Bio-Inspired Technology Group (BITE), Department of Biomechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands.
Department of Biomedical Engineering & Physics, Amsterdam University Medical Centers (AUMC), Amsterdam, The Netherlands.
PLoS One. 2022 Sep 7;17(9):e0274063. doi: 10.1371/journal.pone.0274063. eCollection 2022.
Prostate cancer diagnosis and focal laser ablation treatment both require the insertion of a needle for biopsy and optical fibre positioning. Needle insertion in soft tissues may cause tissue motion and deformation, which can, in turn, result in tissue damage and needle positioning errors. In this study, we present a prototype system making use of a wasp-inspired (bioinspired) self-propelled needle, which is able to move forward with zero external push force, thereby avoiding large tissue motion and deformation. Additionally, the actuation system solely consists of 3D printed parts and is therefore safe to use inside a magnetic resonance imaging (MRI) system. The needle consists of six parallel 0.25-mm diameter Nitinol rods driven by the actuation system. In the prototype, the self-propelled motion is achieved by advancing one needle segment while retracting the others. The advancing needle segment has to overcome a cutting and friction force while the retracting needle segments experience a friction force in the opposite direction. The needle self-propels through the tissue when the friction force of the five retracting needle segments overcomes the sum of the friction and cutting forces of the advancing needle segment. We tested the performance of the prototype in ex vivo human prostate tissue inside a preclinical MRI system in terms of the slip ratio of the needle with respect to the prostate tissue. The results showed that the needle was visible in MR images and that the needle was able to self-propel through the tissue with a slip ratio in the range of 0.78-0.95. The prototype is a step toward self-propelled needles for MRI-guided transperineal laser ablation as a method to treat prostate cancer.
前列腺癌的诊断和局灶性激光消融治疗都需要插入针进行活检和光纤定位。在软组织中插入针可能会导致组织运动和变形，从而导致组织损伤和针定位错误。在这项研究中，我们提出了一个利用黄蜂启发（仿生）自推进针的原型系统，该系统能够在没有外部推力的情况下向前移动，从而避免了大的组织运动和变形。此外，驱动系统仅由 3D 打印部件组成，因此可以安全地用于磁共振成像（MRI）系统内部。该针由 6 根平行的 0.25 毫米直径的镍钛诺棒组成，由驱动系统驱动。在原型中，通过推进一个针段同时缩回其他针段来实现自推进运动。推进的针段在前进时必须克服切割和摩擦力，而缩回的针段在相反方向上经历摩擦力。当五个缩回的针段的摩擦力克服推进的针段的摩擦力和切割力的总和时，针就会在组织中自行推进。我们在临床前 MRI 系统内的离体人前列腺组织中测试了原型的性能，以针相对于前列腺组织的滑移比为指标。结果表明，针在磁共振图像中可见，并且针能够在组织中自行推进，滑移比在 0.78-0.95 范围内。该原型是朝着用于 MRI 引导经会阴激光消融治疗前列腺癌的自推进针迈出的一步。
