It has been widely reported that untethered micro-robots can access hard-to-reach regions within the body to perform a range of medical procedures. However, the narrow operating space limits the ability of such micro-robots to interact with the external environment. Here, inspired by chameleons, we propose a prehensile micro-tentacle with wide-spectral deformability using the micro four-dimensional (4D)-printing technology. The design procedure includes programmable design material distribution and the integration of pH-responsive hydrogels and photoresists via the two-photon polymerization (TPP) process to build pH-responsive actuated joints. The resulting micro-tentacles were able to wrap objects located within a range of >12 times their own volume, wherein the theoretical size range of these entangled objects was found to range from 6.5 to 40 µm. Furthermore, we demonstrate the cell-capturing characteristics of micro-tentacles and confirm their ability to anchor onto specific objects. Such micro-tentacles with a large graspable space and an excellent shape adaptability could be easily integrated into untethered micro-robots in the future, paving the way for their medical application in complex biological environments.

中文翻译：

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4D 打印的微触手表现出广谱变形能力

据广泛报道，不受束缚的微型机器人可以进入体内难以到达的区域来执行一系列医疗程序。然而，狭窄的操作空间限制了此类微型机器人与外部环境交互的能力。在这里，受变色龙的启发，我们提出了一种利用微型四维（4D）打印技术具有宽光谱变形能力的可抓握的微触手。设计程序包括可编程设计材料分布以及通过双光子聚合 (TPP) 工艺集成 pH 响应水凝胶和光致抗蚀剂，以构建 pH 响应驱动关节。由此产生的微触手能够包裹位于其自身体积>12倍范围内的物体，其中这些缠绕物体的理论尺寸范围被发现为6.5至40微米。此外，我们展示了微触手的细胞捕获特性，并确认了它们锚定到特定物体上的能力。这种具有较大可抓取空间和出色形状适应性的微型触手未来可以很容易地集成到不受束缚的微型机器人中，为其在复杂生物环境中的医疗应用铺平道路。