Performance of SU-8 Microchips as Separation Devices and Comparison with Glass Microchips

Sikanen, Tiina; Heikkilä, Liisa; Tuomikoski, Santeri; Ketola, Raimo A.; Kostiainen, Risto; Franssila, Sami; Kotiaho, Tapio

doi:10.1021/ac0703956

Cited by 36 publications

(49 citation statements)

References 51 publications

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“…The SU-8 microchannels were fabricated from SU-8 50 negative photoresist (Microchem, Newton, MA, USA) by using UV-lithography and adhesive bonding techniques, as previously described [27,38]. The PDMS microchannels were fabricated from Sylgard s 184 silicone elastomer (Dow Corning, Midland, MI, USA) by mixing the base elastomer and the curing agent in a ratio of 9:1 w/w and degassing the mixture in vacuum for 1 h. Next, the PDMS was casted on top of an SU-8 master incorporating the microchannel pattern and on top of a plain soda lime glass (Nanofilm, Westlake Village, CA, USA) in order to prepare the bottom and sealing layers, respectively.…”

Section: Microchip Fabricationmentioning

confidence: 99%

“…SU-8 was chosen as the microchip fabrication material because of its favorable chemical stability and manifold patterning possibilities by UV-lithographic and bonding techniques [25]. SU-8 has been utilized not only in microelectromechanical systems [26] but also as structural material in many miniaturized (total) analysis systems, such as microchip-based CE [27,28], LC [29], and ESI/MS [30][31][32][33]. The use of SU-8 in bio-microelectromechanical system applications has also gained a lot of interest recently.…”

Section: Introductionmentioning

confidence: 99%

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Dynamic coating of SU‐8 microfluidic chips with phospholipid disks

et al. 2010

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In this work, PEG-stabilized phosphatidylcholine lipid aggregates (disks), mimicking mammalian cell membranes, were introduced as a new biofouling resistant coating for SU-8 polymer microchannels. A rapid and simple method was developed for immobilization of PEGylated phosphatidylcholine disks in microchannels. Microfluidic chips made from SU-8, PDMS, or glass were dynamically coated with the PEGylated disks followed by characterization of their surface chemistry before and after coating. On the basis of the observed changes in EOF and nonspecific protein adsorption, the affinity of the PEGylated disks was shown to be particularly strong toward SU-8. The PEG-lipid coating enabled permanent change in EOF in SU-8 microchannels with an initial value of 4.5 x 10(-8) m(2) V(-1) s(-1), decreasing to 2.1 x 10(-8) m(2) V(-1) s(-1) (immediately after modification), and, eventually, to 1.5 x 10(-8) m(2) V(-1) s(-1) (7 days after modification) for 9 mM sodium borate (pH 10.5) as BGE. As determined by the Wilhelmy plate measurements and microchip-CE analysis of BSA, the PEG-lipid coating also enabled efficient biofouling shield against protein adsorption, similar to that of low amounts of SDS (3.5 mM) or Tween-20 (80 microM) as buffer additives. These results suggest that dynamically attached PEG-lipid aggregates provide stable, biomimicking surface modification that efficiently reduces biofouling on SU-8.

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Section: Microchip Fabricationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamic coating of SU‐8 microfluidic chips with phospholipid disks

et al. 2010

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“…19 Its surface properties have been exploited to make capillary electrophoresis chips. 20 Its ease of precise patterning has enabled the fabrication of electrospray tips. 21 Its good thermal stability and compatibility with electrode integration have enabled its use in polymerase chain reactors.…”

Section: B Exploration Of Alternative Polymeric Materialsmentioning

confidence: 99%

A practical guide for the fabrication of microfluidic devices using glass and silicon

Iliescu¹,

Taylor²,

Avram³

et al. 2012

Biomicrofluidics

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This paper describes the main protocols that are used for fabricating microfluidic devices from glass and silicon. Methods for micropatterning glass and silicon are surveyed, and their limitations are discussed. Bonding methods that can be used for joining these materials are summarized and key process parameters are indicated. The paper also outlines techniques for forming electrical connections between microfluidic devices and external circuits. A framework is proposed for the synthesis of a complete glass/silicon device fabrication flow. I. WHY USE SILICON AND GLASS IN MICRO-AND NANO-FLUIDIC APPLICATIONS?Micro-and nano-fluidic technology continues to be embraced by biologists, 1-3 chemists, 4 and engineers throughout academia and industry. As its applications have expanded, there has been an explosion in the range of materials and processes used to fabricate these devices. The earliest microfluidic devices (e.g., gas 5 and liquid 6 chromatography devices) were made from silicon and glass and borrowed processes directly from semiconductor and microelectromechanical systems (MEMS) manufacturing. 7 Now, however, many researchers have moved away from silicon and glass, and instead use cast elastomers such as polydimethylsiloxane (PDMS)-which is ideal for swift prototyping-or thermoplastic polymers, which can be hot-embossed or injection-molded and are well suited to inexpensive manufacturing. Yet, there remain many applications where glass and silicon offer advantages over polymeric materials. In this paper, we highlight these advantages and offer a framework for selecting fabrication processes when using silicon and glass. A. The dominance of soft lithographyOver the last decade, PDMS has become virtually the default material for forming microfluidic devices, 8 because of the sheer ease with which it can be cast on to a micro-scale mould and then strongly bonded to glass. 9 The elastomeric nature of the material has been exploited to integrate fluidic valves and pumps on-chip and has simplified the production of multi-layer devices because the soft layers readily conform to each other. 10,11 Yet, the low stiffness (usually <1 MPa) of PDMS relative to amorphous thermoplastics, silicon, and glass has its own a) Authors to whom correspondence should be addressed. Electronic addresses: ciliescu@ibn.a-star.edu.sg and hkt@ntu.edu.sg. 6, 016505 (2012) drawbacks. High aspect-ratio channels are notoriously difficult to fabricate in PDMS because of their propensity to collapse. 12 Moreover, difficulties in automating the handling of such a soft material have hampered efforts to scale up PDMS device manufacturing. Meanwhile, PDMS's high oxygen and water permeabilities have proved both a blessing and a curse in different applications.The hydrophobic nature of PDMS can be an important consideration for some biological applications. In drug screening applications, for example, hydrophobic drugs as well as metabolites (urea or albumin) can be absorbed into the device's material due to hydrophobic--hydrophobic interaction...

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“…Various materials have been employed to fabricate microfluidic chips, such as silicon [22,23], polymers (SU-8) [24][25][26], polymethyl methacrylate [27], glass [28][29][30][31] and poly (dimethylsiloxane) (PDMS) [1,6,32,33]. Koster et al [14] conducted a thorough summary of the materials used for microfluidic chips.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Electro-Sonic Flow Focusing Ionization Microfluidic Chip for Mass Spectrometry

Qian

Chen

et al. 2015

Micromachines

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Increasing research efforts have been recently devoted to the coupling of microfluidic chip-integrated ionization sources to mass spectrometry (MS). Considering the limitations of microfluidic chips coupled with MS such as liquid spreading, dead volume, and manufacturing troubles, this paper proposed a new three-dimensional (3D) flow focusing (FF)-based microfluidic ionizing source. This source was fabricated by using the two-layer soft lithography method with the nozzle placed inside the chip. The proposed FF microfluidic chip can realize two-phase FF with liquid in air regardless of the viscosity ratio of the continuous and dispersed phases. MS results indicated that the proposed FF microfluidic chip can work as a typical electrical ionization source when supplied with high voltage and can serve as a sonic ionization source without high voltage. The electro-sonic FF ionization microfluidic chip is expected to have various applications, particularly in the integrated and portable applications of ionization sources coupling with portable MS in the future.

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Performance of SU-8 Microchips as Separation Devices and Comparison with Glass Microchips

Cited by 36 publications

References 51 publications

Dynamic coating of SU‐8 microfluidic chips with phospholipid disks

Dynamic coating of SU‐8 microfluidic chips with phospholipid disks

A practical guide for the fabrication of microfluidic devices using glass and silicon

Three-Dimensional Electro-Sonic Flow Focusing Ionization Microfluidic Chip for Mass Spectrometry

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