The structural design parameters of a medical microrobot, such as the morphology and surface chemistry, should aim to minimize any physical interactions with the cells of the immune system. However, the same surface-borne design parameters are also critical for the locomotion performance of the microrobots. Understanding the interplay of such parameters targeting high locomotion performance and low immunogenicity at the same time is of paramount importance yet has so far been overlooked. Here, we investigated the interactions of magnetically steerable double-helical microswimmers with mouse macrophage cell lines and splenocytes, freshly harvested from mouse spleens, by systematically changing their helical morphology. We found that the macrophages and splenocytes can recognize and differentially elicit an immune response to helix turn numbers of the microswimmers that otherwise have the same size, bulk physical properties, and surface chemistries. Our findings suggest that the structural optimization of medical microrobots for the locomotion performance and interactions with the immune cells should be considered simultaneously because they are highly entangled and can demand a substantial design compromise from one another. Furthermore, we show that morphology-dependent interactions between macrophages and microswimmers can further present engineering opportunities for biohybrid microrobot designs. We demonstrate immunobots that can combine the steerable mobility of synthetic microswimmers and the immunoregulatory capability of macrophages for potential targeted immunotherapeutic applications.

医用微型机器人的结构设计参数，例如形态和表面化学，应旨在使与免疫系统细胞的任何物理相互作用最小化。但是，相同的表面设计参数对于微型机器人的运动性能也至关重要。同时了解以高运动性能和低免疫原性为目标的这些参数之间的相互作用是最重要的，但迄今为止，这一点已被忽略。在这里，我们通过系统地改变它们的螺旋形态，研究了可磁控双螺旋微泳器与小鼠巨噬细胞系和脾细胞（从小鼠脾脏新鲜收获）的相互作用。我们发现巨噬细胞和脾细胞可以识别并差异性地引发对微游泳者的螺旋转数的免疫反应，否则这些微游泳者具有相同的大小，整体物理性质和表面化学性质。我们的发现表明，应同时考虑医用微型机器人在运动性能和与免疫细胞相互作用方面的结构优化，因为它们高度纠缠，并且可能要求彼此之间进行实质性的设计折衷。此外，我们表明巨噬细胞和微游泳者之间形态依赖的相互作用可以进一步提出生物杂交微型机器人设计的工程机会。