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Van den Eeckhoudt R, Christiaens AS, Ceyssens F, Vangalis V, Verstrepen KJ, Boon N, Tavernier F, Kraft M, Taurino I. Full-electric microfluidic platform to capture, analyze and selectively release single cells. Lab Chip 2023; 23:4276-4286. [PMID: 37668159 DOI: 10.1039/d3lc00645j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/06/2023]
Abstract
Current single-cell technologies require large and expensive equipment, limiting their use to specialized labs. In this paper, we present for the first time a microfluidic device which demonstrates a combined method for full-electric cell capturing, analyzing, and selectively releasing with single-cell resolution. All functionalities are experimentally demonstrated on Saccharomyces cerevisiae. Our microfluidic platform consists of traps centered around a pair of individually accessible coplanar electrodes, positioned under a microfluidic channel. Using this device, we validate our novel Two-Voltage method for trapping single cells by positive dielectrophoresis (pDEP). Cells are attracted to the trap when a high voltage (VH) is applied. A low voltage (VL) holds the already trapped cell in place without attracting additional cells, allowing full control over the number of trapped cells. After trapping, the cells are analyzed by broadband electrochemical impedance spectroscopy. These measurements allow the detection of single cells and the extraction of cell parameters. Additionally, these measurements show a strong correlation between average phase change and cell size, enabling the use of our system for size measurements in biological applications. Finally, our device allows selectively releasing trapped cells by turning off the pDEP signal in their trap. The experimental results show the techniques potential as a full-electric single-cell analysis tool with potential for miniaturization and automation which opens new avenues towards small-scale, high throughput single-cell analysis and sorting lab-on-CMOS devices.
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Affiliation(s)
- Ruben Van den Eeckhoudt
- Micro- and Nanosystems (MNS), Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium.
| | - An-Sofie Christiaens
- Chemical and Biochemical Reactor Engineering and Safety (CREaS), Department of Chemical Engineering, KU Leuven, Leuven, Belgium
| | - Frederik Ceyssens
- Micro- and Nanosystems (MNS), Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium.
- Leuven Institute for Micro- and Nanoscale Integration (LIMNI), KU Leuven, Leuven, Belgium
| | - Vasileios Vangalis
- VIB - KU Leuven Center for Microbiology, Leuven, Belgium
- CMPG Laboratory for Genetics and Genomics, KU Leuven, Leuven, Belgium
| | - Kevin J Verstrepen
- VIB - KU Leuven Center for Microbiology, Leuven, Belgium
- CMPG Laboratory for Genetics and Genomics, KU Leuven, Leuven, Belgium
| | - Nico Boon
- Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Filip Tavernier
- MICAS, Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium
| | - Michael Kraft
- Micro- and Nanosystems (MNS), Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium.
- Leuven Institute for Micro- and Nanoscale Integration (LIMNI), KU Leuven, Leuven, Belgium
| | - Irene Taurino
- Micro- and Nanosystems (MNS), Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium.
- Semiconductor Physics, Department of Physics and Astronomy, KU Leuven, Leuven, Belgium
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Milana E, Gorissen B, De Borre E, Ceyssens F, Reynaerts D, De Volder M. Out-of-Plane Soft Lithography for Soft Pneumatic Microactuator Arrays. Soft Robot 2023; 10:197-204. [PMID: 35704896 DOI: 10.1089/soro.2021.0106] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Elastic pneumatic actuators are fueling new devices and applications in soft robotics. Actuator miniaturization is critical to enable soft microsystems for applications in microfluidics and micromanipulation. This work proposes a fabrication technique to make out-of-plane bending microactuators entirely by soft lithography. The only bonding step required is to seal the embedded fluidic channels, assuring the structural integrity of the microactuators. The process consists of fabricating two SU8 mold halves using different lithographic layers. Polydimethilsiloxane is poured on the bottom mold, which is subsequently aligned and assembled with the top mold. The process allows for out-of-plane actuators with a diameter of 300 μm and for fabricating arrays of up to 36 actuators that are row addressable. These active micropillars have an aspect ratio of 1:1.5 and, when pressurized at 1 bar, show a bending angle of ∼30°.
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Affiliation(s)
- Edoardo Milana
- Department of Mechanical Engineering, KU Leuven and Flanders Make, Leuven, Belgium
| | - Benjamin Gorissen
- Department of Mechanical Engineering, KU Leuven and Flanders Make, Leuven, Belgium
| | - Eline De Borre
- Department of Mechanical Engineering, KU Leuven and Flanders Make, Leuven, Belgium
| | - Frederik Ceyssens
- Department of Electrical Engineering (ESAT), KU Leuven, Leuven, Belgium
| | - Dominiek Reynaerts
- Department of Mechanical Engineering, KU Leuven and Flanders Make, Leuven, Belgium
| | - Michael De Volder
- Department of Mechanical Engineering, KU Leuven and Flanders Make, Leuven, Belgium.,Department of Engineering, Institute for Manufacturing, University of Cambridge, Cambridge, United Kingdom
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Merken L, Schelles M, Ceyssens F, Kraft M, Janssen P. Thin flexible arrays for long-term multi-electrode recordings in macaque primary visual cortex. J Neural Eng 2022; 19. [PMID: 36215972 DOI: 10.1088/1741-2552/ac98e2] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 10/10/2022] [Indexed: 01/11/2023]
Abstract
Objective.Basic, translational and clinical neuroscience are increasingly focusing on large-scale invasive recordings of neuronal activity. However, in large animals such as nonhuman primates and humans-in which the larger brain size with sulci and gyri imposes additional challenges compared to rodents, there is a huge unmet need to record from hundreds of neurons simultaneously anywhere in the brain for long periods of time. Here, we tested the electrical and mechanical properties of thin, flexible multi-electrode arrays (MEAs) inserted into the primary visual cortex of two macaque monkeys, and assessed their magnetic resonance imaging (MRI) compatibility and their capacity to record extracellular activity over a period of 1 year.Approach.To allow insertion of the floating arrays into the visual cortex, the 20 by 100µm2shafts were temporarily strengthened by means of a resorbable poly(lactic-co-glycolic acid) coating.Main results. After manual insertion of the arrays, theex vivoandin vivoMRI compatibility of the arrays proved to be excellent. We recorded clear single-unit activity from up to 50% of the electrodes, and multi-unit activity (MUA) on 60%-100% of the electrodes, which allowed detailed measurements of the receptive fields and the orientation selectivity of the neurons. Even 1 year after insertion, we obtained significant MUA responses on 70%-100% of the electrodes, while the receptive fields remained remarkably stable over the entire recording period.Significance.Thus, the thin and flexible MEAs we tested offer several crucial advantages compared to existing arrays, most notably in terms of brain tissue compliance, scalability, and brain coverage. Future brain-machine interface applications in humans may strongly benefit from this new generation of chronically implanted MEAs.
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Affiliation(s)
- Lara Merken
- Laboratory for Neuro- and Psychophysiology, KU Leuven, Leuven 3000, Belgium.,Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
| | - Maarten Schelles
- Micro- and Nanosystems (MNS), Electrical Engineering Department (ESAT), KU Leuven, Leuven 3000, Belgium.,ReVision Implant NV, Haasrode 3053, Belgium
| | | | - Michael Kraft
- Micro- and Nanosystems (MNS), Electrical Engineering Department (ESAT), KU Leuven, Leuven 3000, Belgium.,Leuven Institute for Micro- and Nanotechnology (LIMNI), Leuven 3000, Belgium
| | - Peter Janssen
- Laboratory for Neuro- and Psychophysiology, KU Leuven, Leuven 3000, Belgium.,Leuven Brain Institute, KU Leuven, Leuven 3000, Belgium
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Jin P, Mattelaer V, Yuan S, Bassyouni M, Simoens K, Zhang X, Ceyssens F, Bernaerts K, Dewil R, Van der Bruggen B. Hydrogel supported positively charged ultrathin polyamide layer with antimicrobial properties via Ag modification. Sep Purif Technol 2022. [DOI: 10.1016/j.seppur.2021.120295] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tchobanian A, Ceyssens F, Cóndor Salgado M, Van Oosterwyck H, Fardim P. Patterned dextran ester films as a tailorable cell culture platform. Carbohydr Polym 2021; 252:117183. [PMID: 33183630 DOI: 10.1016/j.carbpol.2020.117183] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/24/2020] [Accepted: 09/29/2020] [Indexed: 01/22/2023]
Abstract
The elucidation of cell-surface interactions and the development of model platforms to help uncover their underlying mechanisms remains vital to the design of effective biomaterials. To this end, dextran palmitates with varying degrees of substitution were synthesised with a multipurpose functionality: an ability to modulate surface energy through surface chemistry, and an ideal thermal behaviour for patterning. Herein, dextran palmitate films are produced by spin coating, and patterned by thermal nanoimprint lithography with nano-to-microscale topographies. These films of moderately hydrophobic polysaccharide esters with low nanoscale roughness performed as well as fibronectin coatings in the culture of bovine aortic endothelial cells. Upon patterning, they display distinct regions of roughness, restricting cell adhesion to the smoothest surfaces, while guiding multicellular arrangements in the patterned topographies. The development of biomaterial interfaces through topochemical fabrication such as this could prove useful in understanding protein and cell-surface interactions.
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Affiliation(s)
- Armen Tchobanian
- Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium.
| | - Frederik Ceyssens
- Department of Electrical Engineering, ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, B-3001 Heverlee, Belgium.
| | - Mar Cóndor Salgado
- Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300, B-3001 Heverlee, Belgium.
| | - Hans Van Oosterwyck
- Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300, B-3001 Heverlee, Belgium; Prometheus Division of Skeletal Tissue Engineering, KU Leuven, Herestraat 49 - bus 813, Leuven, Belgium.
| | - Pedro Fardim
- Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium.
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Wouters J, Kalender-Atak Z, Minnoye L, Spanier KI, De Waegeneer M, Bravo González-Blas C, Mauduit D, Davie K, Hulselmans G, Najem A, Dewaele M, Pedri D, Rambow F, Makhzami S, Christiaens V, Ceyssens F, Ghanem G, Marine JC, Poovathingal S, Aerts S. Robust gene expression programs underlie recurrent cell states and phenotype switching in melanoma. Nat Cell Biol 2020; 22:986-998. [PMID: 32753671 DOI: 10.1038/s41556-020-0547-3] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 06/23/2020] [Indexed: 02/07/2023]
Abstract
Melanoma cells can switch between a melanocytic and a mesenchymal-like state. Scattered evidence indicates that additional intermediate state(s) may exist. Here, to search for such states and decipher their underlying gene regulatory network (GRN), we studied 10 melanoma cultures using single-cell RNA sequencing (RNA-seq) as well as 26 additional cultures using bulk RNA-seq. Although each culture exhibited a unique transcriptome, we identified shared GRNs that underlie the extreme melanocytic and mesenchymal states and the intermediate state. This intermediate state is corroborated by a distinct chromatin landscape and is governed by the transcription factors SOX6, NFATC2, EGR3, ELF1 and ETV4. Single-cell migration assays confirmed the intermediate migratory phenotype of this state. Using time-series sampling of single cells after knockdown of SOX10, we unravelled the sequential and recurrent arrangement of GRNs during phenotype switching. Taken together, these analyses indicate that an intermediate state exists and is driven by a distinct and stable 'mixed' GRN rather than being a symbiotic heterogeneous mix of cells.
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Affiliation(s)
- Jasper Wouters
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Zeynep Kalender-Atak
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium.,Cancer Research UK Cambridge Institute, University of Cambridge, Cambridge, UK
| | - Liesbeth Minnoye
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Katina I Spanier
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Maxime De Waegeneer
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Carmen Bravo González-Blas
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - David Mauduit
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Kristofer Davie
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Gert Hulselmans
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Ahmad Najem
- Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
| | - Michael Dewaele
- Center for Cancer Biology, VIB-KU Leuven, Leuven, Belgium.,Department of Oncology, KU Leuven, Leuven, Belgium
| | - Dennis Pedri
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Center for Cancer Biology, VIB-KU Leuven, Leuven, Belgium.,Department of Oncology, KU Leuven, Leuven, Belgium.,Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Florian Rambow
- Center for Cancer Biology, VIB-KU Leuven, Leuven, Belgium.,Department of Oncology, KU Leuven, Leuven, Belgium
| | - Samira Makhzami
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Valerie Christiaens
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium.,Department of Human Genetics, KU Leuven, Leuven, Belgium
| | | | - Ghanem Ghanem
- Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
| | - Jean-Christophe Marine
- Center for Cancer Biology, VIB-KU Leuven, Leuven, Belgium.,Department of Oncology, KU Leuven, Leuven, Belgium
| | | | - Stein Aerts
- Center for Brain & Disease Research, VIB-KU Leuven, Leuven, Belgium. .,Department of Human Genetics, KU Leuven, Leuven, Belgium.
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van Daal RJJ, Sun JJ, Ceyssens F, Michon F, Kraft M, Puers R, Kloosterman F. System for recording from multiple flexible polyimide neural probes in freely behaving animals. J Neural Eng 2020; 17:016046. [DOI: 10.1088/1741-2552/ab5e19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Chaudhuri BP, Ceyssens F, Celen S, Bormans G, Kraft M, Puers R. In-vivo Intradermal Delivery of Co-57 labeled Vitamin B-12, and Subsequent Comparison with Standard Subcutaneous Administration .. Annu Int Conf IEEE Eng Med Biol Soc 2020; 2019:1670-1673. [PMID: 31946217 DOI: 10.1109/embc.2019.8857543] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Vitamin B-12 (cobalamin) deficiency in humans is a worldwide problem emanating from varied causes such as insufficient dietary intake or malabsorption of the micronutrient due to an underlying condition (absence or failure of intrinsic factor, atrophic gastritis, post-operative bariatric surgery, inflammatory bowel disease, cobalt deficiency etc.). As oral supplementation is limited by its bioavailability due to the absorptive property of intrinsic factor, clinicians often prescribe parenteral forms of administration to replenish diminished levels rapidly. The gold standard in parenteral delivery of cobalamin is subcutaneous and/or intramuscular injections. The relatively large molecular size of cobalamin (1355.39 Da) makes passive transdermal patch-based delivery via the stratum corneum quite challenging. Hence, the primary goal of this study is to investigate the feasibility of intradermal (ID) delivery of Vitamin B-12 via an almost painless microneedle injection and subsequent comparison with standard subcutaneous (SC) delivery. This work reports on a custom-made microneedle device built from a commercial insulin needle and it's use to perform ID delivery of Co-57 radiolabeled Vitamin B-12 in-vivo in rabbits. The pharmacokinetic profile and bioavailability were studied and compared with SC delivery. It is the first comprehensive study, to our best knowledge, that compares a micronutrient (eg. Vitamin B-12) delivery via ID and SC routes in-vivo. While the bioavailability for the SC route is found to be slightly higher compared to the ID route (99% vs. 96%), the Tmax for both are almost identical. Thus, ID delivery of Vitamin B-12 using a microneedle injection could be a viable and minimally invasive alternative to existing parenteral options.
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Wu X, Bai Z, Wang L, Cui G, Yang M, Yang Q, Ma B, Song Q, Tian D, Ceyssens F, Puers R, Kraft M, Zhao W, Wen L. Magnetic Cell Centrifuge Platform Performance Study with Different Microsieve Pore Geometries. Sensors (Basel) 2019; 20:E48. [PMID: 31861791 PMCID: PMC6983067 DOI: 10.3390/s20010048] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [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: 11/11/2019] [Revised: 12/04/2019] [Accepted: 12/17/2019] [Indexed: 12/21/2022]
Abstract
The detection and analysis of circulating tumor cells (CTCs) plays a crucial role in clinical practice. However, the heterogeneity and rarity of CTCs make their capture and separation from peripheral blood very difficult while maintaining their structural integrity and viability. We previously demonstrated the effectiveness of the Magnetic Cell Centrifuge Platform (MCCP), which combined the magnetic-labeling cell separation mechanism with the size-based method. In this paper, a comparison of the effectiveness of different microsieve pore geometries toward MCCP is demonstrated to improve the yield of the target cell capture. Firstly, models of a trapped cell with rectangular and circular pore geometries are presented to compare the contact force using finite element numerical simulations. The device performance is then evaluated with both constant pressure and constant flow rate experimental conditions. In addition, the efficient isolation of magnetically labeled Hela cells with red fluorescent proteins (target cells) from Hela cells with green fluorescent protein (background cells) is validated. The experimental results show that the circular sieves yield 97% purity of the target cells from the sample with a throughput of up to 2 μL/s and 66-fold sample enrichment. This finding will pave the way for the design of a higher efficient MCCP systems.
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Affiliation(s)
- Xinyu Wu
- School of Microelectronics, Beihang University, Beijing 100191, China; (X.W.)
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266104, China
| | - Zhongyang Bai
- School of Microelectronics, Beihang University, Beijing 100191, China; (X.W.)
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266104, China
| | - Lin Wang
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266104, China
| | - Guangchao Cui
- School of Microelectronics, Beihang University, Beijing 100191, China; (X.W.)
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266104, China
| | - Mengzheng Yang
- School of Microelectronics, Beihang University, Beijing 100191, China; (X.W.)
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266104, China
| | - Qing Yang
- School of Microelectronics, Beihang University, Beijing 100191, China; (X.W.)
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266104, China
| | - Bo Ma
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
| | - Qinglin Song
- Qingdao Goertek Microelectronics Research Institute Co., Ltd., Qingdao 266104, China
| | - Dewen Tian
- Qingdao Goertek Microelectronics Research Institute Co., Ltd., Qingdao 266104, China
| | - Frederik Ceyssens
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, B-3001 Leuven, Belgium
| | - Robert Puers
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, B-3001 Leuven, Belgium
| | - Michael Kraft
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, B-3001 Leuven, Belgium
| | - Weisheng Zhao
- School of Microelectronics, Beihang University, Beijing 100191, China; (X.W.)
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266104, China
| | - Lianggong Wen
- School of Microelectronics, Beihang University, Beijing 100191, China; (X.W.)
- Beihang-Goertek Joint Microelectronics Institute, Qingdao Research Institute, Beihang University, Qingdao 266104, China
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Yuan S, Swartenbroekx J, Li Y, Zhu J, Ceyssens F, Zhang R, Volodine A, Li J, Van Puyvelde P, Van der Bruggen B. Facile synthesis of Kevlar nanofibrous membranes via regeneration of hydrogen bonds for organic solvent nanofiltration. J Memb Sci 2019. [DOI: 10.1016/j.memsci.2018.12.047] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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11
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Kil D, Bovet Carmona M, Ceyssens F, Deprez M, Brancato L, Nuttin B, Balschun D, Puers R. Dextran as a Resorbable Coating Material for Flexible Neural Probes. Micromachines (Basel) 2019; 10:mi10010061. [PMID: 30658409 PMCID: PMC6356287 DOI: 10.3390/mi10010061] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 12/27/2018] [Accepted: 01/15/2019] [Indexed: 12/13/2022]
Abstract
In the quest for chronically reliable and bio-tolerable brain interfaces there has been a steady evolution towards the use of highly flexible, polymer-based electrode arrays. The reduced mechanical mismatch between implant and brain tissue has shown to reduce the evoked immune response, which in turn has a positive effect on signal stability and noise. Unfortunately, the low stiffness of the implants also has practical repercussions, making surgical insertion extremely difficult. In this work we explore the use of dextran as a coating material that temporarily stiffens the implant, preventing buckling during insertion. The mechanical properties of dextran coated neural probes are characterized, as well as the different parameters which influence the dissolution rate. Tuning parameters, such as coating thickness and molecular weight of the used dextran, allows customization of the stiffness and dissolution time to precisely match the user's needs. Finally, the immunological response to the coated electrodes was analyzed by performing a histological examination after four months of in vivo testing. The results indicated that a very limited amount of glial scar tissue was formed. Neurons have also infiltrated the area that was initially occupied by the dissolving dextran coating. There was no noticeable drop in neuron density around the site of implantation, confirming the suitability of the coating as a temporary aid during implantation of highly flexible polymer-based neural probes.
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Affiliation(s)
- Dries Kil
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium.
| | - Marta Bovet Carmona
- Laboratory for Biological Psychology, Brain & Cognition, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium.
| | - Frederik Ceyssens
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium.
| | - Marjolijn Deprez
- Experimental Neurosurgery and Neuroanatomy, UZ Herestraat 49 box 7003, 3000 Leuven, Belgium.
| | - Luigi Brancato
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium.
| | - Bart Nuttin
- Experimental Neurosurgery and Neuroanatomy, UZ Herestraat 49 box 7003, 3000 Leuven, Belgium.
| | - Detlef Balschun
- Laboratory for Biological Psychology, Brain & Cognition, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium.
| | - Robert Puers
- ESAT-MICAS, KU Leuven, Kasteelpark Arenberg 10, 3001 Leuven, Belgium.
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12
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Kil D, De Vloo P, Fierens G, Ceyssens F, Hunyadi B, Bertrand A, Nuttin B, Puers R. A foldable electrode array for 3D recording of deep-seated abnormal brain cavities. J Neural Eng 2018; 15:036029. [PMID: 29569571 DOI: 10.1088/1741-2552/aab915] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE This study describes the design and microfabrication of a foldable thin-film neural implant and investigates its suitability for electrical recording of deep-lying brain cavity walls. APPROACH A new type of foldable neural electrode array is presented, which can be inserted through a cannula. The microfabricated electrode is specifically designed for electrical recording of the cavity wall of thalamic lesions resulting from stroke. The proof-of-concept is demonstrated by measurements in rat brain cavities. On implantation, the electrode array unfolds in the brain cavity, contacting the cavity walls and allowing recording at multiple anatomical locations. A three-layer microfabrication process based on UV-lithography and Reactive Ion Etching is described. Electrochemical characterization of the electrode is performed in addition to an in vivo experiment in which the implantation procedure and the unfolding of the electrode are tested and visualized. MAIN RESULTS Electrochemical characterization validated the suitability of the electrode for in vivo use. CT imaging confirmed the unfolding of the electrode in the brain cavity and analysis of recorded local field potentials showed the ability to record neural signals of biological origin. SIGNIFICANCE The conducted research confirms that it is possible to record neural activity from the inside wall of brain cavities at various anatomical locations after a single implantation procedure. This opens up possibilities towards research of abnormal brain cavities and the clinical conditions associated with them, such as central post-stroke pain.
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Affiliation(s)
- Dries Kil
- Department of ESAT-MICAS, KU Leuven, Leuven, Belgium
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Madi M, Ceyssens F, Shorubalko I, Herzig HP, Guldimann B, Giaccari P. Lippmann waveguide spectrometer with enhanced throughput and bandwidth for space and commercial applications. Opt Express 2018; 26:2682-2707. [PMID: 29401806 DOI: 10.1364/oe.26.002682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 01/02/2018] [Indexed: 06/07/2023]
Abstract
This article presents an innovative high spectral resolution waveguide spectrometer, from the concept to the prototype demonstration and the test results. The main goal is to build the smallest possible Fourier transform spectrometer (FTS) with state of the art technology. This waveguide FTS takes advantage of a customized pattern of nano-samplers fabricated on the surface of a planar waveguide that allows the increase of the measurement points necessary for increasing the spectral bandwidth of the FTS in a fully static way. The use of a planar waveguide on the other hand allows enhancing the throughput in a waveguide spectrometer compared to the conventional devices made of single-mode waveguides. A prototype is made in silicon oxynitride/silicon dioxide technology and characterized in the visible range. This waveguide spectrometer shows a nominal bandwidth of 256~nm at a central wavelength of 633~nm thanks to a custom pattern of nanodisks providing a μm sampling interval. The implementation of this innovative waveguide FTS for a real-case scenario is explored and further development of such device for the imaging FTS application is discussed.
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Abstract
A robust and low cost ionic liquid based strain sensor is fabricated for high strain measurements in biomedical applications (up to 40 % and higher). A tubular 5 mm long silicone microchannel with an inner diameter of 310 µm and an outer diameter of 650 µm is filled with an ionic liquid. Three ionic liquids have been investigated: 1-butyl-1-methylpyrrolidinium bis (trifluoromethylsulfonyl) imide, ethylammonium nitrate and cholinium ethanoate. When the channel is axially stretched, geometrical deformations change the electrical impedance of the liquid channel. The sensors display a linear response and low hysteresis with an average gauge factors of 1.99 for strains up to 40 %. Additionally, to fix the sensor by surgical stitching to soft biological tissue, a sensor with tube clamps consisting of photopatternable SU-8 epoxy-based resin is proposed.
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Affiliation(s)
- Grim Keulemans
- KU Leuven, ESAT-MICAS, Kasteelpark Arenberg 10, 3001, Heverlee, Belgium.
| | - Frederik Ceyssens
- KU Leuven, ESAT-MICAS, Kasteelpark Arenberg 10, 3001, Heverlee, Belgium
| | - Robert Puers
- KU Leuven, ESAT-MICAS, Kasteelpark Arenberg 10, 3001, Heverlee, Belgium
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Ceyssens F, Deprez M, Turner N, Kil D, van Kuyck K, Welkenhuysen M, Nuttin B, Badylak S, Puers R. Extracellular matrix proteins as temporary coating for thin-film neural implants. J Neural Eng 2017; 14:014001. [DOI: 10.1088/1741-2552/14/1/014001] [Citation(s) in RCA: 7] [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] [Indexed: 11/11/2022]
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Chaudhuri BP, Ceyssens F, Van Hoof C, Puers R. A novel method for monolithic fabrication of polymer microneedles on a platform for transdermal drug delivery. Annu Int Conf IEEE Eng Med Biol Soc 2013; 2013:156-9. [PMID: 24109648 DOI: 10.1109/embc.2013.6609461] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This paper reports on the creation of a novel method for monolithic fabrication of out-of-plane polymer (SU-8) microneedles incorporating sharpness of needle-tips, hollowness of needle lumen as well as a platform on which the microneedles stand orthogonally with the hollow of the needle lumen continuous through the platform. In essence, both the microneedle as well as the platform on which it stands, are made of the same polymer material, rendering the process monolithic. The microneedle tips produced were quite sharp with tip diameters ranging between 5 to 10 µm, needle heights greater than 1 mm and resulting aspect ratio of 40. Further, mechanical tests performed on the fabricated microneedles demonstrate a critical compressive failure load of about 173 mN on average per microneedle, which translates into a safety factor greater than one for skin penetration.
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Witters D, Knez K, Ceyssens F, Puers R, Lammertyn J. Digital microfluidics-enabled single-molecule detection by printing and sealing single magnetic beads in femtoliter droplets. Lab Chip 2013; 13:2047-54. [PMID: 23609603 DOI: 10.1039/c3lc50119a] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Digital microfluidics is introduced as a novel platform with unique advantages for performing single-molecule detection. We demonstrate how superparamagnetic beads, used for capturing single protein molecules, can be printed with unprecedentedly high loading efficiency and single bead resolution on an electrowetting-on-dielectric-based digital microfluidic chip by micropatterning the Teflon-AF surface of the device. By transporting droplets containing suspended superparamagnetic beads over a hydrophilic-in-hydrophobic micropatterned Teflon-AF surface, single beads are trapped inside the hydrophilic microwells due to their selective wettability and tailored dimensions. Digital microfluidics presents the following advantages for printing and sealing magnetic beads for single-molecule detection: (i) droplets containing suspended beads can be transported back and forth over the array of hydrophilic microwells to obtain high loading efficiencies of microwells with single beads, (ii) the use of hydrophilic-in-hydrophobic patterns permits the use of a magnet to speed up the bead transfer process to the wells, while the receding droplet meniscus removes excess beads off the chip surface and thereby shortens the bead patterning time, and (iii) reagents can be transported over the printed beads multiple times, while capillary forces and a magnet hold the printed beads in place. High loading efficiencies (98% with a CV of 0.9%) of single beads in microwells were obtained by transporting droplets of suspended beads over the array 10 times in less than 1 min, which is much higher than previously reported methods (40-60%), while the total surface area needed for performing single-molecule detection can be decreased. The performance of the device was demonstrated by fluorescent detection of the presence of the biotinylated enzyme β-galactosidase on streptavidin-coated beads with a linear dynamic range of 4 orders of magnitude ranging from 10 aM to 90 fM.
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Affiliation(s)
- Daan Witters
- KU Leuven - University of Leuven, BIOSYST-MeBioS, Willem de Croylaan 42, Leuven, Belgium
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Witters D, Vergauwe N, Vermeir S, Ceyssens F, Liekens S, Puers R, Lammertyn J. Biofunctionalization of electrowetting-on-dielectric digital microfluidic chips for miniaturized cell-based applications. Lab Chip 2011; 11:2790-4. [PMID: 21720645 DOI: 10.1039/c1lc20340a] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this paper we report on the controlled biofunctionalization of the hydrophobic layer of electrowetting-on-dielectric (EWOD) based microfluidic chips with the aim to execute (adherent) cell-based assays. The biofunctionalization technique involves a dry lift-off method with an easy to remove Parylene-C mask and allows the creation of spatially controlled micropatches of biomolecules in the Teflon-AF(®) layer of the chip. Compared to conventional methods, this method (i) is fully biocompatible; and (ii) leaves the hydrophobicity of the chip surface unaffected by the fabrication process, which is a crucial feature for digital microfluidic chips. In addition, full control of the geometry and the dimensions of the micropatches is achieved, allowing cells to be arrayed as cell clusters or as single cells on the digital microfluidic chip surface. The dry Parylene-C lift-off technique proves to have great potential for precise biofunctionalization of digital microfluidic chips, and can enhance their use for heterogeneous bio-assays that are of interest in various biomedical applications.
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Affiliation(s)
- Daan Witters
- BIOSYST-MeBioS, Willem de Croylaan 42, Leuven, Belgium
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Chaudhri BP, Ceyssens F, Neves HP, La Manna A, Van Hoof C, Puers R. Out-of-plane, high strength, polymer microneedles for transdermal drug delivery. Annu Int Conf IEEE Eng Med Biol Soc 2011; 2011:3680-3683. [PMID: 22255138 DOI: 10.1109/iembs.2011.6090622] [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] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This paper reports on the high strength of high-aspect ratio (> 50) hollow, polymer microneedles fabricated out-of-plane using a fairly repeatable fabrication process. Further, these microneedle tips were sharpened by a molding principle, with a simple anisotropic etch of silicon wafer. Also, an enhanced elegant process was explored to incorporate the mounting of the microneedle onto a platform without using any additional material, such that the bore of the microneedle is continuous with the bore of the platform in order to facilitate microfluidic delivery through the hollow needles. The high aspect ratio microneedles undergo failure at the critical load of around 4 N, while the insertion force for such a needle into agar gel, which is a fairly good equivalent of the human skin due to its inherent visco-elastic properties, is 7 mN, which translates into a safety factor (ratio of critical loading force to the maximum applied force) of greater than 500 thus, making it adequately strong for skin penetration.
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Chaudhri BP, Ceyssens F, Guan T, La Manna A, Neves HP, Van Hoof C, Puers R. High Strength, Polymer Microneedles For Transdermal Drug Delivery. ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.proeng.2011.12.340] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [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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Smal O, Dehez B, Raucent B, De Volder M, Peirs J, Reynaerts D, Ceyssens F, Coosemans J, Puers R. Modelling, characterization and testing of an ortho-planar micro-valve. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s12213-008-0015-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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