Fang Hui, Zhao Jianing, Yu Ki Jun, Song Enming, Farimani Amir Barati, Chiang Chia-Han, Jin Xin, Xue Yeguang, Xu Dong, Du Wenbo, Seo Kyung Jin, Zhong Yiding, Yang Zijian, Won Sang Min, Fang Guanhua, Choi Seo Woo, Chaudhuri Santanu, Huang Yonggang, Alam Muhammad Ashraful, Viventi Jonathan, Aluru N R, Rogers John A
Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801; Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL 61801; Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801.
Proc Natl Acad Sci U S A. 2016 Oct 18;113(42):11682-11687. doi: 10.1073/pnas.1605269113.
Materials that can serve as long-lived barriers to biofluids are essential to the development of any type of chronic electronic implant. Devices such as cardiac pacemakers and cochlear implants use bulk metal or ceramic packages as hermetic enclosures for the electronics. Emerging classes of flexible, biointegrated electronic systems demand similar levels of isolation from biofluids but with thin, compliant films that can simultaneously serve as biointerfaces for sensing and/or actuation while in contact with the soft, curved, and moving surfaces of target organs. This paper introduces a solution to this materials challenge that combines (i) ultrathin, pristine layers of silicon dioxide (SiO) thermally grown on device-grade silicon wafers, and (ii) processing schemes that allow integration of these materials onto flexible electronic platforms. Accelerated lifetime tests suggest robust barrier characteristics on timescales that approach 70 y, in layers that are sufficiently thin (less than 1 μm) to avoid significant compromises in mechanical flexibility or in electrical interface fidelity. Detailed studies of temperature- and thickness-dependent electrical and physical properties reveal the key characteristics. Molecular simulations highlight essential aspects of the chemistry that governs interactions between the SiO and surrounding water. Examples of use with passive and active components in high-performance flexible electronic devices suggest broad utility in advanced chronic implants.
对于任何类型的慢性电子植入物的开发而言，能够作为生物流体长期屏障的材料至关重要。诸如心脏起搏器和人工耳蜗等设备使用块状金属或陶瓷封装作为电子元件的密封外壳。新兴的柔性生物集成电子系统类别需要与生物流体达到类似程度的隔离，但需要使用薄的、柔顺的薄膜，这些薄膜在与目标器官的柔软、弯曲和移动表面接触时，能够同时作为用于传感和/或驱动的生物界面。本文介绍了一种应对这种材料挑战的解决方案，该方案结合了：（i）在器件级硅晶圆上热生长的超薄纯净二氧化硅（SiO）层，以及（ii）允许将这些材料集成到柔性电子平台上的加工方案。加速寿命测试表明，在接近70年的时间尺度上，这些足够薄（小于1μm）的层具有强大的屏障特性，从而避免在机械柔韧性或电界面保真度方面出现重大折衷。对温度和厚度依赖性电学和物理性质的详细研究揭示了关键特性。分子模拟突出了控制SiO与周围水之间相互作用的化学的重要方面。在高性能柔性电子设备中与无源和有源组件一起使用的示例表明，其在先进的慢性植入物中具有广泛的用途。
