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Electrodeposition and Micro-Mechanical Property Characterization of Nickel–Cobalt Alloys toward Design of MEMS Components. ELECTROCHEM 2022. [DOI: 10.3390/electrochem3020012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Nickel–cobalt alloys were prepared by alloy electrodeposition with a sulfamate bath, and the mechanical properties on the micro-scale were evaluated for the application as micro-components in miniaturized electronic devices. Nickel bromide and a commercially available surface brightener were used as the additives. The cobalt content increased from 21.5 to 60.1 at.% after addition of nickel bromide into the bath, and the grain size refined from 21.1 to 13.2 nm when the surface brightener was used. The mechanical properties on the micro-scale were evaluated by micro-compression test using micro-pillar type specimens fabricated by a focused ion beam system to take the sample size effect into consideration. The yield strength of the nickel–cobalt alloy having an average grain size at 13.9 nm and cobalt content of 66.6 at.% reached 2.37 GPa, revealing influences from the sample size, grain boundary strengthening, and solid solution strengthening effects.
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Yang Q, Enríquez Á, Devathasan D, Thompson CA, Nayee D, Harris R, Satoski D, Obeng-Gyasi B, Lee A, Bentley RT, Lee H. Application of magnetically actuated self-clearing catheter for rapid in situ blood clot clearance in hemorrhagic stroke treatment. Nat Commun 2022; 13:520. [PMID: 35082280 PMCID: PMC8791973 DOI: 10.1038/s41467-022-28101-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 01/06/2022] [Indexed: 11/08/2022] Open
Abstract
Maintaining the patency of indwelling drainage devices is critical in preventing further complications following an intraventricular hemorrhage (IVH) and other chronic disease management. Surgeons often use drainage devices to remove blood and cerebrospinal fluid but these catheters frequently become occluded with hematoma. Using an implantable magnetic microactuator, we created a self-clearing catheter that can generate large enough forces to break down obstructive blood clots by applying time-varying magnetic fields. In a blood-circulating model, our self-clearing catheters demonstrated a > 7x longer functionality than traditional catheters (211 vs. 27 min) and maintained a low pressure for longer periods (239 vs. 79 min). Using a porcine IVH model, the self-clearing catheters showed a greater survival rate than control catheters (86% vs. 0%) over the course of 6 weeks. The treated animals also had significantly smaller ventricle sizes 1 week after implantation compared to the control animals with traditional catheters. Our results suggest that these magnetic microactuator-embedded smart catheters can expedite the removal of blood from the ventricles and potentially improve the outcomes of critical patients suffering from often deadly IVH.
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Affiliation(s)
- Qi Yang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
| | - Ángel Enríquez
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN, 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA
| | - Dillon Devathasan
- College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Craig A Thompson
- College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Dillan Nayee
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN, 47907, USA
| | - Ryan Harris
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN, 47907, USA
| | - Douglas Satoski
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN, 47907, USA
| | - Barnabas Obeng-Gyasi
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN, 47907, USA
| | - Albert Lee
- Goodman Campbell Brain and Spine, Indianapolis, IN, 46202, USA
| | - R Timothy Bentley
- College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Hyowon Lee
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907, USA.
- Center for Implantable Devices, Purdue University, West Lafayette, IN, 47907, USA.
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, 47907, USA.
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Abstract
The growing trend for personalized medicine calls for more reliable implantable biosensors that are capable of continuously monitoring target analytes for extended periods (i.e., >30 d). While promising biosensors for various applications are constantly being developed in the laboratories across the world, many struggle to maintain reliable functionality in complex in vivo environments over time. In this review, we explore the impact of various biotic and abiotic failure modes on the reliability of implantable biosensors. We discuss various design considerations for the development of chronically reliable implantable biosensors with a specific focus on strategies to combat biofouling, which is a fundamental challenge for many implantable devices. Briefly, we introduce the process of the foreign body response and compare the in vitro and the in vivo performances of state-of-the-art implantable biosensors. We then discuss the latest development in material science to minimize and delay biofouling including the usage of various hydrophilic, biomimetic, drug-eluting, zwitterionic, and other smart polymer materials. We also explore a number of active anti-biofouling approaches including stimuli-responsive materials and mechanical actuation. Finally, we conclude this topical review with a discussion on future research opportunities towards more reliable implantable biosensors.
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Yunas J, Mulyanti B, Hamidah I, Mohd Said M, Pawinanto RE, Wan Ali WAF, Subandi A, Hamzah AA, Latif R, Yeop Majlis B. Polymer-Based MEMS Electromagnetic Actuator for Biomedical Application: A Review. Polymers (Basel) 2020; 12:E1184. [PMID: 32455993 PMCID: PMC7284590 DOI: 10.3390/polym12051184] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/27/2020] [Accepted: 04/28/2020] [Indexed: 12/22/2022] Open
Abstract
In this study, we present a comprehensive review of polymer-based microelectromechanical systems (MEMS) electromagnetic (EM) actuators and their implementation in the biomedical engineering field. The purpose of this review is to provide a comprehensive summary on the latest development of electromagnetically driven microactuators for biomedical application that is focused on the movable structure development made of polymers. The discussion does not only focus on the polymeric material part itself, but also covers the basic mechanism of the mechanical actuation, the state of the art of the membrane development and its application. In this review, a clear description about the scheme used to drive the micro-actuators, the concept of mechanical deformation of the movable magnetic membrane and its interaction with actuator system are described in detail. Some comparisons are made to scrutinize the advantages and disadvantages of electromagnetic MEMS actuator performance. The previous studies and explanations on the technology used to fabricate the polymer-based membrane component of the electromagnetically driven microactuators system are presented. The study on the materials and the synthesis method implemented during the fabrication process for the development of the actuators are also briefly described in this review. Furthermore, potential applications of polymer-based MEMS EM actuators in the biomedical field are also described. It is concluded that much progress has been made in the material development of the actuator. The technology trend has moved from the use of bulk magnetic material to using magnetic polymer composites. The future benefits of these compact flexible material employments will offer a wide range of potential implementation of polymer composites in wearable and portable biomedical device applications.
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Affiliation(s)
- Jumril Yunas
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (W.A.F.W.A.); (A.S.); (A.A.H.); (R.L.); (B.Y.M.)
| | - Budi Mulyanti
- Faculty of Engineering and Vocational Education, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi 207, Bandung 40154, Indonesia; (B.M.); (I.H.)
| | - Ida Hamidah
- Faculty of Engineering and Vocational Education, Universitas Pendidikan Indonesia, Jl. Dr. Setiabudhi 207, Bandung 40154, Indonesia; (B.M.); (I.H.)
| | - Muzalifah Mohd Said
- Faculty of Electronics and Computer Engineering (FKEKK), Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, Durian Tunggal 76100, Melaka, Malaysia;
| | - Roer Eka Pawinanto
- Malaysia-Japan International Institute of Technology (MJIIT), Universiti Teknologi Malaysia (UTM), Kuala Lumpur 54100, Malaysia;
| | - Wan Amar Fikri Wan Ali
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (W.A.F.W.A.); (A.S.); (A.A.H.); (R.L.); (B.Y.M.)
| | - Ayub Subandi
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (W.A.F.W.A.); (A.S.); (A.A.H.); (R.L.); (B.Y.M.)
| | - Azrul Azlan Hamzah
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (W.A.F.W.A.); (A.S.); (A.A.H.); (R.L.); (B.Y.M.)
| | - Rhonira Latif
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (W.A.F.W.A.); (A.S.); (A.A.H.); (R.L.); (B.Y.M.)
| | - Burhanuddin Yeop Majlis
- Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia; (W.A.F.W.A.); (A.S.); (A.A.H.); (R.L.); (B.Y.M.)
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Tachatos N, Chappel E, Dumont-Fillon D, Meboldt M, Daners MS. Posture related in-vitro characterization of a flow regulated MEMS CSF valve. Biomed Microdevices 2020; 22:21. [PMID: 32088807 DOI: 10.1007/s10544-020-0471-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Overdrainage in upright position is one of the most prevalent issues in treating hydrocephalus with a cerebrospinal fluid (CSF) shunt. Anti-siphon devices (ASDs) are employed to reduce this problem. A novel microelectromechanical system (MEMS)-based valve, termed Chronoflow device, aims to regulate CSF drainage indifferently of the body posture. With this study, the suitability of this MEMS-based valve is evaluated regarding its use for the treatment of hydrocephalus, particularly for the prevention of overdrainage and blockage. In total, four Chronoflow devices were tested. An established in-vitro hardware-in-the-loop (HIL) test bed was used to investigate the valves regarding their pressure-flow characteristics, their behaviors towards CSF dynamics, and their capabilities to prevent CSF overdrainage in upright position. Additionally, a contamination test was conducted to evaluate the susceptibility of the device to blockage due to particles. All valves tested regulated the drainage rate at similar nominal flows and independently of posture. The pressure-flow relation measured, however, was notably higher than numerically calculated. Regarding the CSF dynamics, the first three valves tested led to a decreased steady-state intracranial pressure in supine position and showed stable drainage rate in upright position. During the transitional phase from supine to upright and vice versa, the valves continuously adjusted the outflow resistance, which resulted in a stable transitional phase preventing overdrainage. Yet, the fourth valve showed continuous overdrainage in upright position due to an increased nominal flow. However, after several test iterations the nominal flow decreased and stabilized at a level similar to that of the first three valves tested. The contamination test showed that most particles initially adhere to the pillars and spread throughout the cavity of the valve as the concentration of particles increases, thereby affecting the displacement of the membrane. The devices generally provide a stable flow regulation and prevent overdrainage in upright position. Specifically, their drainage behaviors during the posture changes are very effective. However, they also showed high hysteresis and sensitivity towards particle contamination, which resulted in initial increased and altering nominal flows after many test iterations. This result suggests that the MEMS design presented lacks robustness. Yet, an upstream filter and specific coatings on the fluid pathway may increase significantly its reliability.
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Affiliation(s)
- Nikolaos Tachatos
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Tannenstrasse 3, CLA G 21.1, 8092, Zurich, Switzerland
| | | | | | - Mirko Meboldt
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Tannenstrasse 3, CLA G 21.1, 8092, Zurich, Switzerland
| | - Marianne Schmid Daners
- Product Development Group Zurich, Department of Mechanical and Process Engineering, ETH Zurich, Tannenstrasse 3, CLA G 21.1, 8092, Zurich, Switzerland.
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Yang Q, Lee A, Bentley RT, Lee H. Piezoresistor-Embedded Multifunctional Magnetic Microactuators for Implantable Self-Clearing Catheter. IEEE SENSORS JOURNAL 2019; 19:1373-1378. [PMID: 31579395 PMCID: PMC6774376 DOI: 10.1109/jsen.2018.2880576] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Indwelling catheters are used widely in medicine to treat various chronic medical conditions. However, chronic implantation of catheters often leads to a premature failure due to biofilm accumulation. Previously we reported on the development of a self-clearing catheter by integrating polymer-based microscale magnetic actuators. The microactuator provides an active anti-biofouling mechanism to disrupt and remove adsorbed biofilm on demand using an externally applied stimulus. During an in vivo evaluation of self-clearing catheter, we realized that it is important to periodically monitor the performance of implanted microactuators. Here we integrate gold-based piezoresistive strain-gauge on our magnetic microactuators to directly monitor the device deflection with good sensitivity (0.035%/Deg) and linear range (±30°). With the integrated strain-gauge, we demonstrate the multi-functional capabilities of our magnetic microactuators that enable device alignment, flow-rate measurement, and obstruction detection and removal towards the development of chronically implantable self-clearing smart catheter.
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Affiliation(s)
- Qi Yang
- Department of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907 USA
| | - Albert Lee
- Goodman Campbell Brain and Spine, Department of Neurological Surgery, Indiana University, Indianapolis, IN 46202 USA
| | - R Timothy Bentley
- College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907 USA
| | - Hyowon Lee
- Weldon School of Biomedical Engineering, Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907 USA
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7
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Yang Q, Park H, Nguyen TN, Rhoads JF, Lee A, Bentley RT, Judy JW, Lee H. Anti-biofouling implantable catheter using thin-film magnetic microactuators. SENSORS AND ACTUATORS. B, CHEMICAL 2018; 273:1694-1704. [PMID: 34276138 PMCID: PMC8281922 DOI: 10.1016/j.snb.2018.07.044] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Here we report on the development of polyimide-based flexible magnetic actuators for actively combating biofouling that occurs in many chronically implanted devices. The thin-film flexible devices are microfabricated and integrated into a single-pore silicone catheter to demonstrate a proof-of-concept for a self-clearing smart catheter. The static and dynamic mechanical responses of the thin-film magnetic microdevices were quantitatively measured and compared to theoretical values. The mechanical fatigue properties of these polyimide-based microdevices were also characterized up to 300 million cycles. Finally, the biofouling removal capabilities of magnetically powered microdevices were demonstrated using bovine serum albumin and bioconjugated microbeads. Our results indicate that these thin-film microdevices are capable of significantly reducing the amount of biofouling. At the same time, we demonstrated that these microdevices are mechanically robust enough to withstand a large number of actuation cycles during its chronic implantation.
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Affiliation(s)
- Qi Yang
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN 47907, USA
| | - Hyunsu Park
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN 47907, USA
| | - Tran N.H. Nguyen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN 47907, USA
| | - Jeffrey F. Rhoads
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA
- School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Ray W. Herrick Laboratories, Purdue University, West Lafayette, IN 47907, USA
| | - Albert Lee
- Goodman Campbell Brain and Spine Department of Neurological Surgery Indiana University, Indianapolis, IN 46202, USA
| | - R. Timothy Bentley
- College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA
| | - Jack W. Judy
- Department of Electrical and Computer Engineering Nanoscience Institute for Medical and Engineering Technologies University of Florida, Gainesville, FL 32611, USA
| | - Hyowon Lee
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN 47907, USA
- Center for Implantable Devices, Purdue University, West Lafayette, IN 47907, USA
- Corresponding author at: Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr., West Lafayette, IN 47907, USA. (H. Lee)
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Sane A, Tangen K, Frim D, Singh MR, Linninger A. Cellular Obstruction Clearance in Proximal Ventricular Catheters Using Low-Voltage Joule Heating. IEEE Trans Biomed Eng 2018; 65:2503-2511. [DOI: 10.1109/tbme.2018.2802418] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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John S. Low-cost rapid prototyping of liquid crystal polymer based magnetic microactuators for glaucoma drainage devices. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:4212-4215. [PMID: 28269212 DOI: 10.1109/embc.2016.7591656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Glaucoma is one of the leading causes of blindness in the world. Although there is no cure for glaucoma, pharmaceutical or surgical interventions are known to delay the progression of this debilitating disease. In recent years, implantation of glaucoma drainage devices (GDD) have increased due to their ability to manage IOP better than other therapeutic approaches. However, only 50% of the implanted devices remain functional after 5 years often due to biofouling. Here, we report our latest progress towards developing self-clearing GDDs using integrated magnetic microactuators. Our hypothesis is that these magnetic microdevices can provide local mechanical perturbations to prophylactically remove biological accumulation. To reduce the cost and increase the throughput of fabrication, we utilize a maskless photolithography setup and commercially available liquid crystal polymer foils to create prototype devices. The mechanical response of the devices is reported and compared with the theoretical values.
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Miller J, Rhoads JF, Linnes J. Polyimide-based magnetic microactuators for biofouling removal. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:5757-5760. [PMID: 28269562 DOI: 10.1109/embc.2016.7592035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Here we report on the development of novel polyimide-based flexible magnetic actuators for improving hydrocephalus shunts. The static and dynamic mechanical responses of the thin-film magnetic microdevices were quantitatively measured. The bacteria-removing capabilities of the microfabricated devices were also evaluated. Although additional evaluations are necessary, the preliminary results show promising potential for combatting bacteria-induced biofouling. Lastly, the thin-film microdevices are integrated into a single-pore silicone catheter to demonstrate a proof-of-concept, MEMS-enabled self-clearing, smart catheter.
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Jandial R, Choy C, Levy DM, Chen MY, Ansari KI. Astrocyte-induced Reelin expression drives proliferation of Her2 + breast cancer metastases. Clin Exp Metastasis 2017; 34:185-196. [PMID: 28210910 DOI: 10.1007/s10585-017-9839-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 02/09/2017] [Indexed: 12/17/2022]
Abstract
Breast cancer metastasis to the brain develops after a clinical latency of years to even decades, suggesting that colonization of the brain is the most challenging step of the metastatic cascade. However, the underlying mechanisms used by breast cancer cells to successfully colonize the brain's microenvironment remain elusive. Reelin is an archetypal extracellular glycoprotein that regulates migration, proliferation, and lamination of neurons. It is epigenetically silenced in various cancers, and its expression in multiple myelomas is linked to poor patient survival. We found that Reelin expression was low in primary breast cancer tissue. However, its expression was significantly higher in Her2+ breast cancers metastasizing to the brain. In particular, Reelin was highly expressed in the tumor periphery adjacent to surrounding astrocytes. This augmented Reelin expression was seen in Her2+ metastases, but not in triple negative (TN) primary tumors or in TN breast to brain metastasis cells co-cultured with astrocytes. Furthermore, the elevated expression was sustained in Her2+ cells grown in the presence of the DNA methyltransferase inhibitor 5-azacytidine, indicating epigenetic regulation of Reelin expression. The relative growth and rate of spheroids formation derived from Her2+ primary and BBM cells co-cultured with astrocytes were higher than those of TN primary and BBM cells, and knockdown of both Reelin and Her2 suppressed the astrocyte-induced growth and spheroid forming ability of Her2+ cells. Collectively, our results indicate that within the neural niche, astrocytes epigenetically regulate Reelin expression and its interaction with Her2 leading to increased proliferation and survival fitness.
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Affiliation(s)
- Rahul Jandial
- Division of Neurosurgery, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, CA, 91010, USA.
| | - Cecilia Choy
- Division of Neurosurgery, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, CA, 91010, USA
| | - Danielle M Levy
- Division of Neurosurgery, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, CA, 91010, USA
| | - Mike Y Chen
- Division of Neurosurgery, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, CA, 91010, USA
| | - Khairul I Ansari
- Division of Neurosurgery, Beckman Research Institute, City of Hope, 1500 E. Duarte Rd, Duarte, CA, 91010, USA.
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13
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Lee H, Kolahi K, Bergsneider M, Judy JW. Mechanical Evaluation of Unobstructing Magnetic Microactuators for Implantable Ventricular Catheters. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS : A JOINT IEEE AND ASME PUBLICATION ON MICROSTRUCTURES, MICROACTUATORS, MICROSENSORS, AND MICROSYSTEMS 2014; 23:795-802. [PMID: 29151776 PMCID: PMC5693250 DOI: 10.1109/jmems.2014.2321377] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Here, we report on the development and evaluation of novel unobstructing magnetic microactuators for maintaining the patency of implantable ventricular catheters used in hydrocephalus application. The treatment of hydrocephalus requires chronic implantation of a shunt system to divert excess cerebrospinal fluid from the brain. These shunt systems suffer from a high failure rate (>40%) within the first year of implantation, often due to biological accumulation. Previously, we have shown that magnetic microactuators can be used to remove biological blockage. The new cantilever-based magnetic microactuator presented in this paper improves upon the previous torsional design using a bimorph to induce a postrelease out-of-plane deflection that will prevent the device from occluding the pore at rest. The mechanical evaluations (i.e., postrelease deflection, static and dynamic responses) of fabricated devices are reported and compared with theoretical values.
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Affiliation(s)
- Hyowon Lee
- NeuroEngineering Training Program, Biomedical Engineering Interdepartmental Program, University of California at Los Angeles, Los Angeles, CA 90095 USA. He is now with the St. Jude Medical, Implantable Electronic Systems Division, Plano, TX 75024 USA
| | - Kameran Kolahi
- Mathematics Department, University of California at Los Angeles, Los Angeles, CA 90095 USA
| | - Marvin Bergsneider
- NeuroEngineering Training Program, Biomedical Engineering Interdepartmental Program, Neurosurgery, School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095 USA
| | - Jack W Judy
- NeuroEngineering Training Program, Biomedical Engineering Interdepartmental Program, Department of Electrical Engineering, University of California at Los Angeles, Los Angeles, CA 90095 USA. He is now with the Nanoscience Institute for Medical and Engineering Technology, University of Florida, Gainesville, FL 32611 USA
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14
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Johansson SB, Eklund A, Malm J, Stemme G, Roxhed N. A MEMS-based passive hydrocephalus shunt for body position controlled intracranial pressure regulation. Biomed Microdevices 2014; 16:529-36. [PMID: 24609991 DOI: 10.1007/s10544-014-9855-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This paper reports a novel micro electro mechanical system (MEMS) valve with posture controlled flow characteristics for improved treatment of hydrocephalus, a disease that is characterized by elevated pressure in the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord. In contrast to conventional differential pressure CSF valves, the CSF valve presented here features a third port which utilizes hydrostatic pressure from a pressure compensating catheter to adapt CSF drainage to optimized levels irrespective of body position. Prototypes have been fabricated using standard MEMS manufacturing processes and the experimental evaluation successfully showed that the flow rate was adjustable with a varying hydrostatic pressure on the third port. Measured data showed that flow rate was at near ideal values at laying body position and that the flow rate can be adjusted to optimal values at standing body position by selecting an appropriate length of the pressure compensating catheter. This is the first pressure balanced CSF valve intended for body position controlled CSF pressure regulation.
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Affiliation(s)
- Staffan B Johansson
- Micro and Nanosystems, KTH Royal Institute of Technology, Osquldas Väg 10, 10044, Stockholm, Sweden,
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15
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Lee H, Xu Q, Shellock FG, Bergsneider M, Judy JW. Evaluation of magnetic resonance imaging issues for implantable microfabricated magnetic actuators. Biomed Microdevices 2014; 16:153-61. [PMID: 24077662 PMCID: PMC3969409 DOI: 10.1007/s10544-013-9815-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The mechanical robustness of microfabricated torsional magnetic actuators in withstanding the strong static fields (7 T) and time-varying field gradients (17 T/m) produced by an MR system was studied in this investigation. The static and dynamic mechanical characteristics of 30 devices were quantitatively measured before and after exposure to both strong uniform and non-uniform magnetic fields. The results showed no statistically significant change in both the static and dynamic mechanical performance, which mitigate concerns about the mechanical stability of these devices in association with MR systems under the conditions used for this assessment. The MR-induced heating was also measured in a 3-T/128-MHz MR system. The results showed a minimal increase (1.6 °C) in temperature due to the presence of the magnetic microactuator array. Finally, the size of the MR-image artifacts created by the magnetic microdevices were quantified. The signal loss caused by the devices was approximately four times greater than the size of the device.
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Affiliation(s)
- Hyowon Lee
- Biomedical Engineering Interdepartmental Program, Department of Electrical Engineering, University of California, Los Angeles, 420 Westwood Plaza, Engineering IV 64-144, Los Angeles, CA, 90095, USA, Tel.: +310-691-4965
| | - Qing Xu
- Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA, 90095
| | - Frank G. Shellock
- Department of Radiology and Medicine, National Science Foundation Engineering Research Center, Keck School of Medicine, University of Southern California, Los Angeles, CA, 90089
| | - Marvin Bergsneider
- Biomedical Engineering Interdepartmental Program, Department of Neurosurgery, University of California, Los Angeles, Los Angeles, CA, 90095
| | - Jack W. Judy
- Biomedical Engineering Interdepartmental Program, Department of Electrical Engineering, University of California, Los Angeles, Los Angeles, CA, 90095
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Lutz BR, Venkataraman P, Browd SR. New and improved ways to treat hydrocephalus: Pursuit of a smart shunt. Surg Neurol Int 2013; 4:S38-50. [PMID: 23653889 PMCID: PMC3642745 DOI: 10.4103/2152-7806.109197] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 11/08/2012] [Indexed: 11/14/2022] Open
Abstract
The most common treatment for hydrocephalus is placement of a cerebrospinal fluid shunt to supplement or replace lost drainage capacity. Shunts are life-saving devices but are notorious for high failure rates, difficulty of diagnosing failure, and limited control options. Shunt designs have changed little since their introduction in 1950s, and the few changes introduced have had little to no impact on these long-standing problems. For decades, the community has envisioned a “smart shunt” that could provide advanced control, diagnostics, and communication based on implanted sensors, feedback control, and telemetry. The most emphasized contribution of smart shunts is the potential for advanced control algorithms, such as weaning from shunt dependency and personalized control. With sensor-based control comes the opportunity to provide data to the physician on patient condition and shunt function, perhaps even by a smart phone. An often ignored but highly valuable contribution would be designs that correct the high failure rates of existing shunts. Despite the long history and increasing development activity in the past decade, patients are yet to see a commercialized smart shunt. Most smart shunt development focuses on concepts or on isolated technical features, but successful smart shunt designs will be a balance between technical feasibility, economic viability, and acceptable regulatory risk. Here, we present the status of this effort and a framework for understanding the challenges and opportunities that will guide introduction of smart shunts into patient care.
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Affiliation(s)
- Barry R Lutz
- Department of Bioengineering, University of Washington, Seattle, WA, USA
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