Xiong Junfeng, Zhang Junkai, Zhong Yukun, Song Xiaoxia, Wang Haoying, Cheang U Kei
School of Mechatronics Engineering, Harbin Institute of Technology, Harbin, China.
Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, China.
Front Bioeng Biotechnol. 2023 Mar 7;11:1086106. doi: 10.3389/fbioe.2023.1086106. eCollection 2023.
Ultraviolet lithography is a very promising technology used for the batch fabrication of biomedical microswimmers. However, creating microswimmers that can swim at low Reynolds number using biocompatible materials while retaining strong magnetic properties and excellent biomedical functionality is a great challenge. Most of the previously reported biomedical microswimmers possess either strong magnetic properties by using non-biocompatible nickel coating or good biocompatibility by using iron oxide particle-embedded hydrogel with weak magnetism, but not both. Alternatively, iron oxide nanoparticles can be coated on the surface of microswimmers to improve magnetic properties; however, this method limited the usability of the microswimmers' surfaces. To address these shortcomings, this work utilized an synthesis technique to generate high magnetic content inside hydrogel-based achiral planar microswimmers while leaving their surfaces free to be functionalized for SERS detection. The hydrogel matrices of the magnetically actuated hydrogel-based microswimmers were first prepared by ultraviolet lithography. Then, the high concentration of iron oxide was achieved through multiple continuous coprecipitation cycles. Finally, the SERS detection capability of magnetically actuated hydrogel-based microswimmers was enabled by uniformly growing silver nanoparticles on the surface of the microswimmers. In the motion control tests, the microswimmers showed a high swimming efficiency, high step-out frequency, and consistent synchronized motion. Furthermore, the magnetically actuated hydrogel-based microswimmers were able to improve the detection efficiency of analytes under magnetic guidance.
紫外光刻是一种非常有前途的技术，用于批量制造生物医学微泳器。然而，使用生物相容性材料制造能够在低雷诺数下游泳的微泳器，同时保持强磁性和优异的生物医学功能，是一项巨大的挑战。大多数先前报道的生物医学微泳器要么通过使用非生物相容性镍涂层具有强磁性，要么通过使用磁性较弱的氧化铁颗粒嵌入水凝胶具有良好的生物相容性，但不能同时具备这两者。或者，可以将氧化铁纳米颗粒涂覆在微泳器表面以改善磁性；然而，这种方法限制了微泳器表面的可用性。为了解决这些缺点，这项工作利用一种合成技术在基于水凝胶的非手性平面微泳器内部产生高磁含量，同时使其表面可自由功能化以用于表面增强拉曼光谱（SERS）检测。基于水凝胶的磁驱动微泳器的水凝胶基质首先通过紫外光刻制备。然后，通过多次连续共沉淀循环实现高浓度的氧化铁。最后，通过在微泳器表面均匀生长银纳米颗粒，实现了基于水凝胶的磁驱动微泳器的SERS检测能力。在运动控制测试中，微泳器表现出高游泳效率、高跳出频率和一致的同步运动。此外，基于水凝胶的磁驱动微泳器能够在磁引导下提高分析物的检测效率。
