Characterization of miniaturized RLC resonators made of biodegradable materials for wireless implant applications
Characterization of miniaturized RLC resonators made of biodegradable materials for wireless implant applications
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DOI：
10.1016/j.sna.2012.08.039
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发表时间：
2013-01-15
影响因子：
4.6
通讯作者：
Hierold, Christofer
中科院分区：
文献类型：
--
作者：
Boutry, Clementine M.;Chandrahalim, Hengky;Hierold, Christofer
作为朝向制造用于体内操作的完全生物可降解植入物的最终目标的第一步，制造并表征由生物可降解材料制成的小型化射频（RF）驱动的电阻器-电感器-电容器（RLC）谐振器。采用电火花加工方法制备了由可生物降解金属（镁、铁、镁合金和铁合金）制成的谐振器，采用模压成型结合激光切割方法制备了由可生物降解导电聚合物复合材料（聚乳酸-聚吡咯、PLLA-PPy和聚（ε-己内酯）-聚吡咯、PCL-PPy）制成的谐振器。RLC谐振器的无载谐振频率f（无载）和无载品质因数Q（无载）由电容耦合和电感耦合测量获得。对于金属谐振器，f（无载）和Q（无载）分别为0.5- 1GHz和8-410;对于聚合物谐振器，f（无载）和Q（无载）分别为2.0- 3.4GHz和6-19。用于制造RLC谐振器的材料的RF电导率和RF相对磁导率从电容耦合测量结合有限元模拟进行评估。最后，在一个类似人体的环境中的性能进行了评估。即使在很大程度上衰减，对于金属谐振器和聚合物谐振器，在RLC谐振器和测量线圈之间放置6 mm的肌肉/脂肪组织的情况下，谐振峰值仍然是可检测的。因此，所有研究的生物可降解材料都可以适合于制作植入体内的生物传感器的无源无线通信设备。在这种研究状态下，镁是制造RLC谐振器的最有前途的候选者，因为它结合了高电导率（高Q）和有前途的生物降解特性。或者，如果需要更快的生物降解和更高的植入物机械性能，镁合金可能是感兴趣的。另一方面，可生物降解的导电聚合物PCL-PPy和PLLA-PPy也是令人感兴趣的，因为它们重量轻，在制造过程中具有更高的灵活性，与磁共振成像的相容性和对X射线的透明性。(C)2012爱思唯尔有限公司版权所有。
As a first step toward the ultimate goal of making fully biodegradable implants for in vivo operation, miniaturized radio frequency (RF)-driven resistor-inductor-capacitor (RLC) resonators made of biodegradable materials are fabricated and characterized. The resonators made of biodegradable metals (magnesium, iron, Mg- and Fe-alloys) are fabricated by electric discharge machining, while the resonators made of biodegradable conducting polymer composites (polylactide-polypyrrole, PLLA-PPy and poly(epsilon-caprolactone)-polypyrrole, PCL-PPy) are fabricated by compression molding combined with laser-cutting. The unloaded resonant frequency f(unloaded) and unloaded quality factor Q(unloaded) of the RLC resonators are obtained from capacitive coupling and inductive coupling measurements. f(unloaded) and Q(unloaded) are found to be 0.5-1 GHz and 8-410 for the metal resonators, and 2.0-3.4 GHz and 6-19 for the polymer resonators, respectively. The RF conductivity and RF relative permeability of the materials used to fabricate the RLC resonators are evaluated from capacitive coupling measurements combined with finite element simulations. Finally, the performance in a human body-like environment is evaluated. Even if largely attenuated, the resonance peak remained detectable with 6 mm of muscle/fat tissue placed between the RLC resonator and the measurements coil, for both metal and polymer resonators. As a conclusion, all the investigated biodegradable materials can be suitable to fabricate passive wireless communication devices for biosensors implanted inside the body. At this state of the research, magnesium is the most promising candidate to fabricate RLC resonators, since it combines high conductivity (high Q) and promising biodegradation properties. Alternatively, the Mg-alloy could be of interest if faster biodegradation and higher mechanical performance of the implant is required. On the other hand, the biodegradable conducting polymers PCL-PPy and PLLA-PPy are also of interest because of their light weight, higher flexibility in the fabrication process, compatibility with magnetic resonance imaging and transparency to X-rays. (C) 2012 Elsevier B.V. All rights reserved.