The stability of the laser bonded titanium coated glass/polyimide microjoints were studied in-vivo (by implanting on the rat brain surface for 10 days) and were compared with the earlier in-vitro (by soaking in artificial cerebrospinal fluid, CSF at 37°C for one week) data. In the current state, the strength of the joints were measured by a specially designed instrument called "pressure test" equipment where the samples were subjected to a variable pressure load (using high pressure nitrogen) controlled by a pressure regulator. The strength of the joints seems to degrade as a result of soaking in rat brain. The bond degradation in rat brain implants is similar compared to those soaked in CSF solution. Polyimide uptakes water through existing pores in it and also water gets in the joint region through the edges of the samples. Water might have caused oxidation of the chemical bonds which are thought to have formed by the laser fabrication process. Water availability at the joint region in implanted samples is less than that of the CSF soaked samples- which explains the better retention of the joint strength of the vivo samples. The average failure load from pressure test was found to be 1.4 N/mm, which is below the average tensile strength of the joint (7.3 N/mm) as published elsewhere by the authors. The difference between the joint strengths results from the difference in applied mechanical (joint peeling in pressure testing and joint shearing in tensile testing) loads and loading rates by the experiments.
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机译：体内研究了激光结合的钛涂层玻璃/聚酰亚胺微接头的稳定性（通过在大鼠脑表面植入10天），并与早期体外比较（通过在37°C的人工脑脊液CSF中浸泡）进行了比较。 C个星期）的数据。在当前状态下，通过特殊设计的称为“压力测试”设备的仪器来测量接头的强度，在该仪器中，样品承受由压力调节器控制的可变压力负载（使用高压氮气）。由于浸泡在大鼠大脑中，关节的强度似乎下降了。大鼠脑植入物中的键降解与浸泡在CSF溶液中的键降解相似。聚酰亚胺通过其中现有的孔吸收水，水也通过样品的边缘进入接缝区域。水可能会导致化学键的氧化，该化学键被认为是由激光制造过程形成的。植入样品中关节区域的水分利用率低于CSF浸泡样品中的水分利用率，这说明了体内样品的关节强度得以更好地保留。压力测试的平均破坏载荷为1.4 N / mm，低于作者在其他地方发表的接头的平均抗拉强度（7.3 N / mm）。接头强度之间的差异是由于实验施加的机械载荷（压力测试中的接头剥离和拉伸测试中的接头剪切）和载荷率的差异而导致的。
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