Magnetic microrobots can be actuated in fuel-free conditions and are envisioned for biomedical applications related to targeted delivery and therapy in a minimally invasive manner. However, mass fabrication of microrobots with precise propulsion performance and excellent therapeutic efficacy is still challenging, especially in a predictable and controllable manner. Herein, we propose a facile technique for mass production of magnetic microrobots with multiple functions using Spirulina (Sp.) as biotemplate. Core−shell-structured Pd@Au nanoparticles (NPs) were synthesized in Sp. cells by electroless deposition, working as photothermal conversion agents. Subsequently, the Fe 3 O 4 NPs were deposited onto the surface of the obtained (Pd@Au)@Sp. particles via a sol−gel process, enabling them to be magnetically actuated. Moreover, the anticancer drug doxorubicin (DOX) was loaded on the (Pd@Au)/Fe 3 O

The enhancement of dielectric constant in a polymer while maintaining low loss through composite methods has been challenging. In this paper, we report that through designing multi-layered structures with carbon nanofiber (CNF)/poly(vinylidene fluoride) (PVDF) composites intercalated by a pure PVDF layer, enhanced dielectric constant and low loss were achieved. The dielectric loss was similar to that of pure PVDF at high frequencies and even lower than pure PVDF at low frequencies. The results were achieved by designing special multi-layered structures including CNF/PVDF composite layers. The multi-layered sandwich-like or laminate structure composites with transversely heterogeneous CNF distributions were prepared using a simple two-step processing including solution casting and compression molding methods. The dielectric constant obtained from the sandwich structure containing 5, 7 and 15 wt% CNF/PVDF composite layers is even more independent of the frequency in a wide range from 10(2) to 10(6) Hz. Furthermore, the effects of the heterogeneous CNF distribution on the dielectric properties were studied by designing different multi-layered composite structures with varying architecture while maintaining the same CNF concentration level. It is shown that varying this stack-up architecture of different CNF distributions plays an important role in the enhancement level of the dielectric constant while having negligible effect on the dielectric loss of the nanocomposite, which is determined mainly by the CNF loading content.

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