Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931, USA.
Marine Ecology and Telemetry Research (MarEcoTel), Seabeck, WA 98380, USA.
Molecules. 2022 Aug 15;27(16):5196. doi: 10.3390/molecules27165196.
Traditional open surgery complications are typically due to trauma caused by accessing the procedural site rather than the procedure itself. Minimally invasive surgery allows for fewer complications as microdevices operate through small incisions or natural orifices. However, current minimally invasive tools typically have restricted maneuverability, accessibility, and positional control of microdevices. Thermomagnetic-responsive microgrippers are microscopic multi-fingered devices that respond to temperature changes due to the presence of thermal-responsive polymers. Polymeric devices, made of poly(N-isopropylacrylamide-co-acrylic acid) (pNIPAM-AAc) and polypropylene fumarate (PPF), self-fold due to swelling and contracting of the hydrogel layer. In comparison, soft metallic devices feature a pre-stressed metal bilayer and polymer hinges that soften with increased temperature. Both types of microdevices can self-actuate when exposed to the elevated temperature of a cancerous tumor region, allowing for direct targeting for biopsies. Microgrippers can also be doped to become magnetically responsive, allowing for direction without tethers and the retrieval of microdevices containing excised tissue. The smaller size of stimuli-responsive microgrippers allows for their movement through hard-to-reach areas within the body and the successful extraction of intact cells, RNA and DNA. This review discusses the mechanisms of thermal- and magnetic-responsive microdevices and recent advances in microgripper technology to improve minimally invasive surgical techniques.
传统的开放式手术并发症通常是由于进入手术部位造成的创伤，而不是手术本身。微创手术的并发症较少，因为微器械通过小切口或自然孔道操作。然而，目前的微创手术工具通常具有有限的可操作性、可及性和微器械的位置控制能力。热磁响应式微夹钳是一种微观多指设备，对存在热响应聚合物的温度变化做出响应。由聚（N-异丙基丙烯酰胺-co-丙烯酸）（pNIPAM-AAc）和聚富马酸丙二醇酯（PPF）制成的聚合物设备由于水凝胶层的膨胀和收缩而自折叠。相比之下，软金属器件具有预加应力的金属双层和聚合物铰链，随着温度的升高而软化。这两种类型的微设备在暴露于癌性肿瘤区域的高温时都可以自行启动，从而可以直接针对活检进行靶向治疗。微夹钳也可以掺杂以变得对磁场有响应，从而无需系绳即可进行定位，并可以取回包含切除组织的微设备。刺激响应式微夹钳的较小尺寸允许其在体内难以到达的区域移动，并成功提取完整的细胞、RNA 和 DNA。本文综述了热磁响应微设备的工作机制以及微夹钳技术的最新进展，以改善微创手术技术。
