We fabricated a novel patch type flexible dry electrode for long-term bio signal monitoring by mixing carbon nanofibers (CNFs) in biocompatible-elastomer (MED6015). The CNFs are high conductivity, low price and easy dispersed in elastomer uniformly related with CNTs (Carbon nanotubes). The fabricated CNFs electrodes are coated with sticky elastomer (MG7-9850) to attach on skins without any other adhesive. The mixing ratio of CNFs and elastomer is diverse to compare electrical and mechanical characteristics. ECG (Electrocardiography) signal quality, sweat effects and motion effects are evaluated and the fabricated electrode was shown good quality of signals and tolerant from both effects. Also the electrode was shown to be biocompatible from biocompatibility test. These electrodes could be used for the long-term measurement of bio potential monitoring and wearable devices.

Electrodes should be adhered onto the body steadily under motion, and implanted stably into the tissue without any damages while maintaining conformal contact. Although most electrodes are fabricated with biocompatible materials, they should be shielded from tissues to prevent mechanical delamination from the device itself and to avoid adverse effects such as irritation, allergic reactions, or inflammation. Herein, we demonstrate a simple process for the development of a flexible and implantable capacitive electrode based on a minimal incision accessible design with polyimide (PI) and Gold/Titanium (Au/Ti) layers and completely encapsulated in a polydimethylsiloxane (PDMS) substrate. Electrodes of three different sizes (recording site diameters of 1.8 mm, 2.8 mm, and 3.8 mm, respectively) were fabricated and examined in this work. Electrocardiography (ECG) was recorded in the dorsal area of the rat for 4 weeks for biological signal checkup. We obtained stable and robust ECG signals owing to the intrinsic property of capacitive coupling, with almost no leakage current compared to the direct contact electrode for the applied current over the range of 0 to 10 mA. These results indicate that our electrode can be used to detect bio-signals effectively in the long term, and can play a role in electroceuticals in the near future.

Background and ObjectivesDuring minimally invasive surgery (MIS), it is impossible to directly detect marked clips around tumors via palpation. Therefore, we developed a novel method and device using Radio Frequency IDentification (RFID) technology to detect the position of clips during minimally invasive gastrectomy or colectomy.MethodsThe feasibility of the RFID‐based detection system was evaluated in an animal experiment consisting of seven swine. The primary outcome was to successfully detect the location of RFID clips in the stomach and colon. The secondary outcome measures were to detect time (time during the intracorporeal detection of the RFID clip), and accuracy (distance between the RFID clip and the detected site).ResultsA total of 25 detection attempts (14 in the stomach and 11 in the colon) using the RFID antenna had a 100% success rate. The median detection time was 32.5 s (range, 15‐119 s) for the stomach and 28.0 s (range, 8‐87 s) for the colon. The median detection distance was 6.5 mm (range, 4‐18 mm) for the stomach and 6.0 mm (range, 3‐13 mm) for the colon.ConclusionsWe demonstrated favorable results for a RFID system that detects the position of gastric and colon tumors in real‐time during MIS.

This paper describes an intrafascicular neural interface for peripheral nerve implantation. The flexible penetrating microelectrode array with varying lengths (vl-FPMA), interconnection cable, wireless recording and stimulator modules were designed and fabricated to detect neural signals from the peripheral nerves or to stimulate them. The vl-FPMA consisted of silicon needles and polydimethylsiloxane (PDMS) platform supporting the needles. The length of electrode needles varied from 600 to 1000 μm. The interconnection cable was fabricated as parylene-metal-parylene sandwiched structure. The wireless recording/stimulation modules were also developed and connected with the electrodes. The integrated system was implanted in the sciatic nerve of beagles and the recording capability of the integrated system was demonstrated successfully.

Alginate microribbons with longitudinally grooved microstructures are continuously fabricated by means of a microfluidic system. The number and dimensions of the microgroovesare successfully controlled by regulation of the slit-shaped channel (yellow in figure). This method opens up the possibility of mass production of scaffolds for tissue engineering purposes, as it is proved that the grooved flat fibers can be used to align other types of cells in culture.

We fabricated a carbon nanotube (CNT)/ polydimethylsiloxane (PDMS) composite-based dry ECG electrode that can be readily connected to conventional ECG devices, and showed its long-term wearable monitoring capability and robustness to motion and sweat. While the dispersion of CNTs in PDMS is challenging, we optimized the process to disperse untreated CNTs within PDMS by mechanical force only. The electrical and mechanical characteristics of the CNT/PDMS electrode were tested according to the concentration of CNTs and its thickness. The performances of ECG electrodes were evaluated by using 36 types of electrodes which were fabricated with different concentrations of CNTs, and with a differing diameter and thickness. The ECG signals were obtained by using electrodes of diverse sizes to observe the effects of motion and sweat, and the proposed electrode was shown to be robust to both factors. The CNT concentration and diameter of the electrodes were critical parameters in obtaining high-quality ECG signals. The electrode was shown to be biocompatible from the cytotoxicity test. A seven-day continuous wearability test showed that the quality of the ECG signal did not degrade over time, and skin reactions such as itching or erythema were not observed. This electrode could be used for the long-term measurement of other electrical biosignals for ubiquitous health monitoring including EMG, EEG, and ERG.

Purpose Diverse commercial implantable medical devices were developed for the convenience and life-quality of patients, and tether-free diagnostics and therapeutics. Those devices need implantable cable, which connects each part of their devices for transcutaneous energy or signal transfer. For prolonged implantation into human body, it should be safe, robust, and be long-term operable without failure. In this paper, we introduce an implantable PDMS-coated cable.Methods By using PDMS as an encapsulation material, we developed a biocompatible, flexible and durable cable. Several tests were carried out for the evaluation of cable performance. Leakage test confirmed that coating using PDMS was sufficient to prevent the invasion of body fluid to conducting wire. Tensile test, torsion-durability test and bending-durability test demonstrated its mechanical durability and robustness to motion. The resistance variation recorded in the durability test was monitored to verify the electrical stability during movement of cable. Experiments of subcutaneous tissue implantation for 8 weeks were performed to observe the degree of biocompatibility as an implantable cable.Results & conclusions Our cable was mechanically stable and biocompatible enough to be used for long term implantable medical devices.

In this paper, we propose a method for interconnecting soft polyimide (PI) electrodes using anisotropic conductive films (ACFs). Reliable and automated bonding was achieved through development of a desktop thermocompressive bonding device that could simultaneously deliver appropriate temperatures and pressures to the interconnection area. The bonding conditions were optimized by changing the bonding temperature and bonding pressure. The electrical properties were characterized by measuring the contact resistance of the ACF bonding area, yielding a measure that was used to optimize the applied pressure and temperature. The optimal conditions consisted of applying a pressure of 4 kg f/cm(2) and a temperature of 180 °C for 20 s. Although ACF base bonding is widely used in industry (e.g., liquid crystal display manufacturing), this study constitutes the first trial of a biomedical application. We performed a preliminary in vivo biocompatibility investigation of ACF bonded area. Using the optimized temperature and pressure conditions, we interconnected a 40-channel PI multielectrode device for measuring electroencephalography (EEG) signals from the skulls of mice. The electrical properties of electrode were characterized by measuring the impedance. Finally, EEG signals were measured from the mice skulls using the fabricated devices to investigate suitability for application to biomedical devices.

Advances in wireless communication and embedded systems together with miniaturization technologies have made body area communication and networking a viable solution in military as well as civilian applications. However, the body communication is a singular phenomenon and has not been well defined due to its unconventional communication environment. For example, wireless communication signal can be delivered from an electrode to the other, both of which are attached to the body, through the body surface as well as wirelessly through the air. The former type of body communication can be modeled as a simple circuit, an electrostatic coupling, or a waveguide. This paper presents GNU Radio/USRP (Universal Software Radio Peripheral)-based body communication platform, which is flexible as it is easy to change communication parameters by simply modifying the software code. We conducted experiments using this platform to present the effect of communication parameters such as modulation, frequency, and keying in combination with different types of electrodes on communication efficiency.

We describe here a simple and novel method to fabricate polyimide (PI) electrodes without a complex process to release completed PI electrodes from the substrates after full-curing process. We separated the PI electrodes from the Si-wafer prior to full-curing process, and these non full-cured electrodes were placed between the Kapton films, and we performed full-curing process with these sandwiched electrodes. Then, PI electrodes were easily and clearly released from the substrate without the sacrificial layers. We assessed the mechanical properties of fabricated electrodes comparing with non full-cured PI electrodes to investigate the full-curing effect between Kapton films. The electrical property was evaluated by measuring the impedance. Testing of the cyto-toxicity of full-cured electrodes using human mesenchymal stem cells (hMSCs) and mouse fibroblasts (L929) was carried out and the electrodes fabricated by proposed method were nontoxic and could be used as implantable electrodes. We also found that the electrodes, uniformly spread on the surface of mouse skulls while maintaining close contact, could successfully measure multichannel EEG signals.

In this paper, we introduce a novel wearable electrode for an intra-body area network (I-BAN) by employing the advantages of polyimide (PI) which is a well-known substrate material for flexible electrodes and polydimethylsiloxane (PDMS) which is a biocompatible and representative soft-lithography adaptable material. Electrodes were patterned onto thin and flexible PI substrates and encapsulated in PDMS to enhance skin compatibility. For this purpose, we developed an electrode fabrication process on thin PI substrates and a PDMS encapsulation technique by bonding two PDMS layers on the front and back surfaces of the PI electrode. The mechanical property and communication performance of electrodes were characterized through spectrum analysis to optimize the role as an I-BAN electrode. Skin-compatibility and cyto-toxicity tests using human mesenchymal stem cells (hMSCs) were carried out to demonstrate the non-toxicity of the electrode after continuous wearing. Sinusoidal signals of 45 MHz were successfully transmitted with high fidelity between electrodes separated by 30 cm.

In this paper, we have developed 40 channel multiple electrodes mounted on the surface of mouse's skull using polyimide substrate and tested its performance by measuring EEG signals. The recording site of the electrode was electroplated by Pt to enhance both contact impedance and adhesive strength by applying proper current, cleaning surface and removing H(2) gas bubbles. For in vivo test, the electrode was placed on the skull of F1 mouse and EEG signals were measured. We observed the suitability of electrode for measuring EEG signals from multiple areas on the skull. The spectrum of EEG signal to change was observed by urethane administration.

Background/Aims: Because longer and/or more frequent dialysis has potential clinical benefits, home hemodialysis (HHD) systems should provide flexible renal replacement therapies. We propose a new cold dialysate regeneration system that requires 10 l per treatment for HHD. Methods: We designed a dialysate regeneration system using cold dialysate and 2 activated carbon columns alternatively switched between adsorption and desorption. Urea adsorption ratios were compared in three different conditions; cold dialysate (5.7°C), normal dialysate (36.8°C), and cold dialysate with washing. In vivo tests (n = 8) were conducted to validate this system. Results: The urea removal ratios were 20.0 ± 1.7% in cold dialysate, 36.0 ± 1.7% in normal dialysate, and 82.5 ± 1.2% in cold dialysate with washing. In animal experiments, the urea reduction ratio was 60.9 ± 6.3%, Kt/V was 1.0 ± 0.2, and serum electrolytes remained stable. Conclusion: The proposed cold dialysate regeneration system using a small volume of dialysate will be useful for HHD.

Legionella is an important cause of both community-acquired and nosocomial pneumonias. In this chapter, the authors produced 17 monoclonal antibodies (mAbs) against the recombinant PAL (rPAL) cloned from Legionella pneumophila serogroup (sg) 1 and investigated antigenic diversity of the peptidoglycan-associated lipoprotein (PAL) proteins from soluble fractions of 16 Legionella species including 22 serogroups by mAb reactivity patterns in ELISA. Soluble antigens from Legionella strains (L. pneumophila sg 1, 3, 4, 5, and 6; L. annisa; L. dumoffii; L. gormanii; L. jordanis; L. micdadei; L. oakridgensis; L. sainthelensi; L. bozemanii sg 1 and 2; L. longbeachae sg 1 and 2; L. Hackeliae sg 1) were prepared by the method of Berdal et al. The authors concluded that antigenic diversity of a Legionella species–common PAL protein is present among Legionella species and that developing diagnostic agents using a Legionella antigen, even if it is conserved, might be better for separately detecting L. pneumophila species and non-pneumophila Legionella species.

Purpose of study: Therapeutic hypothermia is used with increasing frequncy as a tool to mitigate neurologic injury. The International Liaison Committe on Resuscitation recommends using hypothermia following cardiac arrest. Nowadays, Although there are so many methods inducing mild hypothermia, We need more effective, safe, easier method. so, I made brain cooling prototype with Peltier element. Then did feasibility study. Methods used: I made system like Fig.1. Cooling Efficiency of the peltier element is 50W. The system can fall down the cooling surface to -10°C during 10min. without load. The surface was contacted with dog(about 35kg)’s vertex. Then the system had been worked for 30 min. Whereafter the temp. of scalp, anus(as body’s temp.) and ear(as brain’s temp.) were measured. All the process were done three times.FigureSummarize results: After 30 min, The temp. of scalp is 10°C, and maintaining the temp. within range ±1°C. Also, Brain’s temp. are 0.6°C lower than Body’s. Though there are much room for reforming system, This system with peltier is feasible.