Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA.
Biomed Microdevices. 2010 Jun;12(3):477-84. doi: 10.1007/s10544-010-9404-7.
This paper presents the in situ and ex vivo evaluation of a system that wirelessly monitors the accumulation of intimal tissue and sludge in a biliary stent. The sensing element, located within the stent, is a magnetoelastic resonator that is queried by a wireless radio frequency signal. The in situ testing uses a commercially-available self-expanding biliary stent enhanced with a 1 mm x 25 mm magnetoelastic ribbon sensor (formed from Metglas 2605SA1). The stent has a conformal magnetic layer (consisting of strontium ferrite particles suspended in polydimethylsiloxane) that biases the sensor. The external interrogation module is able to acquire a signal from the sensor from a distance of at least 5 cm while the sensor is implanted in a porcine carcass and loaded with biological fluids. The ex vivo testing uses bile harvested from the porcine carcass. The response of a 1 mm x 25 mm magnetoelastic ribbon sensor is first calibrated with fluids of known density and viscosity, and the calibrated sensor is used to estimate that the viscosity of the harvested bile is 2.7-3.7 cP. The test results presented in this paper illustrate the fundamental usability of the system when the sensor is implanted, loaded by biological fluids, and interrogated in a surgical setup.
本文介绍了一种无线监测胆道支架内膜组织和淤泥积累的系统的原位和离体评估。传感元件位于支架内，是一个磁弹体谐振器，由无线射频信号查询。原位测试使用了一种市售的自扩张胆道支架，其增强了一个 1 毫米 x 25 毫米的磁弹体带式传感器（由 Metglas 2605SA1 制成）。支架具有一个顺应性的磁性层（由悬浮在聚二甲基硅氧烷中的锶铁氧体颗粒组成），该磁性层对传感器进行偏置。外部询问模块能够从至少 5 厘米的距离获取传感器的信号，而传感器被植入猪尸体并加载生物流体。离体测试使用从猪尸体中提取的胆汁。首先用已知密度和粘度的流体校准 1 毫米 x 25 毫米磁弹体带式传感器的响应，然后使用校准后的传感器估计所采集的胆汁的粘度为 2.7-3.7 cP。本文介绍的测试结果说明了该系统在传感器植入、被生物流体加载以及在手术设置中被询问时的基本可用性。
