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Srbova L, Arasalo O, Lehtonen AJ, Pokki J. Measuring mechanical cues for modeling the stromal matrix in 3D cell cultures. Soft Matter 2024; 20:3483-3498. [PMID: 38587658 DOI: 10.1039/d3sm01425h] [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: 04/09/2024]
Abstract
A breast-cancer tumor develops within a stroma, a tissue where a complex extracellular matrix surrounds cells, mediating the cancer progression through biomechanical and -chemical cues. Current materials partially mimic the stromal matrix in 3D cell cultures but methods for measuring the mechanical properties of the matrix at cell-relevant-length scales and stromal-stiffness levels are lacking. Here, to address this gap, we developed a characterization approach that employs probe-based microrheometry and Bayesian modeling to quantify length-scale-dependent mechanics and mechanical heterogeneity as in the stromal matrix. We examined the interpenetrating network (IPN) composed of alginate scaffolds (for adjusting mechanics) and type-1 collagen (a stromal-matrix constituent). We analyzed viscoelasticity: absolute-shear moduli (stiffness/elasticity) and phase angles (viscous and elastic characteristics). We determined the relationship between microrheometry and rheometry information. Microrheometry reveals lower stiffness at cell-relevant scales, compared to macroscale rheometry, with dependency on the length scale (10 to 100 μm). These data show increasing IPN stiffness with crosslinking until saturation (≃15 mM of Ca2+). Furthermore, we report that IPN stiffness can be adjusted by modulating collagen concentration and interconnectivity (by polymerization temperature). The IPNs are heterogeneous structurally (in SEM) and mechanically. Interestingly, increased alginate crosslinking changes IPN heterogeneity in stiffness but not in phase angle, until the saturation. In contrast, such changes are undetectable in alginate scaffolds. Our nonlinear viscoelasticity analysis at tumor-cell-exerted strains shows that only the softer IPNs stiffen with strain, like the stromal-collagen constituent. In summary, our approach can quantify the stromal-matrix-related viscoelasticity and is likely applicable to other materials in 3D culture.
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Affiliation(s)
- Linda Srbova
- Department of Electrical Engineering and Automation, Aalto University, Espoo, FI-02150, Finland.
| | - Ossi Arasalo
- Department of Electrical Engineering and Automation, Aalto University, Espoo, FI-02150, Finland.
| | - Arttu J Lehtonen
- Department of Electrical Engineering and Automation, Aalto University, Espoo, FI-02150, Finland.
| | - Juho Pokki
- Department of Electrical Engineering and Automation, Aalto University, Espoo, FI-02150, Finland.
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2
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Mäntylä VM, Lehtonen AJ, Korhonen V, Srbova L, Pokki J. Quantifying the Influence of X-Ray Irradiation on Cell-Size-Scale Viscoelasticity of Collagen Type 1. J Biomech Eng 2024; 146:044501. [PMID: 38183220 DOI: 10.1115/1.4064404] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 12/27/2023] [Indexed: 01/07/2024]
Abstract
X-rays are widely used in mammography and radiotherapy of breast cancer. The research has focused on the effects of X-rays on cells in breast tissues, instead of the tissues' nonliving material, extracellular matrix. It is unclear what the influence of X-ray irradiation is on the matrix's mechanical cues, known to regulate malignant cancer-cell behaviors. Here, we developed a technique based on magnetic microrheology that can quantify the influence of X-ray irradiation on matrix viscoelasticity--or (solid-like) elastic and (liquid-like) viscous characteristics--at cell-size scales. To model breast-tissue extracellular matrix, we used the primary component of the tissue matrix, collagen type 1, as it is for control, and as irradiated by X-rays (tube voltage 50 kV). We used a magnetic microrheometer to measure collagen matrices using 10-μm-diameter magnetic probes. In each matrix, the probes were nanomanipulated using controlled magnetic forces by the microrheometer while the probes' displacements were detected to measure the viscoelasticity. The collagen-matrix data involve with a typical spatial variation in viscoelasticity. We find that higher irradiation doses (320 Gy) locally reduce stiffness (soften) collagen matrices and increase their loss tangent, indicating an elevated liquid-like nature. For lower, clinically relevant irradiation doses (54 Gy), we find insignificant matrix-viscoelasticity changes. We provide this irradiation-related technique for detection, and modification, of matrix viscoelastic cues at cell-size scales. The technique enables enhanced characterization of irradiated tissue constituents in a variety of breast-cancer radiotherapy types.
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Affiliation(s)
- Väinö Mikael Mäntylä
- Department of Electrical Engineering and Automation, Aalto University, Espoo FI-02150, Finland
| | - Arttu Juhani Lehtonen
- Department of Electrical Engineering and Automation, Aalto University, Espoo FI-02150, Finland
| | - Vesa Korhonen
- Department of Electrical Engineering and Automation, Aalto University, Espoo FI-02150, Finland
| | - Linda Srbova
- Department of Electrical Engineering and Automation, Aalto University, Espoo FI-02150, Finland
| | - Juho Pokki
- ASME Professional Mem. Department of Electrical Engineering and Automation, Aalto University, Espoo FI-02150, Finland
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3
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Heilala M, Lehtonen A, Arasalo O, Peura A, Pokki J, Ikkala O, Nonappa, Klefström J, Munne PM. Fibrin Stiffness Regulates Phenotypic Plasticity of Metastatic Breast Cancer Cells. Adv Healthc Mater 2023; 12:e2301137. [PMID: 37671812 DOI: 10.1002/adhm.202301137] [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] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 08/18/2023] [Indexed: 09/07/2023]
Abstract
The extracellular matrix (ECM)-regulated phenotypic plasticity is crucial for metastatic progression of triple negative breast cancer (TNBC). While ECM faithful cell-based models are available for in situ and invasive tumors, such as cell aggregate cultures in reconstituted basement membrane and in collagenous gels, there are no ECM faithful models for metastatic circulating tumor cells (CTCs). Such models are essential to represent the stage of metastasis where clinical relevance and therapeutic opportunities are significant. Here, CTC-like DU4475 TNBC cells are cultured in mechanically tunable 3D fibrin hydrogels. This is motivated, as in circulation fibrin aids CTC survival by forming a protective coating reducing shear stress and immune cell-mediated cytotoxicity and promotes several stages of late metastatic processes at the interface between circulation and tissue. This work shows that fibrin hydrogels support DU4475 cell growth, resulting in spheroid formation. Furthermore, increasing fibrin stiffness from 57 to 175 Pa leads to highly motile, actin and tubulin containing cellular protrusions, which are associated with specific cell morphology and gene expression patterns that markedly differ from basement membrane or suspension cultures. Thus, mechanically tunable fibrin gels reveal specific matrix-based regulation of TNBC cell phenotype and offer scaffolds for CTC-like cells with better mechano-biological properties than liquid.
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Affiliation(s)
- Maria Heilala
- Department of Applied Physics, Aalto University, P.O. Box 15100, Aalto, Espoo, FI-00076, Finland
| | - Arttu Lehtonen
- Department of Electrical Engineering and Automation, Aalto University, P.O. Box 12200, Aalto, Espoo, FI-00076, Finland
| | - Ossi Arasalo
- Department of Electrical Engineering and Automation, Aalto University, P.O. Box 12200, Aalto, Espoo, FI-00076, Finland
| | - Aino Peura
- Finnish Cancer Institute and FICAN South, Helsinki University Hospital & Cancer Cell Circuitry Laboratory, Translational Cancer Medicine, Medical Faculty, University of Helsinki, P.O. Box 63 (Haartmaninkatu 8), Helsinki, 00014, Finland
| | - Juho Pokki
- Department of Electrical Engineering and Automation, Aalto University, P.O. Box 12200, Aalto, Espoo, FI-00076, Finland
| | - Olli Ikkala
- Department of Applied Physics, Aalto University, P.O. Box 15100, Aalto, Espoo, FI-00076, Finland
| | - Nonappa
- Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 541, Tampere, FI-33720, Finland
| | - Juha Klefström
- Finnish Cancer Institute and FICAN South, Helsinki University Hospital & Cancer Cell Circuitry Laboratory, Translational Cancer Medicine, Medical Faculty, University of Helsinki, P.O. Box 63 (Haartmaninkatu 8), Helsinki, 00014, Finland
| | - Pauliina M Munne
- Finnish Cancer Institute and FICAN South, Helsinki University Hospital & Cancer Cell Circuitry Laboratory, Translational Cancer Medicine, Medical Faculty, University of Helsinki, P.O. Box 63 (Haartmaninkatu 8), Helsinki, 00014, Finland
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4
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Lehtonen AJ, Arasalo O, Srbova L, Heilala M, Pokki J. Magnetic microrheometry of tumor-relevant stiffness levels and probabilistic quantification of viscoelasticity differences inside 3D cell culture matrices. PLoS One 2023; 18:e0282511. [PMID: 36947558 PMCID: PMC10032533 DOI: 10.1371/journal.pone.0282511] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 02/16/2023] [Indexed: 03/23/2023] Open
Abstract
The progression of breast cancer involves cancer-cell invasions of extracellular matrices. To investigate the progression, 3D cell cultures are widely used along with different types of matrices. Currently, the matrices are often characterized using parallel-plate rheometry for matrix viscoelasticity, or liquid-like viscous and stiffness-related elastic characteristics. The characterization reveals averaged information and sample-to-sample variation, yet, it neglects internal heterogeneity within matrices, experienced by cancer cells in 3D culture. Techniques using optical tweezers and magnetic microrheometry have measured heterogeneity in viscoelasticity in 3D culture. However, there is a lack of probabilistic heterogeneity quantification and cell-size-relevant, microscale-viscoelasticity measurements at breast-tumor tissue stiffness up to ≃10 kPa in Young's modulus. Here, we have advanced methods, for the purpose, which use a magnetic microrheometer that applies forces on magnetic spheres within matrices, and detects the spheres displacements. We present probabilistic heterogeneity quantification using microscale-viscoelasticity measurements in 3D culture matrices at breast-tumor-relevant stiffness levels. Bayesian multilevel modeling was employed to distinguish heterogeneity in viscoelasticity from the effects of experimental design and measurement errors. We report about the heterogeneity of breast-tumor-relevant agarose, GrowDex, GrowDex-collagen and fibrin matrices. The degree of heterogeneity differs for stiffness, and phase angle (i.e. ratio between viscous and elastic characteristics). Concerning stiffness, agarose and GrowDex show the lowest and highest heterogeneity, respectively. Concerning phase angle, fibrin and GrowDex-collagen present the lowest and the highest heterogeneity, respectively. While this heterogeneity information involves softer matrices, probed by ≃30 μm magnetic spheres, we employ larger ≃100 μm spheres to increase magnetic forces and acquire a sufficient displacement signal-to-noise ratio in stiffer matrices. Thus, we show pointwise microscale viscoelasticity measurements within agarose matrices up to Young's moduli of 10 kPa. These results establish methods that combine magnetic microrheometry and Bayesian multilevel modeling for enhanced heterogeneity analysis within 3D culture matrices.
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Affiliation(s)
- Arttu J Lehtonen
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
| | - Ossi Arasalo
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
| | - Linda Srbova
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
| | - Maria Heilala
- Department of Applied Physics, Aalto University, Espoo, Finland
| | - Juho Pokki
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
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5
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Sikic L, Schulman E, Kosklin A, Saraswathibhatla A, Chaudhuri O, Pokki J. Nanoscale Tracking Combined with Cell-Scale Microrheology Reveals Stepwise Increases in Force Generated by Cancer Cell Protrusions. Nano Lett 2022; 22:7742-7750. [PMID: 35950832 PMCID: PMC9523704 DOI: 10.1021/acs.nanolett.2c01327] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/26/2022] [Indexed: 06/15/2023]
Abstract
In early breast cancer progression, cancer cells invade through a nanoporous basement membrane (BM) as a first key step toward metastasis. This invasion is thought to be mediated by a combination of proteases, which biochemically degrade BM matrix, and physical forces, which mechanically open up holes in the matrix. To date, techniques that quantify cellular forces of BM invasion in 3D culture have been unavailable. Here, we developed cellular-force measurements for breast cancer cell invasion in 3D culture that combine multiple-particle tracking of force-induced BM-matrix displacements at the nanoscale, and magnetic microrheometry of localized matrix mechanics. We find that cancer-cell protrusions exert forces from picoNewtons up to nanoNewtons during invasion. Strikingly, the protrusions extension involves stepwise increases in force, in steps of 0.2 to 0.5 nN exerted from every 30 s to 6 min. Thus, this technique reveals previously unreported dynamics of force generation by invasive protrusions in cancer cells.
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Affiliation(s)
- Luka Sikic
- Department
of Electrical Engineering and Automation, Aalto University, Espoo, FI-02150,Finland
| | - Ester Schulman
- Department
of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Anna Kosklin
- Department
of Electrical Engineering and Automation, Aalto University, Espoo, FI-02150,Finland
| | - Aashrith Saraswathibhatla
- Department
of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Ovijit Chaudhuri
- Department
of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - Juho Pokki
- Department
of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
- Department
of Electrical Engineering and Automation, Aalto University, Espoo, FI-02150,Finland
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Munne PM, Martikainen L, Räty I, Bertula K, Nonappa, Ruuska J, Ala-Hongisto H, Peura A, Hollmann B, Euro L, Yavuz K, Patrikainen L, Salmela M, Pokki J, Kivento M, Väänänen J, Suomi T, Nevalaita L, Mutka M, Kovanen P, Leidenius M, Meretoja T, Hukkinen K, Monni O, Pouwels J, Sahu B, Mattson J, Joensuu H, Heikkilä P, Elo LL, Metcalfe C, Junttila MR, Ikkala O, Klefström J. Compressive stress-mediated p38 activation required for ERα + phenotype in breast cancer. Nat Commun 2021; 12:6967. [PMID: 34845227 PMCID: PMC8630031 DOI: 10.1038/s41467-021-27220-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 11/04/2021] [Indexed: 01/01/2023] Open
Abstract
Breast cancer is now globally the most frequent cancer and leading cause of women's death. Two thirds of breast cancers express the luminal estrogen receptor-positive (ERα + ) phenotype that is initially responsive to antihormonal therapies, but drug resistance emerges. A major barrier to the understanding of the ERα-pathway biology and therapeutic discoveries is the restricted repertoire of luminal ERα + breast cancer models. The ERα + phenotype is not stable in cultured cells for reasons not fully understood. We examine 400 patient-derived breast epithelial and breast cancer explant cultures (PDECs) grown in various three-dimensional matrix scaffolds, finding that ERα is primarily regulated by the matrix stiffness. Matrix stiffness upregulates the ERα signaling via stress-mediated p38 activation and H3K27me3-mediated epigenetic regulation. The finding that the matrix stiffness is a central cue to the ERα phenotype reveals a mechanobiological component in breast tissue hormonal signaling and enables the development of novel therapeutic interventions. Subject terms: ER-positive (ER + ), breast cancer, ex vivo model, preclinical model, PDEC, stiffness, p38 SAPK.
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Affiliation(s)
- Pauliina M Munne
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland
| | - Lahja Martikainen
- Department of Applied Physics, Molecular Materials Group, Aalto University School of Science, PO Box, 15100, FI-00076, Espoo, Finland
| | - Iiris Räty
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland
| | - Kia Bertula
- Department of Applied Physics, Molecular Materials Group, Aalto University School of Science, PO Box, 15100, FI-00076, Espoo, Finland
| | - Nonappa
- Department of Applied Physics, Molecular Materials Group, Aalto University School of Science, PO Box, 15100, FI-00076, Espoo, Finland
- Department of Bioproducts and Biosystems, Aalto University School of Chemical Engineering, Espoo, Finland
| | - Janika Ruuska
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland
| | - Hanna Ala-Hongisto
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland
| | - Aino Peura
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland
| | - Babette Hollmann
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland
| | - Lilya Euro
- Research Program of Stem Cells and Metabolism, Biomedicum Helsinki, University of Helsinki, 00290, Helsinki, Finland
| | - Kerim Yavuz
- Applied Tumor Genomics Research Program, Enhancer Biology Laboratory, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Linda Patrikainen
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland
| | - Maria Salmela
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland
| | - Juho Pokki
- Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland
| | - Mikko Kivento
- Applied Tumor Genomics Research Program, Faculty of Medicine, Oncogenomics Laboratory, University of Helsinki, Helsinki, Finland
| | - Juho Väänänen
- Applied Tumor Genomics Research Program, Faculty of Medicine, Oncogenomics Laboratory, University of Helsinki, Helsinki, Finland
| | - Tomi Suomi
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, FI-20520, Turku, Finland
| | - Liina Nevalaita
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland
| | - Minna Mutka
- Department of Pathology, HUSLAB and Haartman Institute, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - Panu Kovanen
- Department of Pathology, HUSLAB and Haartman Institute, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - Marjut Leidenius
- Breast Surgery Unit, Helsinki University Central Hospital, Helsinki, Finland
| | - Tuomo Meretoja
- Breast Surgery Unit, Helsinki University Central Hospital, Helsinki, Finland
| | - Katja Hukkinen
- Department of Mammography, Helsinki University Central Hospital, Helsinki, Finland
| | - Outi Monni
- Applied Tumor Genomics Research Program, Faculty of Medicine, Oncogenomics Laboratory, University of Helsinki, Helsinki, Finland
| | - Jeroen Pouwels
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland
| | - Biswajyoti Sahu
- Applied Tumor Genomics Research Program, Enhancer Biology Laboratory, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Johanna Mattson
- Department of Oncology, University of Helsinki & Helsinki University Hospital, Helsinki, Finland
| | - Heikki Joensuu
- Department of Oncology, University of Helsinki & Helsinki University Hospital, Helsinki, Finland
| | - Päivi Heikkilä
- Department of Pathology, HUSLAB and Haartman Institute, Helsinki University Central Hospital and University of Helsinki, Helsinki, Finland
| | - Laura L Elo
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, FI-20520, Turku, Finland
| | - Ciara Metcalfe
- Genentech Inc., 1 DNA Way, South San Francisco, CA, 94080, USA
| | | | - Olli Ikkala
- Department of Applied Physics, Molecular Materials Group, Aalto University School of Science, PO Box, 15100, FI-00076, Espoo, Finland
- Department of Bioproducts and Biosystems, Aalto University School of Chemical Engineering, Espoo, Finland
| | - Juha Klefström
- Finnish Cancer Institute, FICAN South Helsinki University Hospital & Translational Cancer Medicine, Medical Faculty, University of Helsinki. Cancer Cell Circuitry Laboratory, PO Box 63 Haartmaninkatu 8, 00014 University of Helsinki, Helsinki, Finland.
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Pokki J, Zisi I, Schulman E, Indana D, Chaudhuri O. Magnetic probe-based microrheology reveals local softening and stiffening of 3D collagen matrices by fibroblasts. Biomed Microdevices 2021; 23:27. [PMID: 33900463 PMCID: PMC8076128 DOI: 10.1007/s10544-021-00547-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [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] [Indexed: 12/14/2022]
Abstract
Changes in extracellular matrix stiffness impact a variety of biological processes including cancer progression. However, cells also actively remodel the matrices they interact with, dynamically altering the matrix mechanics they respond to. Further, cells not only react to matrix stiffness, but also have a distinct reaction to matrix viscoelasticity. The impact of cell-driven matrix remodeling on matrix stiffness and viscoelasticity at the microscale remains unclear, as existing methods to measure mechanics are largely at the bulk scale or probe only the surface of matrices, and focus on stiffness. Yet, establishing the impact of the matrix remodeling at the microscale is crucial to obtaining an understanding of mechanotransduction in biological matrices, and biological matrices are not just elastic, but are viscoelastic. Here, we advanced magnetic probe-based microrheology to overcome its previous limitations in measuring viscoelasticity at the cell-size-scale spatial resolution within 3D cell cultures that have tissue-relevant stiffness levels up to a Young's modulus of 0.5 kPa. Our magnetic microrheometers exert controlled magnetic forces on magnetic microprobes within reconstituted extracellular matrices and detect microprobe displacement responses to measure matrix viscoelasticity and determine the frequency-dependent shear modulus (stiffness), the loss tangent, and spatial heterogeneity. We applied these tools to investigate how microscale viscoelasticity of collagen matrices is altered by fibroblast cells as they contract collagen gels, a process studied extensively at the macroscale. Interestingly, we found that fibroblasts first soften the matrix locally over the first 32 hours of culture, and then progressively stiffen the matrix thereafter. Fibroblast activity also progressively increased the matrix loss tangent. We confirmed that the softening is caused by matrix-metalloproteinase-mediated collagen degradation, whereas stiffening is associated with local alignment and densification of collagen fibers around the fibroblasts. This work paves the way for the use of measurement systems that quantify microscale viscoelasticity within 3D cell cultures for studies of cell-matrix interactions in cancer progression and other areas.
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Affiliation(s)
- Juho Pokki
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA. .,Department of Electrical Engineering and Automation, Aalto University, Espoo, Finland.
| | - Iliana Zisi
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Ester Schulman
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Dhiraj Indana
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
| | - Ovijit Chaudhuri
- Department of Mechanical Engineering, Stanford University, Stanford, CA, USA
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8
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Vuorinen V, Aarnio M, Alava M, Alopaeus V, Atanasova N, Auvinen M, Balasubramanian N, Bordbar H, Erästö P, Grande R, Hayward N, Hellsten A, Hostikka S, Hokkanen J, Kaario O, Karvinen A, Kivistö I, Korhonen M, Kosonen R, Kuusela J, Lestinen S, Laurila E, Nieminen HJ, Peltonen P, Pokki J, Puisto A, Råback P, Salmenjoki H, Sironen T, Österberg M. Modelling aerosol transport and virus exposure with numerical simulations in relation to SARS-CoV-2 transmission by inhalation indoors. Saf Sci 2020; 130:104866. [PMID: 32834511 PMCID: PMC7428778 DOI: 10.1016/j.ssci.2020.104866] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 05/31/2020] [Indexed: 05/03/2023]
Abstract
We provide research findings on the physics of aerosol and droplet dispersion relevant to the hypothesized aerosol transmission of SARS-CoV-2 during the current pandemic. We utilize physics-based modeling at different levels of complexity, along with previous literature on coronaviruses, to investigate the possibility of airborne transmission. The previous literature, our 0D-3D simulations by various physics-based models, and theoretical calculations, indicate that the typical size range of speech and cough originated droplets ( d ⩽ 20 μ m ) allows lingering in the air for O ( 1 h ) so that they could be inhaled. Consistent with the previous literature, numerical evidence on the rapid drying process of even large droplets, up to sizes O ( 100 μ m ) , into droplet nuclei/aerosols is provided. Based on the literature and the public media sources, we provide evidence that the individuals, who have been tested positive on COVID-19, could have been exposed to aerosols/droplet nuclei by inhaling them in significant numbers e.g. O ( 100 ) . By 3D scale-resolving computational fluid dynamics (CFD) simulations, we give various examples on the transport and dilution of aerosols ( d ⩽ 20 μ m ) over distances O ( 10 m ) in generic environments. We study susceptible and infected individuals in generic public places by Monte-Carlo modelling. The developed model takes into account the locally varying aerosol concentration levels which the susceptible accumulate via inhalation. The introduced concept, 'exposure time' to virus containing aerosols is proposed to complement the traditional 'safety distance' thinking. We show that the exposure time to inhale O ( 100 ) aerosols could range from O ( 1 s ) to O ( 1 min ) or even to O ( 1 h ) depending on the situation. The Monte-Carlo simulations, along with the theory, provide clear quantitative insight to the exposure time in different public indoor environments.
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Affiliation(s)
- Ville Vuorinen
- Department of Mechanical Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Mia Aarnio
- Atmospheric Dispersion Modelling, Atmospheric Composition Research, Finnish Meteorological Institute, FI-00101 Helsinki, Finland
| | - Mikko Alava
- Department of Applied Physics, Aalto University, FI-00076 AALTO, Finland
| | - Ville Alopaeus
- Department of Chemical and Metallurgical Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Nina Atanasova
- Atmospheric Dispersion Modelling, Atmospheric Composition Research, Finnish Meteorological Institute, FI-00101 Helsinki, Finland
- Molecular and Integrative Biosciences Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Finland
| | - Mikko Auvinen
- Atmospheric Dispersion Modelling, Atmospheric Composition Research, Finnish Meteorological Institute, FI-00101 Helsinki, Finland
| | | | - Hadi Bordbar
- Department of Civil Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Panu Erästö
- Department of Information and Service Management, Aalto University, FI-00076 AALTO, Finland
| | - Rafael Grande
- Department of Bioproducts and Biosystems, Aalto University, FI-00076 AALTO, Finland
| | - Nick Hayward
- Department of Neuroscience and Biomedical Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Antti Hellsten
- Atmospheric Dispersion Modelling, Atmospheric Composition Research, Finnish Meteorological Institute, FI-00101 Helsinki, Finland
| | - Simo Hostikka
- Department of Civil Engineering, Aalto University, FI-00076 AALTO, Finland
| | | | - Ossi Kaario
- Department of Mechanical Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Aku Karvinen
- VTT Technical Research Centre of Finland Ltd, Finland
| | - Ilkka Kivistö
- VTT Technical Research Centre of Finland Ltd, Finland
| | - Marko Korhonen
- Department of Applied Physics, Aalto University, FI-00076 AALTO, Finland
| | - Risto Kosonen
- Department of Mechanical Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Janne Kuusela
- Emergency Department, Mikkeli Central Hospital, The South Savo Social and Health Care Authority, FI-50100, Finland
| | - Sami Lestinen
- Department of Mechanical Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Erkki Laurila
- Department of Mechanical Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Heikki J Nieminen
- Department of Neuroscience and Biomedical Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Petteri Peltonen
- Department of Mechanical Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Juho Pokki
- Department of Chemical and Metallurgical Engineering, Aalto University, FI-00076 AALTO, Finland
| | - Antti Puisto
- Department of Applied Physics, Aalto University, FI-00076 AALTO, Finland
| | - Peter Råback
- CSC-IT Center for Science Ltd, FI-02101, Finland
| | - Henri Salmenjoki
- Department of Applied Physics, Aalto University, FI-00076 AALTO, Finland
| | - Tarja Sironen
- Department of Virology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Monika Österberg
- Department of Bioproducts and Biosystems, Aalto University, FI-00076 AALTO, Finland
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Hu C, Aeschlimann F, Chatzipirpiridis G, Pokki J, Chen X, Puigmarti-Luis J, Nelson BJ, Pané S. Spatiotemporally controlled electrodeposition of magnetically driven micromachines based on the inverse opal architecture. Electrochem commun 2017. [DOI: 10.1016/j.elecom.2017.06.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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10
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Buttinoni I, Steinacher M, Spanke HT, Pokki J, Bahmann S, Nelson B, Foffi G, Isa L. Colloidal polycrystalline monolayers under oscillatory shear. Phys Rev E 2017; 95:012610. [PMID: 28208468 DOI: 10.1103/physreve.95.012610] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Indexed: 11/07/2022]
Abstract
In this paper we probe the structural response to oscillatory shear deformations of polycrystalline monolayers of soft repulsive colloids with varying area fraction over a broad range of frequencies and amplitudes. The particles are confined at a fluid interface, sheared using a magnetic microdisk, and imaged through optical microscopy. The structural and mechanical response of soft materials is highly dependent on their microstructure. If crystals are well understood and deform through the creation and mobilization of specific defects, the situation is much more complex for disordered jammed materials, where identifying structural motifs defining plastically rearranging regions remains an elusive task. Our materials fall between these two classes and allow the identification of clear pathways for structural evolution. In particular, we demonstrate that large enough strains are able to fluidize the system, identifying critical strains that fulfill a local Lindemann criterion. Conversely, smaller strains lead to localized and erratic irreversible particle rearrangements due to the motion of structural defects. In this regime, oscillatory shear promotes defect annealing and leads to the growth of large crystalline domains. Numerical simulations help identify the population of rearranging particles with those exhibiting the largest deviatoric stresses and indicate that structural evolution proceeds towards the minimization of the stress stored in the system. The particles showing high deviatoric stresses are localized around grain boundaries and defects, providing a simple criterion to spot regions likely to rearrange plastically under oscillatory shear.
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Affiliation(s)
- Ivo Buttinoni
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Mathias Steinacher
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Hendrik Th Spanke
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
| | - Juho Pokki
- Institute of Robotics and Intelligent Systems, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Severin Bahmann
- Institute of Robotics and Intelligent Systems, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Bradley Nelson
- Institute of Robotics and Intelligent Systems, ETH Zurich, CH-8092, Zurich, Switzerland
| | - Giuseppe Foffi
- Laboratoire de Physique des Solides, CNRS, Université Paris-Sud, Université Paris-Saclay, Orsay 91405, France
| | - Lucio Isa
- Laboratory for Interfaces, Soft Matter and Assembly, Department of Materials, ETH Zurich, CH-8093, Zurich, Switzerland
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11
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Pokki J, Ergeneman O, Chatzipirpiridis G, Lühmann T, Sort J, Pellicer E, Pot SA, Spiess BM, Pané S, Nelson BJ. Protective coatings for intraocular wirelessly controlled microrobots for implantation: Corrosion, cell culture, andin vivoanimal tests. J Biomed Mater Res B Appl Biomater 2016; 105:836-845. [DOI: 10.1002/jbm.b.33618] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 11/22/2015] [Accepted: 01/03/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Juho Pokki
- Institute of Robotics and Intelligent Systems, ETH Zurich; CH-8092 Zurich DE-97074 Switzerland
| | - Olgaç Ergeneman
- Institute of Robotics and Intelligent Systems, ETH Zurich; CH-8092 Zurich DE-97074 Switzerland
| | - George Chatzipirpiridis
- Institute of Robotics and Intelligent Systems, ETH Zurich; CH-8092 Zurich DE-97074 Switzerland
| | - Tessa Lühmann
- Institute for Pharmacy and Food Chemistry, University of Würzburg; DE-97070 Würzburg Germany
| | - Jordi Sort
- Institució Catalana de Recerca i Estudis Avançats (ICREA) and Departament de Física, Universitat Autònoma de Barcelona; E-08193 Bellaterra Spain
- Departament de Física; Universitat Autònoma de Barcelona; E-08193 Bellaterra Spain
| | - Eva Pellicer
- Departament de Física; Universitat Autònoma de Barcelona; E-08193 Bellaterra Spain
| | - Simon A. Pot
- Equine Department, Vetsuisse Faculty, University of Zurich; CH-8057 Zurich Switzerland
| | - Bernhard M. Spiess
- Equine Department, Vetsuisse Faculty, University of Zurich; CH-8057 Zurich Switzerland
| | - Salvador Pané
- Institute of Robotics and Intelligent Systems, ETH Zurich; CH-8092 Zurich DE-97074 Switzerland
| | - Bradley J. Nelson
- Institute of Robotics and Intelligent Systems, ETH Zurich; CH-8092 Zurich DE-97074 Switzerland
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12
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Pokki J, Parmar J, Ergeneman O, Torun H, Guerrero M, Pellicer E, Sort J, Pané S, Nelson BJ. Mobility-Enhancing Coatings for Vitreoretinal Surgical Devices: Hydrophilic and Enzymatic Coatings Investigated by Microrheology. ACS Appl Mater Interfaces 2015; 7:22018-22028. [PMID: 26359763 DOI: 10.1021/acsami.5b06937] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [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: 06/05/2023]
Abstract
Ophthalmic wireless microrobots are proposed for minimally invasive vitreoretinal surgery. Devices in the vitreous experience nonlinear mobility as a result of the complex mechanical properties of the vitreous and its interaction with the devices. A microdevice that will minimize its interaction with the macromolecules of the vitreous (i.e., mainly hyaluronan (HA) and collagen) can be utilized for ophthalmic surgeries. Although a few studies on the interactions between the vitreous and microdevices exist, there is no literature on the influence of coatings on these interactions. This paper presents how coatings on devices affect mobility in the vitreous. Surgical catheters in the vasculature use hydrophilic polymer coatings that reduce biomolecular absorption and enhance mobility. In this work such polymers, polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), and HA coatings were utilized, and their effects on mobility in the vitreous were characterized. Hydrophilic titanium dioxide (TiO2) coating was also developed and characterized. Collagenase and hyaluronidase enzymes were coated on probes' surfaces with a view to enhancing their mobility by enzymatic digestion of the collagen and HA of the vitreous, respectively. To model the human vitreous, ex vivo porcine vitreous and collagen were used. For studying the effects of hyaluronidase, the vitreous and HA were used. The hydrophilic and enzymatic coatings were characterized by oscillatory magnetic microrheology. The statistical significance of the mean relative displacements (i.e., mobility) of the coated probes with respect to control probes was assessed. All studied hydrophilic coatings improve mobility, except for HA which decreases mobility potentially due to bonding with vitreal macromolecules. TiO2 coating improves mobility in collagen by 28.3% and in the vitreous by 15.4%. PEG and PVP coatings improve mobility in collagen by 19.4 and by 39.6%, respectively, but their improvement in the vitreous is insignificant at a 95% confidence level (CL). HA coating affects mobility by reducing it in collagen by 35.6% (statistically significant) and in the vitreous by 16.8% (insignificant change at 95% CL). The coatings cause similar effects in collagen and in the vitreous. However, the effects are lower in the vitreous, which can be due to a lower concentration of collagen in the vitreous than in the prepared collagen samples. The coatings based on enzymatic activity increase mobility (i.e., >40% after 15 min experiments in the vitreous models) more than the hydrophilic coatings based on physicochemical interactions. However, the enzymes have time-dependent effects, and they dissolve from the probe surface with time. The presented results are useful for researchers and companies developing ophthalmic devices. They also pave the way to understanding how to adjust mobility of a microdevice in a complex fluid by choice of an appropriate coating.
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Affiliation(s)
- Juho Pokki
- Institute of Robotics and Intelligent Systems, ETH Zurich , Zurich, Switzerland
| | - Jemish Parmar
- Institute of Robotics and Intelligent Systems, ETH Zurich , Zurich, Switzerland
| | - Olgaç Ergeneman
- Institute of Robotics and Intelligent Systems, ETH Zurich , Zurich, Switzerland
| | - Hamdi Torun
- Department of Electrical and Electronics Engineering, Boğaziçi University , Istanbul, Turkey
- Center for Life Sciences and Technologies, Boğaziçi University , Istanbul, Turkey
| | - Miguel Guerrero
- Departament de Física, Universitat Autònoma de Barcelona , Bellaterra, Spain
| | - Eva Pellicer
- Departament de Física, Universitat Autònoma de Barcelona , Bellaterra, Spain
| | - Jordi Sort
- Departament de Física, Universitat Autònoma de Barcelona , Bellaterra, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA) , Barcelona, Spain
| | - Salvador Pané
- Institute of Robotics and Intelligent Systems, ETH Zurich , Zurich, Switzerland
| | - Bradley J Nelson
- Institute of Robotics and Intelligent Systems, ETH Zurich , Zurich, Switzerland
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Pokki J, Ergeneman O, Sevim S, Enzmann V, Torun H, Nelson BJ. Measuring localized viscoelasticity of the vitreous body using intraocular microprobes. Biomed Microdevices 2015; 17:85. [DOI: 10.1007/s10544-015-9988-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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14
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Jang B, Gutman E, Stucki N, Seitz BF, Wendel-García PD, Newton T, Pokki J, Ergeneman O, Pané S, Or Y, Nelson BJ. Undulatory Locomotion of Magnetic Multilink Nanoswimmers. Nano Lett 2015; 15:4829-4833. [PMID: 26029795 DOI: 10.1021/acs.nanolett.5b01981] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Micro- and nanorobots operating in low Reynolds number fluid environments require specialized swimming strategies for efficient locomotion. Prior research has focused on designs mimicking the rotary corkscrew motion of bacterial flagella or the planar beating motion of eukaryotic flagella. These biologically inspired designs are typically of uniform construction along their flagellar axis. This work demonstrates for the first time planar undulations of composite multilink nanowire-based chains (diameter 200 nm) induced by a planar-oscillating magnetic field. Those chains comprise an elastic eukaryote-like polypyrrole tail and rigid magnetic nickel links connected by flexible polymer bilayer hinges. The multilink design exhibits a high swimming efficiency. Furthermore, the manufacturing process enables tuning the geometrical and material properties to specific applications.
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Affiliation(s)
- Bumjin Jang
- †Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Emiliya Gutman
- ‡Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa, 3200003, Israel
| | - Nicolai Stucki
- †Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Benedikt F Seitz
- †Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Pedro D Wendel-García
- †Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Taylor Newton
- †Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Juho Pokki
- †Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Olgaç Ergeneman
- †Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Salvador Pané
- †Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Yizhar Or
- ‡Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa, 3200003, Israel
| | - Bradley J Nelson
- †Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, CH-8092, Switzerland
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15
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Chatzipirpiridis G, Ergeneman O, Pokki J, Ullrich F, Fusco S, Ortega JA, Sivaraman KM, Nelson BJ, Pané S. Electroforming of implantable tubular magnetic microrobots for wireless ophthalmologic applications. Adv Healthc Mater 2015; 4:209-14. [PMID: 24986087 DOI: 10.1002/adhm.201400256] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [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: 05/14/2014] [Indexed: 01/12/2023]
Abstract
Magnetic tubular implantable micro-robots are batch fabricated by electroforming. These microdevices can be used in targeted drug delivery and minimally invasive surgery for ophthalmologic applications. These tubular shapes are fitted into a 23-gauge needle enabling sutureless injections. Using a 5-degree-of-freedom magnetic manipulation system, the microimplants are conveniently maneuvered in biological environments. To increase their functionality, the tubes are coated with biocompatible films and can be successfully filled with drugs.
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Affiliation(s)
| | - Olgaç Ergeneman
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Juho Pokki
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Franziska Ullrich
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Stefano Fusco
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - José A. Ortega
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Kartik M. Sivaraman
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Bradley J. Nelson
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Salvador Pané
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
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16
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Chatzipirpiridis G, Ergeneman O, Pokki J, Ullrich F, Fusco S, Ortega JA, Sivaraman KM, Nelson BJ, Pané S. Microrobotics: Electroforming of Implantable Tubular Magnetic Microrobots for Wireless Ophthalmologic Applications (Adv. Healthcare Mater. 2/2015). Adv Healthc Mater 2015. [DOI: 10.1002/adhm.201570011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Olgaç Ergeneman
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Juho Pokki
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Franziska Ullrich
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Stefano Fusco
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - José A. Ortega
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Kartik M. Sivaraman
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Bradley J. Nelson
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
| | - Salvador Pané
- Institute of Robotics & Intelligent Systems (IRIS); ETH Zürich; Zurich Switzerland
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17
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Fusco S, Ullrich F, Pokki J, Chatzipirpiridis G, Özkale B, Sivaraman KM, Ergeneman O, Pané S, Nelson BJ. Microrobots: a new era in ocular drug delivery. Expert Opin Drug Deliv 2014; 11:1815-26. [DOI: 10.1517/17425247.2014.938633] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [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)
- Stefano Fusco
- Institute of Robotics and Intelligent Systems, ETH Zurich,
Tannenstrasse 3, Zurich, 8037, Switzerland
| | - Franziska Ullrich
- Institute of Robotics and Intelligent Systems, ETH Zurich,
Tannenstrasse 3, Zurich, 8037, Switzerland
| | - Juho Pokki
- Institute of Robotics and Intelligent Systems, ETH Zurich,
Tannenstrasse 3, Zurich, 8037, Switzerland
| | - George Chatzipirpiridis
- Institute of Robotics and Intelligent Systems, ETH Zurich,
Tannenstrasse 3, Zurich, 8037, Switzerland
| | - Berna Özkale
- Institute of Robotics and Intelligent Systems, ETH Zurich,
Tannenstrasse 3, Zurich, 8037, Switzerland
| | - Kartik M Sivaraman
- Institute of Robotics and Intelligent Systems, ETH Zurich,
Tannenstrasse 3, Zurich, 8037, Switzerland
| | - Olgaç Ergeneman
- Institute of Robotics and Intelligent Systems, ETH Zurich,
Tannenstrasse 3, Zurich, 8037, Switzerland
| | - Salvador Pané
- Institute of Robotics and Intelligent Systems, ETH Zurich,
Tannenstrasse 3, Zurich, 8037, Switzerland
| | - Bradley J Nelson
- Institute of Robotics and Intelligent Systems, ETH Zurich,
Tannenstrasse 3, Zurich, 8037, Switzerland
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18
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Huang TY, Qiu F, Tung HW, Peyer KE, Shamsudhin N, Pokki J, Zhang L, Chen XB, Nelson BJ, Sakar MS. Cooperative manipulation and transport of microobjects using multiple helical microcarriers. RSC Adv 2014. [DOI: 10.1039/c4ra02260b] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
We report a cooperative transport strategy that uses engineered microbars and multiple helical microcarriers. Cooperation of microcarriers generates higher propulsive forces while application of forces at multiple locations results in motion control with multiple degrees of freedom.
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Affiliation(s)
- Tian-Yun Huang
- School of Control Science and Engineering
- Dalian University of Technology
- Dalian, China
- School of Electronics and Information Engineering
- Liaoning University of Science and Technology
| | - Famin Qiu
- Institute of Robotics and Intelligent Systems
- ETH Zurich
- , Switzerland
| | - Hsi-Wen Tung
- Institute of Robotics and Intelligent Systems
- ETH Zurich
- , Switzerland
| | - Kathrin E. Peyer
- Institute of Robotics and Intelligent Systems
- ETH Zurich
- , Switzerland
| | - Naveen Shamsudhin
- Institute of Robotics and Intelligent Systems
- ETH Zurich
- , Switzerland
| | - Juho Pokki
- Institute of Robotics and Intelligent Systems
- ETH Zurich
- , Switzerland
| | - Li Zhang
- Department of Mechanical and Automation Engineering
- The Chinese University of Hong Kong
- , China
| | - Xue-Bo Chen
- School of Electronics and Information Engineering
- Liaoning University of Science and Technology
- Anshan, China
| | - Bradley J. Nelson
- Institute of Robotics and Intelligent Systems
- ETH Zurich
- , Switzerland
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Ullrich F, Bergeles C, Pokki J, Ergeneman O, Erni S, Chatzipirpiridis G, Pané S, Framme C, Nelson BJ. Mobility Experiments With Microrobots for Minimally Invasive Intraocular Surgery. ACTA ACUST UNITED AC 2013; 54:2853-63. [DOI: 10.1167/iovs.13-11825] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Franziska Ullrich
- Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland
| | - Christos Bergeles
- Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland 2Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Juho Pokki
- Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland
| | - Olgac Ergeneman
- Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland
| | - Sandro Erni
- Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland
| | | | - Salvador Pané
- Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland
| | - Carsten Framme
- Inselspital, Universitätsspital Bern, Bern, Switzerland 4Hannover Medical School (MHH), Hannover, Germany
| | - Bradley J. Nelson
- Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland
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Pokki J, Ergeneman O, Bergeles C, Torun H, Nelson BJ. Localized viscoelasticity measurements with untethered intravitreal microrobots. Annu Int Conf IEEE Eng Med Biol Soc 2013; 2012:2813-6. [PMID: 23366510 DOI: 10.1109/embc.2012.6346549] [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: 11/06/2022]
Abstract
Microrobots are a promising tool for medical interventions and micromanipulation. In this paper, we explore the concept of using microrobots for microrheology. Untethered magnetically actuated microrobots were used to characterize one of the most complex biofluids, the vitreous humor. In this work we began by experimentally characterizing the viscoelastic properties of an artificial vitreous humor. For comparison, its properties were also measured using special microcantilevers in an atomic force microscope (AFM) setup. Subsequently, an untethered device was used to study the vitreous humor of a porcine eye, which is a valid ex-vivo model of a human eye. Its viscoelasticity model was extracted, which was in agreement with the model of the artificial vitreous. The existing characterization methodology requires eye and vitreous humor dissection for the microrheology measurements. We envision that the method proposed here can be used in in vivo.
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Affiliation(s)
- Juho Pokki
- Institute of Robotics and Intelligent Systems, ETH Zurich, 8092 Zurich, Switzerland. jpokki at ethz.ch
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Wang Z, Pokki J, Ergeneman O, Nelson BJ, Hirai S. Viscoelastic interaction between intraocular microrobots and vitreous humor: a finite element approach. Annu Int Conf IEEE Eng Med Biol Soc 2013; 2013:4937-4940. [PMID: 24110842 DOI: 10.1109/embc.2013.6610655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Vitreous humor exhibits complex biomechanical properties and determination of these properties is essential for designing ophthalmic biomedical microdevices. In this paper, the viscoelastic properties of porcine vitreous humor were studied based on ex vivo creep experiments, in which a microrobot was magnetically actuated inside the vitreous. A three-dimensional (3D) finite element (FE) model was proposed to simulate the viscoelastic interaction between the microrobot and porcine vitreous humor. An optimization-based method was employed to estimate the viscoelastic parameters of the vitreous humor. The proposed model successfully validated the experimental measurements. The estimated parameters were compared with published data in literature. The model was then used to study the shape-dependent interaction of the microrobot with the vitreous humor. The methods presented in this paper can be used for the optimization of ophthalmic microrobots and microsurgical tools.
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Ergeneman O, Chatzipirpiridis G, Pokki J, Marín-Suárez M, Sotiriou GA, Medina-Rodríguez S, Sánchez JFF, Fernández-Gutiérrez A, Pané S, Nelson BJ. In vitro oxygen sensing using intraocular microrobots. IEEE Trans Biomed Eng 2012; 59:3104-9. [PMID: 22955866 DOI: 10.1109/tbme.2012.2216264] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We present a luminescence oxygen sensor integrated with a wireless intraocular microrobot for minimally-invasive diagnosis. This microrobot can be accurately controlled in the intraocular cavity by applying magnetic fields. The microrobot consists of a magnetic body susceptible to magnetic fields and a sensor coating. This coating embodies Pt(II) octaethylporphine (PtOEP) dyes as the luminescence material and polystyrene as a supporting matrix, and it can be wirelessly excited and read out by optical means. The sensor works based on quenching of luminescence in the presence of oxygen. The excitation and emission spectrum, response time, and oxygen sensitivity of the sensor were characterized using a spectrometer. A custom device was designed and built to use this sensor for intraocular measurements with the microrobot. Due to the intrinsic nature of luminescence lifetimes, a frequency-domain lifetime measurement approach was used. An alternative sensor design with increased performance was demonstrated by using poly(styrene-co-maleic anhydride) (PS-MA) and PtOEP nanospheres.
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Affiliation(s)
- Olgaç Ergeneman
- Multiscale Robotics Laboratory, Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich 8092, Switzerland.
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Pokki J, Ergeneman O, Sivaraman KM, Ozkale B, Zeeshan MA, Lühmann T, Nelson BJ, Pané S. Electroplated porous polypyrrole nanostructures patterned by colloidal lithography for drug-delivery applications. Nanoscale 2012; 4:3083-3088. [PMID: 22422198 DOI: 10.1039/c2nr30192j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [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
Porous nanostructures of polypyrrole (Ppy) were fabricated using colloidal lithography and electrochemical techniques for potential applications in drug delivery. A sequential fabrication method was developed and optimized to maximize the coverage of the Ppy nanostructures and to obtain a homogeneous layer over the substrate. This was realized by masking with electrophoretically-assembled polystyrene (PS) nanospheres and then electroplating. Drug/biomolecule adsorption and the release characteristics for the porous nanostructures of Ppy were investigated using rhodamine B (Rh-B). Rh-B is an easily detectable small hydrophobic molecule that is used as a model for many drugs or biological substances. The porous Ppy nanostructures with an enhanced surface area exhibited higher Rh-B loading capacity than bulk planar films of Ppy. Moreover, tunability of surface morphology for further applications (e.g., sensing, cell adhesion) was demonstrated.
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Affiliation(s)
- J Pokki
- Multi-Scale Robotics Lab/Institute of Robotics and Intelligent Systems, ETH Zurich, 8092 Zurich, Switzerland
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Abstract
For this study, we have collected puncture force data from the vasculature of the chorioallantoic membranes (CAM) of developing chicken embryos to examine forces required for retinal vein cannulation. The CAM vessels of a developing chicken embryo have been shown to be an appropriate model for human retinal veins. The effect of microneedle geometry and vessel size on puncture forces was investigated. The results of this work are important for researchers working on robotic vitreoretinal surgical systems.
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Affiliation(s)
- Olgaç Ergeneman
- Institute of Robotics and Intelligent Systems, ETH Zurich, 8092 Zurich, Switzerland
| | - Juho Pokki
- Institute of Robotics and Intelligent Systems, ETH Zurich, 8092 Zurich, Switzerland
| | - Vanda Počepcová
- Institute of Robotics and Intelligent Systems, ETH Zurich, 8092 Zurich, Switzerland
| | - Heike Hall
- Cells and BioMaterials, Department of Materials, ETH Zurich, 8093 Zurich, Switzerland
| | - Jake J. Abbott
- Department of Mechanical Engineering, University of Utah, Salt Lake City, Utah, 84112
| | - Bradley J. Nelson
- Institute of Robotics and Intelligent Systems, ETH Zurich, 8092 Zurich, Switzerland
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Ergeneman O, Chatzipirpiridis G, Gelderblom FB, Pokki J, Pané S, Marín Suárez Del Toro M, Fernández Sánchez JF, Sotiriou GA, Nelson BJ. Oxygen sensing using microrobots. Annu Int Conf IEEE Eng Med Biol Soc 2010; 2010:1958-1961. [PMID: 21097007 DOI: 10.1109/iembs.2010.5627612] [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: 05/30/2023]
Abstract
We present a luminescence oxygen sensor incorporated in a wireless intraocular microrobot for minimally-invasive diagnosis. This microrobot can be accurately controlled in the intraocular cavity by applying magnetic fields. The microrobot consists of a magnetic body susceptible to magnetic fields and a sensor coating. This coating embodies Pt(II) octaethylporphine (PtOEP) dyes as the luminescence material and polystyrene as a supporting matrix, and it can be wirelessly excited and read out by optical means. The sensor works based on quenching of luminescence in the presence of oxygen. The excitation and emission spectrum, response time, and oxygen sensitivity of the sensor were characterized using a spectrometer. A custom device was designed and built to use this sensor for intraocular measurements with the microrobot. Due to the intrinsic nature of luminescence lifetimes, a frequency-domain lifetime measurement approach was employed. An alternative sensor implementation using poly(styrene-co-maleic anhydride) (PS-MA) and PtOEP was successfully demonstrated with nanospheres to increase sensor performance.
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Affiliation(s)
- Olgac Ergeneman
- Multiscale Robotics Laboratory, Institute of Robotics and Intelligent Systems, ETH Zurich, 8092, Switzerland.
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