High-performance, multifunctional bacteria-driven microswimmers are introduced using an optimized design and fabrication method for targeted drug delivery applications. These microswimmers are made of mostly single Escherichia coli bacterium attached to the surface of drug-loaded polyelectrolyte multilayer (PEM) microparticles with embedded magnetic nanoparticles. The PEM drug carriers are 1 μm in diameter and are intentionally fabricated with a more viscoelastic material than the particles previously studied in the literature. The resulting stochastic microswimmers are able to swim at mean speeds of up to 22.5 μm/s. They can be guided and targeted to specific cells, because they exhibit biased and directional motion under a chemoattractant gradient and a magnetic field, respectively. Moreover, we demonstrate the microswimmers delivering doxorubicin anticancer drug molecules, encapsulated in the polyelectrolyte multilayers, to 4T1 breast cancer cells under magnetic guidance in vitro. The results reveal the feasibility of using these active multifunctional bacteria-driven microswimmers to perform targeted drug delivery with significantly enhanced drug transfer, when compared with the passive PEM microparticles.

中文翻译：

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多功能细菌驱动微泳器，用于靶向活性药物输送

通过针对目标药物输送应用的优化设计和制造方法，引入了高性能，多功能细菌驱动的微游泳器。这些微泳器主要由单一大肠杆菌组成细菌附着在带有嵌入式磁性纳米粒子的载药聚电解质多层（PEM）微粒的表面上。PEM药物载体的直径为1μm，并有意用比文献中先前研究的颗粒更具粘弹性的材料制造。最终的随机微游泳者能够以高达22.5μm/ s的平均速度游泳。它们可以被引导并靶向特定的细胞，因为它们分别在趋化因子梯度和磁场下表现出偏向和定向运动。此外，我们展示了微包裹器在体外磁引导下将包裹在聚电解质多层中的阿霉素抗癌药物分子递送至4T1乳腺癌细胞。结果表明，与被动式PEM微粒相比，使用这些主动多功能细菌驱动的微掠器进行靶向药物递送并显着增强了药物转移的可行性。