Components for integrated poly(dimethylsiloxane) microfluidic systems

Ng, Jessamine M. K.; Gitlin, Irina; Stroock, Abraham D.; Whitesides, George M.

doi:10.1002/1522-2683(200210)23:20<3461::aid-elps3461>3.0.co;2-8

Cited by 576 publications

(411 citation statements)

References 70 publications

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“…[1][2][3] Electro-osmotic flow ͑EOF͒ is often employed in PDMS and other microchips for various biomicrofluidic applications. 4 The knowledge of electro-osmotic characteristics is then essential for microchip design and process control.…”

Section: Introductionmentioning

confidence: 99%

Study on surface properties of PDMS microfluidic chips treated with albumin

Schrott¹,

Slouka²,

Červenka³

et al. 2009

Biomicrofluidics

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Electrokinetic properties and morphology of PDMS microfluidic chips intended for bioassays are studied. The chips are fabricated by a casting method followed by polymerization bonding. Microchannels are coated with 1% solution of bovine serum albumin ͑BSA͒ in Tris buffer. Albumin passively adsorbs on the PDMS surface. Electrokinetic characteristics ͑electro-osmotic velocity, electro-osmotic mobility, and zeta potential͒ of the coated PDMS channels are experimentally determined as functions of the electric field strength and the characteristic electrolyte concentration. Atomic force microscopy ͑AFM͒ analysis of the surface reveals a "peak and ridge" structure of the protein layer and an imperfect substrate coating. On the basis of the AFM observation, several topologies of the BSA-PDMS surface are proposed. A nonslip mathematical model of the electro-osmotic flow is then numerically analyzed. It is found that the electrokinetic characteristics computed for a channel with the homogeneous distribution of a fixed electric charge do not fit the experimental data. Heterogeneous distribution of the fixed electric charge and the surface roughness is thus taken into account. When a flat PDMS surface with electric charge heterogeneities is considered, the numerical results are in very good agreement with our experimental data. An optimization analysis finally allowed the determination of the surface concentration of the electric charge and the degree of the PDMS surface coating. The obtained findings can be important for correct prediction and possibly for robust control of behavior of electrically driven PDMS microfluidic chips. The proposed method of the electro-osmotic flow analysis at surfaces with a heterogeneous distribution of the surface electric charge can also be exploited in the interpretation of experimental studies dealing with protein-solid phase interactions or substrate coatings.

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Section: Introductionmentioning

confidence: 99%

Study on surface properties of PDMS microfluidic chips treated with albumin

Schrott¹,

Slouka²,

Červenka³

et al. 2009

Biomicrofluidics

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“…Recently, microfluidic systems and biochips made from lowcost polymeric materials such as poly(dimethsiloxane) (PDMS), [9][10][11][12] poly(methylmethacrylate) (PMMA), [13][14][15] and others (see Becker and Locascio 16 for a comprehensive review) as opposed to traditional materials such as glass or silicon have become more and more prevalent. The primary attractiveness of these materials is that they tend to involve simpler and significantly less expensive manufacturing techniques (for example: casting, injection and replica moulding, and hot embossing), 16 however they are also amenable to surface modification [17][18] and the wide variety of physiochemical properties allows the matching of specific polymers to particular applications.…”

Section: Introductionmentioning

confidence: 99%

Joule heating and heat transfer in poly(dimethylsiloxane) microfluidic systems

2003

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Joule heating is a significant problem in electrokinetically driven microfluidic chips, particularly polymeric systems where low thermal conductivities amplify the difficulty in rejecting this internally generated heat. In this work, a combined experimental (using a microscale thermometry technique) and numerical (using a 3D "whole-chip" finite element model) approach is used to examine Joule heating and heat transfer at a microchannel intersection in poly(dimethylsiloxane) (PDMS), and hybrid PDMS/Glass microfluidic systems. In general the numerical predictions and the experimental results agree quite well (typically within ± 3 °C), both showing dramatic temperature gradients at the intersection. At high potential field strengths a nearly five fold increase in the maximum buffer temperature was observed in the PDMS/PDMS chips over the PDMS/Glass systems. The detailed numerical analysis revealed that the vast majority of steady state heat rejection is through lower substrate of the chip, which was significantly impeded in the former case by the lower thermal conductivity PDMS substrate. The observed higher buffer temperature also lead to a number of significant secondary effects including a near doubling of the volume flow rate. Simple guidelines are proposed for improving polymeric chip design and thereby extend the capabilities of these microfluidic systems.

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“…The difference is possibly related to the surface rearrangements that would bring hydrophobic groups to material surface. 1 Amino groups are less hydrophilic than silanol groups, and the surface energy of N 2 plasma-activated PDMS is lower than that of oxygen plasma-activated PDMS. Consequently, such a surface rearrangement in N 2 plasma-activated PDMS is slower and less significant than that in oxygen plasma-activated PDMS.…”

Section: Resultsmentioning

confidence: 99%

“…SU-8 photoresist SU-8 is widely used to prepare the master molds for replication of PDMS (polydimethylsiloxane) microfluidic channels, 1 but it is also directly used for fabricating microfluidic channels. When the material is directly used for channel fabrication, it is simple to integrate the channel with sensors and other components through standard mask alignment and photolithographic processes.…”

Section: Introductionmentioning

confidence: 99%

Sealing SU-8 microfluidic channels using PDMS

et al. 2011

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A simple method of irreversibly sealing SU-8 microfluidic channels using PDMS is reported in this paper. The method is based on inducing a chemical reaction between PDMS and SU-8 by first generating amino groups on PDMS surface using N 2 plasma treatment, then allowing the amino groups to react with the residual epoxy groups on SU-8 surface at an elevated temperature. The N 2 plasma treatment of PDMS can be conducted using an ordinary plasma chamber and high purity N 2 , while the residual epoxy groups on SU-8 surface can be preserved by post-exposure baking SU-8 at a temperature no higher than 95 C. The resultant chemical bonding between PDMS and SU-8 using the method create an interface that can withstand a stress that is greater than the bulk strength of PDMS. The bond is permanent and is long-term resistant to water. The method was applied in fabricating SU-8 microfluidi-photonic integrated devices, and the obtained devices were tested to show desirable performance.

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Components for integrated poly(dimethylsiloxane) microfluidic systems

Cited by 576 publications

References 70 publications

Study on surface properties of PDMS microfluidic chips treated with albumin

Study on surface properties of PDMS microfluidic chips treated with albumin

Joule heating and heat transfer in poly(dimethylsiloxane) microfluidic systems

Sealing SU-8 microfluidic channels using PDMS

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