| 1. |
- Carlborg, Carl Fredrik, et al.
(författare)
-
A High-Yield Process for 3-D Large-Scale Integrated Microfluidic Networks in PDMS
- 2010
-
Ingår i: Journal of microelectromechanical systems. - 1057-7157 .- 1941-0158. ; 19:5, s. 1050-1057
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents an uncomplicated high-yield fabrication process for creating large-scale integrated (LSI) 3-D microfluidic networks in poly(dimethylsiloxane) (PDMS). The key innovation lays in the robust definition of miniaturized out-of-plane fluidic interconnecting channels (=vias) between stacked layers of microfluidic channels in standard PDMS. Unblocked vias are essential for creating 3-D microfluidic networks. Previous methods either suffered from limited yield in achieving unblocked vias due to residual membranes obstructing the vias after polymerization, or required complicated and/or manual procedures to remove the blocking membranes. In contrast, our method prevents the formation of residual membranes by inhibiting the PDMS polymerization on top of the mold features that define the vias. In addition to providing unblocked vias, the inhibition process also leaves a partially cured, sticky flat-top surface that adheres well to other surfaces and that allows self-sealing stacking of several PDMS layers. We demonstrate the new method by manufacturing a densely perforated PDMS membrane and an LSI 3-D PDMS microfluidic channel network. We also characterize the inhibition mechanism and study the critical process parameters. We demonstrate that the method is suitable for structuring PDMS layers with a thickness down to 10 mu m.
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| 2. |
- Carlborg, Carl Fredrik, et al.
(författare)
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A packaged optical slot-waveguide ring resonator sensor array for multiplex label-free assays in labs-on-chips
- 2010
-
Ingår i: Lab on a Chip. - : Royal Society of Chemistry (RSC). - 1473-0197 .- 1473-0189. ; 10:3, s. 281-290
-
Tidskriftsartikel (refereegranskat)abstract
- We present the design, fabrication, and characterisation of an array of optical slot-waveguide ring resonator sensors, integrated with microfluidic sample handling in a compact cartridge, for multiplexed real-time label-free biosensing. Multiplexing not only enables high throughput, but also provides reference channels for drift compensation and control experiments. Our use of alignment tolerant surface gratings to couple light into the optical chip enables quick replacement of cartridges in the read-out instrument. Furthermore, our novel use of a dual surface-energy adhesive film to bond a hard plastic shell directly to the PDMS microfluidic network allows for fast and leak-tight assembly of compact cartridges with tightly spaced fluidic interconnects. The high sensitivity of the slot-waveguide resonators, combined with on-chip referencing and physical modelling, yields a volume refractive index detection limit of 5 x 10(-6) refractive index units (RIUs) and a surface mass density detection limit of 0.9 pg mm(-2), to our knowledge the best reported values for integrated planar ring resonators.
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| 3. |
- Carlborg, Carl Fredrik, 1981-, et al.
(författare)
-
BEYOND PDMS: : OFF-STOCHIOMETRY THIOL-ENE BASED SOFT LITHOGRAPHY FOR RAPID PROTOTYPING OF MICROFLUIDIC DEVICES
- 2010
-
Ingår i: 14th International Conference on Miniaturized Systems for Chemistry and Life Sciences (micro TAS 2010). - 9781618390622 ; , s. 70-72
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Konferensbidrag (refereegranskat)abstract
- We present an easy to use, rapid fabrication platform for microfluidic systems, based on micro-molding of novel thiolene based polymer formulations. The novel fabrication platform addresses major drawbacks of PDMS by allowing large freedom in material and surface properties, including: (photo)patterning of stable surface modifications, bonding without plasma treatment, rapid UV or thermal curing, variable E-modulus, minimized leaching of uncured components [1] and suppressed non-specific binding of biomolecules [2]. This process is potentially suited for both rapid prototyping in the laboratory and medium-scale commercial production, bridging the “development gap”.
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| 4. |
- Carlborg, Carl Fredrik, et al.
(författare)
-
Beyond PDMS: off-stoichiometry thiol–ene (OSTE) based soft lithography for rapid prototyping of microfluidic devices
- 2011
-
Ingår i: Lab on a Chip. - : RSC Publishing. - 1473-0197 .- 1473-0189. ; 11:18, s. 3136-3147
-
Tidskriftsartikel (refereegranskat)abstract
- In this article we introduce a novel polymer platform based on off-stoichiometry thiol–enes (OSTEs), aiming to bridge the gap between research prototyping and commercial production of microfluidic devices. The polymers are based on the versatile UV-curable thiol–ene chemistry but takes advantage of off-stoichiometry ratios to enable important features for a prototyping system, such as one-step surface modifications, tuneable mechanical properties and leakage free sealing through direct UV-bonding. The platform exhibits many similarities with PDMS, such as rapid prototyping and uncomplicated processing but can at the same time mirror the mechanical and chemical properties of both PDMS as well as commercial grade thermoplastics. The OSTE-prepolymer can be cast using standard SU-8 on silicon masters and a table-top UV-lamp, the surface modifications are precisely grafted using a stencil mask and the bonding requires only a single UV-exposure. To illustrate the potential of the material we demonstrate key concepts important in microfluidic chip fabrication such as patterned surface modifications for hydrophobic stops, pneumatic valves using UV-lamination of stiff and rubbery materials as well as micromachining of chip-to-world connectors in the OSTE-materials.
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| 5. |
- Carlborg, Carl Fredrik, et al.
(författare)
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Biosticker : patterned microfluidic stickers for rapid integration with microarrays
- 2011
-
Ingår i: The 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences (microTAS 2011). - : Chemical and Biological Microsystems Society. - 9781618395955 ; , s. 311-313
-
Konferensbidrag (refereegranskat)abstract
- We present a one-step, reversible, and biocompatible bonding method of a stiff patterned microfluidic "Biosticker", based on off-stoichiometry thiol-ene (OSTE) polymers [1], to state-of-the-art spotted microarray surfaces. The method aims at improving and simplifying the batch back-end processing of microarrays. We illustrate its ease of use in two applications: a high sensitivity flow-through protein assay; and a DNA-hybridization test. Read-out was performed in a standard highvolume array scanner, and showed excellent spot homogeneity and intensity. The Biosticker is aimed to be a plug-in for existing microarray platforms to enable faster protein assays and DNA hybridizations through mass transport optimization.
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| 6. |
- Carlborg, Carl Fredrik, et al.
(författare)
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Continuous flow switching by pneumatic actuation of the air lubrication layer on superhydrophobic microchannel walls
- 2008
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Ingår i: 21st IEEE International Conference on Micro Electro Mechanical Systems (IEEE MEMS 2008). - : IEEE conference proceedings. - 9781424417926 ; , s. 599-602
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Konferensbidrag (refereegranskat)abstract
- This paper introduces and experimentally verifies a method for robust, active control of friction reduction in microchannels, enabling new flow control applications and overcoming previous limitations with regard to sustainable liquid pressure. The air pockets trapped at asuperhydrophobic micrograting during liquid priming are coupled to an actively controlled pressure source, allowing the pressure difference over the air/liquid interface to be dynamically adjusted. This allows for manipulating the friction reduction properties of the surface, enabling active control of liquid mass flow through the channel. It also permits for sustainable air lubrication at theoretically unlimited liquid pressures, without loss of superhydrophobic properties. With the non-optimized grating used in the experiment, a difference in liquid mass flow of 4.8 % is obtained by alternatively collapsing and recreating the air pockets using the coupled pressure source, which is in line with a FE analysis of the same geometry. A FE analysis of a more optimized geometry predicts a mass flow change of over 30%, which would make possible new microfluidic devices based on local friction control. It is also experimentally shown that our method allows for sustainable liquid pressure 3 times higher than the Laplace pressure of a passive device.
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| 7. |
- Carlborg, Carl Fredrik, 1981-
(författare)
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Development of materials, surfaces and manufacturing methods for microfluidic applications
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents technological advancements in microfluidics. The overall goals of the work are to develop new miniaturized tests for point-of-care diagnostics and robust super-lubricating surfaces for friction reduction. To achieve these goals, novel materials, surfaces and manufacturing methods in microfluidics have been developed.Point-of-care diagnostic tests are portable miniaturized instruments that downscale and automate medical tests previously performed in the central laboratories of hospitals. The instruments are used in the doctor’s office, in the emergency room or at home as self-tests. By bringing the analysis closer to the patient, the likelihood of an accurate diagnosis, or a quick therapy adjustment is increased. Already today, there are point-of-care tests available on the market, for example blood glucose tests, rapid streptococcus tests and pregnancy tests. However, for more advanced diagnostic tests, such as DNA-tests or antibody analysis, integration of microfluidic functions for mass transport and sample preparation is required. The problem is that the polymer materials used in academic development are not always suited for prototyping microfluidic components for sensitive biosensors. Despite the enormous work that has gone into the field, very few technical solutions have been implemented commercially.The first part of the work deals with the development of prototype point of-care tests. The research has focused on two major areas: developing new manufacturing methods to leverage the performance of existing materials and developing a novel polymer material platform, adapted for the extreme demands on surfaces and materials in miniaturized laboratories. The novel manufacturing methods allow complex 3D channel networks and the integration of materials with different surface properties. The novel material platform is based on a novel off-stoichiometry formulation of thiol-enes (OSTE) and has very attractive material and manufacturing properties from a lab-on-chip perspective, such as, chemically stable surfaces, low absorption of small molecules, facile and inexpensive manufacturing process and a biocompatible bonding method. As the OSTE-platform can mirror many of the properties of commercially used polymers, while at the same time having an inexpensive and facile manufacturing method, it has potential to bridge the gap between research and commercial production.Friction in liquid flows is a critical limiting factor in microfluidics, where friction is the dominant force, but also in marine applications where frictional losses are responsible for a large part of the total energy consumption of sea vessels. Microstructured surfaces can drastically reduce the frictional losses by trapping a layer of air bubbles on the surface that can act as an air bearing for the liquid flow. The problem is that these trapped air bubbles collapse at the liquid pressures encountered in practical applications.The last part of the thesis is devoted to the development of novel low fluidfriction surfaces with increased robustness but also with active control of the surface friction. The results show that the novel surfaces can resist up to three times higher liquid pressure than previous designs, while keeping the same friction reducing capacity. The novel designs represent the first step towards practical implementation of micro-structured surfaces for friction reduction.
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| 8. |
- Carlborg, Carl Fredrik, et al.
(författare)
-
Functional Off-Stoichiometry Thiol-ene-epoxy Thermosets Featuring Temporally Controlled Curing Stages via an UV/UV Dual Cure Process
- 2014
-
Ingår i: Journal of Polymer Science Part A. - : John Wiley & Sons. - 0887-624X .- 1099-0518. ; 52:18, s. 2604-2615
-
Tidskriftsartikel (refereegranskat)abstract
- We present a facile two-stage UV/UV activation method for the polymerization of off-stoichiometry thiol-ene-epoxy, OSTE+, networks. We show that the handling and processing of these epoxy-based resins is made easier by introducing a material with a controlled curing technique based on two steps, where the first step offers excellent processing capabilities, and the second step yields a polymer with suitable end-properties. We investigate the sequential thiol-ene and thiol-epoxy reactions during these steps by studying the mechanical properties, functional group conversion, water absorption, hydrolytic stability, and thermal stability in several different thiol-ene-epoxy formulations. Finally, we conclude that the curing stages can be separated for up to 24 h, which is promising for the usefulness of this technique in industrial applications.
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| 9. |
- Carlborg, Carl Fredrik, et al.
(författare)
-
LARGE SCALE INTEGRATED 3D MICROFLUIDIC NETWORKS THROUGH HIGH YIELD FABRICATION OF VERTICAL VIAS IN PDMS
- 2010
-
Ingår i: MEMS 2010. - : IEEE conference proceedings. - 9781424457649 ; , s. 240-243
-
Konferensbidrag (refereegranskat)abstract
- This paper introduces a robust, high yield, single-step fabrication method for creating densely spaced, miniaturized out-of-plane fluidic interconnecting channels (=vias) in standard poly(dimethylsiloxane) PDMS. Unblocked vias are essential for creating 3D microfluidic networks. Previously reported methods either had low yield, because of residual membranes covering the vias after polymerization, or required complicated extra steps to remove the blocking membranes.In contrast, our method prevents the formation of residual membranes by inhibition of the polymerization on top of the protuding mold features defining the vias locations. In addition to providing unblocked vias, the inhibition also leaves a flat partially cured, sticky top surface that adheres well to other surfaces and allows self-sealing stacking of several PDMS layers. We demonstrate the new method by manufacturing a densely perforated PDMS membrane and a large scale integrated (LSI) 3D PDMS microfluidic channel network. Our method enables batch manufacturing of complex fluidic devices by speeding up and simplifying the fabrication of complex microfluidic components in standard PDMS.
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| 10. |
- Carlborg, Carl Fredrik, 1981-, et al.
(författare)
-
LOW TEMPERATURE “CLICK” WAFER BONDING OF OFF-STOICHIOMETRY THIOL-ENE (OSTE) POLYMERS TO SILICON
- 2011
-
Ingår i: 15th International Conference on Miniaturized Systems for Chemistry and Life Sciences (microTAS 2011). - 9781618395955 ; , s. 1143-1145
-
Konferensbidrag (refereegranskat)abstract
- We present a low temperature (< 37°C) wafer-scale microfluidic batch packaging process using covalent, dry bonding of offstoichiometry thiol-ene polymers (OSTE), enabling rapid, bio-compatible integration of fluidics on wafer-scale in combination with excellent polymer properties.
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| 11. |
- Carlborg, Carl Fredrik, et al.
(författare)
-
Microchannels with substantial friction reduction at large pressure and large flow
- 2009
-
Ingår i: Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems. ; , s. 39-42
-
Konferensbidrag (refereegranskat)abstract
- This paper introduces and experimentally verifies a self-regulating method for reducing the friction losses in large microchannels at high liquid pressures and large liquid flows, overcoming limitations with regard to sustainable liquid pressure on a superhydrophobic surface. Our design of the superhydrophobic channel creates an automatic adjustment of the gas pressure in the lubricating air layer to the local liquid pressure in the channel. This is achieved by pneumatically connecting the liquid in the microchannel to the air pockets trapped at channel wall trough a pressure feedback channel. When liquid enters the feedback channel it compresses the air and increases the pressure in the air pocket. This reduces the pressure drop over the air-liquid interface and increases the maximum sustainable liquid pressure. We define a dimensionless fluidic number, WF = PLDh/ ?cos?C, which expresses the fluidic energy carrying capacity of a superhydrophobic microchannel. We experimentally verified that our geometry can sustain several times higher liquid pressure before collapsing, and we measured better friction reducing properties at higher WF values than in previous works. This method could be applicable for reducing near-wall laminar friction in both micro-and macroscale flows.
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| 12. |
- Carlborg, Carl Fredrik, 1981-, et al.
(författare)
-
RELIABLE BATCH MANUFACTURING OF MINIATURIZED VERTICAL VIAS IN SOFT POLYMER REPLICA MOLDING
- 2007
-
Ingår i: 11th International Conference on Miniaturized Systems for Chemistry and Life Sciences (microTAS 2007). ; , s. 527-529
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Konferensbidrag (refereegranskat)abstract
- We introduce and have successfully tested an uncomplicated polydimethylsiloxane (PDMS) compatible method for batch manufacturing vertical microfluidic interconnects via a surface inhibition of cationic photopolymerization. The yield of the maskless method is 100%. Moreover, the method enhances bond strength with subsequently laminated polymer layers.
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| 13. |
- Carlborg, Carl Fredrik, et al.
(författare)
-
Sustained Superhydrophobic Friction Reduction at High Liquid Pressures and Large Flows
- 2011
-
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 27:1, s. 487-493
-
Tidskriftsartikel (refereegranskat)abstract
- This Article introduces and experimentally explores a novel self-regulating method for reducing the friction losses in large microchannels at high liquid pressures and large liquid flows, overcoming previous limitations with regard to sustainable liquid pressure on a superhydrophobic surface. Our design of the superhydrophobic channel automatically adjusts the gas pressure in the lubricating air layer to the local liquid pressure in the channel. This is achieved by pneumatically connecting the liquid in the microchannel to the gas-pockets trapped at the channel wall through a pressure feedback channel. When liquid enters the feedback channel, it compresses the air and increases the pressure in the gas-pocket. This reduces the pressure drop over the gas liquid interface and increases the maximum sustainable liquid pressure. We define a dimensionless figure of merit for superhydropbic flows, W-F = PLD/gamma cos(theta(c)), which expresses the fluidic energy carrying capacity of a superhydrophobic microchannel. We experimentally verify that our geometry can sustain three times higher liquid pressure before collapsing, and we measured better friction-reducing properties at higher W-F values than in previous works. The design is ultimately limited in time by the gas-exchange over the gas-liquid interface at pressures exceeding the Laplace pressure. This method could be applicable for reducing near-wall laminar friction in both micro and macro scale flows.
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| 14. |
- Carlborg, Carl Fredrik, et al.
(författare)
-
Thermal boundary resistance between single-walled carbon nanotubes and surrounding matrices
- 2008
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 78:20, s. 205406-
-
Tidskriftsartikel (refereegranskat)abstract
- Thermal boundary resistance (TBR) between a single-walled carbon nanotube (SWNT) and matrices of solid and liquid argon was investigated by performing classical molecular-dynamics simulations. Thermal boundary conductance (TBC), i.e., inverse of TBR, was quantified for a range of nanotube lengths by applying a picosecond heat pulse to the SWNT and observing the relaxation. The SWNT-length effect on the TBC was confirmed to be absent for SWNT lengths from 20 to 500 A. The heat transfer mechanism was studied in detail and phonon spectrum analysis provided evidence that the resonant coupling between the low-frequency modes of the SWNT and the argon matrix is present both in solid and liquid argon cases. The heat transfer mechanism was qualitatively analyzed by calculating the spectral temperature of the SWNT in different frequency regimes. It was found that the low-frequency modes that are resonantly coupled to the argon matrix relaxes roughly ten times faster than the overall TBC time scale, depending on the surrounding matrix. However, such resonant coupling was found to transfer little energy despite a popular picture of the linear transfer path. The analysis suggests that intrananotube energy transfer from high-frequency modes to low-frequency ones is slower than the interfacial heat transfer to the argon matrix.
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| 15. |
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| 16. |
- Guo, Maoxiang, et al.
(författare)
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LONG-TERM STORAGE OF NANOLITRE AND PICOLITRE LIQUID VOLUMES IN POLYMER MICROFLUIDIC DEVICES
- 2015
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Ingår i: the 19th International Conference on Miniaturized Systems for Chemistry and Life Sciences (Micro TAS). - : The Chemical and Biological Microsystems Society. - 9780979806483 ; , s. 1386-1388
-
Konferensbidrag (refereegranskat)abstract
- We introduce uncomplicated nanolitre (23 nL) and picolitre (3.5 pL) liquid volume encapsulation in Off-Stoichiometry Thiol-Ene-Epoxy polymer (OSTEmerTM322) wells using spontaneous room- temperature bonding of gold films to thiol and thioether groups present on the surface of the polymer for leak free sealing. First, we show liquid encapsulation within nL, and pL polymer wells by utilizing 100 nm thin Au-film transfer-bonding onto intermediately cured, and micropatterned OSTEmerTM322. This approach yielded 3 magnitude orders smaller liquid volume encapsulation than previously reported. Secondly, we show that encapsulated liquid can be stored for >116 h. Finally, we demonstrate encapsulated liquid release by thermopneumatic bursting. We conclude that OSTEmerTM322 is excellent for metal-film sealant integration in polymer microfluidic devices.
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| 17. |
- Gylfason, Kristinn B., 1978-, et al.
(författare)
-
A packaged optical slot-waveguide ring resonator sensor array for multiplex assays in labs-on-chip
- 2009
-
Ingår i: Proceedings of Conference, MicroTAS 2009 - The 13th International Conference on Miniaturized Systems for Chemistry and Life Sciences. - : Chemical and Biological Microsystems Society. - 9780979806421 ; , s. 2004-2006
-
Konferensbidrag (refereegranskat)abstract
- We present the design, fabrication, and characterization of a packaged array of individually addressable slot-waveguide ring resonator sensors in a compact cartridge for sensitive, label-free, multiplex assays. The novel use of a dual surfaceenergy adhesive film enables simple generic packaging method for multiple sensors in a single cartridge. The use of optical slot-waveguides, and drift compensation by on-chip light splitting to reference sensors, gives the best refractive-index limit of detection reported for planar ring resonator sensors.
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| 18. |
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| 19. |
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| 20. |
- Gylfason, Kristinn, 1978-, et al.
(författare)
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On-chip temperature compensation in an integrated slot-waveguide ring resonator refractive index sensor array
- 2010
-
Ingår i: Optics Express. - 1094-4087. ; 18:4, s. 3226-3237
-
Tidskriftsartikel (refereegranskat)abstract
- We present an experimental study of an integrated slot-waveguide refractive index sensor array fabricated in silicon nitride on silica. We study the temperature dependence of the slot-waveguide ring resonator sensors and find that they show a low temperature dependence of -16.6 pm/K, while at the same time a large refractive index sensitivity of 240 nm per refractive index unit. Furthermore, by using on-chip temperature referencing, a differential temperature sensitivity of only 0.3 pm/K is obtained, without individual sensor calibration. This low value indicates good sensor-to-sensor repeatability, thus enabling use in highly parallel chemical assays. We demonstrate refractive index measurements during temperature drift and show a detection limit of 8.8 x 10(-6) refractive index units in a 7 K temperature operating window, without external temperature control. Finally, we suggest the possibility of athermal slot-waveguide sensor design.
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| 21. |
- Hansson, Jonas, et al.
(författare)
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Low gas permeable and non-absorbent rubbery OSTE+ for pneumatic microvalves
- 2014
-
Ingår i: Proceedings of the 27th IEEE International Conference on Micro Electro Mechanical Systems (MEMS 2014). - : IEEE conference proceedings. - 9781479935093 ; , s. 987-990
-
Konferensbidrag (refereegranskat)abstract
- In this paper we introduce a new polymer for use in microfluidic applications, based on the off-stoichiometric thiol–ene-epoxy (OSTE+) polymer system, but with rubbery properties. We characterize and benchmark the new polymer against PDMS. We demonstrate that Rubbery OSTE+: has more than 90% lower permeability to gases compared to PDMS, has little to no absorption of dissolved molecules, can be layer bonded in room temperature without the need for adhesives or plasma treatment, can be structured by standard micro-molding manufacturing, and shows similar performance as PDMS for pneumatic microvalves, albeit allowing handling of larger pressure.
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| 22. |
- Haraldsson, Tommy, et al.
(författare)
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OSTE - a novel polymer system developed for Lab-on-Chip
- 2014
-
Ingår i: Proceedings of SPIE Volume 8976. - : SPIE - International Society for Optical Engineering. - 9780819498892 ; , s. 897608-
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Konferensbidrag (refereegranskat)abstract
- OSTE polymer has the aim to address today's dissemination gap between successful lab-on-chip research and the healthcare setting. We have formulated and demonstrated a novel, superior, polymer system, OSTE, and its manufacturing platform, which is based on the mixture of three monomers: thiols, -enes and epoxies. The uniqueness of the OSTE approach stems from the curing in two distinct steps: after the first cure, an intermediate polymer is formed which is ideally suited for surface modifications and bonding; after the second cure we obtain an inert and robust polymer. Our vision is that OSTE has the potential to form a de-facto standard for research and development of high performance labs-on-chip in academia and industry.
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| 23. |
- Karlsson, J. Mikael, 1982-, et al.
(författare)
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Fabrication and transfer of fragile 3D PDMS microstructures
- 2012
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Ingår i: Journal of Micromechanics and Microengineering. - : IOP Publishing. - 0960-1317 .- 1361-6439. ; 22:8, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- We present a method for PDMS microfabrication of fragile membranes and 3D fluidic networks, using a surface modified water-dissolvable release material, poly(vinyl alcohol), as a tool for handling, transfer and release of fragile polymer microstructures. The method is well suited for the fabrication of complex multilayer microfluidic devices, here shown for a PDMS device with a thin gas permeable membrane and closely spaced holes for vertical interlayer connections fabricated in a single layer. To the authors knowledge, this constitutes the most advanced PDMS fabrication method for the combination of thin, fragile structures and 3D fluidics networks, and hence a considerable step in the direction of making PDMS fabrication of complex microfluidic devices a routine endeavour.
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| 24. |
- Karlsson, J. Mikael, 1982-, et al.
(författare)
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Low-stress transfer bonding using floatation
- 2012
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Ingår i: Journal of Micromechanics and Microengineering. - : Institute of Physics Publishing (IOPP). - 0960-1317 .- 1361-6439. ; 22:7, s. 075005-075011
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Tidskriftsartikel (refereegranskat)abstract
- A novel method for transferring thin, large-area polymer layers from a mould and its subsequent bonding to a destination substrate is presented here. Buoyancy is used for transfer via floatation to allow the release of internal stress in the polymer and to avoid induced strain. Additionally, floatation leads to wrinkle-free contact between the polymer layer and its destination substrate, an important feature for the transfer of large-area polymer sheets. Poly(vinyl alcohol) is used as a release film on the mould, from which the device polymer layer is released using ultrasonication. The polymer layer floats from the mould to a destination surface, to which it automatically aligns. Here, the method is demonstrated by the successful manufacturing of a 4 '' sized, triple microfluidic layer PDMS stack on a silicon wafer, containing a total of 48 large-area, fragile membranes, each with a thickness of 50 mu m.
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| 25. |
- Karlsson, J. Mikael, et al.
(författare)
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Off-Stoichiometry Improves Photostructuring of Thiol-Enes Through Diffusion-Induced Monomer Depletion
- 2016
-
Ingår i: Microsystems and Nanoengineering. - : Nature Publishing Group. - 2055-7434. ; 2
-
Tidskriftsartikel (refereegranskat)abstract
- Thiol-enes are a group of alternating copolymers with highly ordered networks used in a wide range of applications. Here, “click” chemistry photostructuring in off-stoichiometric thiol-enes is shown to induce microscale polymeric compositional gradients due to species diffusion between non-illuminated and illuminated regions, creating two narrow zones with distinct composition on either side of the photomask feature boundary: a densely cross-linked zone in the illuminated region and a zone with an unpolymerized highly off-stoichiometric monomer composition in the non-illuminated region. By the use of confocal Raman microscopy, it is here explained how species diffusion causes such intricate compositional gradients in the polymer, and how off-stoichiometry results in improved image transfer accuracy in thiol-ene photostructuring. Furthermore, increasing the functional group off-stoichiometry and decreasing photomask feature size is shown to amplify the induced gradients, which potentially leads to a new methodology for microstructuring.
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| 26. |
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| 27. |
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| 28. |
- Pardon, Gaspard, 1983-, et al.
(författare)
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Rapid mold-free manufacturing of microfluidic devices with robust and spatially directed surface modifications
- 2014
-
Ingår i: Microfluidics and Nanofluidics. - : Springer Berlin/Heidelberg. - 1613-4982 .- 1613-4990. ; 17:4, s. 773-779
-
Tidskriftsartikel (refereegranskat)abstract
- A new method that allows for mold-free, rapid and easy-to-use proto- typing of micro uidic devices comprising channels, access holes and surface modied patterns, is presented. The innovative method is based on direct photolithographic patterning of an o-stoichiometry thiol-ene (OSTE) polymer formulation, tailor-made for photolithography, which oers unprecedented spatial resolution and allow for ecient, robust and reliable, room temperature surface modication and glue-free, covalent room temperature bonding. This mold-free process does not require cleanroom equipment and therefore allows for rapid, i.e. less than one hour, design-fabricate-test cycles, using a material suited for larger scale production. The excellent photolithographic properties of this new OSTE formulation allow for high-resolution patterning in hundreds of micrometers thick layers, 200 m thick in this work. Moreover, we demonstrate robust (covalent) and spatially controlled modication of the microchannel surfaces with a contact angle of 76 degrees to hydrophobic/hydrophilic areas with contact angles of 102 and 43 degrees, respectively.
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| 29. |
- Saharil, Farizah, et al.
(författare)
-
Biocompatible "click" wafer bonding for microfluidic devices
- 2012
-
Ingår i: Lab on a Chip. - : RSC Publishing. - 1473-0197 .- 1473-0189. ; 12:17, s. 3032-3035
-
Tidskriftsartikel (refereegranskat)abstract
- We introduce a novel dry wafer bonding concept designed for permanent attachment of micromolded polymer structures to surface functionalized silicon substrates. The method, designed for simultaneous fabrication of many lab-on-chip devices, utilizes a chemically reactive polymer microfluidic structure, which rapidly bonds to a functionalized substrate via "click" chemistry reactions. The microfluidic structure consists of an off-stoichiometry thiol-ene (OSTE) polymer with a very high density of surface bound thiol groups and the substrate is a silicon wafer that has been functionalized with common bio-linker molecules. We demonstrate here void free, and low temperature (<37 degrees C) bonding of a batch of OSTE microfluidic layers to a silane functionalized silicon wafer.
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| 30. |
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| 31. |
- Shiomi, J., et al.
(författare)
-
Heat and mass transport in carbon nantubes
- 2010
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Ingår i: 2010 14th International Heat Transfer Conference. - : ASME Press. - 9780791849415 ; , s. 487-493
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Konferensbidrag (refereegranskat)abstract
- We have investigated heat and mass transport in singlewalled carbon nanotubes (SWNTs) using molecular dynamics methods. Particular attention was paid on the non-equilibrium dynamics at the interface between SWNT and other materials, which strongly manifests in nanoscale. In the first part, we have investigated the heat transport through the interface between SWNTs and surrounding argon matrices in liquid and solid phases. By analyzing the energy relaxation from SWNT to the matrices using non-stationary molecular dynamics simulations, elastic and inelastic thermal energy transports across the interface were separately quantified. The result reveals that the elastic interaction transports energy much faster than the inelastic one, but carries much smaller energy due to slow intra-SWNT phonon relaxation. In the second part, we have investigated a possibility to utilize nonequilibrium thermal interface to transport water through an SWNT. By applying the longitudinal temperature gradient to the SWNT, it is demonstrated that the water cluster is efficiently driven at average acceleration proportional to the temperature gradient. However, the transport simulations with a junction of two different SWNTs suggest that an angstrom diameter difference may result in a significant drag for small diameter SWNTs.
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| 32. |
- Shiomi, Junichiro, et al.
(författare)
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Low dimensional heat and mass transport in carbon nanotubes
- 2010
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Ingår i: Proceedings of the ASME Micro/Nanoscale Heat and Mass Transfer International Conference 2009, MNHMT2009. - 9780791843895 ; , s. 337-346
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Konferensbidrag (refereegranskat)abstract
- This report covers various issues related to heat and mass transport in carbon nanotubes. Heat and mass transport under quasi-one-dimensional confinement has been investigated using molecular dynamics simulations. It is shown that the quasi-ballistic heat conduction manifests in the length and diameter dependences of carbon nanotube thermal conductance. Such quasi-ballistic nature of carbon nanotube heat conduction also influences the thermal boundary conductance between carbon nanotubes and the surrounding materials. The quasi-one-dimensional structure also influences the mass transport of water through carbon nanotubes. The confinement gives rise to strongly directional dynamic properties of water. Here, it is demonstrated that the confined water can be efficiently transported by using the temperature gradient. Furthermore, the simulations reveal the diameter-dependent anisotropic dielectric properties, which could be used to identify intrusion of water into carbon nanotubes.
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| 33. |
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| 34. |
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| 35. |
- Zhou, Xiamo, 1990-, et al.
(författare)
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Rapid Fabrication Of OSTE+ Microfluidic Devices With Lithographically Defined Hydrophobic/ Hydrophilic Patterns And Biocompatible Chip Sealing
- 2013
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Ingår i: 17th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2013. - Freiburg, Germany : NO. ; , s. 134-136
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Konferensbidrag (refereegranskat)abstract
- Here we present an uncomplicated and robust method for rapid prototyping of microfluidic devices featuring: 1) lithographically defined, permanently surface modified hydrophilic and hydrophobic regions with contact angles varying from 18o to 118o, in which all four channel walls are surface modified in a single step using polymer chain grafting; 2) polymer chains grafted from open surfaces before bonding, making this method suitable for batch fabrication; 3) biomolecule-compatible, room temperature, dry, homogeneous chip-sealing, in which native as well as hydrophobic/hydrophilic modified OSTE+ surfaces allow for epoxy-epoxy and thiol-epoxy covalent bonding, hence greatly simplifying alignment and dramatically increasing device yields. We demonstrate the method with a functional microfluidic device. This represents a complete, simplified and robust method for batch-manufacturing compatible prototyping of microfluidic devices with tunable mechanical and surface properties.
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| 36. |
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| 37. |
- Zhou, Xiamo, 1990-, et al.
(författare)
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Thiol–ene–epoxy thermoset for low-temperature bonding to biofunctionalized microarray surfaces
- 2017
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Ingår i: Lab on a Chip. - : Royal Society of Chemistry. - 1473-0197 .- 1473-0189. ; 17:21, s. 3672-3681
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Tidskriftsartikel (refereegranskat)abstract
- One way to improve the sensitivity and throughput of miniaturized biomolecular assays is to integrate microfluidics to enhance the transport efficiency of biomolecules to the reaction sites. Such microfluidic integration requires bonding of a prefabricated microfluidic gasket to an assay surface without destroying its biological activity. In this paper we address the largely unmet challenge to accomplish a proper seal between a microfluidic gasket and a protein surface, with maintained biological activity and without contaminating the surface or blocking the microfluidic channels. We introduce a novel dual cure polymer resin for the formation of microfluidic gaskets that can be room-temperature bonded to a range of substrates using only UVA light. This polymer is the first polymer that features over a month of shelf life between the structure formation and the bonding, moreover the fully cured polymer gaskets feature the following set of properties suitable for microfluidics: high stiffness, which prevents microfluidic channel collapse during handling; very limited absorption of biomolecules; and no significant leaching of uncured monomers. We describe the novel polymer resin and its characteristics, study through FT-IR, and demonstrate its use as microfluidic well-arrays bonded onto protein array slides at room temperature followed by multiplexed immunoassays. The results confirm maintained biological activity and show high repeatability between protein arrays. This new approach for integrating microfluidic gaskets to biofunctionalised surfaces has the potential to improve sample throughput and decrease manufacturing costs for miniaturized biomolecular systems.
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