Yang Yang, Shi Wentao, Yang Boguang, Xiong Tiandi, Li Zhong Alan, Ren Hongliang
Department of Electronic Engineering, The Chinese University of Hong Kong, Hong Kong, SAR, China.
Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong, SAR, China.
Nat Commun. 2025 Jul 31;16(1):7023. doi: 10.1038/s41467-025-60928-6.
Submillimeter-scale ferromagnetic soft continuums (FSCs) own innate skills in performing desirable and delicate bending for confined space navigation, especially in biological lumens. However, such tiny structures are difficult to endow with complex designs, thereby challenging to realize more sophisticated functions for various purposes, especially in vivo therapies and manipulations. Inspired by grafting for muscles and plants, we propose submillimeter-scale FSCs that can actively divide into pieces at any region, and conversely, the pieces can actively graft to each other to form the original structure or novel shapes. We define these functions as regrafting, comprising self-division and self-mergence. Implementing regrafting implies actively switching between two opposing characteristics: sufficient continuum structural strength for steering loads and a low fracture strength for division and mergence. Therefore, we developed ferromagnetic thermoplastic soft materials to replace the widely applied thermoset materials for continuums and shed the commonly required coating layers. Being made of the ferromagnetic material family that can undergo reversible elastomer-fluid transitions, the proposed FSCs can perform arbitrary division-mergence and navigate confined spaces for multiple endoscopic tasks in one go. Endowed with enhanced flexibility and reconfigurability in situ by regrafting, the proposed FSCs may open a multifunctional path for operating a wider range of biomedical tasks.
亚毫米级铁磁软连续体（FSCs）在为受限空间导航执行理想且精细的弯曲方面具有天生的能力，尤其是在生物腔体内。然而，这种微小结构难以赋予复杂设计，因此难以实现用于各种目的的更复杂功能，特别是在体内治疗和操作方面。受肌肉和植物嫁接的启发，我们提出了亚毫米级的FSCs，其能够在任何区域主动分裂成片段，反之，这些片段能够主动相互嫁接以形成原始结构或新形状。我们将这些功能定义为再嫁接，包括自我分裂和自我融合。实现再嫁接意味着在两种相反特性之间进行主动切换：用于承受负载的足够连续结构强度以及用于分裂和融合的低断裂强度。因此，我们开发了铁磁热塑性软材料来替代广泛应用于连续体的热固性材料，并去除通常所需的涂层。所提出的FSCs由能够经历可逆弹性体 - 流体转变的铁磁材料制成，可以一次性执行任意的分裂 - 融合并在受限空间中导航以完成多项内窥镜任务。通过再嫁接赋予其增强的原位灵活性和可重构性，所提出的FSCs可能为开展更广泛的生物医学任务开辟一条多功能途径。
