Recent developments in functional organic polymer coatings for biomedical applications in implanted devices

Organic polymer coatings have been commonly used in biomedical field,which play an important role in achieving biological antifouling,drug delivery,and bacteriostasis.With the continuous development of polymer science,organic polymer coatings can be designed with complex and advanced functions,which is conducive to the construction of biomedical materials with different performances.According to different physical and chemical properties of materials,biomedical organic polymer coating materials are classified into zwitterionic polymers,non-ionic polymers,and biomacromolecules.The strategies of combining coatings with substrates include physical adsorption,chemical grafting,and self-adhesion.Though the coating materials and construction methods are different,many biomedical polymer coatings have been developed to achieve excellent performances,i.e.,enhanced lubrication,anti-inflammation,antifouling,antibacterial,drug release,anti-encrustation,anti-thrombosis,etc.Consequently,a large number of biomedical polymer coatings have been used in artificial lungs,ureteral stent,vascular flow diverter,and artificial joints.In this review,we summarize different types,properties,construction methods,biological functions,and clinical applications of biomedical organic polymer coatings,and prospect future direction for development of organic polymer coatings in biomedical field.It is anticipated that this review can be useful for the design and synthesis of functional organic polymer coatings with various biomedical purposes.

Expert consensus on the clinical application of totally implantable venous access devices in the upper arm(2022 Edition)

With the widespread adoption of ultrasound guidance,Seldinger puncture techniques,and intracardiac electrical positioning technology for the placement of peripherally inserted central catheters in recent years,an increasing number of medical staff and patients now accept peripheral placement of totally implantable venous access devices(TIVADs)in the upper arm.This approach has the advantage of completely avoiding the risks of hemothorax,pneumothorax,and neck and chest scarring.Medical specialties presently engaged in this study in China include internal medicine,surgery,anesthesiology,and interventional departments.However,command over implantation techniques,treatment of complications,and proper use and maintenance of TIVAD remain uneven among different medical units.Moreover,currently,there are no established quality control standards for implantation techniques or specifications for handling complications.Thus,this expert consensus is proposed to improve the success rate of TIVAD implantation via the upper-arm approach,reduce complication rates,and ensure patient safety.This consensus elaborates on the technical indications and contraindications,procedures and technical points,treatment of complications,and the use and maintenance of upper-arm TIVAD,thus providing a practical reference for medical staff.

Geriatric issues in patients with or being considered for implanted cardiac rhythm devices: a case-based review

1 Introduction Virtually all cardiovascular diseases including arrhythmias,valve disease,coronary artery disease and heart failure(HF)are increasingly common with advancing age.^([1])Age and disease-related changes in the heart including fibrosis in the atrial and ventricular myocardium and conduction system,scar tissue from myocardial infarction or other cardiomyopathic processes,increased inflammatory cytokines and changes to ion channels are just some of the factors that predispose older adults to arrhythmias.^([2]).

Gut-targeted therapies for type 2 diabetes mellitus: A review

Type 2 diabetes mellitus(T2DM)is a chronic metabolic disorder characterized by hyperglycemia and insulin resistance.The global prevalence of T2DM has reached epidemic proportions,affecting approximately 463 million adults worldwide in 2019.Current treatments for T2DM include lifestyle modifications,oral antidiabetic agents,and insulin therapy.However,these therapies may carry side effects and fail to achieve optimal glycemic control in some patients.Therefore,there is a growing interest in the role of gut microbiota and more gut-targeted therapies in the management of T2DM.The gut microbiota,which refers to the community of microorganisms that inhabit the human gut,has been shown to play a crucial role in the regulation of glucose metabolism and insulin sensitivity.Alterations in gut microbiota composition and diversity have been observed in T2DM patients,with a reduction in beneficial bacteria and an increase in pathogenic bacteria.This dysbiosis may contribute to the pathogenesis of the disease by promoting inflammation and impairing gut barrier function.Several gut-targeted therapies have been developed to modulate the gut microbiota and improve glycemic control in T2DM.One potential approach is the use of probio-tics,which are live microorganisms that confer health benefits to the host when administered in adequate amounts.Several randomized controlled trials have demonstrated that certain probiotics,such as Lactobacillus and Bifidobacterium species,can improve glycemic control and insulin sensitivity in T2DM patients.Mechanisms may include the production of short-chain fatty acids,the improvement of gut barrier function,and the reduction of inflammation.Another gut-targeted therapy is fecal microbiota transplantation(FMT),which involves the transfer of fecal material from a healthy donor to a recipient.FMT has been used successfully in the treatment of Clostridioides difficile infection and is now being investigated as a potential therapy for T2DM.A recent randomized controlled trial showed that FMT from lean donors improved glucose metabolism and insulin sensitivity in T2DM patients with obesity.However,FMT carries potential risks,including transmission of infectious agents and alterations in the recipient's gut microbiota that may be undesirable.In addition to probiotics and FMT,other gut-targeted therapies are being investigated for the management of T2DM,such as prebiotics,synbiotics,and postbiotics.Prebiotics are dietary fibers that promote the growth of beneficial gut bacteria,while synbiotics combine probiotics and prebiotics.Postbiotics refer to the metabolic products of probiotics that may have beneficial effects on the host.The NIH SPARC program,or the Stimulating Peripheral Activity to Relieve Conditions,is a research initiative aimed at developing new therapies for a variety of health conditions,including T2DM.The SPARC program focuses on using electrical stimulation to activate peripheral nerves and organs,in order to regulate glucose levels in the body.The goal of this approach is to develop targeted,non-invasive therapies that can help patients better manage their diabetes.One promising area of research within the SPARC program is the use of electrical stimulation to activate the vagus nerve,which plays an important role in regulating glucose metabolism.Studies have shown that vagus nerve stimulation can improve insulin sensitivity and lower blood glucose levels in patients with T2DM.Gut-targeted therapies,such as probiotics and FMT,have shown potential for improving glycemic control and insulin sensitivity in T2DM patients.However,further research is needed to determine the optimal dose,duration,and safety of these therapies.

Glaucoma drainage device implantation and cyclophotocoagulation in the management of refractory glaucoma after Descemet-stripping automated endothelial keratoplasty

AIM:To compare the surgical outcomes of glaucoma drainage device implantation(GDI)and trans-scleral neodymium:YAG cyclophotocoagulation(CPC)in the management of refractory glaucoma after Descemetstripping automated endothelial keratoplasty(DSAEK).METHODS:This retrospective study on observational case series enrolled 29 patients who underwent DSAEK and posterior anti-glaucoma surgery(15 with GDI and 14 with CPC).The main outcome measures were intraocular pressure(IOP),glaucoma surgery success rate(defined as IOP of 6–21 mm Hg without additional anti-glaucoma operation),number of glaucoma medications,endothelial graft status,and best-corrected visual acuity(BCVA).RESULTS:The mean follow-up time was 34.1 and 21.0mo for DSAEK or glaucoma surgeries,both for the GDI and CPC groups.Both groups showed significant IOP reduction after glaucoma surgery.The GDI group presented a significantly higher success rate in IOP control than the CPC group(60%vs 21.4%,P=0.03).Both procedures significantly decreased the number of glaucoma medications(P=0.03).Forty percent and 57%of cases in the GDI and the CPC group,respectively,experienced endothelial graft failure during follow-up(P=0.36).Significantly worse BCVA after surgery was observed in the CPC group but not in the GDI group.CONCLUSION:Both GDI and CPC significantly decrease IOP in eyes with glaucoma after DSAEK.GDI is preferable to CPC in refractory glaucoma cases after DSAEK,as it manifests a significantly higher success rate for IOP control,similar endothelial graft failure rate,and relatively preserves BCVA than CPC.

Design of Floating Mass Type Piezoelectric Actuator for Implantable Middle Ear Hearing Devices

To overcome some of the problems inherent in conventional heating aids such as low gain at high fi＇equencies due to acoustic feedback, discomfort in occlusion of the extemal ear canal and so on, implantable middle ear hearing devices （IMEHDs） have been developed over the past two decades. For such kinds of IMEHDs, this paper presents the design of a floating mass piezoelectric actuator using a PMN-30%PT stack as a new type of vibrator. The proposed piezoelectric actuator consists of only three components of a piezoelectric stack, a metal case and a clamp. For the purpose of aiding the design of this actuator, a coupling biomechanics model of human middle ear and the piezoelectric actuator was constructed. This model was built based on a complete set of computerized tomography section images of a healthy volunteer＇s left ear by reverse engineering technology. The validity of this model was confirmed by comparing the motion of the tympanic membrane and stapes footplate obtained by this model with published experimental measurements on human temporal bones. It is shown that the designed actuator can be implanted on the incus long process by a simple surgical operation, and the stapes footplate displacement by its excitation at 10.5 V root-mean-square（RMS） voltage was equivalent to that from acoustic stimulation at 100 dB sound pressure level（SPL）, which is adequate stimulation to the ossicular chain. The corresponding power consumption is 0.04 mW per volt of excitation at 1 kHz, which is low enough for the transducer to be used in an implantable middle ear device.

Volume conduction energy transfer for implantable devices

A common model of power supply for implantable devices was established to study factors affecting volume conduction energy transfer. Electromagnetic and equivalent circuit models were constructed to study the effect of separation between the source electrode pairs on volume conduction energy transfer. In addition, the parameters of external signal including waveform, amplitude and frequency were analyzed. As the current amplitude did not lead to tissue injury and the current frequency did not cause nerve excitability, the recommended separation be- tween the source electrodes was 3 cm, the proposed waveform of signal source was sinusoidal wave and the opti- mal frequency was 200 KHz. In agar experiment and swine skin experiment, the current transfer efficiencies were 28.13% and 20.65%, respectively, and the energy transfer efficiencies were 9.86% and 6.90%, respectively. In conclusion, we can achieve optimal efficiency of energy transfer by appropriately setting the separation between the source electrode parameters of the signal source.

Effects of medically generated electromagnetic interference from medical devices on cardiac implantable electronic devices: A review

As cardiac implantable electronic devices(CIED)become more prevalent,it is important to acknowledge potential electromagnetic interference(EMI)from other sources,such as internal and external electronic devices and procedures and its effect on these devices.EMI from other sources can potentially inhibit pacing and trigger shocks in permanent pacemakers(PPM)and implantable cardioverter defibrillators(ICD),respectively.This review analyzes potential EMI amongst CIED and left ventricular assist device,deep brain stimulators,spinal cord stimulators,transcutaneous electrical nerve stimulators,and throughout an array of procedures,such as endoscopy,bronchoscopy,and procedures involving electrocautery.Although there is evidence to support EMI from internal and external devices and during procedures,there is a lack of large multicenter studies,and,as a result,current management guidelines are based primarily on expert opinion and anecdotal experience.We aim to provide a general overview of PPM/ICD function,review documented EMI effect on these devices,and acknowledge current management of CIED interference.

Clinical Course of Lung Cancer Patients with Subcutaneously Implanted Central Venous Access Device Ports from the Time of Receiving Chemotherapy to the Endpoint of Cancer

Background: As the prognosis of lung cancer (LC) patients improves, subcutaneously implanted central venous access device ports (CV-ports) have frequently been used for continuing chemotherapy (CC) or palliative care (PC). In this study, we examined the clinical course of LC patients with subcutaneously implanted CV-ports from the time of receiving chemotherapy to the endpoint of cancer. Materials and Methods: We retrospectively reviewed the clinical data and treatment history of LC patients with subcutaneously implanted CV-ports between June 2008 and November 2013 using clinical records and a pharmacy database. Results: Of the 132 LC patients with subcutaneously implanted CV-ports, 79 (59.8%) had CV-ports for CC (the CC group) and 53 (40.2%) had CV-ports for PC (the PC group). After CV-port implantation, LC patients in the CC group received a median of two regimens with a median of 6 cycles. The median survival time of patients in the CC and PC groups was 457 and 44 days, respectively. In the CC group, the median survival time of small cell and non-small cell LC patients was 342 (95% confidence interval, 235 - 627) and 563 (95% confidence interval, 368 - 728) days, respectively. Nine patients (6.8%) had their CV-ports removed due to complications. Forty (30.3%) of the 132 enrolled patients were referred for at-home PC. The at-home death rate observed among these 40 patients was 30.0% (N = 12). Conclusion: CV-ports may contribute to seamless oncological care.

Self-powered and self-sensing devices based on piezoelectric energy harvesting

Wearable devices,interactive human-machine interface equipment,wireless sensors,and small-scale cleaning devices play crucial roles in biomedical implantation,disease treatment,health monitoring,environmental purification,etc.These devices require a sustainable energy source to work effectively.With the consideration of the global energy crisis and environmental pollution,researchers are exploring new,stable,and environmentally friendly methods to power these low-powered devices.Mechanical energy is one of the most abundant natural energy sources.Converting mechanical energy from the ambient environment or host structures into electrical energy via the direct piezoelectric effect is an efficient energy harvesting technique.This paper reviews the application of advanced piezoelectric materials,and small-scale self-powered and self-sensing piezoelectric devices at the cubic centimeter scale in energy harvesting and health monitoring of human,animal,machinery,roads,bridges,as well as the pollutant degradation of the environment.Some of these devices have the capability to not only harvest mechanical energy but also enable real-time monitoring and analysis of the electrical signals generated by the direct piezoelectric effect,facilitating prompt decision-making and appropriate responses.In addition,potential challenges and future prospects of small-scale self-powered and self-sensing piezoelectric devices are discussed.

Materials advancements for the safety and patency of implantable cardiovascular devices

Implantable cardiovascular devices have revolutionized the management of cardiovascular diseases,significantly enhancing patients’quality of life.With the increasing demand of cardiac implantable electronic devices,the imperative for novel device development is evident.This review article first elaborates the mechanisms underlying foreign body response and infection,elucidating the complex interplay between implanted constructs and host tissues.The discussion then focuses on current advancements in materials science and engineering aimed at mitigating these challenges.Material innovations,such as drugeluting materials,surface modifications,and biomimetic materials,are explored as strategies to modulate these responses and to prevent fibrotic or thrombotic complications and infection.Finally,future directions in materials development for implantable cardiovascular devices are introduced.By addressing safety and patency concerns through innovative material strategies,this article aims to guide the research and development of advanced materials for both current and future cardiovascular implantable devices,ultimately improving patient outcomes and advancing cardiovascular disease treatment.

The gender difference of utilization of cardiac implantable electronic device in China： data from Arrhythmia Interventional Therapy Data Registry

Background Cardiac implantable electronic devices （CIEDs） greatly improve survival and life quality of patients. However, there are gender differences regarding both the utilization and benefit of these devices. In this prospective CIED registry, we aim to appraise the gender differences in CIED utilization in China. Methods Twenty centers from 14 provinces in China were included in our registry study. All patients who underwent a CIED implantation in these twenty centers between Jan 2015 and Dec 2016 were included. Results A total of 8570 patients were enrolled in the baseline cohort, including 7203 pacemaker, 664 implantable cardiac defibrillators （ICD） implants and 703 cardiac resynchronization therapy device （CRT/D）. Totally, 4117 （48.0%） CIED patients were female, and more than 59% pacemaker patients were female, but women account only one third of ICD or CRT/D implantation in this registry. There were significant differences between genders at pacemaker and ICD indications. Female was more likely received a pacemaker due to sick sinus syndrome （SSS） （63.9% vs. 51.0%, P 〈 0.001）. Female patients receiving an ICD were more likely due to cardiac ion channel disease （29.2% vs. 4.2%, P 〈 0.001）. The percentage of utilization of dual-chamber pacemaker in female patients was significantly higher than male （85.3% vs. 81.1%, P 〈 0.001）. But male patients were more likely received a cardiac resynchronization therapy devices with defibrillator than female （56.5% vs. 41.9%, P = 0.001）. In pacemaker patient, male was more likely to have structure heart disease （31.3% vs. 28.0%, P = 0.002）. In ICD patient, male patients were more likely to have ischemic heart disease （48.2% vs. 29.2%, P 〈 0.001）. The mean age of women at the time of CRT/D implantation was older than men （P = 0.014）. Nonischemic cardiomyopathy （70.9%） was the most common etiology in the patients who underwent the treat？ment of CRT/D, no matter male or female. Conclusions In real-world setting, female do have different epidemiology, pathophysiology and clinical presentation of many cardiac rhythm disorders when compared with male, and all these factors may affect the utilization of CIED implantation. But it also possibility that cultural and socioeconomic features may play a role in this apparent discrimination.

Recent Techniques for Harvesting Energy from the Human Body

The human body contains a near-infinite supply of energy in chemical,thermal,and mechanical forms.However,the majority of implantable and wear-able devices are still operated by batteries,whose insufficient capacity and large size limit their lifespan and increase the risk of hazardous material leakage.Such energy can be used to exceed the battery power limits of implantable and wear-able devices.Moreover,novel materials and fabrication methods can be used to create various medical therapies and life-enhancing technologies.This review paper focuses on energy-harvesting technologies used in medical and health applications,primarily power collectors from the human body.Current approaches to energy harvesting from the bodies of living subjects for self-powered electronics are summarized.Using the human body as an energy source encompasses numer-ous topics:thermoelectric generators,power harvesting by kinetic energy,cardi-ovascular energy harvesting,and blood pressure.The review considers various perspectives on future research,which can provide a new forum for advancing new technologies for the diagnosis,treatment,and prevention of diseases by integrating different energy harvesters with advanced electronics.

A bio-instructive parylene-based conformal coating suppresses thrombosis and intimal hyperplasia of implantable vascular devices

Implantable vascular devices are widely used in clinical treatments for various vascular diseases. However, current approved clinical implantable vascular devices generally have high failure rates primarily due to their surface lacking inherent functional endothelium. Here, inspired by the pathological mechanisms of vascular device failure and physiological functions of native endothelium, we developed a new generation of bioactive parylene (poly(p-xylylene))-based conformal coating to address these challenges of the vascular devices. This coating used a polyethylene glycol (PEG) linker to introduce an endothelial progenitor cell (EPC) specific binding ligand LXW7 (cGRGDdvc) onto the vascular devices for preventing platelet adhesion and selectively capturing endogenous EPCs. Also, we confirmed the long-term stability and function of this coating in human serum. Using two vascular disease-related large animal models, a porcine carotid artery interposition model and a porcine carotid artery-jugular vein arteriovenous graft model, we demonstrated that this coating enabled rapid generation of self-renewable “living” endothelium on the blood contacting surface of the expanded polytetrafluoroethylene (ePTFE) grafts after implantation. We expect this easy-to-apply conformal coating will present a promising avenue to engineer surface properties of “off-the-shelf” implantable vascular devices for long-lasting performance in the clinical settings.

Re-evaluation of Transvenous Lead Extraction with Modified Standard Technique: A Prospective Study in 229 Patients

As new-type powered sheaths are expensive and unavailable, the standard lead extraction techniques remain the mainstay in clinical applications in many countries. The purpose of this study was to re-evaluate the clinical application of the standard lead extraction techniques and equipment, and make some procedural modifications and innovations. In our center, between January 2006 and May 2012, 229 patients （median, 66 years） who underwent lead extraction due to infection and lead malfunc- tion were registered and followed up prospectively with respect to clinical features, reasons for lead ex- traction, technical characteristics, and clinical prognosis. A total of 440 leads had to be extracted trans- venously by using special tools from 229 patients （male, 72.1%）. Vegetations 〉1 cm were detected in six patients. Locking Stylets were applied for 398 （90.5%） leads. Telescoping dilator polypropylene sheaths and counter traction technique were used for 202 （45.9%） leads due to lead adhesion, and the mean im- plant duration of the 202 leads was longer than the other 238 leads （48.9±22.6 vs. 26.6±17.8 months; P 〈0.01）. In addition, modified isolation and snare techniques were used for 56 leads （12.7%）. Minor and major procedure-related complications occurred in three （1.3%） and four （1.7%） cases respectively, in- cluding one death （0.4%）. Severe lead residue occurred in one case. Complete procedural success rate was 96.1% （423/440）, and clinical success rate was 98.9% （435/440）. The median follow-up period was 18 （1-76） months. No infection- and procedure-related death occurred in our series. Our data demon- strated that high clinical success rate of transvenous lead extraction can be guaranteed by making full use of the standard lead extraction techniques and equipment with individualized modifications.

CIED implantation in elderly patients： a single-center experience

Thanks to the development of new medical technologies and improvement in medical care the last decades are characterized by the growth of elderly＇s number. The median age of the world＇s population is increasing because of a decline in birth rates and a 20-year increase in the average life span during the second half of the 20th century.

Remote monitoring of implantable cardioverters defibrillators:a comparison of acceptance between octogenarians and younger patients

Background Remote monitoring(RM)is increasingly employed for all types of cardiac implantable devices(CIED).However,there are only limited data on the acceptance of RM by the elderly.The aim of our study was to ascertain how octogenarians assess RM technologies compared to younger,presumably technically more literate patients,and what concerns or technical problems the system presents to both groups of patients.Methods The trial was designed as a descriptive,register-based single-center study.The study population consisted of all consecutive patients≥80 years of age(group A,n=94)and all consecutive patients aged≤40 years(group B,n=71),who had undergone implantation of an implantable cardioverter-defibrillator(ICD)between the years of 2009 and 2018 and were using a Home Monitoring?(HM,Biotronik,Berlin,Germany)system.All patients fulfilling entry criteria were approached with a request to participate in the survey.Results A total of 85(90.4%)and 65(91.5%)valid surveys were obtained for groups A and B,respectively.Ninety-two percent of patients in both groups(P=0.903)were satisfied with the limited number of planned ambulatory follow-ups(i.e.,once a year).All patients in both groups(100%)reported that they were satisfied with the HM system,and 97%and 94%of patients in Groups A and B,respectively,ranked it highly beneficial(P=0.68).A significant proportion of patients in both groups were completely unaware of any health-related benefits associated with the use of the HM system(42%in Group A vs.49%in Group B,P=0.4).Among the most frequently reported personal benefits of HM were a sense of safety and security and savings on travel expenses and time.5%and 9%of patients in Groups A and B,respectively,reported that usage of HM caused them some degree of psychological stress(P=0.27).Nearly all patients in both groups reported receiving information on HM from their doctor after ICD implantation.None of Group A reported receiving information from a nurse either before or after ICD implantation,while 14%of Group B patients reported receiving information from a nurse after,but not before ICD implantation.Seven and 51%(P<0.0001)of patients in Group A and B,respectively,sought additional information about HM post-discharge.Conclusions The HM system received good marks and was much appreciated,even in patients over 80 years of age.The level of acceptance and potential psychological stress resulting from RM technology appears to be about the same in older patients as in younger patients.The majority of octogenarians either did not fully understand the clinical benefits of the system or mistakenly thought that the HM system was a substitute for emergency 24-h surveillance.These results highlight the need for better patient education relative to RM technology,with one option being to delegate more of this educational process to specially trained nurses.

Risk profiles and outcomes of patients receiving antibacterial cardiovascular implantable electronic device envelopes:A retrospective analysis

BACKGROUND Cardiovascular implantable electronic devices(CIEDs)are implanted in an increasing number of patients each year,which has led to an increase in the risk of CIED infection.Antibacterial CIED envelopes locally deliver antibiotics to the implant site over a short-term period and have been shown to reduce the risk of implant site infection.These envelopes are derived from either biologic or nonbiologic materials.There is a paucity of data examining patient risk profiles and outcomes from using these envelope materials in the clinical setting and comparing these results to patients receiving no envelope with their CIED implantation.AIM To evaluate risk profiles and outcomes of patients who underwent CIED procedures with an antibacterial envelope or no envelope.METHODS After obtaining Internal Review Board approval,the records of consecutive patients who underwent a CIED implantation procedure by a single physician between March 2017 and December 2019 were retrospectively collected from our hospital.A total of 248 patients within this period were identified and reviewed through 12 mo of follow up.The CIED procedures used either no envelope(n=57),a biologic envelope(CanGaroo®,Aziyo Biologics)that was pre-hydrated by the physician with vancomycin and gentamicin(n=89),or a non-biologic envelope(Tyrx^(TM),Medtronic)that was coated with a resorbable polymer containing the drug substances rifampin and minocycline by the manufacturer(n=102).Patient selection for receiving either no envelope or an envelope(and which envelope to use)was determined by the treating physician.Statistical analyses were performed between the 3 groups(CanGaroo,Tyrx,and no envelope),and also between the No Envelope and Any Envelope groups by an independent,experienced biostatistician.RESULTS On average,patients who received any envelope(biologic or non-biologic)were younger(70.7±14.0 vs 74.9±10.6,P=0.017),had a greater number of infection risk factors(81.2%vs 49.1%,P<0.001),received more high-powered devices(37.2%vs 5.8%,P=0.004),and were undergoing more reoperative procedures(47.1%vs 0.0%,P<0.001)than patients who received no envelope.Between the two envelopes,biologic envelopes tended to be used more often in higher risk patients(84.3%vs 78.4%)and reoperative procedures(62.9%vs 33.3%)than non-biologic envelopes.The rate of CIED implant site pocket infection was low(any envelope 0.5%vs no envelope 0.0%)and was statistically equivalent between the two envelope groups.Other reported adverse events(lead dislodgement,lead or pocket revision,device migration or erosion,twiddler’s syndrome,and erythema/fever)were low and statistically equivalent between groups(biologic 2.2%,non-biologic 3.9%,no envelope 1.8%).CONCLUSION CIED infection rates for biologic and non-biologic antibacterial envelopes are similar.Antibacterial envelopes may benefit patients who are higher risk for infection,however additional studies are warranted to confirm this.

Optimization of Bio-Implantable Power Transmission Efficiency Based on Input Impedance

Recently,the inductive coupling link is the most robust method for powering implanted biomedical devices,such as micro-system stimulators,cochlear implants,and retinal implants.This research provides a novel theoretical and mathematical analysis to optimize the inductive coupling link efficiency driven by efficient proposed class-E power amplifiers using high and optimum input impedance.The design of the coupling link is based on two pairs of aligned,single-layer,planar spiral circular coils with a proposed geometric dimension,operating at a resonant frequency of 13.56 MHz.Both transmitter and receiver coils are small in size.Implanted device resistance varies from 200Ωto 500Ωwith 50Ωof stepes.When the conventional load resistance of power amplifiers is 50Ω,the efficiency is 45%;when the optimum resonant load is 41.89Ωwith a coupling coefficient of 0.087,the efficiency increases to 49%.The efficiency optimization is reached by calculating the matching network for the external LC tank of the transmitter coil.The proposed design may be suitable for active implantable devices.

Feasibility of a Chronic Foreign Body Infection Model Studying the Influence of TiO2 Nanotube Layers on Bacterial Contamination

Bacterial infections on the surface of medical devices are a significant problem in therapeutic approach, especially when implants are used in the living. In cardiology, pacemaker generator pocket surfaces, made in titanium alloy can be colonized by pathogen microorganism. This contamination represents a major risk of sepsis, endocarditis and localized infections for patients. A way to limit this bacterial contamination is to modify the surface topography using nano-structuration process of the titanium alloy surface of the implanted devices. The aim of this study is to evaluate the influence of TiO2 nanotube layers on bacterial infection in the living, considering the feasibility of an animal model of chronic foreign body infection. TiO2 nanotube layers prepared by electrochemical anodization of Ti foil in 0.4 wt% hydrofluoric acid solution were implanted subcutaneously in Wistar rats. Three weeks after implantation, TiO2 implants were contaminated by a Staphylococcus epidermilis strain using two different concentrations at 106 and 108 colony forming unit (CFU) in order to induce a sufficient infection level and to avoid unwanted over infection consequences on rats health during the experiments. After 28 days in the living, 75% of nanotube layers initially submitted to the 108 CFU inoculum were contaminated while only 25% nanotube layers initially submitted to the 106 CFU inoculum remained infected. This significant result underlines the influence of TiO2 nanotube layers in decreasing the infection level. Our in vitro experiments showed that the synthesized TiO2 nanotubes indeed decreased the Staphylococcus epidermilis adhesion compared to unanodized Ti foil.