Soft Microbots for in vivo Transport

微型机器人领域旨在开发能够执行传统仪器目前无法完成的任务的非常小的机器。微型机器人通常用于体内生物医学应用，可用于将化疗药物输送到特定位置，以治疗癌症或在中风或心脏病的情况下打破血管阻塞。然而，在制造微型机器人和为它们提供动力方面仍然存在挑战，特别是当需要生物相容性材料时。该奖项将研究和测试软液体微型机器人的使用，该机器人具有磁性外壳，可以在外部磁场的作用下进行定向滚动。该方法采用乳化技术制备，易于合成，易于控制，增强生物相容性，有效给药。这些柔软的微型机器人在表面上的运动与它们的刚性对手不同。该奖项将研究软微型机器人在外加磁场下在各种软硬表面上的牵引和运动，以增强和优化其目标应用的运动。微型机器人的运动具有挑战性，因为微尺度流体流动的可逆性，这一限制可以通过打破与附近表面的流场对称性来克服。当沿着界面移动时，滚动的微型机器人比滑动的移动速度快，因为它们的摩擦系数要小得多。这一现象已被用于旋转的轮状微型机器人，用于靶向小动脉中的闭塞血栓，递送药物，并通过机械和生化作用的结合诱导溶解。然而，最近的研究使用了刚性微型机器人，这些机器人滚动效率低下，有明显的滑动，并且难以在受限环境中导航。为了解决这些缺点，该奖项建议使用基于超顺磁性皮克林乳液的软微型机器人。它们将提供增强的生物相容性和大的药物包封能力，并可以改变其形状，通过适应与体内粘弹性环境的相互作用来增强牵引力。将制作软皮克林乳液微型机器人，并研究它们在各种表面和各种环境下的传输性质。这些软体微型机器人在各种仿生环境中运输和递送药物的能力也将被探索。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The field of microrobotics seeks to develop very small machines capable of performing tasks that cannot currently be accomplished with traditional instruments. Often targeted for biomedical applications within the body, microrobots (microbots) could be used to deliver chemotherapeutic drugs to specific locations to treat cancer or to break up blockages within blood vessels as in the case of stroke or in heart diseases. Challenges remain however both in fabricating microbots and powering them, especially when biocompatible materials are desired. This award will study and test the use of soft liquid microbots, created with a magnetic shell that allows directed rolling with application of an external magnetic field. Fabricated using emulsion-based techniques, this approach allows for easy synthesis, ready control, enhanced biocompatibility, and efficient drug delivery. The motion of these soft microbots over surfaces is different from their rigid counterparts. This award will investigate the traction and movement of soft microbots over a variety of hard and soft surfaces under the applied magnetic fields to enhance and optimize their movement for targeted applications. Microbot locomotion is challenging because of the reversible nature of microscale fluid flow, a limitation that can be overcome by breaking flow-field symmetry with a nearby surface. When translating along an interface, rolling microbots travel faster than sliding ones because of their significantly smaller friction coefficient. This phenomenon has been utilized with rotating wheel-shaped microbots for targeting occlusive clots located in small arteries, delivering drugs, and inducing lysis via a combination of mechanical and biochemical action. Recent studies, however, have used rigid microbots that roll inefficiently with significant slip and difficulty navigating confined environments. Addressing these drawbacks, this award proposes the use of soft microbots based on superparamagnetic Pickering emulsions. They will provide enhanced biocompatibility and large drug encapsulation capacity and can alter their shape to enhance traction by accommodating interactions with viscoelastic in vivo environments. Soft Pickering emulsion microbots will be fabricated and the nature of their transport on various surfaces and in various environments will be investigated. The ability of these soft microbots to transport and deliver drugs within various biomimetic environments will also be explored.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.