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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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Stefanov BA, Fussenegger M. Biomarker-driven feedback control of synthetic biology systems for next-generation personalized medicine. Front Bioeng Biotechnol 2022; 10:986210. [PMID: 36225597 PMCID: PMC9548536 DOI: 10.3389/fbioe.2022.986210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 09/06/2022] [Indexed: 11/13/2022] Open
Abstract
Many current clinical therapies for chronic diseases involve administration of drugs using dosage and bioavailability parameters estimated for a generalized population. This standard approach carries the risk of under dosing, which may result in ineffective treatment, or overdosing, which may cause undesirable side effects. Consequently, maintaining a drug concentration in the therapeutic window often requires frequent monitoring, adversely affecting the patient’s quality of life. In contrast, endogenous biosystems have evolved finely tuned feedback control loops that govern the physiological functions of the body based on multiple input parameters. To provide personalized treatment for chronic diseases, therefore, we require synthetic systems that can similarly generate a calibrated therapeutic response. Such engineered autonomous closed-loop devices should incorporate a sensor that actively tracks and evaluates the disease severity based on one or more biomarkers, as well as components that utilize these molecular inputs to bio compute and deliver the appropriate level of therapeutic output. Here, we review recent advances in applications of the closed-loop design principle in biomedical implants for treating severe and chronic diseases, highlighting translational studies of cellular therapies. We describe the engineering principles and components of closed-loop therapeutic devices, and discuss their potential to become a key pillar of personalized medicine.
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Affiliation(s)
| | - Martin Fussenegger
- ETH Zürich, Department of Biosystems Science and Engineering, Basel, Switzerland
- Faculty of Life Science, University of Basel, Basel, Switzerland
- *Correspondence: Martin Fussenegger,
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In vivo closed-loop control of a locust's leg using nerve stimulation. Sci Rep 2022; 12:10864. [PMID: 35760828 PMCID: PMC9237135 DOI: 10.1038/s41598-022-13679-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 05/10/2022] [Indexed: 01/17/2023] Open
Abstract
Activity of an innervated tissue can be modulated based on an acquired biomarker through feedback loops. How to convert this biomarker into a meaningful stimulation pattern is still a topic of intensive research. In this article, we present a simple closed-loop mechanism to control the mean angle of a locust’s leg in real time by modulating the frequency of the stimulation on its extensor motor nerve. The nerve is interfaced with a custom-designed cuff electrode and the feedback loop is implemented online with a proportional control algorithm, which runs solely on a microcontroller without the need of an external computer. The results show that the system can be controlled with a single-input, single-output feedback loop. The model described in this article can serve as a primer for young researchers to learn about neural control in biological systems before applying these concepts in advanced systems. We expect that the approach can be advanced to achieve control over more complex movements by increasing the number of recorded biomarkers and selective stimulation units.
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Seaton BT, Heien ML. Biocompatible reference electrodes to enhance chronic electrochemical signal fidelity in vivo. Anal Bioanal Chem 2021; 413:6689-6701. [PMID: 34595560 DOI: 10.1007/s00216-021-03640-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/27/2021] [Accepted: 08/30/2021] [Indexed: 12/17/2022]
Abstract
In vivo electrochemistry is a vital tool of neuroscience that allows for the detection, identification, and quantification of neurotransmitters, their metabolites, and other important analytes. One important goal of in vivo electrochemistry is a better understanding of progressive neurological disorders (e.g., Parkinson's disease). A complete understanding of such disorders can only be achieved through a combination of acute (i.e., minutes to hours) and chronic (i.e., days or longer) experimentation. Chronic studies are more challenging because they require prolonged implantation of electrodes, which elicits an immune response, leading to glial encapsulation of the electrodes and altered electrode performance (i.e., biofouling). Biofouling leads to increased electrode impedance and reference electrode polarization, both of which diminish the selectivity and sensitivity of in vivo electrochemical measurements. The increased impedance factor has been successfully mitigated previously with the use of a counter electrode, but the challenge of reference electrode polarization remains. The commonly used Ag/AgCl reference electrode lacks the long-term potential stability in vivo required for chronic measurements. In addition, the cytotoxicity of Ag/AgCl adversely affects animal experimentation and prohibits implantation in humans, hindering translational research progress. Thus, a move toward biocompatible reference electrodes with superior chronic potential stability is necessary. Two qualifying materials, iridium oxide and boron-doped diamond, are introduced and discussed in terms of their electrochemical properties, biocompatibilities, fabrication methods, and applications. In vivo electrochemistry continues to advance toward more chronic experimentation in both animal models and humans, necessitating the utilization of biocompatible reference electrodes that should provide superior potential stability and allow for unprecedented chronic signal fidelity when used with a counter electrode for impedance mitigation.
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Affiliation(s)
- Blake T Seaton
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, USA
| | - Michael L Heien
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, AZ, 85721, USA.
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Cracchiolo M, Ottaviani MM, Panarese A, Strauss I, Vallone F, Mazzoni A, Micera S. Bioelectronic medicine for the autonomic nervous system: clinical applications and perspectives. J Neural Eng 2021; 18. [PMID: 33592597 DOI: 10.1088/1741-2552/abe6b9] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 02/16/2021] [Indexed: 12/11/2022]
Abstract
Bioelectronic medicine (BM) is an emerging new approach for developing novel neuromodulation therapies for pathologies that have been previously treated with pharmacological approaches. In this review, we will focus on the neuromodulation of autonomic nervous system (ANS) activity with implantable devices, a field of BM that has already demonstrated the ability to treat a variety of conditions, from inflammation to metabolic and cognitive disorders. Recent discoveries about immune responses to ANS stimulation are the laying foundation for a new field holding great potential for medical advancement and therapies and involving an increasing number of research groups around the world, with funding from international public agencies and private investors. Here, we summarize the current achievements and future perspectives for clinical applications of neural decoding and stimulation of the ANS. First, we present the main clinical results achieved so far by different BM approaches and discuss the challenges encountered in fully exploiting the potential of neuromodulatory strategies. Then, we present current preclinical studies aimed at overcoming the present limitations by looking for optimal anatomical targets, developing novel neural interface technology, and conceiving more efficient signal processing strategies. Finally, we explore the prospects for translating these advancements into clinical practice.
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Affiliation(s)
- Marina Cracchiolo
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Matteo Maria Ottaviani
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Alessandro Panarese
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Ivo Strauss
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Fabio Vallone
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Alberto Mazzoni
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy
| | - Silvestro Micera
- The BioRobotics Institute and Department of Excellence in Robotics & AI, The BioRobotics Institute, Scuola Superiore Sant'Anna, Pisa, Italy.,Bertarelli Foundation Chair in Translational NeuroEngineering, Centre for Neuroprosthetics and Institute of Bioengineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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A review for the peripheral nerve interface designer. J Neurosci Methods 2019; 332:108523. [PMID: 31743684 DOI: 10.1016/j.jneumeth.2019.108523] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 11/14/2019] [Accepted: 11/15/2019] [Indexed: 12/11/2022]
Abstract
Informational density and relative accessibility of the peripheral nervous system make it an attractive site for therapeutic intervention. Electrode-based electrophysiological interfaces with peripheral nerves have been under development since the 1960s and, for several applications, have seen widespread clinical implementation. However, many applications require a combination of neural target resolution and stability which has thus far eluded existing peripheral nerve interfaces (PNIs). With the goal of aiding PNI designers in development of devices that meet the demands of next-generation applications, this review seeks to collect and present practical considerations and best practices which emerge from the literature, including both lessons learned during early PNI development and recent ideas. Fundamental and practical principles guiding PNI design are reviewed, followed by an updated and critical account of existing PNI designs and strategies. Finally, a brief survey of in vitro and in vivo PNI characterization methods is presented.
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Mirza KB, Golden CT, Nikolic K, Toumazou C. Closed-Loop Implantable Therapeutic Neuromodulation Systems Based on Neurochemical Monitoring. Front Neurosci 2019; 13:808. [PMID: 31481864 PMCID: PMC6710388 DOI: 10.3389/fnins.2019.00808] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 07/19/2019] [Indexed: 12/29/2022] Open
Abstract
Closed-loop or intelligent neuromodulation allows adjustable, personalized neuromodulation which usually incorporates the recording of a biomarker, followed by implementation of an algorithm which decides the timing (when?) and strength (how much?) of stimulation. Closed-loop neuromodulation has been shown to have greater benefits compared to open-loop neuromodulation, particularly for therapeutic applications such as pharmacoresistant epilepsy, movement disorders and potentially for psychological disorders such as depression or drug addiction. However, an important aspect of the technique is selection of an appropriate, preferably neural biomarker. Neurochemical sensing can provide high resolution biomarker monitoring for various neurological disorders as well as offer deeper insight into neurological mechanisms. The chemicals of interest being measured, could be ions such as potassium (K+), sodium (Na+), calcium (Ca2+), chloride (Cl−), hydrogen (H+) or neurotransmitters such as dopamine, serotonin and glutamate. This review focusses on the different building blocks necessary for a neurochemical, closed-loop neuromodulation system including biomarkers, sensors and data processing algorithms. Furthermore, it also highlights the merits and drawbacks of using this biomarker modality.
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Affiliation(s)
- Khalid B Mirza
- Department of Electrical and Electronic Engineering, Centre for Bio-Inspired Technology, Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - Caroline T Golden
- Department of Electrical and Electronic Engineering, Centre for Bio-Inspired Technology, Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - Konstantin Nikolic
- Department of Electrical and Electronic Engineering, Centre for Bio-Inspired Technology, Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
| | - Christofer Toumazou
- Department of Electrical and Electronic Engineering, Centre for Bio-Inspired Technology, Institute of Biomedical Engineering, Imperial College London, London, United Kingdom
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Cork SC. The role of the vagus nerve in appetite control: Implications for the pathogenesis of obesity. J Neuroendocrinol 2018; 30:e12643. [PMID: 30203877 DOI: 10.1111/jne.12643] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 09/05/2018] [Accepted: 09/05/2018] [Indexed: 12/14/2022]
Abstract
The communication between the gut and the brain is important for the control of energy homeostasis. In response to food intake, enteroendocrine cells secrete gut hormones, which ultimately suppress appetite through centrally-mediated processes. Increasing evidence implicates the vagus nerve as an important conduit in transmitting these signals from the gastrointestinal tract to the brain. Studies have demonstrated that many of the gut hormones secreted from enteroendocrine cells signal through the vagus nerve, and the sensitivity of the vagus to these signals is regulated by feeding status. Furthermore, evidence suggests that a reduction in the ability of the vagus nerve to respond to the switch between a "fasted" and "fed" state, retaining sensitivity to orexigenic signals when fed or a reduced ability to respond to satiety hormones, may contribute to obesity. This review draws together the evidence that the vagus nerve is a crucial component of appetite regulation via the gut-brain axis, with a particular emphasis on experimental techniques and future developments.
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Affiliation(s)
- Simon C Cork
- Section of Endocrinology and Investigative Medicine, Division of Endocrinology, Diabetes and Metabolism, Imperial College London, London, UK
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Mirza KB, Alenda A, Eftekhar A, Grossman N, Nikolic K, Bloom SR, Toumazou C. Influence of Cholecystokinin-8 on Compound Nerve Action Potentials from Ventral Gastric Vagus in Rats. Int J Neural Syst 2018; 28:1850006. [PMID: 29631504 DOI: 10.1142/s0129065718500065] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Vagus Nerve Stimulation (VNS) has shown great promise as a potential therapy for a number of conditions, such as epilepsy, depression and for Neurometabolic Therapies, especially for treating obesity. The objective of this study was to characterize the left ventral subdiaphragmatic gastric trunk of vagus nerve (SubDiaGVN) and to analyze the influence of intravenous injection of gut hormone cholecystokinin octapeptide (CCK-8) on compound nerve action potential (CNAP) observed on the same branch, with the aim of understanding the impact of hormones on VNS and incorporating the methods and results into closed loop implant design. METHODS The cervical region of the left vagus nerve (CerVN) of male Wistar rats was stimulated with electric current and the elicited CNAPs were recorded on the SubDiaGVN under four different conditions: Control (no injection), Saline, CCK1 (100[Formula: see text]pmol/kg) and CCK2 (1000[Formula: see text]pmol/kg) injections. RESULTS We identified the presence of A[Formula: see text], B, C1, C2, C3 and C4 fibers with their respective velocity ranges. Intravenous administration of CCK in vivo results in selective, statistically significant reduction of CNAP components originating from A and B fibers, but with no discernible effect on the C fibers in [Formula: see text] animals. The affected CNAP components exhibit statistically significant ([Formula: see text] and [Formula: see text]) higher normalized stimulation thresholds. CONCLUSION This approach of characterizing the vagus nerve can be used in closed loop systems to determine when to initiate VNS and also to tune the stimulation dose, which is patient-specific and changes over time.
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Affiliation(s)
- Khalid B Mirza
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
| | - Andrea Alenda
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
| | - Amir Eftekhar
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
| | - Nir Grossman
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
| | - Konstantin Nikolic
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
| | - Stephen R Bloom
- † Division of Diabetes, Endocrinology and Metabolism, Section of Endocrinology and Investigative Medicine, Imperial College London, W12 0NN, UK
| | - Christofer Toumazou
- * Institute of Biomedical Engineering, Department of Electrical and Electronic Engineering, Imperial College London, SW7 2AZ, UK
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