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Clément P, Ackermann J, Sahin-Solmaz N, Herbertz S, Boero G, Kruss S, Brugger J. Comparison of electrical and optical transduction modes of DNA-wrapped SWCNT nanosensors for the reversible detection of neurotransmitters. Biosens Bioelectron 2022; 216:114642. [DOI: 10.1016/j.bios.2022.114642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/05/2022] [Accepted: 08/15/2022] [Indexed: 11/02/2022]
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2
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Conde-Rubio A, Liu X, Boero G, Brugger J. Edge-Contact MoS 2 Transistors Fabricated Using Thermal Scanning Probe Lithography. ACS Appl Mater Interfaces 2022; 14:42328-42336. [PMID: 36070441 PMCID: PMC9501915 DOI: 10.1021/acsami.2c10150] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
The science and engineering of two-dimensional materials (2DMs), in particular, of 2D semiconductors, is advancing at a thriving pace. It is well known that these delicate few-atoms thick materials can be damaged during the processing toward their integration into final devices. Thermal scanning probe lithography (t-SPL) is a gentle alternative to the typically used electron beam lithography to fabricate these devices avoiding the use of electrons, which are well known to deteriorate the 2DMs' properties. Here, t-SPL is used for the fabrication of MoS2-based field effect transistors (FETs). In particular, the use of t-SPL is demonstrated for the first time for the fabrication of edge-contact MoS2 FETs, combining the hot-tip patterning and Ar+ milling to etch the 2DM. To avoid contamination of the contact interface by atmospheric gas molecules, etching and metal deposition are performed without breaking the vacuum conditions in between. With this process, edge-contact MoS2 FETs are successfully fabricated and characterized. On/off ratios up to 108 and 109 are obtained at room temperature in air and vacuum, respectively, i.e., comparable with the best values reported in the literature.
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Gompelmann D, Sinn K, Brugger J, Bernitzky D, Mosleh B, Prosch H, Geleff S, Blessing A, Tiefenbacher A, Hoetzenecker K, Idzko M, Hoda MA. Correlation of PD-L1 expression on tumour cells between diagnostic biopsies and surgical specimens of lung cancer in real life with respect to biopsy techniques and neoadjuvant treatment. J Cancer Res Clin Oncol 2022; 149:1747-1754. [PMID: 35708777 PMCID: PMC10097774 DOI: 10.1007/s00432-022-04080-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 05/19/2022] [Indexed: 12/25/2022]
Abstract
PURPOSES Programmed death-ligand 1 (PD-L1) testing is performed mainly on biopsy specimens in patients with advanced lung cancer. It is questionable whether the small amount of tissue analysed in biopsies may represent the true PD-L1 expression of a tumour. METHODS In this retrospective study, PD-L1 expression on tumour cells derived from bronchoscopy brush cytology, endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA), endobronchial biopsy, transbronchial biopsy (TBB) and computed tomography (CT)-guided transthoracic biopsy was compared to the PD-L1 expression of the corresponding surgical resection in lung cancer patients with regard to neoadjuvant treatment in-between. RESULTS A quantitative comparison between the diagnostic biopsy of the primary tumour with corresponding resected surgical specimens in a total of 113 lung cancer patients (60% male, mean age 65 ± 9 years) revealed a statistically significant correlation of PD-L1 expression on tumour cells (r = 0.58, p< 0.001), for patients without neoadjuvant treatment in-between and for patients who underwent neoadjuvant treatment (both p < 0.001). Using a cut-off value of ≥ 50% PD-L1 TPS for comparing the biopsy samples and resected specimens, the concordance rate was 78% with a Cohen's Kappa of 0.45. CONCLUSION A statistically significant concordance for PD-L1 expression on tumour cells between biopsies from primary lung tumour and resected specimen was found, but of uncertain clinical accuracy. The use of a cut-off value of ≥ 50% PD-L1 TPS resulted only in a moderate agreement. Therefore, the interpretation of the PD-L1 determined form biopsy specimens status should only be considered with caution for treatment decisionsQuery.
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Affiliation(s)
- D Gompelmann
- Division of Pulmonology, Department of Internal Medicine II, Medical University Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.
| | - K Sinn
- Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria
| | - J Brugger
- Department for Medical Statistics, Informatics and Intelligent Systems, Medical University of Vienna, Vienna, Austria
| | - D Bernitzky
- Division of Pulmonology, Department of Internal Medicine II, Medical University Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - B Mosleh
- Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria
| | - H Prosch
- Department for Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | - S Geleff
- Department of Pathology, Medical University Vienna, Vienna, Austria
| | - A Blessing
- Department of Pathology, Medical University Vienna, Vienna, Austria
| | - A Tiefenbacher
- Department of Pathology, Medical University Vienna, Vienna, Austria
| | - K Hoetzenecker
- Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria
| | - M Idzko
- Division of Pulmonology, Department of Internal Medicine II, Medical University Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria
| | - M A Hoda
- Department of Thoracic Surgery, Medical University Vienna, Vienna, Austria
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4
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Sivelli G, Conley GM, Herrera C, Marable K, Rodriguez KJ, Bollwein H, Sudano MJ, Brugger J, Simpson AJ, Boero G, Grisi M. NMR spectroscopy of a single mammalian early stage embryo. J Magn Reson 2022; 335:107142. [PMID: 34999310 DOI: 10.1016/j.jmr.2021.107142] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 12/22/2021] [Accepted: 12/26/2021] [Indexed: 06/14/2023]
Abstract
The resolving power, chemical sensitivity and non-invasive nature of NMR have made it an established technique for in vivo studies of large organisms both for research and clinical applications. NMR would clearly be beneficial for analysis of entities at the microscopic scale of about 1 nL (the nanoliter scale), typical of early development of mammalian embryos, microtissues and organoids: the scale where the building blocks of complex organisms could be observed. However, the handling of such small samples (about 100 µm) and sensitivity issues have prevented a widespread adoption of NMR. In this article we show how these limitations can be overcome to obtain NMR spectra of a mammalian embryo in its early stage. To achieve this we employ ultra-compact micro-chip technologies in combination with 3D-printed micro-structures. Such device is packaged for use as plug & play sensor and it shows sufficient sensitivity to resolve NMR signals from individual bovine pre-implantation embryos. The embryos in this study are obtained through In Vitro Fertilization (IVF) techniques, transported cryopreserved to the NMR laboratory, and measured shortly after thawing. In less than 1 h these spherical samples of just 130-190 µm produce distinct spectral peaks, largely originating from lipids contained inside them. We further observe how the spectra vary from one sample to another despite their optical and morphological similarities, suggesting that the method can further develop into a non-invasive embryo assay for selection prior to embryo transfer.
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Affiliation(s)
| | | | - Carolina Herrera
- Clinic of Reproductive Medicine, Department for Farm Animals, University of Zurich, 8057 Zurich, Switzerland
| | | | - Kyle J Rodriguez
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Heinrich Bollwein
- Clinic of Reproductive Medicine, Department for Farm Animals, University of Zurich, 8057 Zurich, Switzerland
| | - Mateus J Sudano
- Department of Genetics and Evolution, Federal University of São Carlos, São Carlos, SP, Brazil
| | - Jürgen Brugger
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andre J Simpson
- Environmental NMR Center, University of Toronto, Scarborough Campus, 1265 Military Trail, Toronto M1C1A5, Canada
| | - Giovanni Boero
- Environmental NMR Center, University of Toronto, Scarborough Campus, 1265 Military Trail, Toronto M1C1A5, Canada
| | - Marco Grisi
- Annaida Technologies SA, Lausanne, Switzerland.
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5
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Sun YC, Boero G, Brugger J. Stretchable Conductors Fabricated by Stencil Lithography and Centrifugal Force-Assisted Patterning of Liquid Metal. ACS Appl Electron Mater 2021; 3:5423-5432. [PMID: 34977587 PMCID: PMC8717634 DOI: 10.1021/acsaelm.1c00884] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 11/16/2021] [Indexed: 05/26/2023]
Abstract
Embedding liquid metals (LMs) into an elastomer is emerging as a promising strategy for stretchable conductors. Existing manufacturing techniques are struggling between spatial resolution and process complexity and are limited to chemically resistant substrates. Here, we report on a hybrid process combining stencil lithography and centrifugal force-assisted patterning of liquid metal for the development of LM-based stretchable conductors. The selective wetting behavior of oxide-removed eutectic gallium-indium (EGaIn) on metal patterns defined by stencil lithography enables micrometer scale LM patterns on an elastomeric substrate. Stencil lithography allows for defining metal regions without harsh chemical treatments, making it suitable for a wide range of substrates. Microscale LM patterns are achieved by efficiently removing the excess material by the centrifugal forces experienced from spinning the substrate. The proposed approach allows for the creation of LM patterns with a line width as small as 2 μm on a stretchable poly(dimethylsiloxane) (PDMS) substrate. The electrical measurement results show that the fabricated EGaIn devices can endure 40% mechanical strain over several thousands of cycles. Furthermore, a stencil design using microbridges is proposed to address the mechanical stability issue in stencil lithography. An EGaIn conductor with a serpentine structure and an interdigitated capacitor are fabricated and characterized. The results demonstrate that the patterned serpentine conductors retain their functionality with applied mechanical strain up to 80%. The performance of the interdigitated capacitors upon applied strain is in good agreement with the theoretical estimation. Finally, we demonstrate our approach also on poly(octamethylene maleate (anhydride) citrate) (POMaC) substrates to broaden the use of the proposed method to not only flexible and stretchable but also biodegradable substrates, opening a way for in vivo transient microsystem engineering. The work presented here provides a versatile and reliable approach for manufacturing stretchable conductors.
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Fischer A, Siebenrock T, Liebau K, Hertwig A, Hahn R, Anwar M, Pesta M, Timmermann I, Brugger J, Posch M, Tamandl D, Ringl H, Hiesmayr M. Association of ct skeletal muscle area and density with age: a prospective study in 200 non-critically ill patients. Clin Nutr ESPEN 2021. [DOI: 10.1016/j.clnesp.2021.09.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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Schick MA, Pippir J, Struck MF, Brugger J, Neuhaus W, Wunder C. Comparison of hydroxyethylstarch (HES 130/0.4) and 5% human albumin for volume substitution in pediatric neurosurgery: A retrospective, single center study. BMC Res Notes 2021; 14:434. [PMID: 34838152 PMCID: PMC8627096 DOI: 10.1186/s13104-021-05836-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/03/2021] [Indexed: 11/10/2022] Open
Abstract
Objective Colloid solutions are commonly used to maintain perioperative fluid homeostasis. In regard to perioperative infant-centered care, data about the impact of colloids are rare. New data suggest a possible positive effect of hydroxyethyl starch (HES) concerning blood brain barrier. Therefore we conduct a retrospective single center study of children scheduled for neurosurgery, age < five with a blood loss > 10% of body blood volume, receiving either 6% HES 130/0.4 or 5% human albumin (HA). Results Out of 913 patients, 86 were included (HES = 30; HA = 56). Compared to HES [16.4 ± 9.2 ml/kg body weight (mean ± SD)] HA group received more colloid volume (25.7 ± 11.3), which had more blood loss [HA 54.8 ± 45.0; HES 30.5 ± 30.0 (%) estimated blood volume] and higher fluid balances. Fibrinogen was decreased and activated partial thromboplastin time was elevated in HA group. Urinary output, creatinine and urea levels did not differ between the two groups. Serum calcium, total protein levels were lower in HES group. HA treated infants tended to have shorter ICU and hospital stays. We conclude that none of the investigated colloid solutions were without leverage to infants. Consequently randomized controlled trials about perioperative goal-directed fluid replacement of children undergoing (neuro)-surgery with major blood loss are needed. Supplementary Information The online version contains supplementary material available at 10.1186/s13104-021-05836-w.
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Affiliation(s)
- Martin A Schick
- Department of Anesthesiology and Critical Care, Medical Center - University of Freiburg, Freiburg, Germany. .,Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Jonas Pippir
- Department for Anesthesiology, Intensive Care Medicine, Emergency Medicine, Pain Therapy and Palliative Care, Klinikum am Steinenberg, Reutlingen, Germany
| | - Manuel F Struck
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Leipzig, Leipzig, Germany
| | - Jürgen Brugger
- Department of Anaesthesiology, Intensive Care, Emergency and Pain Medicine, University Hospital Wuerzburg, Wuerzburg, Germany
| | - Winfried Neuhaus
- Competence Unit Molecular Diagnostics, Center Health and Bioresources, AIT - Austrian Institute of Technology GmbH, Vienna, Austria
| | - Christian Wunder
- Department of Anesthesiology and Intensive Care Medicine, Robert-Bosch-Krankenhaus, Stuttgart, Germany
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8
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Liu X, Sachan AK, Howell ST, Conde-Rubio A, Knoll AW, Boero G, Zenobi R, Brugger J. Thermomechanical Nanostraining of Two-Dimensional Materials. Nano Lett 2020; 20:8250-8257. [PMID: 33030906 PMCID: PMC7662931 DOI: 10.1021/acs.nanolett.0c03358] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/27/2020] [Indexed: 05/07/2023]
Abstract
Local bandgap tuning in two-dimensional (2D) materials is of significant importance for electronic and optoelectronic devices but achieving controllable and reproducible strain engineering at the nanoscale remains a challenge. Here, we report on thermomechanical nanoindentation with a scanning probe to create strain nanopatterns in 2D transition metal dichalcogenides and graphene, enabling arbitrary patterns with a modulated bandgap at a spatial resolution down to 20 nm. The 2D material is in contact via van der Waals interactions with a thin polymer layer underneath that deforms due to the heat and indentation force from the heated probe. Specifically, we demonstrate that the local bandgap of molybdenum disulfide (MoS2) is spatially modulated up to 10% and is tunable up to 180 meV in magnitude at a linear rate of about -70 meV per percent of strain. The technique provides a versatile tool for investigating the localized strain engineering of 2D materials with nanometer-scale resolution.
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Affiliation(s)
- Xia Liu
- Microsystems
Laboratory, École Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Amit Kumar Sachan
- Department
of Chemistry and Applied Biosciences, ETH
Zurich, 8093 Zurich, Switzerland
| | - Samuel Tobias Howell
- Microsystems
Laboratory, École Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Ana Conde-Rubio
- Microsystems
Laboratory, École Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Armin W. Knoll
- IBM
Research - Zurich, Säumerstrasse
4, 8803 Rüschlikon, Switzerland
| | - Giovanni Boero
- Microsystems
Laboratory, École Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Renato Zenobi
- Department
of Chemistry and Applied Biosciences, ETH
Zurich, 8093 Zurich, Switzerland
| | - Jürgen Brugger
- Microsystems
Laboratory, École Polytechnique Fédérale
de Lausanne (EPFL), 1015 Lausanne, Switzerland
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9
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Grisi M, Conley GM, Rodriguez KJ, Riva E, Egli L, Moritz W, Lichtenberg J, Brugger J, Boero G. NMR microsystem for label-free characterization of 3D nanoliter microtissues. Sci Rep 2020; 10:18306. [PMID: 33110145 PMCID: PMC7758329 DOI: 10.1038/s41598-020-75480-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 10/13/2020] [Indexed: 02/06/2023] Open
Abstract
Performing chemical analysis at the nanoliter (nL) scale is of paramount importance for medicine, drug development, toxicology, and research. Despite the numerous methodologies available, a tool for obtaining chemical information non-invasively is still missing at this scale. Observer effects, sample destruction and complex preparatory procedures remain a necessary compromise. Among non-invasive spectroscopic techniques, one able to provide holistic and highly resolved chemical information in-vivo is nuclear magnetic resonance (NMR). For its renowned informative power and ability to foster discoveries and life-saving applications, efficient NMR at microscopic scales is highly sought after, but so far technical limitations could not match the stringent necessities of microbiology, such as biocompatible handling, ease of use, and high throughput. Here we introduce a novel microsystem, which combines CMOS technology with 3D microfabrication, enabling nL NMR as a platform tool for non-invasive spectroscopy of organoids, 3D cell cultures, and early stage embryos. In this study we show its application to microlivers models simulating non-alcoholic fatty liver disease, demonstrating detection of lipid metabolism dynamics in a time frame of 14 days based on 117 measurements of single 3D human liver microtissues.
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Affiliation(s)
- Marco Grisi
- Annaida Technologies SA, Lausanne, Switzerland.
| | | | - Kyle J Rodriguez
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Erika Riva
- Service de Gastro-Entérologie et D'hépatologie, CHUV, Epalinges, Switzerland
| | | | | | | | - Jürgen Brugger
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Giovanni Boero
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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10
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Meligrana G, Ferrari S, Lucherini L, Celè J, Colò F, Brugger J, Ricciardi C, Ruffo R, Gerbaldi C. Na
3
V
2
(PO
4
)
3
‐Supported Electrospun Carbon Nanofiber Nonwoven Fabric as Self‐Standing Na‐Ion Cell Cathode. ChemElectroChem 2020. [DOI: 10.1002/celc.202000345] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- G. Meligrana
- Group for Applied Materials and Electrochemistry (GAME Lab) Department of Applied Science and Technology (DISAT) Politecnico di Torino Corso Duca degli Abruzzi 24 10129 Torino Italy
| | - S. Ferrari
- Department of Pharmacy University of Chieti Pescara “G. d'Annunzio” Via dei Vestini 31 66100 Chieti Italy
| | - L. Lucherini
- Department of Applied Science and Technology (DISAT) Politecnico di Torino Corso Duca degli Abruzzi 24 10129 Torino Italy
- Microsystems Laboratory École Polytechnique Fédérale de Lausanne – EPFL 1015 Lausanne Switzerland
| | - J. Celè
- Department of Applied Science and Technology (DISAT) Politecnico di Torino Corso Duca degli Abruzzi 24 10129 Torino Italy
- Microsystems Laboratory École Polytechnique Fédérale de Lausanne – EPFL 1015 Lausanne Switzerland
| | - F. Colò
- Group for Applied Materials and Electrochemistry (GAME Lab) Department of Applied Science and Technology (DISAT) Politecnico di Torino Corso Duca degli Abruzzi 24 10129 Torino Italy
| | - J. Brugger
- Microsystems Laboratory École Polytechnique Fédérale de Lausanne – EPFL 1015 Lausanne Switzerland
| | - C. Ricciardi
- Department of Applied Science and Technology (DISAT) Politecnico di Torino Corso Duca degli Abruzzi 24 10129 Torino Italy
| | - R. Ruffo
- Department of Materials Science Università di Milano-Bicocca Via Roberto Cozzi 55 20125 Milano Italy
| | - C. Gerbaldi
- Group for Applied Materials and Electrochemistry (GAME Lab) Department of Applied Science and Technology (DISAT) Politecnico di Torino Corso Duca degli Abruzzi 24 10129 Torino Italy
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11
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Altree-Williams A, Brugger J, Pring A, Bedrikovetsky P. Coupled reactive flow and dissolution with changing reactive surface and porosity. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.05.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Grisi M, Montinaro E, Vincent F, Pethö L, Letizia MC, Volpe B, Harris N, Beck A, Guidetti R, Gijs M, Michler J, Brugger J, Boero G. CMOS and 3D Printing for NMR Spectroscopy at the Single Embryo Scale. Chimia (Aarau) 2019; 73:635. [PMID: 31431222 DOI: 10.2533/chimia.2019.635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/26/2024] Open
Affiliation(s)
- Marco Grisi
- Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne
| | - Enrica Montinaro
- Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne
| | | | - Laszlo Pethö
- Swiss Federal Laboratories for Materials Science and Technology (EMPA), CH-3602 Thun
| | - Maria Cristina Letizia
- Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne
| | - Beatrice Volpe
- Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne
| | - Nicola Harris
- Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne
| | | | | | - Martin Gijs
- Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne
| | - Johann Michler
- Swiss Federal Laboratories for Materials Science and Technology (EMPA), CH-3602 Thun
| | - Jürgen Brugger
- Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne
| | - Giovanni Boero
- Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 17, CH-1015 Lausanne;,
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Altree-Williams A, Brugger J, Pring A, Bedrikovetsky P. Exact Solution for Coupled Reactive Flow and Dissolution with Porosity Changes. Transp Porous Media 2018. [DOI: 10.1007/s11242-018-1088-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Montinaro E, Grisi M, Letizia MC, Pethö L, Gijs MAM, Guidetti R, Michler J, Brugger J, Boero G. 3D printed microchannels for sub-nL NMR spectroscopy. PLoS One 2018; 13:e0192780. [PMID: 29742104 PMCID: PMC5942786 DOI: 10.1371/journal.pone.0192780] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 01/30/2018] [Indexed: 11/19/2022] Open
Abstract
Nuclear magnetic resonance (NMR) experiments on subnanoliter (sub-nL) volumes are hindered by the limited sensitivity of the detector and the difficulties in positioning and holding such small samples in proximity of the detector. In this work, we report on NMR experiments on liquid and biological entities immersed in liquids having volumes down to 100 pL. These measurements are enabled by the fabrication of high spatial resolution 3D printed microfluidic structures, specifically conceived to guide and confine sub-nL samples in the sub-nL most sensitive volume of a single-chip integrated NMR probe. The microfluidic structures are fabricated using a two-photon polymerization 3D printing technique having a resolution better than 1 μm3. The high spatial resolution 3D printing approach adopted here allows to rapidly fabricate complex microfluidic structures tailored to position, hold, and feed biological samples, with a design that maximizes the NMR signals amplitude and minimizes the static magnetic field inhomogeneities. The layer separating the sample from the microcoil, crucial to exploit the volume of maximum sensitivity of the detector, has a thickness of 10 μm. To demonstrate the potential of this approach, we report NMR experiments on sub-nL intact biological entities in liquid media, specifically ova of the tardigrade Richtersius coronifer and sections of Caenorhabditis elegans nematodes. We show a sensitivity of 2.5x1013 spins/Hz1/2 on 1H nuclei at 7 T, sufficient to detect 6 pmol of 1H nuclei of endogenous compounds in active volumes down to 100 pL and in a measurement time of 3 hours. Spectral resolutions of 0.01 ppm in liquid samples and of 0.1 ppm in the investigated biological entities are also demonstrated. The obtained results may indicate a route for NMR studies at the single unit level of important biological entities having sub-nL volumes, such as living microscopic organisms and eggs of several mammalians, humans included.
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Affiliation(s)
- E. Montinaro
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory for Microsystems, Lausanne, Switzerland
| | - M. Grisi
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory for Microsystems, Lausanne, Switzerland
| | - M. C. Letizia
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory for Microsystems, Lausanne, Switzerland
| | - L. Pethö
- Swiss Federal Laboratories for Materials Science and Technology (EMPA), Laboratory for Mechanics of Materials and Nanostructures, Thun, Switzerland
| | - M. A. M. Gijs
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory for Microsystems, Lausanne, Switzerland
| | - R. Guidetti
- University of Modena and Reggio Emilia, Department of Life Sciences, Modena, Italy
| | - J. Michler
- Swiss Federal Laboratories for Materials Science and Technology (EMPA), Laboratory for Mechanics of Materials and Nanostructures, Thun, Switzerland
| | - J. Brugger
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory for Microsystems, Lausanne, Switzerland
| | - G. Boero
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory for Microsystems, Lausanne, Switzerland
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15
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Sharma I, Batra Y, Flauraud V, Brugger J, Mehta BR. Growth of Large-Area 2D MoS₂ Arrays at Pre-Defined Locations Using Stencil Mask Lithography. J Nanosci Nanotechnol 2018; 18:1824-1832. [PMID: 29448666 DOI: 10.1166/jnn.2018.14265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The growth of MoS2 layers of desired dimensions at predefined locations is essential for fabricating opto-electronic devices based solely on MoS2 or on hetero-structures based on MoS2. Here we present a new route for patterned growth of MoS2 by combining radio frequency (RF) magnetron sputtering, stencil mask lithography and vapour phase sulfurization. The present method does not involve chemical etchants and organic photoresist and hence provides a simplified process of achieving MoS2 patterns. Here, the control over the number of layers (mono, few and bulk) of MoS2 is achieved by varying the thickness of Mo films. The statistical variation in thickness i.e., number of MoS2 layers within the individual patterns is investigated from Raman mappings which revealed the uniform growth of 3-4 MoS2 layers. From Kelvin probe force microscopy, the surface potential values of MoS2 patterns lie in the range -350 to -370 mV, which is consistent with 2D MoS2 layer with thickness of 3-4 layers. The surface potential analysis across individual patterns indicates weakly n-type doping of few layers MoS2 with Fermi level located ~0.83-0.85 eV below the conduction band edge.
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Affiliation(s)
- Intu Sharma
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - Yogita Batra
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016, India
| | - V Flauraud
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Jürgen Brugger
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Bodh Raj Mehta
- Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016, India
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16
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Missen OP, Mills SJ, Welch MD, Spratt J, Rumsey MS, Birch WD, Brugger J. The crystal structure of cesbronite, Cu 3TeO 4(OH) 4: a novel sheet tellurate topology. Acta Crystallogr B Struct Sci Cryst Eng Mater 2018. [DOI: 10.1107/s205252061701647x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The crystal structure of cesbronite has been determined using single-crystal X-ray diffraction and supported by electron-microprobe analysis, powder diffraction and Raman spectroscopy. Cesbronite is orthorhombic, space group Cmcm, with a = 2.93172 (16), b = 11.8414 (6), c = 8.6047 (4) Å and V = 298.72 (3) Å3. The chemical formula of cesbronite has been revised to CuII
3TeVIO4(OH)4 from CuII
5(TeIVO3)2(OH)6·2H2O. This change has been accepted by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, Proposal 17-C. The previously reported oxidation state of tellurium has been shown to be incorrect; the crystal structure, bond valence studies and charge balance clearly show tellurium to be hexavalent. The crystal structure of cesbronite is formed from corrugated sheets of edge-sharing CuO6 and (Cu0.5Te0.5)O6 octahedra. The structure determined here is an average structure that has underlying ordering of Cu and Te at one of the two metal sites, designated as M, which has an occupancy Cu0.5Te0.5. This averaging probably arises from an absence of correlation between adjacent polyhedral sheets, as there are two different hydrogen-bonding configurations linking sheets that are related by a ½a offset. Randomised stacking of these two configurations results in the superposition of Cu and Te and leads to the Cu0.5Te0.5 occupancy of the M site in the average structure. Bond-valence analysis is used to choose the most probable Cu/Te ordering scheme and also to identify protonation sites (OH). The chosen ordering scheme and its associated OH sites are shown to be consistent with the revised chemical formula.
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17
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Winkler PM, Regmi R, Flauraud V, Brugger J, Rigneault H, Wenger J, García-Parajo MF. Optical Antenna-Based Fluorescence Correlation Spectroscopy to Probe the Nanoscale Dynamics of Biological Membranes. J Phys Chem Lett 2018; 9:110-119. [PMID: 29240442 DOI: 10.1021/acs.jpclett.7b02818] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The plasma membrane of living cells is compartmentalized at multiple spatial scales ranging from the nano- to the mesoscale. This nonrandom organization is crucial for a large number of cellular functions. At the nanoscale, cell membranes organize into dynamic nanoassemblies enriched by cholesterol, sphingolipids, and certain types of proteins. Investigating these nanoassemblies known as lipid rafts is of paramount interest in fundamental cell biology. However, this goal requires simultaneous nanometer spatial precision and microsecond temporal resolution, which is beyond the reach of common microscopes. Optical antennas based on metallic nanostructures efficiently enhance and confine light into nanometer dimensions, breaching the diffraction limit of light. In this Perspective, we discuss recent progress combining optical antennas with fluorescence correlation spectroscopy (FCS) to monitor microsecond dynamics at nanoscale spatial dimensions. These new developments offer numerous opportunities to investigate lipid and protein dynamics in both mimetic and native biological membranes.
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Affiliation(s)
- Pamina M Winkler
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain
| | - Raju Regmi
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel , Marseille, France
| | - Valentin Flauraud
- Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Jürgen Brugger
- Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Hervé Rigneault
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel , Marseille, France
| | - Jérôme Wenger
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel , Marseille, France
| | - María F García-Parajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain
- ICREA , Pg. Lluís Companys 23, 08010 Barcelona, Spain
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18
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Zimmermann ST, Balkenende DWR, Lavrenova A, Weder C, Brugger J. Nanopatterning of a Stimuli-Responsive Fluorescent Supramolecular Polymer by Thermal Scanning Probe Lithography. ACS Appl Mater Interfaces 2017; 9:41454-41461. [PMID: 29077391 PMCID: PMC5709779 DOI: 10.1021/acsami.7b13672] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Accepted: 10/27/2017] [Indexed: 05/24/2023]
Abstract
The miniaturization of nanometer-sized multicolor fluorescent features is of continuous significance for counterfeit security features, data storage, and sensors. Recent advances in engineering of stimuli-responsive supramolecular polymeric materials that respond upon exposure to heat or mechanical force by changing their fluorescence characteristics open new opportunities as functional lithographic resists. Here, we demonstrate the patterning of a thermochromic supramolecular material by thermal scanning probe lithography (t-SPL), an emerging nanofabrication technique, which allows for ultrafast indentation with a heated probe, resulting in both fluorescent and topographic nanofeatures. t-SPL indentation reveals a linear relationship between the temperature at which material softening occurs and the indentation force in the range from 200 to 500 nN. The softening temperature decreases as the heating time increases from 4 μs to 1 ms, following time-temperature superposition behavior. Our results herein confirm that the fluorescence contrast, perceivable as a shift from red to green, was obtained by kinetic trapping of the dissociated state due to ultrarapid cooling when the probe is removed. We use t-SPL to create highly customized fluorescence patterns up to 40 × 40 μm2 in size with a spatial resolution of 86 nm and change the pitch size to modify the fluorescence intensity when observed by fluorescence microscopy. As an application, multifaceted security features with nanometer resolution are explored.
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Affiliation(s)
- Samuel Tobias Zimmermann
- Microsystems Laboratory, École Polytechnique Fédérale
de Lausanne, CH-1015 Lausanne, Switzerland
| | | | - Anna Lavrenova
- Adolphe Merkle Institute, University of
Fribourg, 1700 Fribourg, Switzerland
| | - Christoph Weder
- Adolphe Merkle Institute, University of
Fribourg, 1700 Fribourg, Switzerland
| | - Jürgen Brugger
- Microsystems Laboratory, École Polytechnique Fédérale
de Lausanne, CH-1015 Lausanne, Switzerland
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19
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Regmi R, Winkler PM, Flauraud V, Borgman KJE, Manzo C, Brugger J, Rigneault H, Wenger J, García-Parajo MF. Planar Optical Nanoantennas Resolve Cholesterol-Dependent Nanoscale Heterogeneities in the Plasma Membrane of Living Cells. Nano Lett 2017; 17:6295-6302. [PMID: 28926278 DOI: 10.1021/acs.nanolett.7b02973] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Optical nanoantennas can efficiently confine light into nanoscopic hotspots, enabling single-molecule detection sensitivity at biological relevant conditions. This innovative approach to breach the diffraction limit offers a versatile platform to investigate the dynamics of individual biomolecules in living cell membranes and their partitioning into cholesterol-dependent lipid nanodomains. Here, we present optical nanoantenna arrays with accessible surface hotspots to study the characteristic diffusion dynamics of phosphoethanolamine (PE) and sphingomyelin (SM) in the plasma membrane of living cells at the nanoscale. Fluorescence burst analysis and fluorescence correlation spectroscopy performed on nanoantennas of different gap sizes show that, unlike PE, SM is transiently trapped in cholesterol-enriched nanodomains of 10 nm diameter with short characteristic times around 100 μs. The removal of cholesterol led to the free diffusion of SM, consistent with the dispersion of nanodomains. Our results are consistent with the existence of highly transient and fluctuating nanoscale assemblies enriched by cholesterol and sphingolipids in living cell membranes, also known as lipid rafts. Quantitative data on sphingolipids partitioning into lipid rafts is crucial to understand the spatiotemporal heterogeneous organization of transient molecular complexes on the membrane of living cells at the nanoscale. The proposed technique is fully biocompatible and thus provides various opportunities for biophysics and live cell research to reveal details that remain hidden in confocal diffraction-limited measurements.
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Affiliation(s)
- Raju Regmi
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain
- Aix Marseille Univ , CNRS, Centrale Marseille, Institut Fresnel, Marseille, France
| | - Pamina M Winkler
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain
| | - Valentin Flauraud
- Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Kyra J E Borgman
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain
| | - Carlo Manzo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain
| | - Jürgen Brugger
- Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Hervé Rigneault
- Aix Marseille Univ , CNRS, Centrale Marseille, Institut Fresnel, Marseille, France
| | - Jérôme Wenger
- Aix Marseille Univ , CNRS, Centrale Marseille, Institut Fresnel, Marseille, France
| | - María F García-Parajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology , 08860 Barcelona, Spain
- ICREA , Pg. Lluı́s Companys 23, 08010 Barcelona, Spain
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20
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Oellers T, König D, Kostka A, Xie S, Brugger J, Ludwig A. Shape Memory Micro- and Nanowire Libraries for the High-Throughput Investigation of Scaling Effects. ACS Comb Sci 2017; 19:574-584. [PMID: 28759201 DOI: 10.1021/acscombsci.7b00065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The scaling behavior of Ti-Ni-Cu shape memory thin-film micro- and nanowires of different geometry is investigated with respect to its influence on the martensitic transformation properties. Two processes for the high-throughput fabrication of Ti-Ni-Cu micro- to nanoscale thin film wire libraries and the subsequent investigation of the transformation properties are reported. The libraries are fabricated with compositional and geometrical (wire width) variations to investigate the influence of these parameters on the transformation properties. Interesting behaviors were observed: Phase transformation temperatures change in the range from 1 to 72 °C (austenite finish, (Af), 13 to 66 °C (martensite start, Ms) and the thermal hysteresis from -3.5 to 20 K. It is shown that a vanishing hysteresis can be achieved for special combinations of sample geometry and composition.
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Affiliation(s)
- Tobias Oellers
- Institute
for Materials, Faculty of Mechanical Engineering, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | - Dennis König
- Institute
for Materials, Faculty of Mechanical Engineering, Ruhr-Universität Bochum, 44801 Bochum, Germany
| | | | - Shenqie Xie
- Ecole
Polytechnique Federale de Lausanne (EPFL), Laboratoire de Microsystemes, CH-1015 Lausanne, Switzerland
| | - Jürgen Brugger
- Ecole
Polytechnique Federale de Lausanne (EPFL), Laboratoire de Microsystemes, CH-1015 Lausanne, Switzerland
| | - Alfred Ludwig
- Institute
for Materials, Faculty of Mechanical Engineering, Ruhr-Universität Bochum, 44801 Bochum, Germany
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21
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Winkler PM, Regmi R, Flauraud V, Brugger J, Rigneault H, Wenger J, García-Parajo MF. Transient Nanoscopic Phase Separation in Biological Lipid Membranes Resolved by Planar Plasmonic Antennas. ACS Nano 2017; 11:7241-7250. [PMID: 28696660 DOI: 10.1021/acsnano.7b03177] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Nanoscale membrane assemblies of sphingolipids, cholesterol, and certain proteins, also known as lipid rafts, play a crucial role in facilitating a broad range of important cell functions. Whereas on living cell membranes lipid rafts have been postulated to have nanoscopic dimensions and to be highly transient, the existence of a similar type of dynamic nanodomains in multicomponent lipid bilayers has been questioned. Here, we perform fluorescence correlation spectroscopy on planar plasmonic antenna arrays with different nanogap sizes to assess the dynamic nanoscale organization of mimetic biological membranes. Our approach takes advantage of the highly enhanced and confined excitation light provided by the nanoantennas together with their outstanding planarity to investigate membrane regions as small as 10 nm in size with microsecond time resolution. Our diffusion data are consistent with the coexistence of transient nanoscopic domains in both the liquid-ordered and the liquid-disordered microscopic phases of multicomponent lipid bilayers. These nanodomains have characteristic residence times between 30 and 150 μs and sizes around 10 nm, as inferred from the diffusion data. Thus, although microscale phase separation occurs on mimetic membranes, nanoscopic domains also coexist, suggesting that these transient assemblies might be similar to those occurring in living cells, which in the absence of raft-stabilizing proteins are poised to be short-lived. Importantly, our work underscores the high potential of photonic nanoantennas to interrogate the nanoscale heterogeneity of native biological membranes with ultrahigh spatiotemporal resolution.
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Affiliation(s)
- Pamina M Winkler
- Institut de Ciencies Fotoniques (ICFO), The Barcelona Institute of Science and Technology , Barcelona, Spain
| | - Raju Regmi
- Institut de Ciencies Fotoniques (ICFO), The Barcelona Institute of Science and Technology , Barcelona, Spain
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel , Marseille, France
| | - Valentin Flauraud
- Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Jürgen Brugger
- Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Hervé Rigneault
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel , Marseille, France
| | - Jérôme Wenger
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel , Marseille, France
| | - María F García-Parajo
- Institut de Ciencies Fotoniques (ICFO), The Barcelona Institute of Science and Technology , Barcelona, Spain
- ICREA , Pg. Lluís Companys 23, 08010 Barcelona, Spain
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22
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Fesenko P, Flauraud V, Xie S, Kang E, Uemura T, Brugger J, Genoe J, Heremans P, Rolin C. Growth Of Organic Semiconductor Thin Films with Multi-Micron Domain Size and Fabrication of Organic Transistors Using a Stencil Nanosieve. ACS Appl Mater Interfaces 2017; 9:23314-23318. [PMID: 28678470 DOI: 10.1021/acsami.7b06584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
To grow small molecule semiconductor thin films with domain size larger than modern-day device sizes, we evaporate the material through a dense array of small apertures, called a stencil nanosieve. The aperture size of 0.5 μm results in low nucleation density, whereas the aperture-to-aperture distance of 0.5 μm provides sufficient crosstalk between neighboring apertures through the diffusion of adsorbed molecules. By integrating the nanosieve in the channel area of a thin-film transistor mask, we show a route for patterning both the organic semiconductor and the metal contacts of thin-film transistors using one mask only and without mask realignment.
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Affiliation(s)
- Pavlo Fesenko
- imec , Large Area Electronics, Kapeldreef 75, 3001 Leuven, Belgium
- KU Leuven , Department of Electrical Engineering, Kasteelpark Arenberg 10, 3001 Leuven, Belgium
| | | | - Shenqi Xie
- EPFL , Microsystems Laboratory, CH-1015 Lausanne, Switzerland
| | - Enpu Kang
- imec , Large Area Electronics, Kapeldreef 75, 3001 Leuven, Belgium
| | - Takafumi Uemura
- The Institute of Scientific and Industrial Research (ISIR), Osaka University , 8-1 Mihogaoka, Ibaraki, 567-0047 Osaka, Japan
| | - Jürgen Brugger
- EPFL , Microsystems Laboratory, CH-1015 Lausanne, Switzerland
| | - Jan Genoe
- imec , Large Area Electronics, Kapeldreef 75, 3001 Leuven, Belgium
- KU Leuven , Department of Electrical Engineering, Kasteelpark Arenberg 10, 3001 Leuven, Belgium
| | - Paul Heremans
- imec , Large Area Electronics, Kapeldreef 75, 3001 Leuven, Belgium
- KU Leuven , Department of Electrical Engineering, Kasteelpark Arenberg 10, 3001 Leuven, Belgium
| | - Cédric Rolin
- imec , Large Area Electronics, Kapeldreef 75, 3001 Leuven, Belgium
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23
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Matheoud AV, Gualco G, Jeong M, Zivkovic I, Brugger J, Rønnow HM, Anders J, Boero G. Single-chip electron spin resonance detectors operating at 50GHz, 92GHz, and 146GHz. J Magn Reson 2017; 278:113-121. [PMID: 28388496 DOI: 10.1016/j.jmr.2017.03.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 03/21/2017] [Accepted: 03/22/2017] [Indexed: 06/07/2023]
Abstract
We report on the design and characterization of single-chip electron spin resonance (ESR) detectors operating at 50GHz, 92GHz, and 146GHz. The core of the single-chip ESR detectors is an integrated LC-oscillator, formed by a single turn aluminum planar coil, a metal-oxide-metal capacitor, and two metal-oxide semiconductor field effect transistors used as negative resistance network. On the same chip, a second, nominally identical, LC-oscillator together with a mixer and an output buffer are also integrated. Thanks to the slightly asymmetric capacitance of the mixer inputs, a signal at a few hundreds of MHz is obtained at the output of the mixer. The mixer is used for frequency down-conversion, with the aim to obtain an output signal at a frequency easily manageable off-chip. The coil diameters are 120μm, 70μm, and 45μm for the U-band, W-band, and the D-band oscillators, respectively. The experimental frequency noises at 100kHz offset from the carrier are 90Hz/Hz1/2, 300Hz/Hz1/2, and 700Hz/Hz1/2 at 300K, respectively. The ESR spectra are obtained by measuring the frequency variations of the single-chip oscillators as a function of the applied magnetic field. The experimental spin sensitivities, as measured with a sample of α,γ-bisdiphenylene-β-phenylallyl (BDPA)/benzene complex, are 1×108spins/Hz1/2, 4×107spins/Hz1/2, 2×107spins/Hz1/2 at 300K, respectively. We also show the possibility to perform experiments up to 360GHz by means of the higher harmonics in the microwave field produced by the integrated single-chip LC-oscillators.
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Affiliation(s)
| | - Gabriele Gualco
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Minki Jeong
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Ivica Zivkovic
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Jürgen Brugger
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | - Henrik M Rønnow
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland
| | | | - Giovanni Boero
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
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24
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Flauraud V, Bernasconi GD, Butet J, Alexander DTL, Martin OJF, Brugger J. Mode Coupling in Plasmonic Heterodimers Probed with Electron Energy Loss Spectroscopy. ACS Nano 2017; 11:3485-3495. [PMID: 28290663 DOI: 10.1021/acsnano.6b08589] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
While plasmonic antennas composed of building blocks made of the same material have been thoroughly studied, recent investigations have highlighted the unique opportunities enabled by making compositionally asymmetric plasmonic systems. So far, mainly heterostructures composed of nanospheres and nanodiscs have been investigated, revealing opportunities for the design of Fano resonant nanostructures, directional scattering, sensing and catalytic applications. In this article, an improved fabrication method is reported that enables precise tuning of the heterodimer geometry, with interparticle distances made down to a few nanometers between Au-Ag and Au-Al nanoparticles. A wide range of mode energy detuning and coupling conditions are observed by near field hyperspectral imaging performed with electron energy loss spectroscopy, supported by full wave analysis numerical simulations. These results provide direct insights into the mode hybridization of plasmonic heterodimers, pointing out the influence of each dimer constituent in the overall electromagnetic response. By relating the coupling of nondipolar modes and plasmon-interband interaction with the dimer geometry, this work facilitates the development of plasmonic heterostructures with tailored responses, beyond the possibilities offered by homodimers.
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Affiliation(s)
- Valentin Flauraud
- Microsystems Laboratory, Institute of Microtechnique, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Gabriel D Bernasconi
- Nanophotonics and Metrology Laboratory, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Jérémy Butet
- Nanophotonics and Metrology Laboratory, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Duncan T L Alexander
- Interdisciplinary Centre for Electron Microscopy (CIME), École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Olivier J F Martin
- Nanophotonics and Metrology Laboratory, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Jürgen Brugger
- Microsystems Laboratory, Institute of Microtechnique, École Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
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25
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Flauraud V, Regmi R, Winkler PM, Alexander DTL, Rigneault H, van Hulst NF, García-Parajo MF, Wenger J, Brugger J. In-Plane Plasmonic Antenna Arrays with Surface Nanogaps for Giant Fluorescence Enhancement. Nano Lett 2017; 17:1703-1710. [PMID: 28182429 DOI: 10.1021/acs.nanolett.6b04978] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Optical nanoantennas have a great potential for enhancing light-matter interactions at the nanometer scale, yet fabrication accuracy and lack of scalability currently limit ultimate antenna performance and applications. In most designs, the region of maximum field localization and enhancement (i.e., hotspot) is not readily accessible to the sample because it is buried into the nanostructure. Moreover, current large-scale fabrication techniques lack reproducible geometrical control below 20 nm. Here, we describe a new nanofabrication technique that applies planarization, etch back, and template stripping to expose the excitation hotspot at the surface, providing a major improvement over conventional electron beam lithography methods. We present large flat surface arrays of in-plane nanoantennas, featuring gaps as small as 10 nm with sharp edges, excellent reproducibility and full surface accessibility of the hotspot confined region. The novel fabrication approach drastically improves the optical performance of plasmonic nanoantennas to yield giant fluorescence enhancement factors up to 104-105 times, together with nanoscale detection volumes in the 20 zL range. The method is fully scalable and adaptable to a wide range of antenna designs. We foresee broad applications by the use of these in-plane antenna geometries ranging from large-scale ultrasensitive sensor chips to microfluidics and live cell membrane investigations.
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Affiliation(s)
- Valentin Flauraud
- Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Raju Regmi
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Pamina M Winkler
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
| | - Duncan T L Alexander
- Interdisciplinary Center for Electron Microscopy (CIME) Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
| | - Hervé Rigneault
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France
| | - Niek F van Hulst
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA , Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - María F García-Parajo
- ICFO-Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain
- ICREA , Pg. Lluís Companys 23, 08010 Barcelona, Spain
| | - Jérôme Wenger
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, F-13013 Marseille, France
| | - Jürgen Brugger
- Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne , 1015 Lausanne, Switzerland
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Chavarria MA, Matheoud AV, Marmillod P, Liu Y, Kong D, Brugger J, Boero G. High sensitivity field asymmetric ion mobility spectrometer. Rev Sci Instrum 2017; 88:035115. [PMID: 28372433 DOI: 10.1063/1.4978960] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A high sensitivity field asymmetric ion mobility spectrometer (FAIMS) was designed, fabricated, and tested. The main components of the system are a 10.6 eV UV photoionization source, an ion filter driven by a high voltage/high frequency n-MOS inverter circuit, and a low noise ion detector. The ion filter electronics are capable to generate square waveforms with peak-to-peak voltages up to 1000 V at frequencies up to 1 MHz with adjustable duty cycles. The ion detector current amplifier has a gain up to 1012 V/A with an effective equivalent input noise level down to about 1 fA/Hz1/2 during operation with the ion filter at the maximum voltage and frequency. The FAIMS system was characterized by detecting different standard chemical compounds. Additionally, we investigated the use of a synchronous modulation/demodulation technique to improve the signal-to-noise ratio in FAIMS measurements. In particular, we implemented the modulation of the compensation voltage with the synchronous demodulation of the ion current. The analysis of the measurements at low concentration levels led to an extrapolated limit of detection for acetone of 10 ppt with an averaging time of 1 s.
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Affiliation(s)
- Mario A Chavarria
- Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | | | | | - Youjiang Liu
- State Key Laboratory of Transducer Technology, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China
| | - Deyi Kong
- State Key Laboratory of Transducer Technology, Hefei Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei 230031, China
| | - Jürgen Brugger
- Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
| | - Giovanni Boero
- Ecole Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
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Gauvin M, Alnasser T, Terver E, Abid I, Mlayah A, Xie S, Brugger J, Viallet B, Ressier L, Grisolia J. Plasmonic photo-current in freestanding monolayered gold nanoparticle membranes. Nanoscale 2016; 8:16162-16167. [PMID: 27714145 DOI: 10.1039/c6nr05091c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report on photo-current generation in freestanding monolayered gold nanoparticle membranes excited by using a focused laser beam. The absence of a substrate leads to a 50% increase of the photo-current at the surface plasmon resonance. This current is attributed to a combination of trap state dynamics and bolometric effects in a nanocomposite medium yielding a temperature rise of 40 K.
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Affiliation(s)
- M Gauvin
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France.
| | - T Alnasser
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France.
| | - E Terver
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France. and Université de Toulouse, CEMES-CNRS, 29 rue Jeanne Marvig, BP 94347, F-31055 Toulouse Cedex 4, France
| | - I Abid
- Université de Toulouse, CEMES-CNRS, 29 rue Jeanne Marvig, BP 94347, F-31055 Toulouse Cedex 4, France
| | - A Mlayah
- Université de Toulouse, CEMES-CNRS, 29 rue Jeanne Marvig, BP 94347, F-31055 Toulouse Cedex 4, France
| | - S Xie
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne, Station 17, 1015 Lausanne, Switzerland
| | - J Brugger
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne, Station 17, 1015 Lausanne, Switzerland
| | - B Viallet
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France.
| | - L Ressier
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France.
| | - J Grisolia
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France.
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Gauvin M, Grisolia J, Alnasser T, Viallet B, Xie S, Brugger J, Ressier L. Electro-mechanical sensing in freestanding monolayered gold nanoparticle membranes. Nanoscale 2016; 8:11363-11370. [PMID: 27194578 DOI: 10.1039/c6nr02004f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The electro-mechanical sensing properties of freestanding monolayered membranes of dodecanethiol coated 7 nm gold nanoparticles (NPs) are investigated using AFM force spectroscopy and conductive AFM simultaneously. The electrical resistance of the NP membranes increases sensitively with the point-load force applied in the center of the membranes using an AFM tip. Numerical simulations of electronic conduction in a hexagonally close-packed two-dimensional (2D) array of NPs under point load-deformation are carried out on the basis of electronic transport measurements at low temperatures and strain modeling of the NP membranes by finite element analysis. These simulations, supporting AFM-based electro-mechanical measurements, attribute the high strain sensitivity of the monolayered NP membranes to the exponential dependence of the tunnel electron transport in 2D NP arrays on the strain-induced length variation of the interparticle junctions. This work thus evidences a new class of highly sensitive nano-electro-mechanical systems based on freestanding monolayered gold NP membranes.
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Affiliation(s)
- M Gauvin
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France.
| | - J Grisolia
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France.
| | - T Alnasser
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France.
| | - B Viallet
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France.
| | - S Xie
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne, Station 17, 1015 Lausanne, Switzerland
| | - J Brugger
- Microsystems Laboratory, École Polytechnique Fédérale de Lausanne, Station 17, 1015 Lausanne, Switzerland
| | - L Ressier
- Université de Toulouse, LPCNO, INSA-CNRS-UPS, 135 avenue de Rangueil, Toulouse 31077, France.
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Dalcanale F, Grossenbacher J, Blugan G, Gullo MR, Brugger J, Tevaearai H, Graule T, Kuebler J. Rapid carbon nanotubes suspension in organic solvents using organosilicon polymers. J Colloid Interface Sci 2016; 470:123-131. [DOI: 10.1016/j.jcis.2016.02.050] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 02/22/2016] [Indexed: 11/29/2022]
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Abstract
This letter reports on a novel fabrication method for 3D metal nanostructures using high-throughput nanostencil lithography. Aperture clogging, which occurs on the stencil membranes during physical vapor deposition, is leveraged to create complex topographies on the nanoscale. The precision of the 3D nanofabrication method is studied in terms of geometric parameters and material types. The versatility of the technique is demonstrated by various symmetric and chiral patterns made of Al and Au.
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Affiliation(s)
- F Yesilkoy
- EPFL STI IMT LMIS1, CH-1015 Lausanne, Switzerland. and The University of Tokyo IIS CIRMM, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - V Flauraud
- EPFL STI IMT LMIS1, CH-1015 Lausanne, Switzerland.
| | - M Rüegg
- EPFL STI IMT LMIS1, CH-1015 Lausanne, Switzerland.
| | - B J Kim
- The University of Tokyo IIS CIRMM, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan
| | - J Brugger
- EPFL STI IMT LMIS1, CH-1015 Lausanne, Switzerland.
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Yesilkoy F, Ueno R, Desbiolles BXE, Grisi M, Sakai Y, Kim BJ, Brugger J. Highly efficient and gentle trapping of single cells in large microfluidic arrays for time-lapse experiments. Biomicrofluidics 2016; 10:014120. [PMID: 26909126 PMCID: PMC4760974 DOI: 10.1063/1.4942457] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 02/09/2016] [Indexed: 05/24/2023]
Abstract
The isolation of single biological cells and their further cultivation in dedicated arrayed chambers are key to the collection of statistically reliable temporal data in cell-based biological experiments. In this work, we present a hydrodynamic single cell trapping and culturing platform that facilitates cell observation and experimentation using standard bio-lab equipment. The proposed design leverages the stochastic position of the cells as they flow into the structured microfluidic channels, where hundreds of single cells are then arrayed in nanoliter chambers for simultaneous cell specific data collection. Numerical simulation tools are used to devise and implement a hydrodynamic cell trapping mechanism that is minimally detrimental to the cell cycle and retains high overall trapping efficiency (∼70%) with the capability of reaching high fill factors (>90%) in short loading times (1-4 min) in a 400-trap device. A Monte Carlo model is developed using the design parameters to estimate the system trapping efficiencies, which show strong agreement with the experimentally acquired data. As proof of concept, arrayed mammalian tissue cells (MIA PaCa-2) are cultured in the microfluidic chambers for two days without viability problems.
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Affiliation(s)
| | - R Ueno
- Institute of Industrial Science, The University of Tokyo , Meguro-ku, Tokyo 153-8505, Japan
| | - B X E Desbiolles
- Microsystems Laboratory, Ecole Polytechnique Federale de Lausanne , 1015 Lausanne, Switzerland
| | - M Grisi
- Microsystems Laboratory, Ecole Polytechnique Federale de Lausanne , 1015 Lausanne, Switzerland
| | - Y Sakai
- Institute of Industrial Science, The University of Tokyo , Meguro-ku, Tokyo 153-8505, Japan
| | - B J Kim
- Institute of Industrial Science, The University of Tokyo , Meguro-ku, Tokyo 153-8505, Japan
| | - J Brugger
- Microsystems Laboratory, Ecole Polytechnique Federale de Lausanne , 1015 Lausanne, Switzerland
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Jacot-Descombes L, Cadarso VJ, Schleunitz A, Grützner S, Klein JJ, Brugger J, Schift H, Grützner G. Organic-inorganic-hybrid-polymer microlens arrays with tailored optical characteristics and multi-focal properties. Opt Express 2015; 23:25365-76. [PMID: 26406732 DOI: 10.1364/oe.23.025365] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Plano-convex microlens arrays of organic-inorganic polymers with tailored optical properties are presented. The fine-tuning of each microlens within an array is achieved by confining inkjet printed drops of the polymeric ink onto pre-patterned substrates. The lens optical properties are thus freely specified, and high numerical apertures from 0.45 to 0.9 and focal lengths between 10 μm and 100 μm are demonstrated, confirming theoretical predictions. Combining nanoimprint lithography approaches and inkjet printing enables using the same material for the microlenses and their substrates, improving the optical performances. Microlens arrays with desired specifications are printed reaching yields up to 100% and high lens reproducibility with standard deviations of the apparent contact angle under 1° and of the numerical apertures and focal lengths under 6%. Microlens arrays involving lenses with different characteristics, e.g. multi focal length, and thus focal planes separated by only few microns are printed with the same reproducibility.
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Flauraud V, van Zanten TS, Mivelle M, Manzo C, Garcia Parajo MF, Brugger J. Large-Scale Arrays of Bowtie Nanoaperture Antennas for Nanoscale Dynamics in Living Cell Membranes. Nano Lett 2015; 15:4176-4182. [PMID: 25926327 DOI: 10.1021/acs.nanolett.5b01335] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present a novel blurring-free stencil lithography patterning technique for high-throughput fabrication of large-scale arrays of nanoaperture optical antennas. The approach relies on dry etching through nanostencils to achieve reproducible and uniform control of nanoantenna geometries at the nanoscale, over millimeter-sizes in a thin aluminum film. We demonstrate the fabrication of over 400 000 bowtie nanoaperture (BNA) antennas on biocompatible substrates, having gap sizes ranging from (80 ± 5) nm down to (20 ± 10) nm. To validate their applicability on live cell research, we used the antenna substrates as hotspots of localized illumination to excite fluorescently labeled lipids on living cell membranes. The high signal-to-background afforded by the BNA arrays allowed the recording of single fluorescent bursts corresponding to the passage of freely diffusing individual lipids through hotspot excitation regions as small as 20 nm. Statistical analysis of burst length and intensity together with simulations demonstrate that the measured signals arise from the ultraconfined excitation region of the antennas. Because these inexpensive antenna arrays are fully biocompatible and amenable to their integration in most fluorescence microscopes, we foresee a large number of applications including the investigation of the plasma membrane of living cells with nanoscale resolution at endogenous expression levels.
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Affiliation(s)
- Valentin Flauraud
- †Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Thomas S van Zanten
- ‡ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona, Spain
| | - Mathieu Mivelle
- ‡ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona, Spain
| | - Carlo Manzo
- ‡ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona, Spain
| | - Maria F Garcia Parajo
- ‡ICFO-Institut de Ciencies Fotoniques, Mediterranean Technology Park, 08860 Castelldefels, Barcelona, Spain
- §ICREA-Institució Catalana de Recerca i Estudis Avançats, 08010 Barcelona, Spain
| | - Jürgen Brugger
- †Microsystems Laboratory, Institute of Microengineering, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
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Ergeneman O, Peters C, Gullo MR, Jacot-Descombes L, Gervasoni S, Özkale B, Fatio P, Cadarso VJ, Mastrangeli M, Pané S, Brugger J, Hierold C, Nelson BJ. Inkjet printed superparamagnetic polymer composite hemispheres with programmed magnetic anisotropy. Nanoscale 2014; 6:10495-10499. [PMID: 24842483 DOI: 10.1039/c3nr06442e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present the fabrication and characterization of large arrays of inkjet-printed superparamagnetic polymer composite (SPMPC) hemispherical microstructures. SPMPCs are appealing for applications in microsystems and nanorobotics due to the added functionality of polymers and the significant magnetic attributes of embedded nanostructures. SPMPC-based microarchitectures can be used to perform different functions wirelessly in various media (e.g. water, solvents) using external magnetic fields: handling and assembling small objects, delivering drugs or biomass, or sensing specific physical or chemical changes. In this work superparamagnetic magnetite nanoparticles are dispersed in SU-8 to form magnetic hemispheres. Magnetically anisotropic hemispheres as well as standard SPMPC hemispheres are fabricated. Magnetic anisotropy is programmed by applying a magnetic field during curing. The distribution of nanoparticles inside the polymer matrix and magnetic characteristics of the SPMPC are investigated. Magnetic manipulation of hemispheres is demonstrated at liquid-liquid interfaces. Different assembly strategies to form lines or geometric shapes from hemispheres as well as their independent dynamic control are demonstrated. Finally, a two-interface assembly strategy is demonstrated to assemble hemispheres into complete spheres for advanced self-assembly tasks.
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Affiliation(s)
- Olgaç Ergeneman
- Multi Scale Robotics Lab, Institute of Robotics and Intelligent Systems, ETH Zurich, Tannenstrasse 3 CLA H15.2, 8092, Zurich, Switzerland.
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35
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Marelli M, Gadhari N, Boero G, Chiquet M, Brugger J. Cell force measurements in 3D microfabricated environments based on compliant cantilevers. Lab Chip 2014; 14:286-293. [PMID: 24217771 DOI: 10.1039/c3lc51021b] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
We report the fabrication, functionalization and testing of microdevices for cell culture and cell traction force measurements in three-dimensions (3D). The devices are composed of bent cantilevers patterned with cell-adhesive spots not lying on the same plane, and thus suspending cells in 3D. The cantilevers are soft enough to undergo micrometric deflections when cells pull on them, allowing cell forces to be measured by means of optical microscopy. Since individual cantilevers are mechanically independent of each other, cell traction forces are determined directly from cantilever deflections. This proves the potential of these new devices as a tool for the quantification of cell mechanics in a system with well-defined 3D geometry and mechanical properties.
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Affiliation(s)
- Mattia Marelli
- École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
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Boero G, Gualco G, Lisowski R, Anders J, Suter D, Brugger J. Room temperature strong coupling between a microwave oscillator and an ensemble of electron spins. J Magn Reson 2013; 231:133-140. [PMID: 23644353 DOI: 10.1016/j.jmr.2013.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 04/05/2013] [Accepted: 04/06/2013] [Indexed: 06/02/2023]
Abstract
We demonstrate theoretically and experimentally the possibility to achieve the strong coupling regime at room temperature with a microwave electronic oscillator coupled with an ensemble of electron spins. The coupled system shows bistable behaviour, with a broad hysteresis and sharp transitions. The coupling strength and the hysteresis width can be adjusted through the number of spins in the ensemble, the temperature, and the microwave field strength.
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Affiliation(s)
- G Boero
- Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne, Switzerland.
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Fairbrother L, Etschmann B, Brugger J, Shapter J, Southam G, Reith F. Biomineralization of gold in biofilms of Cupriavidus metallidurans. Environ Sci Technol 2013; 47:2628-2635. [PMID: 23405956 DOI: 10.1021/es302381d] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Cupriavidus metallidurans, a bacterium capable of reductively precipitating toxic, aqueous gold(I/III)-complexes, dominates biofilm communities on gold (Au) grains from Australia. To examine the importance of C. metallidurans biofilms in secondary Au formation, we assessed the biomineralization potential of biofilms growing in quartz-sand-packed columns to periodic amendment with Au(I)-thiosulfate. In these experiments, >99 wt % of Au, was retained compared to <30 wt % in sterilized and abiotic controls. Biomineralization of Au occurred in the presence of viable biofilms via the formation of intra- and extra-cellular spherical nanoparticles, which aggregated into spheroidal and framboidal microparticles of up to 2 μm in diameter. Aggregates of Au formed around cells, eventually encapsulating and ultimately replacing them. These particles were morphologically analogous to Au-particles commonly observed on natural Au grains. Bacterial cells were connected via exopolymer or nanowires to μm-sized, extracellular Au-aggregates, which would intuitively improve the flow of electrons through the biofilm. This study demonstrates the importance of C. metallidurans biofilms for the detoxification of Au-complexes and demonstrates a central role for bacterial biomineralization in the formation of highly pure Au in surface environments.
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Affiliation(s)
- L Fairbrother
- School of Chemical and Physical Sciences, Flinders University, Adelaide, SA 5001, Australia
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Brigo L, Auzelyte V, Lister KA, Brugger J, Brusatin G. Phenyl-bridged polysilsesquioxane positive and negative resist for electron beam lithography. Nanotechnology 2012; 23:325302. [PMID: 22825028 DOI: 10.1088/0957-4484/23/32/325302] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We present and characterize an organic-inorganic hybrid sol-gel material, phenyl-bridged polysilsesquioxane (ph-PSQ), for use as a new high resolution resist for electron beam lithography (EBL). The resist has a unique characteristic as the only positive tone silica-based resist available for EBL. Exploring the processing parameters has revealed that it is possible to switch the behaviour from negative to positive tone by application of a post-exposure bake (PEB). Based on the results from micro-FTIR spectroscopy, a description of the tone switching mechanisms is proposed. The negative tone behaviour is explained by the etch rate difference between silanol groups and cross-linked silica, present in unexposed and in exposed areas of the films, respectively. In the case of positive tone, after a PEB, the etch rate difference between a thermally densified cross-linked silica network and cage-like silica structures allows us to reveal the pattern. Contrast and sensitivity are estimated under different processing conditions, and the significant parameters for line edge roughness minimization are pointed out. Dense patterns down to 25 nm half-pitch and isolated structures down to 30 nm are demonstrated, exploiting the positive tone, and dense patterns down to 60 nm half-pitch are demonstrated in the negative tone. Etching selectivities in fluorinated gases for ph-PSQ nanostructures on silicon substrates are 1-9 for the positive tone and 1-12 for the negative tone.
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Affiliation(s)
- L Brigo
- Industrial Engineering Department, University of Padova, Padova, 35131, Italy.
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Binetti E, Ingrosso C, Striccoli M, Cosma P, Agostiano A, Pataky K, Brugger J, Curri ML. Nanocomposites based on highly luminescent nanocrystals and semiconducting conjugated polymer for inkjet printing. Nanotechnology 2012; 23:075701. [PMID: 22261314 DOI: 10.1088/0957-4484/23/7/075701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In this work nanocomposites based on organic-capped semiconductor nanocrystals formed of a core of CdSe coated with a shell of ZnS (CdSe@ZnS), with different sizes, and a semiconducting conjugated polymer, namely poly[(9,9-dihexylfluoren-2,7-diyl)-alt- (2,5-dimethyl-1,4-phenylene)] (PF-DMB) have been investigated. The nanocomposites are prepared by mixing the pre-synthesized components in organic solvents, thereby assisting the dispersion of the organic-coated nano-objects in the polymer host. UV-vis steady state and time-resolved spectroscopy along with (photo)electrochemical techniques have been performed to characterize the obtained materials. The study shows that the embedded nanocrystals increase the PF-DMB stability against oxidation and, at the same time, extend the light harvesting capability to the visible spectral region, thus resulting in detectable photocurrent signals. The nanocomposites have been dispensed by means of a piezo-actuated inkjet system. Such inks present viscosity and surface tension properties well suited for stable and reliable drop-on-demand printing using an inkjet printer. The fabrication of arrays of single-color pixels made of the nanocomposites and micrometers in size has been performed. Confocal and atomic force microscopy have confirmed that inkjet-printed microstructures present the intrinsic emission properties of both the embedded nanocrystals and PF-DMB, resulting in a combined luminescence. Finally, the morphology of the printed pixels is influenced by the embedded nanofillers.
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Affiliation(s)
- E Binetti
- Chemistry Department, University 'Aldo Moro' of Bari, via Orabona 4, I-70126 Bari, Italy
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Mionić M, Pataky K, Gaal R, Magrez A, Brugger J, Forró L. Carbon nanotubes–SU8 composite for flexible conductive inkjet printable applications. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm16547c] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ingrosso C, Martin-Olmos C, Llobera A, Innocenti C, Sangregorio C, Striccoli M, Agostiano A, Voigt A, Gruetzner G, Brugger J, Perez-Murano F, Curri ML. Oxide nanocrystal based nanocomposites for fabricating photoplastic AFM probes. Nanoscale 2011; 3:4632-4639. [PMID: 21858377 DOI: 10.1039/c1nr10487j] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on the synthesis, characterization and application of a novel nanocomposite made of a negative tone epoxy based photoresist modified with organic-capped Fe(2)O(3) nanocrystals (NCs). The mechanical properties of the nanocomposite drastically improve upon incorporation of a suitable concentration of NCs in the polymer, without deteriorating its photolithography performance. High aspect ratio 3D microstructures made of the nanocomposite have been fabricated with a uniform surface morphology and with a resolution down to few micrometres. The embedded organic-capped Fe(2)O(3) NCs drastically increase the stiffness and hardness of the epoxy based photoresist matrix, making the final material extremely interesting for manufacturing miniaturized polymer based mechanical devices and systems. In particular, the nanocomposite has been used as structural material for fabricating photoplastic Atomic Force Microscopy (AFM) probes with integrated tips showing outstanding mechanical response and high resolution imaging performance. The fabricated probes consist of straight cantilevers with low stress-gradient and high quality factors, incorporating sharp polymeric tips. They present considerably improved performance compared to pure epoxy based photoresist AFM probes, and to commercial silicon AFM probes.
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Affiliation(s)
- Chiara Ingrosso
- CNR-IPCF Sez. Bari c/o Dipartimento di Chimica, Università di Bari, via Orabona 4, Bari, 70126, Italy
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Cadarso VJ, Perera-Núñez J, Jacot-Descombes L, Pfeiffer K, Ostrzinski U, Voigt A, Llobera A, Grützer G, Brugger J. Microlenses with defined contour shapes. Opt Express 2011; 19:18665-18670. [PMID: 21935235 DOI: 10.1364/oe.19.018665] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Ink-jet printing of optical ink over SU-8 pillars is here proposed as a technology for obtaining microlenses with shape control. To demonstrate the flexibility of this method, microlenses with five different contour shapes (ranging from circular and elliptical to toric or more advanced geometries) have been fabricated. Furthermore, the optical properties of the different fabricated lenses have been experimentally investigated. Focal distance, numerical aperture (NA) and full-width at half maximum (FWHM) of the microlenses have been determined. Arrays of microlenses showed an identical behavior with a standard deviation in the total intensity of only 7%. Additionally, the focal plane of the fabricated symmetric microlenses and the Sturm interval of the non-symmetric ones have been obtained. The experimental results demonstrate the validity and flexibility of the proposed technology.
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Affiliation(s)
- V J Cadarso
- Microsystems laboratory (LMIS1), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.
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Llobera A, Cadarso VJ, Carregal-Romero E, Brugger J, Domínguez C, Fernández-Sánchez C. Fluorophore-doped xerogel antiresonant reflecting optical waveguides. Opt Express 2011; 19:5026-5039. [PMID: 21445138 DOI: 10.1364/oe.19.005026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Rhodamine B and Alexa Fluor 430 fluorophores have been used as doping agents for xerogel waveguides defined over an antiresonant (ARROW) filter. This configuration has a significant level of integration, since it merges the waveguide, the light emitter and the filter in a single photonic element. Different technologies have been combined for their implementation, namely soft lithography, standard silicon-based technology and silicon bulk micromachining. The spectral response of 15-mm long waveguides without fluorophore is first analyzed as a function of the waveguide width. Here, it has been observed how the xerogel used has a high transparency in the visible spectra, having only significant absorption at the wavelength where the ARROW filter is in resonance. In a second step, identical waveguides but doped with two different concentrations of Rhodamine B and Alexa Fluor 430 are studied. In addition to the effect of the filter, fluorophore-doped xerogel waveguides show losses close to -2 dB (equivalent to 2 dB of light emission). In addition, it has been observed how an increase of the fluorophore concentration within the xerogel matrix does not provide with a emission increase, but saturation or even a decrease of this magnitude due to self-absorption. Finally, the total losses of the proposed waveguides are analyzed as a function of their width, obtaining losses close to 5 dB for waveguide widths higher than 50 µm.
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Affiliation(s)
- A Llobera
- Institut de Microelectrònica de Barcelona (IMB-CNM-CSIC), Campus UAB 08193 Barcelona, Spain.
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Gullo MR, Jacot-Descombes L, Aeschimann L, Brugger J. Characterization of Hydrophobic Forces for in Liquid Self-Assembly of Micron-Sized Functional Building Blocks. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/opl.2011.466] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTThis paper presents the experimental and numerical study of hydrophobic interaction forces at nanometer scale in the scope of engineering micron-sized building blocks for self-assembly in liquid. The hydrophobic force distance relation of carbon, Teflon and dodeca-thiols immersed in degassed and deionized water has been measured by atomic force microscopy. Carbon and dodeca-thiols showed comparable attractive and binding forces in the rage of pN/nm2. Teflon showed the weakest binding and no attractive force. Molecular dynamic simulations were performed to correlate the molecular arrangement of water molecules and the hydrophobic interactions measured by atomic force microscopy. The simulations showed a depletion zone of 2Å followed by a layered region of 8Å in the axis perpendicular to the hydrophobic surface.
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Braschler T, Valero A, Colella L, Pataky K, Brugger J, Renaud P. Link between alginate reaction front propagation and general reaction diffusion theory. Anal Chem 2011; 83:2234-42. [PMID: 21351747 DOI: 10.1021/ac103118r] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We provide a common theoretical framework reuniting specific models for the Ca(2+)-alginate system and general reaction diffusion theory along with experimental validation on a microfluidic chip. As a starting point, we use a set of nonlinear, partial differential equations that are traditionally solved numerically: the Mikkelsen-Elgsaeter model. Applying the traveling-wave hypothesis as a major simplification, we obtain an analytical solution. The solution indicates that the fundamental properties of the alginate reaction front are governed by a single dimensionless parameter λ. For small λ values, a large depletion zone accompanies the reaction front. For large λ values, the alginate reacts before having the time to diffuse significantly. We show that the λ parameter is of general importance beyond the alginate model system, as it can be used to classify known solutions for second-order reaction diffusion schemes, along with the novel solution presented here. For experimental validation, we develop a microchip model system, in which the alginate gel formation can be carried out in a highly controlled, essentially 1D environment. The use of a filter barrier enables us to rapidly renew the CaCl(2) solution, while maintaining flow speeds lower than 1 μm/s for the alginate compartment. This allows one to impose an exactly known bulk CaCl(2) concentration and diffusion resistance. This experimental model system, taken together with the theoretical development, enables the determination of the entire set of physicochemical parameters governing the alginate reaction front in a single experiment.
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Brugger J, Schick MA, Brock RW, Baumann A, Muellenbach RM, Roewer N, Wunder C. Carbon monoxide has antioxidative properties in the liver involving p38 MAP kinase pathway in a murine model of systemic inflammation. Microcirculation 2011; 17:504-13. [PMID: 21040116 DOI: 10.1111/j.1549-8719.2010.00044.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Reactive oxygen species (ROS) are important in the hepatocellular injury process during a systemic inflammation. We examined the role of carbon monoxide (CO) on the hepatic generation of ROS with in-vivo and in-vitro models of systemic inflammation. METHODS Using a murine model of bilateral hindlimb ischemia-reperfusion (I/R) we examined the effect of CO treatment on hepatic ROS formation, oxidative status, and cell injury. Cultured HUVEC were used to investigate intracellular pathways. RESULTS CO treatment reduced hepatic lipid peroxidation, re-established total hepatic glutathione and glutathione disulfide (GSH/GSSG) levels and reduced hepatocellular injury. Inhibition of heme oxygenase (HO) during treatment with CO during hindlimb I/R failed to alter the antioxidant qualities provided by CO. The production of ROS after tumor necrosis factor-α (TNF-α) stimulation in HUVEC was diminished after exposure to CO. Treatment with CO during HO inhibition reduced both ROS formation and cell injury. Inhibiting the p38 MAPK (mitogen-activated protein kinase) pathway with pyridinyl imidazol (SB203580) revealed that the antioxidant potential of CO involved the activation of p38 MAPK. CONCLUSIONS CO has direct antioxidant potential independently of any HO activity during systemic inflammation. The antioxidant effects afforded by CO involve the activation of the p38 MAPK pathway.
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Affiliation(s)
- Jürgen Brugger
- Klinik und Poliklinik für Anästhesiologie, University of Würzburg, Würzburg, Germany
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Kiefer T, Villanueva LG, Fargier F, Favier F, Brugger J. Fast and robust hydrogen sensors based on discontinuous palladium films on polyimide, fabricated on a wafer scale. Nanotechnology 2010; 21:505501. [PMID: 21098952 DOI: 10.1088/0957-4484/21/50/505501] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Fast hydrogen sensors based on discontinuous palladium (Pd) films on supporting polyimide layers, fabricated by a cost-efficient and full-wafer compatible process, are presented. The films, deposited by electron-beam evaporation with a nominal thickness of 1.5 nm, consist of isolated Pd islands that are separated by nanoscopic gaps. On hydrogenation, the volume expansion of Pd brings initially separated islands into contact which leads to the creation of new electrical pathways through the film. The supporting polyimide layer provides both sufficient elasticity for the Pd nanoclusters to expand on hydrogenation and a sufficiently high surface energy for good adhesion of both film and contacting electrodes. The novel order of the fabrication processes involves a dicing step prior to the Pd deposition and stencil lithography for the patterning of microelectrodes. This allows us to preserve the as-deposited film properties. The devices work at room temperature, show response times of a few seconds and have a low power consumption of some tens of nW.
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Affiliation(s)
- T Kiefer
- Microsystems Laboratory, Station 17, École Polytéchnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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Klein MJK, Guillaumée M, Wenger B, Andrea Dunbar L, Brugger J, Heinzelmann H, Pugin R. Inexpensive and fast wafer-scale fabrication of nanohole arrays in thin gold films for plasmonics. Nanotechnology 2010; 21:205301. [PMID: 20413837 DOI: 10.1088/0957-4484/21/20/205301] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In this paper, a fast and inexpensive wafer-scale process for the fabrication of arrays of nanoscale holes in thin gold films for plasmonics is shown. The process combines nanosphere lithography using spin-coated polystyrene beads with a sputter-etching process. This allows the batch fabrication of several 1000 microm(2) large hole arrays in 200 nm thick gold films without the use of an adhesion layer for the gold film. The hole size and lattice period can be tuned independently with this method. This allows tuning of the optical properties of the hole arrays for the desired application. An example application, refractive index sensing, is demonstrated.
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Affiliation(s)
- Mona J K Klein
- Centre Suisse d'Electronique et de Microtechnique S.A. (CSEM), Neuchâtel, Switzerland.
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Abstract
A quantitative analysis of blurring and its dependence on the stencil-substrate gap and the deposition parameters in stencil lithography, a high resolution shadow mask technique, is presented. The blurring is manifested in two ways: first, the structure directly deposited on the substrate is larger than the stencil aperture due to geometrical factors, and second, a halo of material is formed surrounding the deposited structure, presumably due to surface diffusion. The blurring is studied as a function of the gap using dedicated stencils that allow a controlled variation of the gap. Our results show a linear relationship between the gap and the blurring of the directly deposited structure. In our configuration, with a material source of approximately 5 mm and a source-substrate distance of 1 m, we find that a gap size of approximately 10 microm enlarges the directly deposited structures by approximately 50 nm. The measured halo varies from 0.2 to 3 microm in width depending on the gap, the stencil aperture size and other deposition parameters. We also show that the blurring can be reduced by decreasing the nominal deposition thickness, the deposition rate and the substrate temperature.
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Affiliation(s)
- O Vazquez-Mena
- Microsystems Laboratory, Ecole Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.
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