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Publications (10 of 409) Show all publications
Hauser, J., Stemme, G. & Roxhed, N. (2019). A BLOOD HEMATOCRIT TEST STRIP. In: : . Paper presented at IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS). , 32
Open this publication in new window or tab >>A BLOOD HEMATOCRIT TEST STRIP
2019 (English)Conference paper, Published paper (Other academic)
Abstract [en]

This paper reports a self-propelled microfluidichematocrit (HCT) test that uses the correlation betweenblood hematocrit and wicking distance of blood in a specialpaper matrix. The enabling feature is a novel blood volumemetering method that allows sampling from the fingertipand reliably generates a highly precise blood volume of47.7 ± 1.9 μl (CV 4%) that is transferred into a porouspaper matrix. A dissolvable valve ensures a relaxed timewindow for blood sampling, making it highly user-friendlyand resilient to overfilling. The presented hematocrit teststrip poses a simple, cheap, equipment-free solution forpatient-centric hematocrit measurements.

National Category
Clinical Laboratory Medicine
Identifiers
urn:nbn:se:kth:diva-250573 (URN)
Conference
IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS)
Note

QC 20190625

Available from: 2019-04-30 Created: 2019-04-30 Last updated: 2019-06-25Bibliographically approved
Hauser, J., Lenk, G., Ullah, S., Beck, O., Stemme, G. & Roxhed, N. (2019). An Autonomous Microfluidic Device for Generating Volume-Defined Dried Plasma Spots. Analytical Chemistry, 91(11), 7125-7130
Open this publication in new window or tab >>An Autonomous Microfluidic Device for Generating Volume-Defined Dried Plasma Spots
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2019 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 11, p. 7125-7130Article in journal (Refereed) Published
Abstract [en]

Obtaining plasma from a blood sample and preparing it for subsequent analysis is currently a laborious process involving experienced health-care professionals and centrifugation. We circumvent this by utilizing capillary forces and microfluidic engineering to develop an autonomous plasma sampling device that filters and stores an exact amount of plasma as a dried plasma spot (DPS) from a whole blood sample in less than 6 min. We tested 24 prototype devices with whole blood from 10 volunteers, various input volumes (40-80 mu L), and different hematocrit levels (39-45%). The resulting mean plasma volume, assessed gravimetrically, was 11.6 mu L with a relative standard deviation similar to manual pipetting (3.0% vs 1.4%). LC-MS/MS analysis of caffeine concentrations in the generated DPS (12 duplicates) showed a strong correlation (R-2 = 0.99) to, but no equivalence with, concentrations prepared from corresponding plasma obtained by centrifugation. The presented autonomous DPS device may enable patient-centric plasma sampling through minimally invasive finger-pricking and allow generatation of volume-defined DPS for quantitative blood analysis.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Biomedical Laboratory Science/Technology
Identifiers
urn:nbn:se:kth:diva-254080 (URN)10.1021/acs.analchem.9b00204 (DOI)000470793800027 ()31063366 (PubMedID)2-s2.0-85066116426 (Scopus ID)
Note

QC 20190625

Available from: 2019-06-25 Created: 2019-06-25 Last updated: 2019-06-25Bibliographically approved
Last, T. S., Roxhed, N. & Stemme, G. (2019). Demonstration of the first self-sealing aerosol spray nozzle for medical drug delivery. In: Demonstration of first self-sealing aerosol spray nozzle for medical drug delivery: . Paper presented at IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS) (pp. 1-4). , 32
Open this publication in new window or tab >>Demonstration of the first self-sealing aerosol spray nozzle for medical drug delivery
2019 (English)In: Demonstration of first self-sealing aerosol spray nozzle for medical drug delivery, 2019, Vol. 32, p. 1-4Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Portable medical inhaler systems are prone to bacterial contamination and ingrowth. Here we demonstrate thefirst valved aerosol spray chip, a system that sprays a microjet when actuated and seals against bacterial ingrowth into the spray nozzle in the closed state by a sufficiently small gap. The sealing mechanism is realized by placing a valve seat directly underneath the spray orifices. We fabricated and characterized spray chips with and without valve mechanism and show that they haveindistinguishable spray performance. Our system aims to enable the safe reuse of spray chips for multiple spray operations over an extended period, lowering the cost of treatment while increasing patient compliance.

Keywords
BioMEMS, drug delivery, fluidic microjet, inertial microfluidics, respiratory tract disease treatment
National Category
Medical and Health Sciences Medical Engineering
Research subject
Medical Technology
Identifiers
urn:nbn:se:kth:diva-251748 (URN)
Conference
IEEE 32nd International Conference on Micro Electro Mechanical Systems (MEMS)
Note

QC 20190819

Available from: 2019-05-21 Created: 2019-05-21 Last updated: 2019-08-19Bibliographically approved
Lenk, G., Ullah, S., Stemme, G., Beck, O. & Roxhed, N. (2019). Evaluation of a Volumetric Dried Blood Spot Card Using a Gravimetric Method and a Bioanalytical Method with Capillary Blood from 44 Volunteers. Analytical Chemistry, 91(9), 5558-5565
Open this publication in new window or tab >>Evaluation of a Volumetric Dried Blood Spot Card Using a Gravimetric Method and a Bioanalytical Method with Capillary Blood from 44 Volunteers
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2019 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 9, p. 5558-5565Article in journal (Refereed) Published
Abstract [en]

Dried blood spot (DBS) sampling is a promising method for collection of microliter blood samples. However, hematocrit-related bias in combination with subpunch analysis can result in inaccurate quantification of analytes in DBS samples. In this study we use a microfluidic DBS card, designed to automatically collect fixed volume DBS samples irrespective of the blood hematocrit, to measure caffeine concentration in normal finger prick samples obtained from 44 human individuals. Caffeine levels originating from blood drops of unknown volume collected on the volumetric microfluidic DBS card were compared to volume-controlled pipetted DBS samples from the same finger prick. Hematocrit independence and volumetric sampling performances were also verified on caffeine-spiked blood samples in vitro, using both LC-MS/MS and gravimetric methods, on hematocrits from 26 to 62%. The gravimetric measurements show an excellent metering performance of the microfluidic DBS card, with a mean blood sample volume of 14.25 μL ± 3.0% (n = 51). A measured mean bias below 2.9% compared to normal hematocrit (47%) demonstrates that there is no significant hematocrit-induced bias. LC-MS/MS measurements confirm low CV and hematocrit independence of the sampling system and exhibit no substantial mean bias compared to pipetted DBS. Tests with 44 individuals demonstrated applicability of the microfluidic DBS card for direct finger prick blood sampling, and measured caffeine concentrations show a good agreement with measurements of pipetted DBS. The presented concept demonstrates a good volumetric performance which can help to improve the accuracy of DBS analysis by analyzing a whole spot, equivalent to a defined volume of liquid blood.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
National Category
Analytical Chemistry
Identifiers
urn:nbn:se:kth:diva-251867 (URN)10.1021/acs.analchem.8b02905 (DOI)000467642100017 ()30856315 (PubMedID)2-s2.0-85064830845 (Scopus ID)
Note

QC 20190528

Available from: 2019-05-28 Created: 2019-05-28 Last updated: 2019-06-11Bibliographically approved
Pagliano, S., Gota, F., Raja, S. N., Dubois, V. J., Stemme, G. & Niklaus, F. (2019). Feedback-free electromigrated tunneling junctions from crack-defined gold nanowires. In: Feedback-free electromigrated tunneling junctions from crack-defined gold nanowires: . Paper presented at 32nd IEEE International Conference on Micro Electro Mechanical Systems, Seoul, Korea, from 27-31 January 2019..
Open this publication in new window or tab >>Feedback-free electromigrated tunneling junctions from crack-defined gold nanowires
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2019 (English)In: Feedback-free electromigrated tunneling junctions from crack-defined gold nanowires, 2019Conference paper, Published paper (Refereed)
Abstract [en]

Tunneling junctions are pairs of electrodes separated by gaps of a few nanometers (< 3 nm) that allow electrons to tunnel across the gap. Tunneling junctions are of great importance for applications such as label-free biomolecule sensing and single molecule electronics, but their fabrication remains difficult and laborious. In this paper, we present a simple 2-stage process for the fabrication of tunneling junctions consisting of electrode pairs made of gold (Au). This is achieved by combining a novel methodology for fabricating crack-defined Au nanowires at wafer-scale with a constant voltage, feedback-free electromigration procedure to form tunneling nanogaps free of debris.

Keywords
tunneling junctions, crack junction, electromigration
National Category
Nano Technology
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-250572 (URN)
Conference
32nd IEEE International Conference on Micro Electro Mechanical Systems, Seoul, Korea, from 27-31 January 2019.
Note

QCR 20190820

Available from: 2019-04-30 Created: 2019-04-30 Last updated: 2019-08-20Bibliographically approved
Enrico, A., Dubois, V. J., Niklaus, F. & Stemme, G. (2019). Scalable Manufacturing of Single Nanowire Devices Using Crack-Defined Shadow Mask Lithography. ACS Applied Materials and Interfaces, 11(8), 8217-8226
Open this publication in new window or tab >>Scalable Manufacturing of Single Nanowire Devices Using Crack-Defined Shadow Mask Lithography
2019 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 11, no 8, p. 8217-8226Article in journal (Refereed) Published
Abstract [en]

Single nanowires (NWs) have a broad range of applications in nanoelectronics, nanomechanics, and nano photonics, but, to date, no technique can produce single sub 20 nm wide NWs with electrical connections in a scalable fashion. In this work, we combine conventional optical and crack lithographies to generate single NW devices with controllable and predictable dimensions and placement and with individual electrical contacts to the NWs. We demonstrate NWs made of gold, platinum, palladium, tungsten, tin, and metal oxides. We have used conventional i-line stepper lithography with a nominal resolution of 365 nm to define crack lithography structures in a shadow mask for large-scale manufacturing of sub-20 nm wide NWs, which is a 20-fold improvement over the resolution that is possible with the utilized stepper lithography. Overall, the proposed method represents an effective approach to generate single NW devices with useful applications in electrochemistry, photonics, and gas- and biosensing.

National Category
Nano Technology
Identifiers
urn:nbn:se:kth:diva-250298 (URN)000460365300061 ()2-s2.0-85061896644 (Scopus ID)
Note

QC 20190430

Available from: 2019-04-29 Created: 2019-04-29 Last updated: 2019-10-31Bibliographically approved
Wang, X., Bleiker, S. J., Edinger, P., Errando-Herranz, C., Roxhed, N., Stemme, G., . . . Niklaus, F. (2019). Wafer-Level Vacuum Sealing by Transfer Bonding of Silicon Caps for Small Footprint and Ultra-Thin MEMS Packages. Journal of microelectromechanical systems, 28(3), 460-471
Open this publication in new window or tab >>Wafer-Level Vacuum Sealing by Transfer Bonding of Silicon Caps for Small Footprint and Ultra-Thin MEMS Packages
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2019 (English)In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 28, no 3, p. 460-471Article in journal (Refereed) Published
Abstract [en]

Vacuum and hermetic packaging is a critical requirement for optimal performance of many micro-electro-mechanical systems (MEMS), vacuum electronics, and quantum devices. However, existing packaging solutions are either elaborate to implement or rely on bulky caps and footprint-consuming seals. Here, we address this problem by demonstrating a wafer-level vacuum packaging method featuring transfer bonding of 25-μm-thin silicon (Si) caps that are transferred from a 100-mm-diameter silicon-on-insulator (SOI) wafer to a cavity wafer to seal the cavities by gold-aluminum (Au-Al) thermo-compression bonding at a low temperature of 250 °C. The resulting wafer-scale sealing yields after wafer dicing are 98% and 100% with sealing rings as narrow as 6 and 9 μm, respectively. Despite the small sealing footprint, the Si caps with 9-μm-wide sealing rings demonstrate a high mean shear strength of 127 MPa. The vacuum levels in the getter-free sealed cavities are measured by residual gas analysis to be as low as 1.3 mbar, based on which a leak rate smaller than 2.8x10-14 mbarL/s is derived. We also show that the thickness of the Si caps can be reduced to 6 μm by post-transfer etching while still maintaining excellent hermeticity. The demonstrated ultra-thin packages can potentially be placed in between the solder bumps in flip-chip interfaces, thereby avoiding the need of through-cap-vias in conventional MEMS packages.

Keywords
Vacuum, hermetic, packaging, sealing, MEMS, ultra-thin package, small footprint, transfer bonding, 3D integration, flip chip, aluminum, gold, thermo-compression bonding.
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-250639 (URN)10.1109/JMEMS.2019.2910985 (DOI)
Funder
EU, Horizon 2020, 780283
Note

QC 20190619

Available from: 2019-04-30 Created: 2019-04-30 Last updated: 2019-09-11Bibliographically approved
Ribet, F., De Luca, E., Ottonello Briano, F., Swillo, M., Roxhed, N. & Stemme, G. (2019). Zero-insertion-loss optical shutter based on electrowetting-on-dielectric actuation of opaque ionic liquid microdroplets. Applied Physics Letters, 115(7), Article ID 073502.
Open this publication in new window or tab >>Zero-insertion-loss optical shutter based on electrowetting-on-dielectric actuation of opaque ionic liquid microdroplets
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2019 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 115, no 7, article id 073502Article in journal (Refereed) Published
Abstract [en]

This article reports a broad-band optical shutter based on microdroplet actuation with zero optical insertion loss in the open state. These features are achieved by electrowetting-on-dielectric (EWOD) actuation of opaque ionic liquid microdroplets. The negligible vapor pressure of ionic liquids allows the device to robustly operate in open air, unlike previously proposed EWOD-based systems in which the light crosses several attenuating and reflective layers, preventing broad-band operation and creating insertion losses > 14%. The presented device provides an attenuation of 78dB in the closed state and a transmission of >99.99999% in the open state and can operate in the visible and mid-infrared wavelength range. Moreover, the switch can sustain larger incoming laser powers (5 mW continuous exposure or up to 3h of continuous exposure at similar to 100mW) compared to the values reported for other state-of-the-art EWOD-based shutters. Additionally, the proposed device is compact, operates with low voltage (<25V peak voltage), and features zero static power consumption.

Place, publisher, year, edition, pages
AMER INST PHYSICS, 2019
National Category
Other Physics Topics
Identifiers
urn:nbn:se:kth:diva-257810 (URN)10.1063/1.5108936 (DOI)000481469900019 ()2-s2.0-85070688345 (Scopus ID)
Note

QC 20190912

Available from: 2019-09-12 Created: 2019-09-12 Last updated: 2019-09-12Bibliographically approved
Ribet, F., De Luca, E., Ottonello Briano, F., Swillo, M., Roxhed, N. & Stemme, G. (2019). Zero-Loss Optical Switch Based on Ionic Liquid Microdroplet Ewod Actuatio. In: 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems and Eurosensors XXXIII, TRANSDUCERS 2019 and EUROSENSORS XXXIII: . Paper presented at 20th International Conference on Solid-State Sensors, Actuators and Microsystems and Eurosensors XXXIII, TRANSDUCERS 2019 and EUROSENSORS XXXIII; Estrel Congress CenterBerlin; Germany; 23 June 2019 through 27 June 2019 (pp. 2290-2293). Institute of Electrical and Electronics Engineers (IEEE), Article ID 8808243.
Open this publication in new window or tab >>Zero-Loss Optical Switch Based on Ionic Liquid Microdroplet Ewod Actuatio
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2019 (English)In: 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems and Eurosensors XXXIII, TRANSDUCERS 2019 and EUROSENSORS XXXIII, Institute of Electrical and Electronics Engineers (IEEE), 2019, p. 2290-2293, article id 8808243Conference paper, Published paper (Refereed)
Abstract [en]

This paper reports the first optical shutter based on electrical actuation of microdroplets featuring zero insertion loss in the open state and broad-band operation. These features are achieved by electrowetting-on-dielectric (EWOD) actuation of ionic liquid microdroplets. Due to their negligible vapor pressure, ionic liquids allow the switch to robustly operate in air, unlike previously proposed systems in which the light had to cross several attenuating and refractive layers. Moreover, this solution enables operation in a much wider wavelength range, e.g. in the infrared spectrum where glass has strong absorption. Additionally, the proposed device requires lower voltage to operate (25 V) and features zero static power consumption.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2019
Keywords
digital microfluidics, Electrowetting-on-dielectric, EWOD, ionic liquids, laser optics, microdroplet actuation, microfluidic device, optical component, optical shutter, optical switch
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-262638 (URN)10.1109/TRANSDUCERS.2019.8808243 (DOI)2-s2.0-85071941407 (Scopus ID)9781728120072 (ISBN)
Conference
20th International Conference on Solid-State Sensors, Actuators and Microsystems and Eurosensors XXXIII, TRANSDUCERS 2019 and EUROSENSORS XXXIII; Estrel Congress CenterBerlin; Germany; 23 June 2019 through 27 June 2019
Note

QC 20191017

Available from: 2019-10-17 Created: 2019-10-17 Last updated: 2019-10-17Bibliographically approved
Gatty, H. K., Stemme, G. & Roxhed, N. (2018). A Miniaturized Amperometric Hydrogen Sulfide Sensor Applicable for Bad Breath Monitoring. Micromachines, 9(12), Article ID 612.
Open this publication in new window or tab >>A Miniaturized Amperometric Hydrogen Sulfide Sensor Applicable for Bad Breath Monitoring
2018 (English)In: Micromachines, ISSN 2072-666X, E-ISSN 2072-666X, Vol. 9, no 12, article id 612Article in journal (Refereed) Published
Abstract [en]

Bad breath or halitosis affects a majority of the population from time to time, causing personal discomfort and social embarrassment. Here, we report on a miniaturized, microelectromechanical systems (MEMS)-based, amperometric hydrogen sulfide (H2S) sensor that potentially allows bad breath quantification through a small handheld device. The sensor is designed to detect H2S gas in the order of parts-per-billion (ppb) and has a measured sensitivity of 0.65 nA/ppb with a response time of 21 s. The sensor was found to be selective to NO and NH3 gases, which are normally present in the oral breath of adults. The ppb-level detection capability of the integrated sensor, combined with its relatively fast response and high sensitivity to H2S, makes the sensor potentially applicable for oral breath monitoring.

Place, publisher, year, edition, pages
MDPI, 2018
Keywords
hydrogen sulfide, amperometric, MEMS, gas sensor, bad breath, halitosis
National Category
Medical Laboratory and Measurements Technologies
Identifiers
urn:nbn:se:kth:diva-242263 (URN)10.3390/mi9120612 (DOI)000455072800003 ()30469481 (PubMedID)2-s2.0-85057839920 (Scopus ID)
Note

QC 20190204

Available from: 2019-02-04 Created: 2019-02-04 Last updated: 2019-02-04Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9552-4234

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