallizations are of particular significance for active pharmaceutical ingredients, proteins, fine chemicals, and nanocrystals. Therefore, it is increasingly adopted as a mainstream technology in crystallization research and development.
63 citations
TL;DR: In this paper, the effect of bend angle as channel geometry to control the surface-driven capillary flow is investigated as a novel approach to control separation time in microfluidic lab-on-a-chip systems.
Abstract: In this research paper, in total 212 individual leakage-free Polymethylmethacrylate (PMMA) microfluidic devices are fabricated by maskless lithography, hot embossing lithography and direct bonding technique. The effect of channel aspect ratio on dyed water flow is investigated using these microfluidic devices. Experimental studies show that the dyed water flow is faster on the surface of higher wettability. The effect of capillary pressure on dyed water flow is studied in the fabricated PMMA microfluidic devices. According to the experimental observations, the centrifugal force has prominent effect on the dyed water flow. Also, the effect of bend angle is investigated on the surface-driven capillary flow of water. The polystyrene microparticles have been separated in the microfluidic lab-on-a-chip systems using the investigated flow features. A 100% separation efficiency is achieved in these lab-on-a-chip systems. These microfluidic lab-on-a-chip systems can be used to separate blood cells from human whole blood for further clinical tests. These experimental studies are important in bioengineering applications. The effect of bend angle as channel geometry to control the surface-driven capillary flow is investigated as a novel approach to control the separation time in microfluidic lab-on-a-chip systems. Also, the effect of surface wettability as surface property to control the surface-driven capillary flow is investigated as a novel approach to control the separation time in microfluidic lab-on-a-chip systems.
6 citations
TL;DR: In this paper, the surface-driven microfluidic flow of aqueous microparticle suspensions with the investigations on the separation time in particle-size based separation mechanism to control these suspensions in the micro fluididic lab-on-a-chip systems.
Abstract: In this work, total 1592 individual leakage-free polymethylmethacrylate (PMMA) microfluidic devices as laboratory-on-a-chip systems are fabricated by maskless lithography, hot embossing lithography, and direct bonding technique. Total 1094 individual Audio Video Interleave Files as experimental outputs related to the surface-driven capillary flow have been recorded and analyzed. The influence of effective viscosity, effect of surface wettability, effect of channel aspect ratio, and effect of centrifugal force on the surface-driven microfluidic flow of aqueous microparticle suspensions have been successfully and individually investigated in these laboratory-on-a-chip systems. Also, 5 micron polystyrene particles have been separated from the aqueous microparticle suspensions in the microfluidic lab-on-a-chip systems of modified design with 98% separation efficiency, and 10 micron polystyrene particles have been separated with 100% separation efficiency. About the novelty of this work, the experimental investigations have been performed on the surface-driven microfluidic flow of aqueous microparticle suspensions with the investigations on the separation time in particle-size based separation mechanism to control these suspensions in the microfluidic lab-on-a-chip systems. This research work contains a total of 10,112 individual experimental outputs obtained using total 30 individual instruments by author’s own hands-on completely during more than three years continuously. Author has performed the experimental investigations on both the fluid statics and fluid dynamics to develop an automated fluid machine.
4 citations
TL;DR: In this article, the effect of surface area to volume ratio on the surface-driven capillary flow of different liquids has been experimentally investigated in these microfluidic devices fabricated by polymethylmethacrylate (PMMA).
Abstract: In this research paper, total 246 individual microfluidic devices have been fabricated by maskless lithography, hot embossing lithography and direct bonding technique. The effect of surface area to volume ratio on the surface-driven capillary flow of different liquids has been experimentally investigated in these microfluidic devices fabricated by polymethylmethacrylate (PMMA). Also, the individual effects of liquid viscosity and surface wettability on the surface-driven capillary flow of different liquids are experimentally investigated. The polystyrene particles of 10μm diameters have been separated from the aqueous microparticle suspensions in the microfluidic lab-on-a-chip systems with 100% separation efficiency. Also, the polystyrene particles of 5μm diameters have been separated from a different set of aqueous microparticle suspensions in the microfluidic lab-on-a-chip systems with 100% separation efficiency. The individual designs of the microfluidic lab-on-a-chip systems are a novel approach in th...
3 citations
DOI•
19 Jun 2018
TL;DR: In this paper, the diamond-like carbon (DLC) is used in the fabrication of micro electromechanical systems (MEMS) and microfluidic devices and different features of DLC are briefly highlighted.
Abstract: In general, diamond-like carbon (DLC) is the hydrogenated amorphous carbon (a-C:H) to be used in the fabrication of micro electromechanical systems (MEMS) and microfluidic devices. Mukhopadhyay as author has recently demonstrated the variation of surface wettability in polymer based microchannels by the use of DLC. Also, DLC can be used as an anti-stiction coating in different applications. In this review, different features of DLC are briefly highlighted. This educational short review is authored as the study material for proposed elective-course on Microfluidics (M.Tech, Theory) in the Department of Mechanical Engineering, National Institute of Technology Arunachal Pradesh, India.
2 citations
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TL;DR: This article presents a review of polymer-based microfluidic systems including their material properties, fabrication methods, device applications, and finally an analysis of the market that drives their development.
1,150 citations
TL;DR: In this article, the authors explored the possibility of the existence of a common scale, which can be used to gauge bond strength between various surfaces and found that the changes in wettability of surfaces owing to various levels of plasma exposure can be a useful parameter to gauge the bond strength.
Abstract: An issue in microfabrication of the fluidic channels in glass/poly (dimethyl siloxane) (PDMS) is the absence of a well-defined study of the bonding strength between the surfaces making up these channels. Although most of the research papers mention the use of oxygen plasma for developing chemical (siloxane) bonds between the participating surfaces, yet they only define a certain set of parameters, tailored to a specific setup. An important requirement of all the microfluidics/biosensors industry is the development of a general regime, which defines a systematic method of gauging the bond strength between the participating surfaces in advance by correlation to a common parameter. This enhances the reliability of the devices and also gives a structured approach to its future large-scale manufacturing. In this paper, we explore the possibility of the existence of a common scale, which can be used to gauge bond strength between various surfaces. We find that the changes in wettability of surfaces owing to various levels of plasma exposure can be a useful parameter to gauge the bond strength. We obtained a good correlation between contact angle of deionized water (a direct measure of wettability) on the PDMS and glass surfaces based on various dosages or oxygen plasma treatment. The exposure was done first in an inductively coupled high-density (ICP) plasma system and then in plasma enhanced chemical vapor deposition (PECVD) system. This was followed by the measurement of bond strength by use or the standardized blister test.
825 citations
TL;DR: In this paper, the authors provide an in-depth look at the state-of-the-art in integrated microfludic devices for a broad range of application areas from on-chip DNA analysis, immunoassays and cytometry to advances in integrated detection technologies for and miniaturized fuel processing devices.
738 citations
TL;DR: This research presents a new class of research tools for the investigation of biochemistry and life processes using lab-on-a-chip formats for chemical sampling with high spatial resolution and the manipulation and measurement of individual molecules.
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682 citations
TL;DR: A review of techniques for sealing thermoplastic microfluidics can be found in this paper, where the authors discuss a number of practical issues surrounding these various bonding methods and discuss a set of unique challenges which must be addressed to achieve optimal sealing results.
Abstract: Thermoplastics are highly attractive substrate materials for microfluidic systems, with important benefits in the development of low cost disposable devices for a host of bioanalytical applications. While significant research activity has been directed towards the formation of microfluidic components in a wide range of thermoplastics, sealing of these components is required for the formation of enclosed microchannels and other microfluidic elements, and thus bonding remains a critical step in any thermoplastic microfabrication process. Unlike silicon and glass, the diverse material properties of thermoplastics opens the door to an extensive array of substrate bonding options, together with a set of unique challenges which must be addressed to achieve optimal sealing results. In this paper we review the range of techniques developed for sealing thermoplastic microfluidics and discuss a number of practical issues surrounding these various bonding methods.
618 citations