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Hoare D, Kingsmore D, Holsgrove M, Russell E, Kirimi MT, Czyzewski J, Mirzai N, Kennedy S, Neale SL, Mercer JR. Realtime monitoring of thrombus formation in vivo using a self-reporting vascular access graft. COMMUNICATIONS MEDICINE 2024; 4:15. [PMID: 38316912 PMCID: PMC10844314 DOI: 10.1038/s43856-024-00436-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 01/10/2024] [Indexed: 02/07/2024] Open
Abstract
BACKGROUND Chronic kidney disease (CKD) affects 10% of the global population costing over a hundred billion dollars per annum and leading to increased risk of cardiovascular disease. Many patients with CKD require regular haemodialyses. Synthetic arteriovenous grafts (AVG) are increasingly used to provide rapid vascular connection for dialysis. Initially, they have excellent patency rates but are critically limited by neointimal hyperplasia at the venous anastomosis, which drives subsequent thrombosis, graft failure and death. METHODS Here, we describe a system in which electrical impedance spectroscopy sensors are incorporated circumferentially into the wall of a synthetic arteriovenous graft. This is combined with an implantable radiotelemetry system for data transmission outside the patient. The system was tested using monolayers of endothelial and smooth muscle cells as well as swine blood and clots with explanted human carotid artery plaques. Sensor testing was then performed in vitro and the device was implanted in vivo in female swine. RESULTS The device can wirelessly report the accumulation of biological material, both cells and blood. Differences are also detected when comparing controls with pathological atheroma. In swine differences between blockage formation in a graft were remotely obtained and wireless reported. CONCLUSIONS Combining electrical impedance spectroscopy and an implantable radiotelemetry system enables graft surveillance. This has the potential to be used for early detection of venous stenosis and blood clot formation in real-time in vivo. In principle, the concept could apply to other cardiovascular diseases and vascular implantable devices.
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Affiliation(s)
- Daniel Hoare
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK
| | - David Kingsmore
- Queen Elizabeth University Hospital, University of Glasgow, Glasgow, UK
| | - Michael Holsgrove
- Bioelectronics Unit, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Ewan Russell
- Bioelectronics Unit, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Mahmut T Kirimi
- Queen Elizabeth University Hospital, University of Glasgow, Glasgow, UK
| | - Jakub Czyzewski
- Bioelectronics Unit, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Nosrat Mirzai
- Bioelectronics Unit, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Simon Kennedy
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK
| | - Steven L Neale
- Centre for Medical and Industrial Ultrasonics, James Watt School of Engineering, University of Glasgow, Glasgow, UK
| | - John R Mercer
- School of Cardiovascular & Metabolic Health, University of Glasgow, Glasgow, UK.
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Seshadri DR, Radwan AN, Bianco ND, Zorman CA, Bogie KM. Flexible and Scalable Dry Conductive Elastomeric Nanocomposites for Surface Stimulation Applications. IEEE Trans Biomed Eng 2023; 70:3461-3468. [PMID: 37352086 DOI: 10.1109/tbme.2023.3289059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2023]
Abstract
OBJECTIVE The study describes the development and testing of a dry surface stimulation flexible electrode (herein referred to as Flexatrode), a low-cost, flexible, and scalable elastomeric nanocomposite using carbon black (CB) and polydimethylsiloxane (PDMS). METHODS Flexatrodes composed of CB and PDMS were developed and tested for mechanical and functional stability up to 7 days. Uniform CB distribution was achieved by optimizing the dispersion process using toluene and methyl-terminated PDMS. Electromechanical testing in the through thickness directions over a long-term duration demonstrated stability of Flexatrode. Thermal stability of Flexatrode for up to a week was tested and validated, thus mitigating concerns of heat generation and deleterious skin reactions such as vasodilation or erythema. RESULTS 25 wt.% CB was determined to be the optimal concentration. Electrical and thermal stability were demonstrated in the through thickness direction. CONCLUSION Flexatrode provides stable electrical properties combined with high flexibility and elasticity. Electrotherapy treated chronic wounds were 81.9% smaller than baseline at day 10. Wounds that received an inactive device (device without any electrical stimulation) were 58.1% smaller than baseline and wounds that received standard of care treatment were 62.2% smaller than baseline. SIGNIFICANCE The increasing need for wearable bioelectronics requiring long-term monitoring/treatment has highlighted the limitations of sustained use of gel-based electrodes. These can include skin irritation, bacterial overgrowth at the electrode site, gel dehydration over time, and signal degradation due to eccrine sweat formation. Flexatrode provides stable performance in a nanocomposite with scalable fabrication, thus providing a promising platform technology for wearable bioelectronics.
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Abyzova E, Dogadina E, Rodriguez RD, Petrov I, Kolesnikova Y, Zhou M, Liu C, Sheremet E. Beyond Tissue replacement: The Emerging role of smart implants in healthcare. Mater Today Bio 2023; 22:100784. [PMID: 37731959 PMCID: PMC10507164 DOI: 10.1016/j.mtbio.2023.100784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/22/2023] Open
Abstract
Smart implants are increasingly used to treat various diseases, track patient status, and restore tissue and organ function. These devices support internal organs, actively stimulate nerves, and monitor essential functions. With continuous monitoring or stimulation, patient observation quality and subsequent treatment can be improved. Additionally, using biodegradable and entirely excreted implant materials eliminates the need for surgical removal, providing a patient-friendly solution. In this review, we classify smart implants and discuss the latest prototypes, materials, and technologies employed in their creation. Our focus lies in exploring medical devices beyond replacing an organ or tissue and incorporating new functionality through sensors and electronic circuits. We also examine the advantages, opportunities, and challenges of creating implantable devices that preserve all critical functions. By presenting an in-depth overview of the current state-of-the-art smart implants, we shed light on persistent issues and limitations while discussing potential avenues for future advancements in materials used for these devices.
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Affiliation(s)
- Elena Abyzova
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, Russia, 634050
| | - Elizaveta Dogadina
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, Russia, 634050
- Institute of Orthopaedic & Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK
| | | | - Ilia Petrov
- Tomsk Polytechnic University, Lenin ave. 30, Tomsk, Russia, 634050
| | | | - Mo Zhou
- Institute of Orthopaedic & Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK
| | - Chaozong Liu
- Institute of Orthopaedic & Musculoskeletal Science, University College London, Royal National Orthopaedic Hospital, Stanmore, HA7 4LP, UK
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Nagalingam N, Raghunathan A, Korede V, Overmars EF, Hung ST, Hartkamp R, Padding JT, Smith CS, Eral HB. Low-cost fluorescence microscope with microfluidic device fabrication for optofluidic applications. HARDWAREX 2023; 14:e00415. [PMID: 37078005 PMCID: PMC10106555 DOI: 10.1016/j.ohx.2023.e00415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Optofluidic devices have revolutionized the manipulation and transportation of fluid at smaller length scales ranging from micrometers to millimeters. We describe a dedicated optical setup for studying laser-induced cavitation inside a microchannel. In a typical experiment, we use a tightly focused laser beam to locally evaporate the solution laced with a dye resulting in the formation of a microbubble. The evolving bubble interface is tracked using high-speed microscopy and digital image analysis. Furthermore, we extend this system to analyze fluid flow through fluorescence-Particle Image Velocimetry (PIV) technique with minimal adaptations. In addition, we demonstrate the protocols for the in-house fabrication of a microchannel tailored to function as a sample holder in this optical setup. In essence, we present a complete guide for constructing a fluorescence microscope from scratch using standard optical components with flexibility in the design and at a lower cost compared to its commercial analogues.
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Affiliation(s)
- Nagaraj Nagalingam
- Process & Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
| | - Aswin Raghunathan
- Process & Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
| | - Vikram Korede
- Process & Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
| | - Edwin F.J. Overmars
- Process & Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
| | - Shih-Te Hung
- Delft Center for Systems and Control, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Remco Hartkamp
- Process & Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
| | - Johan T. Padding
- Process & Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
| | - Carlas S. Smith
- Delft Center for Systems and Control, Delft University of Technology, Mekelweg 2, 2628 CD Delft, The Netherlands
| | - Huseyin Burak Eral
- Process & Energy Department, Delft University of Technology, Leeghwaterstraat 39, 2628 CB Delft, The Netherlands
- Corresponding author.
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Mishra S, Mohanty S, Ramadoss A. Functionality of Flexible Pressure Sensors in Cardiovascular Health Monitoring: A Review. ACS Sens 2022; 7:2495-2520. [PMID: 36036627 DOI: 10.1021/acssensors.2c00942] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
As the highest percentage of global mortality is caused by several cardiovascular diseases (CVD), maintenance and monitoring of a healthy cardiovascular condition have become the primary concern of each and every individual. Simultaneously, recent progress and advances in wearable pressure sensor technology have provided many pathways to monitor and detect underlying cardiovascular illness in terms of irregularities in heart rate, blood pressure, and blood oxygen saturation. These pressure sensors can be comfortably attached onto human skin or can be implanted on the surface of vascular grafts for uninterrupted monitoring of arterial blood pressure. While the traditional monitoring systems are time-consuming, expensive, and not user-friendly, flexible sensor technology has emerged as a promising and dynamic practice to collect important health information at a comparatively low cost in a reliable and user-friendly way. This Review explores the importance and necessity of cardiovascular health monitoring while emphasizing the role of flexible pressure sensors in monitoring patients' health conditions to avoid adverse effects. A comprehensive discussion on the current research progress along with the real-time impact and accessibility of pressure sensors developed for cardiovascular health monitoring applications has been provided.
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Affiliation(s)
- Suvrajyoti Mishra
- School for Advanced Research in Petrochemicals: Laboratory for Advanced Research in Polymeric Materials (LARPM), Central Institute of Petrochemicals Engineering and Technology (CIPET), Bhubaneswar-751024, India
| | - Smita Mohanty
- School for Advanced Research in Petrochemicals: Laboratory for Advanced Research in Polymeric Materials (LARPM), Central Institute of Petrochemicals Engineering and Technology (CIPET), Bhubaneswar-751024, India
| | - Ananthakumar Ramadoss
- School for Advanced Research in Petrochemicals: Laboratory for Advanced Research in Polymeric Materials (LARPM), Central Institute of Petrochemicals Engineering and Technology (CIPET), Bhubaneswar-751024, India
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Development of an Innovative Soft Piezoresistive Biomaterial Based on the Interconnection of Elastomeric PDMS Networks and Electrically-Conductive PEDOT:PSS Sponges. J Funct Biomater 2022; 13:jfb13030135. [PMID: 36135570 PMCID: PMC9500767 DOI: 10.3390/jfb13030135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/04/2022] [Accepted: 08/22/2022] [Indexed: 01/12/2023] Open
Abstract
A deeply interconnected flexible transducer of polydimethylsiloxane (PDMS) and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) was obtained as a material for the application of soft robotics. Firstly, transducers were developed by crosslinking PEDOT:PSS with 3-glycidyloxypropryl-trimethoxysilane (GPTMS) (1, 2 and 3% v/v) and using freeze-drying to obtain porous sponges. The PEDOT:PSS sponges were morphologically characterized, showing porosities mainly between 200 and 600 µm2; such surface area dimensions tend to decrease with increasing degrees of crosslinking. A stability test confirmed a good endurance for up to 28 days for the higher concentrations of the crosslinker tested. Consecutively, the sponges were electromechanically characterized, showing a repeatable and linear resistance variation by the pressure triggers within the limits of their working range (∆RR0 max = 80% for 1-2% v/v of GPTMS). The sponges containing 1% v/v of GPTMS were intertwined with a silicon elastomer to increase their elasticity and water stability. The flexible transducer obtained with this method exhibited moderately lower sensibility and repeatability than the PEDOT:PSS sponges, but the piezoresistive response remained stable under mechanical compression. Furthermore, the transducer displayed a linear behavior when stressed within the limits of its working range. Therefore, it is still valid for pressure sensing and contact detection applications. Lastly, the flexible transducer was submitted to preliminary biological tests that indicate a potential for safe, in vivo sensing applications.
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Broad-Spectrum Theranostics and Biomedical Application of Functionalized Nanomaterials. Polymers (Basel) 2022; 14:polym14061221. [PMID: 35335551 PMCID: PMC8956086 DOI: 10.3390/polym14061221] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/06/2022] [Accepted: 03/15/2022] [Indexed: 12/13/2022] Open
Abstract
Nanotechnology is an important branch of science in therapies known as “nanomedicine” and is the junction of various fields such as material science, chemistry, biology, physics, and optics. Nanomaterials are in the range between 1 and 100 nm in size and provide a large surface area to volume ratio; thus, they can be used for various diseases, including cardiovascular diseases, cancer, bacterial infections, and diabetes. Nanoparticles play a crucial role in therapy as they can enhance the accumulation and release of pharmacological agents, improve targeted delivery and ultimately decrease the intensity of drug side effects. In this review, we discussthe types of nanomaterials that have various biomedical applications. Biomolecules that are often conjugated with nanoparticles are proteins, peptides, DNA, and lipids, which can enhance biocompatibility, stability, and solubility. In this review, we focus on bioconjugation and nanoparticles and also discuss different types of nanoparticles including micelles, liposomes, carbon nanotubes, nanospheres, dendrimers, quantum dots, and metallic nanoparticles and their crucial role in various diseases and clinical applications. Additionally, we review the use of nanomaterials for bio-imaging, drug delivery, biosensing tissue engineering, medical devices, and immunoassays. Understandingthe characteristics and properties of nanoparticles and their interactions with the biological system can help us to develop novel strategies for the treatment, prevention, and diagnosis of many diseases including cancer, pulmonary diseases, etc. In this present review, the importance of various kinds of nanoparticles and their biomedical applications are discussed in much detail.
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8
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Lee HJ, Joyce R, Lee J. Liquid Polymer/Metallic Salt-Based Stretchable Strain Sensor to Evaluate Fruit Growth. ACS APPLIED MATERIALS & INTERFACES 2022; 14:5983-5994. [PMID: 35043613 DOI: 10.1021/acsami.1c21376] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Conventional methods for measuring the various dimensions of a fruit vary from vernier calipers to machine vision systems. This accounts for system bulkiness, high installation charges, and miscellaneous difficulties in continuous and precise monitoring. Considering the limitations, this paper reveals an inventive liquid-state stretchable strain sensor by incorporating poly(ethylene glycol) (PEG) and silver nitrate into an indigenous transparent polymer band. The combination of poly(dimethylsiloxane) (PDMS) and Ecoflex having an optimal mixing ratio (20:80) realized the equilibrium between a large strain, low stress, and less stickiness. The inclusion of a liquid polymer promoted high viscosity and chemical stability, while the addition of a metallic salt enhanced the electrical conductivity of the sensor. The correlation between strain and resistance showed high sensitivity and good repeatability of the PEG-silver nitrate composite. Linear resistance changes were noted with high coefficients of determination (R2 > 0.99) at least up to the strain of 30%. The performance test as a dendrometer on fruits of two different species demonstrated excellent stability of the sensor with increasing ratios from 1.7 to 3.9 kΩ/mm. This tunable elastic band sensor opened up a route toward long-term evaluation-targeted versatile applications such as fruit growth monitoring.
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Affiliation(s)
- Hyun Jae Lee
- Department of Mechanical Engineering, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Robin Joyce
- Department of Mechanical Engineering, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Junghoon Lee
- Department of Mechanical Engineering, College of Engineering, Seoul National University, Seoul 08826, Republic of Korea
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Flexible Strain-Sensitive Silicone-CNT Sensor for Human Motion Detection. BIOENGINEERING (BASEL, SWITZERLAND) 2022; 9:bioengineering9010036. [PMID: 35049745 PMCID: PMC8772866 DOI: 10.3390/bioengineering9010036] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/02/2022] [Accepted: 01/10/2022] [Indexed: 12/12/2022]
Abstract
This article describes the manufacturing technology of biocompatible flexible strain-sensitive sensor based on Ecoflex silicone and multi-walled carbon nanotubes (MWCNT). The sensor demonstrates resistive behavior. Structural, electrical, and mechanical characteristics are compared. It is shown that laser radiation significantly reduces the resistance of the material. Through laser radiation, electrically conductive networks of MWCNT are formed in a silicone matrix. The developed sensor demonstrates highly sensitive characteristics: gauge factor at 100% elongation −4.9, gauge factor at 90° bending −0.9%/deg, stretchability up to 725%, tensile strength 0.7 MPa, modulus of elasticity at 100% 46 kPa, and the temperature coefficient of resistance in the range of 30–40 °C is −2 × 10−3. There is a linear sensor response (with 1 ms response time) with a low hysteresis of ≤3%. An electronic unit for reading and processing sensor signals based on the ATXMEGA8E5-AU microcontroller has been developed. The unit was set to operate the sensor in the range of electrical resistance 5–150 kOhm. The Bluetooth module made it possible to transfer the received data to a personal computer. Currently, in the field of wearable technologies and health monitoring, a vital need is the development of flexible sensors attached to the human body to track various indicators. By integrating the sensor with the joints of the human hand, effective movement sensing has been demonstrated.
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Miranda I, Souza A, Sousa P, Ribeiro J, Castanheira EMS, Lima R, Minas G. Properties and Applications of PDMS for Biomedical Engineering: A Review. J Funct Biomater 2021; 13:2. [PMID: 35076525 PMCID: PMC8788510 DOI: 10.3390/jfb13010002] [Citation(s) in RCA: 149] [Impact Index Per Article: 49.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/13/2021] [Accepted: 12/16/2021] [Indexed: 12/14/2022] Open
Abstract
Polydimethylsiloxane (PDMS) is an elastomer with excellent optical, electrical and mechanical properties, which makes it well-suited for several engineering applications. Due to its biocompatibility, PDMS is widely used for biomedical purposes. This widespread use has also led to the massification of the soft-lithography technique, introduced for facilitating the rapid prototyping of micro and nanostructures using elastomeric materials, most notably PDMS. This technique has allowed advances in microfluidic, electronic and biomedical fields. In this review, an overview of the properties of PDMS and some of its commonly used treatments, aiming at the suitability to those fields' needs, are presented. Applications such as microchips in the biomedical field, replication of cardiovascular flow and medical implants are also reviewed.
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Affiliation(s)
- Inês Miranda
- Center for MicroElectromechanical Systems (CMEMS-UMinho), Campus de Azurém, University of Minho, 4800-058 Guimaraes, Portugal; (I.M.); (P.S.); (G.M.)
| | - Andrews Souza
- MEtRICs, Mechanical Engineering Department, Campus de Azurém, University of Minho, 4800-058 Guimaraes, Portugal;
| | - Paulo Sousa
- Center for MicroElectromechanical Systems (CMEMS-UMinho), Campus de Azurém, University of Minho, 4800-058 Guimaraes, Portugal; (I.M.); (P.S.); (G.M.)
| | - João Ribeiro
- Centro de Investigação de Montanha (CIMO), Campus de Santa Apolónia, Instituto Politécnico de Bragança, 5300-253 Braganca, Portugal;
| | - Elisabete M. S. Castanheira
- Centre of Physics of Minho and Porto Universities (CF-UM-UP), Campus de Gualtar, University of Minho, 4710-057 Braga, Portugal;
| | - Rui Lima
- MEtRICs, Mechanical Engineering Department, Campus de Azurém, University of Minho, 4800-058 Guimaraes, Portugal;
- CEFT, Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Roberto Frias, 4200-465 Porto, Portugal
| | - Graça Minas
- Center for MicroElectromechanical Systems (CMEMS-UMinho), Campus de Azurém, University of Minho, 4800-058 Guimaraes, Portugal; (I.M.); (P.S.); (G.M.)
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Chong H, Lou JJ, Zorman CA, Majerus SJA. Wireless Monitoring of Vascular Pressure Using CB-PDMS Based Flexible Strain Sensor. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:7011-7015. [PMID: 34892717 DOI: 10.1109/embc46164.2021.9630890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Rising pressure within a vascular graft can signal impending failure caused by stenosis or thrombosis, and early detection can improve surgical salvage outcomes. To enable regular graft pressure monitoring, we developed a thin flexible pulsation sensor (FPS) with wireless data readout. A conductive polymer sensing layer is attached to a flexible circuit board and then encapsulated by polydimethylsiloxane (PDMS) for biocompatibility. Due to the FPS' outstanding flexibility in comparison to natural arteries, veins, and synthetic vascular grafts, it can be wrapped around target conduits to monitor blood pressure for short-term surgical and long-term implantation purposes. In this study, we analyze the power spectrum of the FPS data to determine the ideal bandwidth of the wireless FPS device to preserve heart rate and hemodynamic waveforms while rejecting noise. The strain response of FPS wrapped around silicone tube, vascular graft and artery was simulated using COMSOL®, showing a linear relationship between pressure and FPS strain. The optimized bandpass filter of 0.2-10 Hz was simulated and implemented on a flexible polyimide circuit board. The circuit board also included a low- power microcontroller for data conversion and transmission via simple 4-MHz on-off keying. The performance of the prototype was evaluated by recording wireless data from a vascular phantom under different pressure and flow settings. The results indicate that the peak-to-peak FPS voltage responds linearly to RMS blood pressure and systolic-diastolic pressure.Clinical Relevance- Early detection of a failing vascular graft could leverage sensors for near real-time monitoring. The presented wireless flexible sensor measures and transmits vessel distension data as a proxy for internal lumen pressure.
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12
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Herbert R, Lim H, Park S, Kim J, Yeo W. Recent Advances in Printing Technologies of Nanomaterials for Implantable Wireless Systems in Health Monitoring and Diagnosis. Adv Healthc Mater 2021; 10:e2100158. [PMID: 34019731 DOI: 10.1002/adhm.202100158] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 05/03/2021] [Indexed: 12/17/2022]
Abstract
The development of wireless implantable sensors and integrated systems, enabled by advances in flexible and stretchable electronics technologies, is emerging to advance human health monitoring, diagnosis, and treatment. Progress in material and fabrication strategies allows for implantable electronics for unobtrusive monitoring via seamlessly interfacing with tissues and wirelessly communicating. Combining new nanomaterials and customizable printing processes offers unique possibilities for high-performance implantable electronics. Here, this report summarizes the recent progress and advances in nanomaterials and printing technologies to develop wireless implantable sensors and electronics. Advances in materials and printing processes are reviewed with a focus on challenges in implantable applications. Demonstrations of wireless implantable electronics and advantages based on these technologies are discussed. Lastly, existing challenges and future directions of nanomaterials and printing are described.
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Affiliation(s)
- Robert Herbert
- George W. Woodruff School of Mechanical Engineering Center for Human‐Centric Interfaces and Engineering Georgia Institute of Technology Atlanta GA 30332 USA
| | - Hyo‐Ryoung Lim
- George W. Woodruff School of Mechanical Engineering Center for Human‐Centric Interfaces and Engineering Georgia Institute of Technology Atlanta GA 30332 USA
| | - Sehyun Park
- School of Engineering and Computer Science Washington State University Vancouver WA 98686 USA
| | - Jong‐Hoon Kim
- School of Engineering and Computer Science Washington State University Vancouver WA 98686 USA
| | - Woon‐Hong Yeo
- George W. Woodruff School of Mechanical Engineering Center for Human‐Centric Interfaces and Engineering Georgia Institute of Technology Atlanta GA 30332 USA
- Wallace H. Coulter Department of Biomedical Engineering Parker H. Petit Institute for Bioengineering and Biosciences Neural Engineering Center Institute for Materials Institute for Robotics and Intelligent Machines Georgia Institute of Technology Atlanta GA 30332 USA
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Green C, Rogers J, Kovenburg R, Aksak B. Using a conductive sphere as a probe to characterize the sensitivity of soft piezoresistive films. J Appl Polym Sci 2021. [DOI: 10.1002/app.50349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Christopher Green
- Department of Mechanical Engineering Texas Tech University Lubbock Texas USA
| | - Jeremy Rogers
- Department of Mechanical Engineering Texas Tech University Lubbock Texas USA
| | - Robert Kovenburg
- Department of Electrical and Computer Engineering Texas Tech University Lubbock Texas USA
| | - Burak Aksak
- Department of Mechanical Engineering Texas Tech University Lubbock Texas USA
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14
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Wen Z, Zhou H, Zhou J, Chen W, Wu Y, Lin Z. Quantitative Evaluation of Mechanical Stimulation for Tissue-Engineered Blood Vessels. Tissue Eng Part C Methods 2021; 27:337-347. [PMID: 33913766 DOI: 10.1089/ten.tec.2021.0007] [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: 01/01/2023] Open
Abstract
Functional small-diameter tissue-engineered blood vessels (TEBVs) have been developed in silico using biodegradable polymeric scaffolds under pulsatile perfusion. Accurate simulation of physiological mechanical stimulations in vitro is a crucial factor in vascular engineering. However, little is known about the patterns of mechanical stimulation on silicone tubes. This study aimed to determine the optimal mechanical conditions required for inducing circumferential deformations in silicone tubes during in vitro vascular development under pulsatile perfusion. For this purpose, we established a data acquisition (DAQ) system with a laser micrometer and pressure transducers to evaluate changes in the diameter of silicone tubes in response to pulsatile flow and validated the results on cultured TEBVs. The established DAQ system showed satisfactory reproducibility for measuring diameter variation in the in silico model. Furthermore, the hardness and thickness of the silicone tubes affected the mechanical conditioning in the three-dimensional culture system under different working pressures, frequencies, and circumferential deformations. We demonstrated a simple and reliable approach to quantify the circumferential strain and deformations to ensure optimal mechanical stimulation of the cultured TEBVs under pulsatile perfusion. Based on the results, we were able to dynamically culture dense cellularized small-diameter TEBVs. This study highlights the importance of mechanical stimulation in vascular tissue engineering. Impact statement This study demonstrated a direct and noncontact data acquisition system for quantifying the strain on the supporting silicone medium during three-dimensional tissue-engineered blood vessel culture, which can help optimize the mechanical parameters for vascular tissue engineering.
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Affiliation(s)
- Zhang Wen
- Research Department of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, P.R. China
| | - Haohao Zhou
- Department of Biomedical Engineering, School of Medicine, South China University of Technology, Guangzhou, P.R. China
| | - Jiahui Zhou
- Department of Cardiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, P.R. China
| | - Wanwen Chen
- Department of Cardiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, P.R. China
| | - Yueheng Wu
- Research Department of Medical Sciences, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, P.R. China
| | - Zhanyi Lin
- Department of Cardiology, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, P.R. China
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15
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Goldoni R, Ozkan-Aydin Y, Kim YS, Kim J, Zavanelli N, Mahmood M, Liu B, Hammond FL, Goldman DI, Yeo WH. Stretchable Nanocomposite Sensors, Nanomembrane Interconnectors, and Wireless Electronics toward Feedback-Loop Control of a Soft Earthworm Robot. ACS APPLIED MATERIALS & INTERFACES 2020; 12:43388-43397. [PMID: 32791828 DOI: 10.1021/acsami.0c10672] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Sensors that can detect external stimuli and perceive the surrounding areas could offer an ability for soft biomimetic robots to use the sensory feedback for closed-loop control of locomotion. Although various types of biomimetic robots have been developed, few systems have included integrated stretchable sensors and interconnectors with miniaturized electronics. Here, we introduce a soft, stretchable nanocomposite system with built-in wireless electronics with an aim for feedback-loop motion control of a robotic earthworm. The nanostructured strain sensor, based on a carbon nanomaterial and a low-modulus silicone elastomer, allows for seamless integration with the body of the soft robot that can accommodate large strains caused by bending, stretching, and physical interactions with obstacles. A scalable, cost-effective, and screen-printing method manufactures an array of the strain sensors that are conductive and stretchable over 100% with a gauge factor over 38. An array of nanomembrane interconnectors enables a reliable connection between soft sensors and wireless electronics while tolerating the robot's multimodal movements. A set of computational and experimental studies of soft materials, stretchable mechanics, and hybrid packaging provides the key design factors for a reliable, nanocomposite sensor system. The miniaturized wireless circuit, embedded in the robot joint, offers real-time monitoring of strain changes during the motions of a robotic segment. Collectively, the soft sensor system presented in this work shows great potential to be integrated with other flexible, stretchable electronics for applications in soft robotics, wearable devices, and human-machine interfaces.
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Affiliation(s)
- Riccardo Goldoni
- George W. Woodruff School of Mechanical Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Yasemin Ozkan-Aydin
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Yun-Soung Kim
- George W. Woodruff School of Mechanical Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Jongsu Kim
- George W. Woodruff School of Mechanical Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Nathan Zavanelli
- George W. Woodruff School of Mechanical Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Musa Mahmood
- George W. Woodruff School of Mechanical Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Bangyuan Liu
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Frank L Hammond
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Daniel I Goldman
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Woon-Hong Yeo
- George W. Woodruff School of Mechanical Engineering, Institute for Electronics and Nanotechnology, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
- Parker H. Petit Institute for Bioengineering and Biosciences, Neural Engineering Center, Institute for Materials, Institute for Robotics and Intelligent Machines, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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16
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Chong H, Majerus SJ, Bogie KM, Zorman CA. Non‐hermetic packaging of biomedical microsystems from a materials perspective: A review. ACTA ACUST UNITED AC 2020. [DOI: 10.1002/mds3.10082] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Hao Chong
- Department of Electrical, Computer, and Systems Engineering Case Western Reserve University Cleveland OH USA
| | | | - Kath M. Bogie
- APT Center Louis Stokes VA Medical Center Cleveland OH USA
- Department of Orthopaedics Case Western Reserve University School of Medicine Cleveland OH USA
| | - Christian A. Zorman
- Department of Electrical, Computer, and Systems Engineering Case Western Reserve University Cleveland OH USA
- APT Center Louis Stokes VA Medical Center Cleveland OH USA
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