scholarly journals Design of Ceramic Packages for Acoustically Coupled Implantable Medical Devices

2019 ◽  
Author(s):  
Konlin Shen ◽  
Michel M. Maharbiz
Keyword(s):  
Medical Devices ◽  
Failure Modes ◽  
Acoustic Power ◽  
The Body ◽  
Acoustic Energy ◽  
Implantable Medical Devices ◽  
Coupling Energy ◽  
Modal Expansion ◽  
Backscatter Communication

AbstractObjectiveUltrasonic acoustic power transfer is an efficient mechanism for coupling energy to millimeter and sub-millimeter implants in the body. To date, published ultrasonically powered implants have been encapsulated with thin film polymers that are susceptible to well-documented failure modes in vivo, including water penetration and attack by the body. As with all medical implants, packaging with ceramic or metallic materials can reduce water vapor transmission and improve biostability to provide decadal device lifetime. In this paper, we evaluate methods of coupling acoustic energy to the interior of ceramic packages.MethodsThe classic wave approach and modal expansion are used to obtain analytical expressions for acoustic transmission through two different package designs and these approaches are validated experimentally. A candidate package design is demonstrated using alumina packages and titanium lids, designed to be acoustically transparent.ResultsBulk modes are shown to be more effective at coupling acoustic energy to a piezoelectric receiver than flexural modes. Using bulk modes, packaged motes have an overall link efficiency of roughly 10%, compared to 25% for unpackaged motes. Packaging does not have a significant effect on translational misalignment penalties, but does increase angular misalignment penalties. Passive amplitude-modulated backscatter communication is demonstrated.ConclusionThin lids enable the use of acoustically coupled devices even with package materials of very different acoustic impedance. Significance: This work provides an analysis and method for designing packages that enable acoustic coupling with implantable medical devices, which could facilitate clinical translation.

scholarly journals Recommendations for Nanomedicine Human Subjects Research Oversight: An Evolutionary Approach for an Emerging Field

2012 ◽  
Vol 40 (4) ◽  
pp. 716-750 ◽  
Author(s):  
Leili Fatehi ◽  
Susan M. Wolf ◽  
Jeffrey McCullough ◽  
Ralph Hall ◽  
Frances Lawrenz ◽  
...  
Keyword(s):  
Medical Devices ◽  
Human Subjects ◽  
High Surface ◽  
The Body ◽  
Biologically Active ◽  
Implantable Medical Devices ◽  
Research Oversight ◽  
Insoluble Drugs ◽  
Drug Eluting

Nanomedicine is yielding new and improved treatments and diagnostics for a range of diseases and disorders. Nanomedicine applications incorporate materials and components with nanoscale dimensions (often defined as 1-100 nm, but sometimes defined to include dimensions up to 1000 nm, as discussed further below) where novel physiochemical properties emerge as a result of size-dependent phenomena and high surface-to-mass ratio. Nanotherapeutics and in vivo nanodiagnostics are a subset of nanomedicine products that enter the human body. These include drugs, biological products (biologics), implantable medical devices, and combination products that are designed to function in the body in ways unachievable at larger scales. Nanotherapeutics and in vivo nanodiagnostics incorporate materials that are engineered at the nanoscale to express novel properties that are medicinally useful. These nanomedicine applications can also contain nanomaterials that are biologically active, producing interactions that depend on biological triggers. Examples include nanoscale formulations of insoluble drugs to improve bioavailability and pharmacokinetics, drugs encapsulated in hollow nanoparticles with the ability to target and cross cellular and tissue membranes (including the bloodbrain barrier) and to release their payload at a specific time or location, imaging agents that demonstrate novel optical properties to aid in locating micrometastases, and antimicrobial and drug-eluting components or coatings of implantable medical devices such as stents.

scholarly journals Ion Leaching from Implantable Medical Devices

2010 ◽  
Vol 638-642 ◽  
pp. 754-759
Author(s):  
Lawrence E. Eiselstein ◽  
Robert D. Caligiuri
Keyword(s):  
Medical Devices ◽  
Stainless Steels ◽  
The Body ◽  
Cobalt Chromium ◽  
Implantable Medical Devices ◽  
Device Development ◽  
Soluble Ions ◽  
Chromium Alloys

Implantable medical devices must be able to withstand the corrosive environment of the human body for 10 or more years without adverse consequences. Most reported research and development has been on developing materials and devices that are biocompatible and resistant to corrosion-fatigue, pitting, and crevice corrosion. However, little has been directly reported regarding implantable materials with respect to the rate at which they generate soluble ions in-vivo. Most of the biocompatibility studies have been done by examining animal implants and cell cultures rather than examining the rate at which these materials leach ions into the body. This paper will discuss what is currently known about the rate at which common implant materials (such as stainless steels, cobalt-chromium alloys, and nitinol) elute ions under in vitro conditions, what the limitations are of such data, and how this data can be used in medical device development.

scholarly journals Self-rechargeable cardiac pacemaker system with triboelectric nanogenerators

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hanjun Ryu ◽  
Hyun-moon Park ◽  
Moo-Kang Kim ◽  
Bosung Kim ◽  
Hyoun Seok Myoung ◽  
...  
Keyword(s):  
Medical Devices ◽  
Mechanical Energy ◽  
Cardiac Pacemaker ◽  
Operation Time ◽  
Lithium Ion ◽  
The Body ◽  
Body Motion ◽  
Triboelectric Nanogenerator ◽  
Implantable Medical Devices ◽  
Energy Harvesters

AbstractSelf-powered implantable devices have the potential to extend device operation time inside the body and reduce the necessity for high-risk repeated surgery. Without the technological innovation of in vivo energy harvesters driven by biomechanical energy, energy harvesters are insufficient and inconvenient to power titanium-packaged implantable medical devices. Here, we report on a commercial coin battery-sized high-performance inertia-driven triboelectric nanogenerator (I-TENG) based on body motion and gravity. We demonstrate that the enclosed five-stacked I-TENG converts mechanical energy into electricity at 4.9 μW/cm3 (root-mean-square output). In a preclinical test, we show that the device successfully harvests energy using real-time output voltage data monitored via Bluetooth and demonstrate the ability to charge a lithium-ion battery. Furthermore, we successfully integrate a cardiac pacemaker with the I-TENG, and confirm the ventricle pacing and sensing operation mode of the self-rechargeable cardiac pacemaker system. This proof-of-concept device may lead to the development of new self-rechargeable implantable medical devices.

Elastically Bi-Stable Heartbeat Powered Energy Harvester

2014 ◽  
Author(s):  
Andres F. Arrieta ◽  
Paolo Ermanni ◽  
Daniel J. Inman ◽  
M. Amin Karami
Keyword(s):  
Medical Devices ◽  
Composite Laminates ◽  
Energy Harvester ◽  
Experimental Tests ◽  
Implantable Medical Devices ◽  
Vibration Energy Harvester ◽  
Energy Harvesters ◽  
Sufficient Energy ◽  
Frequency Sweeps

We present an MRI-compatible vibration energy harvester for powering implantable medical devices with heartbeat induced vibrations. The state of the art heartbeat-powered energy harvesters are magnetically bi-stable, rendering this devices MRI incompatible. A type of nonlinear harvester exhibiting purely elastic multi-stability based on bi-stable composite laminates is herein proposed for this purpose. The purely elastic nature of the exhibited bi-stability is crucial for powering medical devices as magnetic based multi-stable harvesters are not suitable for implantation. The energy harvester structure based on cantilevered bi-stable laminates used in this paper is inherently nonlinear and is thus MRI compatible. Harmonic frequency sweeps and previously measured signals simulating vibrations produced around the chest area of the human heart are used as vibration inputs to the harvesting device for experimental tests. The results show the capability of harvesting sufficient energy for powering conventional pacemakers with the exact vibration inputs expected during in vivo operation.

scholarly journals Effect of Sterilization on 3-point Dynamic Response to in Vitro Bending of an Mg Implant

2020 ◽  
Author(s):  
Luis Humberto Campos Becerra ◽  
Marco Antonio Loudovic Hernández Rodríguez ◽  
Raúl Lesso Arroyo ◽  
Hugo Esquivel S ◽  
Alejandro Torres Castro
Keyword(s):  
Fatigue Resistance ◽  
Medical Devices ◽  
Initial Period ◽  
The Body ◽  
Sterilization Method ◽  
Toxicological Effects ◽  
Intramedullary Implant ◽  
We43 Alloy

Abstract Background: The aim of the study is to characterize a biomedical magnesium alloy and highlighting the loss of mechanical integrity due to the sterilization method. Ideally, when using these alloys is to delay the onset of degradation so that the implant can support body loads and avoid toxicological effects due to the release of metal ions into the body. Methods: The experimentation was carried out according to the standards of ASTM-F-1264 and ISO-10993-5 for mechanical and biological tests respectively, this testing methodology is carried out in accordance with the monographs of the Pharmacopoeia for the approval of medical devices and obtaining a health registration. An intramedullary implant (IIM) manufactured in magnesium (Mg) WE43 can support loads of the body in the initial period of bone consolidation without compromising the integrity of the fractured area. A system with these characteristics would improve morbidity and health costs by avoiding secondary surgical interventions. As a property, the fatigue resistance of Mg in aggressive environments such as the body environment undergoes progressive degradation, however, the autoclave sterilization method drastically affects fatigue resistance, as demonstrated in tests carried out under in vitro conditions. Coupled with this phenomenon, the relatively poor biocompatibility of Mg WE43 alloys has limited applications where they can be used due to low acceptance rates from agencies such as the FDA. However, Mg alloy with elements such as yttrium and rare earth elements (REEs) have been shown to delay biodegradation depending on the method of sterilization and the physiological solution used.Results: With different sterilization techniques, it may be possible to keep toxicological effects to a minimum while still ensuring a balance between the integrity of fractured bone and implant degradation time. Therefore, the evaluation of fatigue resistance of WE43 specimens sterilized and tested in immersion conditions (enriched Hank's solution) and according to ASTM F-1264, along with the morphological, crystallinity, and biocompatibility characterization of the WE43 alloy allows for a comprehensive evaluation of the mechanical and biological properties of WE43. Conclusions: These results will support decision-making to generate a change in the current perspective of biomaterials utilized in medical devices (MDs), to be considered by manufacturers and health regulatory agencies. An implant manufactured in WE43 alloy can be used as an intramedullary implant, considering keeping elements such as yttrium-REEs below as specified in its designation and with the help of a coating that allows increasing the life of the implant in vivo.

scholarly journals Toxicologic Pathology Forum Opinion Paper: Considerations for Toxicologic Pathologists Evaluating the Safety of Biomaterials and Finished Medical Devices

2018 ◽  
Vol 46 (4) ◽  
pp. 366-371 ◽  
Author(s):  
Shayne C. Gad ◽  
JoAnn C. L. Schuh
Keyword(s):  
Medical Devices ◽  
New Technologies ◽  
Safety Evaluation ◽  
Foreign Body Response ◽  
The Body ◽  
Target Organs ◽  
Tissue Responses ◽  
Dose Control ◽  
Composition Structure

Safety (“biocompatibility”) assessment of medical devices has evolved along a different path than that of drugs, being historically governed more by the considerations and needs of engineers rather than chemists and biologists. As a result, the involvement of veterinary pathologists has been much more limited—almost entirely to evaluating tissue responses in tissues in direct contact with implanted devices. As devices have become more complex in composition, structure, placement, and use, concerns as to adverse systemic responses in patients have called for more comprehensive and thoughtful evaluations of effects throughout the body. Further complexities arise from the increasing marriage of devices and drug/biologic therapeutics to achieve either better dose control and, specifically, in delivery to target organs/tissues or better tolerance of the body to medical devices (i.e., minimization of the foreign body response). The challenge to pathologists is to integrate in new technologies (such as in vivo imaging and immunology) and ways of viewing interactions with patient bodies. To fail to do so will allow the methods and standards for medical device safety evaluation to be based on chemical analysis and then the limited details inherent in literature-based risk assessments.

scholarly journals Toxic Effects of Di-2-ethylhexyl Phthalate: An Overview

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Sai Sandeep Singh Rowdhwal ◽  
Jiaxiang Chen
Keyword(s):  
Animal Models ◽  
Human Health ◽  
Waste Disposal ◽  
Medical Devices ◽  
Daily Basis ◽  
The Body ◽  
Repeated Use ◽  
Ethylhexyl Phthalate

Di-2-ethylhexyl phthalate (DEHP) is extensively used as a plasticizer in many products, especially medical devices, furniture materials, cosmetics, and personal care products. DEHP is noncovalently bound to plastics, and therefore, it will leach out of these products after repeated use, heating, and/or cleaning of the products. Due to the overuse of DEHP in many products, it enters and pollutes the environment through release from industrial settings and plastic waste disposal sites. DEHP can enter the body through inhalation, ingestion, and dermal contact on a daily basis, which has raised some concerns about its safety and its potential effects on human health. The main aim of this review is to give an overview of the endocrine, testicular, ovarian, neural, hepatotoxic, and cardiotoxic effects of DEHP on animal models and humansin vitroandin vivo.

scholarly journals Challenges for the Implantation of Symbiotic Nanostructured Medical Devices

2020 ◽  
Vol 10 (8) ◽  
pp. 2923 ◽  
Author(s):  
Jean-Pierre Alcaraz ◽  
Gauthier Menassol ◽  
Géraldine Penven ◽  
Jacques Thélu ◽  
Sarra El Ichi ◽  
...  
Keyword(s):  
Medical Device ◽  
Medical Devices ◽  
The Body ◽  
Biofuel Cells ◽  
Implantable Medical Devices ◽  
Enzymatic Biofuel Cells ◽  
Starting Point ◽  
Implanted Medical Devices ◽  
Biomimetic Approach ◽  
Implanted Device

We discuss the perspectives of designing implantable medical devices that have the criterion of being symbiotic. Our starting point was whether the implanted device is intended to have any two-way (“duplex”) communication of energy or materials with the body. Such duplex communication extends the existing concepts of a biomaterial and biocompatibility to include the notion that it is important to consider the intended functional use of the implanted medical device. This demands a biomimetic approach to design functional symbiotic implantable medical devices that can be more efficient in mimicking what is happening at the molecular and cellular levels to create stable interfaces that allow for the unfettered exchanges of molecules between an implanted device and a body. Such a duplex level of communication is considered to be a necessary characteristic of symbiotic implanted medical devices that are designed to function for long periods of time inside the body to restore and assist the function of the body. We illustrate these perspectives with experience gained from implanting functional enzymatic biofuel cells.

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