植入式器件的体导电能量传递研究

发布时间：2018-01-19 04:32

本文关键词： 体导电植入式器件电极组间距离仿真能量传递　出处：《南京医科大学》2013年硕士论文　论文类型：学位论文

【摘要】：医用植入式微电子器件发展迅速,应用日渐广泛,如心脏起搏器和人工耳蜗等。植入式器件的供电问题一直是植入式器件的技术关键。尽管存在多种可选的供电方式,但目前只有电池技术和磁感应技术得到广泛的临床应用。电池技术最大缺点是电池使用寿命有限,电能耗尽后必须通过手术方式更换电池,此外电池尺寸也是妨碍植入式器件微型化的关键因素。磁感应技术是将体外电能经皮肤传递到体内植入式器件,但其能量传递效率非常低,感应线圈体积较大,并且会对附近的医疗设备产生射频干扰。为了克服磁感应技术的缺点和延长植入式器件的使用寿命,国外学者提出了利用生物组织的体导电特性将体外电能经皮肤传递到体内植入式器件的体导电能量传递技术,其原理是通过紧贴体外皮肤的电极组,利用生物组织的离子型体液作为传导电电流的载体,将体外信号源的能量传递到体内电极组上,为体内植入式器件直接供电或者对其可充电电池充电。目前国内外学者对该技术进行了初步性研究,基本证明了该技术的可行性,并提出了体导电能量传递的各种具体方案和评价指标。本实验室的前期研究发现,体导电能量传递效率总体高于磁感应方案。影响体导电能量传递效率的关键因素是短路电流的大小,而电极组间距离又是影响短路电流大小的最重要因素。然而,以前的研究并没有对此做细致分析。因此,本课题重点研究电极组间距离对体导电能量传递的影响。此外,以前的研究仅着重在安全电流上,即在不损伤皮肤组织的前提下,对体内植入式器件的可充电电池进行充电。而并没有考虑生物反应,即体外信号源电刺激的频率及幅值对神经系统的影响。作者认为这十分重要。作者在考虑生物反应的基础上,系统地研究观察了体外信号源的波形、幅值及频率对体导电能量传递的影响。本课题分别使用电路仿真软件Multisim 10和有限元仿真软件COMSOL Multiphysics V3.5建立体导电能量传递系统的电路模型和电磁场模型,分析研究了电极组间距离、体外信号源波形、幅值及频率等因素对体导电能量传递的影响,并通过琼脂实验和猪皮实验进行实测,与仿真结果进行对比。根据仿真及实验结果建立通用模型,即在保证电流大小不引起组织损伤、频率选择不造成神经反应的情况下,最适电极组间距是3cm,最佳波形是正弦波、最优频率是200KHz,此时琼脂实验电流及能量传递效率28.13%、9.86%;猪皮实验电流及能量传递效率20.65%、6.90%。理论和实验均表明：生物组织的体导电特性可以有效地将体外电能经皮肤地传递到体内的植入式器件。通过适当设置电极组间距离、信号源波形、幅值及频率,可以获得最大的电流及能量传递效率。同时为了更利于手术植入和更高的能量传递效率,本实验室设计了一种对称式电极,大大抑制了电极间的短路电流,目前处在电极皮肤模型的优化中,近期将进行琼脂和猪皮实验。
[Abstract]:The rapid development of medical implantable microelectronic devices, are widely used, such as pacemakers and cochlear implanted devices. The power supply problem is always the key technology of implantable devices. Although there are a variety of optional power supply mode, but at present only the battery technology and magnetic induction technology has been widely used in clinic. The biggest drawback is the battery life of battery technology Co. the electric energy is depleted, the battery must be replaced by surgery, the key factors in addition to cell size is also interfere with implantable devices miniaturized. Magnetic induction technology is the power to pass through the skin in vitro of implantable devices, but its energy transfer efficiency is very low, the induction coil is larger, and will produce the RF interference to the nearby medical equipment in order to overcome the disadvantages of magnetic induction technology and prolong the service life of the implantable devices, foreign scholars have proposed the use of biological The conductive properties of tissues in vitro body energy transmitted to the body through the skin conductive energy of implantable devices transmission technology, its principle is through the electrode group close to the skin in vitro, using ionic fluids in biological tissue as the carrier conduction current, the energy transferred to the internal electrode group in the signal source, direct implantable devices or power supply to charge the rechargeable battery. The current domestic and foreign scholars on the technology of basic research, proved the feasibility of this technology, and put forward a variety of specific volume conduction energy transfer case and evaluation index. Our previous study found that volume conduction energy transfer efficiency is higher than that of magnetic induction plan. Key factors affecting the efficiency of volume conduction energy delivery is short-circuit current size, and the distance between the electrode group is the most important factor that influences the short-circuit current size. However, the previous studies did not give a detailed analysis. Therefore, this paper focuses on the influence of electrode distance between groups of conductive energy transfer. In addition, previous studies only focused on the safety current, ie without damaging the skin under the charging of rechargeable batteries of implantable devices and. Without considering the effect of in vitro biological response, signal source frequency and amplitude of electrical stimulation of the nervous system. The author thinks that this is very important. The author considering the biological reaction on the systematic study of the in vitro observation signal waveform, amplitude and frequency effects on body conductive energy transfer circuit model and electromagnetic model. This paper use Multisim 10 circuit simulation software and finite element simulation software COMSOL Multiphysics V3.5 to build three-dimensional conductive energy transfer system, analysis of the distance between the electrode group, body The signal source waveform, amplitude and frequency on the influence factors of volume conduction energy transfer, and measured by agar assay and pigskin experiment, compared with the simulation results. According to the results of simulation and experiment to establish a general model to ensure the current size does not cause tissue damage, does not cause the neural response under the condition of frequency selection, the most suitable electrode spacing is 3cm, the best waveform is sine wave, the optimal frequency is 200KHz, the current experimental agar and the energy transfer efficiency of 28.13%, 9.86%; pig experimental current and the energy transfer efficiency of 20.65% 6.90%., the theoretical and experimental results show that: conductive properties of biological tissue can be effectively in power transmission to the implanted through the skin the device body. By properly setting the distance between the electrodes, the signal source waveform, amplitude and frequency, can obtain the current and maximum energy transfer efficiency. At the same time in order to better A symmetrical electrode has been designed in the laboratory to suppress the short circuit current between electrodes. Now, in the optimization of electrode skin model, agar and pigskin experiments will be carried out in the near future.

【学位授予单位】：南京医科大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R318.6

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