Field Of Implantable Medical Devices Research Articles

Advancements in Biocompatible Materials for Enhanced Medical Implants

The incessant evolution of implantable medical devices necessitates parallel advancements in biocompatible materials to ensure optimal compatibility with the complex physiological milieu. This research addresses the critical need for improved biocompatible materials by exploring novel compositions and fabrication techniques. The study aims to enhance the performance and longevity of implantable medical devices, mitigating adverse tissue responses and fostering seamless integration within the biological system. Employing advanced material science principles, the investigation seeks to unravel the intricacies of biocompatibility, focusing on cellular response, inflammation, and long-term stability. The outcome promises to propel the field of implantable medical devices by contributing robust materials that transcend current limitations, fostering safer and more efficacious biomedical interventions.

Application of Medical Implants for Public Health Monitoring and Treatment

The World Health Organisation (WHO) reports that diabetes affects roughly 180 million people worldwide and that cardiovascular illnesses account for nearly 30% of all fatalities worldwide. Applications involving radio frequency (RF) or microwave technology are crucial to medical diagnosis and illness prevention. The most recent developments in the field of implantable medical devices (IMDs), such as biomedical telemetry, allow biosignals to be monitored remotely via wireless communication technology. Providing correct information to the external monitoring station is the primary function of the health maintenance monitoring scheme. Because wireless communication lessens the invasiveness of electromagnetic (EM) medical equipment, it is extremely helpful in improving patient comfort during treatment. The first swallowable pills with sensing capabilities and the introduction of pacemakers in the early 1960s both demonstrated the significance of implantable medical devices (IMDs), which enable disease monitoring and therapy. Using IMDs with wireless connection has allowed for the monitoring of both system performance and patient status. IMDs have been widely employed in healthcare systems to gather real-time signals from biosensors or preprocessed physiological bio-signals for early disease identification, improving treatment quality and promoting healthy living.

Determining carrier frequency for implantable human body communication based on transmission efficiency–electromagnetic interference trade-off

This study proposes a novel methodology for determining the optimal carrier frequency for implantable human body communication (HBC) by focusing on the trade-off between transmission efficiency and electromagnetic interference (EMI) robustness. Traditional radio communication technologies use high-frequency bands, which pose some challenges, such as increased power consumption, EMI with other devices, and security risks. Implantable HBC is a promising alternative, wherein the human body is used as a transmission medium. Through phantom experiments simulating the human abdomen, we assess the transmission characteristics of implantable HBC between an abdominal neurostimulator and an external controller across a frequency range of 1–100 MHz. Results revealed that maximum transmission gain was achieved at 37.2 MHz. Moreover, rapid signal attenuation occurred beyond a minimal distance from the skin, indicating enhanced communication efficiency, reduced EMI, and enhanced information security. An evaluation index (EI) was also proposed to quantitatively assess the balance between transmission efficiency and EMI and determine an appropriate carrier frequency for specific implantable HBC applications. This study advances the field of implantable medical devices by optimizing communication performance while addressing key challenges in EMI and security.

Analyzing the Trends and Global Growth of Energy Harvesting for Implantable Medical Devices (IMDs) Research—A Bibliometric Approach

Implantable medical devices (IMDs) play a crucial role in improving individuals’ well-being and ensuring their safety by providing real-time health data monitoring for recovery. The use of energy harvesting (EH) technology has become increasingly popular among researchers because it offers the potential to extend the battery life of IMDs and reduce their weight. This study successfully examined the expansion of EH in the field of IMDs, the distribution of publications across different countries, and the identification of the most influential authors for potential research collaborations. A bibliometric analysis was conducted to evaluate two metrics: performance and science mapping. Data was collected from the Scopus database from the initial publications until October 2023, encompassing 250 articles published in Englishlanguage journals. The titles, keywords, and abstracts of these publications were analyzed and interpreted using VOS Viewer (version 1.6.19). Furthermore, network analysis using VOS Viewer enabled the identification of key research clusters. The findings reveal a continuous increase in EH for research on infectious and parasitic diseases over the 15-year period from 2008 to 2023. The United States and the University of Bern are recognized as the leading contributors to this field, based on their country and institutional contributions, respectively. The author with the most published papers and citations hails from China. Additionally, this study identifies several opportunities for collaboration with countries, institutions, authors, and research hotspots in EH for IMDs that benefit the reader.

Metamaterial integrated highly efficient wireless power transfer system for implantable medical devices

In this article, a novel and highly efficient metamaterial (MTM) integrated approach is presented for the development of a wireless power transfer system (WPT) specifically tailored for implantable medical devices. The system is designed by using a biocompatible implantable ring slot antenna constructed on a flexible dielectric, functioning as a receiving (Rx) antenna. Additionally, a conventional patch antenna is modelled for the use in free space, serving as an external transmitting (Tx) element. By exploiting the unique characteristics of MTMs, the power transfer efficiency (PTE) of the introduced system is effectively improved. To ensure the system’s performance stability in real-time application scenario, the effects of misalignment (lateral and angular) and the flexibility of the implantable antenna are meticulously performed. The prototypes of the Tx, Rx, and MTM structures are fabricated, and comprehensive measurements are performed in human-equivalent tissue models, such as skin-mimicking gel and minced pork. Both the simulated and measured results established the proposed methodology, showcasing marked improvements in PTE due to the use of MTMs. The efficiency of the pioneering MTM-integrated WPT system increases from 0.19% to 3.07% in skin-mimicking gel and from 0.24% to 3.26% in minced pork, respectively. This study highlights the potential of MTM-integrated WPT systems in advancing the field of implantable medical devices and expanding their practical applicability.

Research Progress of Four-dimensional Hydrogels in Implantable Medical Devices

Four-dimensional (4D) printing is an emerging technology that combines science and engineering techniques. The term, "4D printing" was coined in 2013 and since then it has attracted a lot of interests due to its unique ability to have structural or functional transformations over time in response to external stimuli. The most important element of 4D printing is the responsive material. The recent progress research of hydrogels and related new technologies for 4D printing was summarized in the field of implanted medical devices at home and abroad in this paper. Then, it was pointed out the problems of responsive materials for 4D printing. Finally, it was prospected that the development of 4D printing technology in the field of implantable medical devices.

Construction of novel antimicrobial peptide-modified extracellular matrix biologic scaffold material

In the field of implantable medical devices, the antibacterial extracellular matrix (ECM) biologic scaffold, which is constructed by modifying biomaterials with antibacterial peptides, has excellent potential. An antibacterial peptide–modified ECM scaffold was formed with chitosan (CS), antimicrobial peptide (AMP), and ECM scaffold. Chitosan has a firm positive-charge surface and can combine with the ECM scaffold material to form a positive-charge layer on the surface. The surface potential was characterized using a surface potential map. Infrared spectroscopy and scanning electron microscopy (SEM) were used to observe the scaffold surface characteristics and cell morphology. Fluorescence staining and MTS assay kit were used to assess cytotoxicity and biocompatibility. To evaluate the antibacterial and repairing effects on the infected wounds in vivo, a subcutaneous antibacterial test of rabbit back was conducted. The antibacterial peptide–modified ECM scaffold was successfully formed and presented an excellent three-dimensional micro-surface porous structure. The antibacterial peptide–modified ECM scaffold could be effectively-prepared by surface modification and activation. Fluorescence staining tests showed good cell adhesion, proliferation ability, and cell affinity. The in vivo experiment indicated that the antibacterial ECM scaffold had antibacterial and healing-promotion abilities.

Bio-compatible bio-fuel cells for medical devices

Due to increasing human health disorders like diabetes, heart rate fluctuations, and different ocular complications, implantable medical devices (IMD) and wearable devices are continuously developed. These can be used not only in medical facilities but also at work stations and homes. The main focus is to develop comfortable and economical medical devices. For this, bio-compatible bio-fuel cells have been employed for power generation and to overcome the replacement issues. The category of bio-chemical and electrode reaction plays an important role to classify the fuel cells (FC). These may include an enzymatic biofuel cell (EBFC), precious metal FC or a microbial fuel cell (MFC). EBFC can be seen effectively applied to pacemakers and glucometers due to their high activity within mild conditions. However, the short life span is still a major challenge. In this review article, we have discussed the earlier researches in the field of implantable medical devices utilizing enzymes, precious metals, and microorganism as catalysts. Moreover, we have critically discussed various applications of FCs for in-vitro medical devices i.e. glucometer, alcohol testers, wound treatment device, and more. Safety is the foremost concern in these devices. Along with this, special attention has been given to recently developed optical contact lenses as an alternative to glucometers. The fuel cell implantations is at the early stages of testing and the results have been in the favor of commercializing these devices.

The role of magnesium ions in bone regeneration involves the canonical Wnt signaling pathway

Magnesium (Mg)-based implants have become of interest to both academia and the medical industry. The attraction largely is due to Mg’s biodegradability and ability to enhance bone healing and formation. However, the underlying mechanism of how Mg regulates osteogenesis is still unclear. Based on our previous in vivo and molecular signaling work demonstrating the osteogenic effect of Mg, the current study aims to extend this work at the molecular level especially that we also observed and quantified mineral deposits in the bone marrow space in a rabbit ulna fracture model with Mg plates and screws. Histological analysis and quantitative results of micro-CT showed mineralized deposition and a significant increase in bone volume at 8 weeks and 16 weeks post-operative. These in vivo results led us to focus on studying the effect of Mg2+ on human bone marrow stromal cells (hBMSCs). The data presented in this manuscript demonstrate the activation of the canonical Wnt signaling pathway in hBMSCs when treated with 10 mM Mg2+. With additional Mg2+ present, the protein expression of active β-catenin was significantly increased to a level similar to that of the positive control. Immunocytochemistry and the increased expression of LEF1 and Dkk1, downstream target genes that are controlled directly by active β-catenin, demonstrated the protein translocation and the activation of transcription. Taken together, these data suggest that Mg2+ induces an osteogenic effect in the bone marrow space by activating the canonical Wnt signaling pathway, which in turn causes BMSCs to differentiate toward the osteoblast lineage. Statement of SignificanceMagnesium (Mg)-based alloys are being studied to be used in the field of implantable medical devices due to its natural biodegradability and the potential ability to promote bone regeneration. Despite many in vivo studies that demonstrated an increased new bone growth by implanting Mg-based devices, the underlying mechanism of this effect is still unclear. In order to safely use Mg-based implants on human and better control the osteogenic effect, it is necessary to understand the corresponding cellular response in the targeted area. The present study provides the rationale to study Mg ions on bone marrow stromal cells and shows the activation of canonical Wnt signaling pathway that promotes osteogenesis by in vivo and in vitro approaches.

L-DOPA as a small molecule surrogate to promote angiogenesis and prevent dexamethasone-induced ischemia

The foreign body response to implantable biosensors has been successfully countered through the use of corticosteroids, such as dexamethasone. However, while controlling inflammation, dexamethasone also decreases angiogenesis, which may lead to delayed analyte readings. The concurrent application of VEGF with dexamethasone increases angiogenesis, but VEGF has physical stability issues and is not cost-effective. The use of l-DOPA, a small molecule drug shown to up-regulate VEGF in the Parkinsonian brain, can potentially resolve these issues by substituting for VEGF. In this work, l-DOPA was used for the first time as a pro-angiogenic agent to counteract dexamethasone-induced ischemia. Angiogenesis was modeled using the CAM assay and changes in blood vessel formation were recorded with both manual and digital techniques. As expected, dexamethasone reduced blood vessel formation in the CAM. Application of l-DOPA, on the other hand, increased blood vessel formation when dexamethasone and l-DOPA were administered simultaneously. This novel finding suggests the utility of l-DOPA in the field of implantable medical devices, such as biosensors, as well as tissue engineering applications where both a vascularized tissue environment and control of tissue response is desired.

Coupled Resonance Energy Transfer Over Gigahertz Frequency Range Using Ceramic Filled Cavity for Medical Implanted Sensors

A wireless power transmission (WPT) system based on a magnetically coupled coil-based resonance is the predominating technology in most WPT applications. In the field of implantable medical devices, however, the energy transfer operation is highly limited by the size of the receiver and also the loss properties of dispersive human tissue. Since the low gigahertz range has been considered as the optimal transfer frequency, an alternative to the lossy coil resonator should be studied and developed. In this paper, an original transmitter solution is presented that considers the needs for strong magnetic dominant near-field and weak far-field radiation even at low gigahertz frequency. A half-closed partially ceramic-filled cavity resonator is described on the basis of an accurate, but analytical model. Design parameters are also studied using a full-wave simulation software package and measurement results of a resonator-to-resonator transfer scheme are presented, which show a good agreement with simulation results. An efficiency above 65% can be obtained within the distance comparable to the diameter of the resonator (60.5 mm) in this case study. Subsequently, energy transmission between the proposed cavity resonator and a small-sized copper coil of 3 mm of diameter is investigated. Measurement results show that the efficiency is above 34% within 20 mm and above 8.2% within 40 mm, which is much higher than the conventional coil-to-coil transmission scheme.

A Review of Implantable Patch Antennas for Biomedical Telemetry: Challenges and Solutions [Wireless Corner

Biomedical telemetry permits the transmission (telemetering) of physiological signals at a distance. One of its latest developments is in the field of implantable medical devices (IMDs). Patch antennas currently are receiving significant scientific interest for integration into the implantable medical devices and radio-frequency (RF)-enabled biotelemetry, because of their high flexibility in design, conformability, and shape. The design of implantable patch antennas has gained considerable attention for dealing with issues related to biocompatibility, miniaturization, patient safety, improved quality of communication with exterior monitoring/control equipment, and insensitivity to detuning. Numerical and experimental investigations for implantable patch antennas are also highly intriguing. The objective of this paper is to provide an overview of these challenges, and discuss the ways in which they have been dealt with so far in the literature.