Uptake of substances into living mammalian cells by microwave induced perturbation of the plasma membrane

Delivering foreign molecules and genetic material into cells is a crucial process in life sciences and biotechnology, resulting in great interest in effective cell transfection methods. Importantly, physical transfection methods allow delivery of molecules of different chemical composition and are, thus, very flexible. Here, we investigated the influence of microwave radiation on the transfection and survival of mammalian cells. We made use of an optimized microwave-poration device and analyzed its performance (frequency and electric field strength) in comparison with simulations. We, then, tested the effect of microwave irradiation on cells and found that 18 GHz had the least impact on cell survival, viability, cell division and genotoxicity while 10 GHz drastically impacted cell physiology. Using live-cell fluorescence microscopy and image analysis, we tested the uptake of small chemical substances, which was most efficient at 18 GHz and correlated with electric field strength and frequency. Finally, we were able to obtain cellular uptake of molecules of molecules of very different chemical composition and sizes up to whole immunoglobulin antibodies. In conclusion, microwave-induced poration enables the uptake of widely different substances directly into mammalian cells growing as adherent cultures and with low physiological impact.

将外源分子与遗传物质递送入细胞是生命科学与生物技术领域的关键流程，这也使得高效细胞转染（transfection）方法受到广泛关注。尤为重要的是，物理转染方法可递送不同化学组成的分子，因此具备极强的灵活性。本研究探究了微波辐射对哺乳动物细胞转染与细胞存活的影响。我们采用了一款优化后的微波穿孔（microwave-poration）装置，并将其性能参数（频率与电场强度）与仿真结果进行了对比分析。随后我们测试了微波辐照对细胞的作用，发现18 GHz对细胞存活、活性、细胞分裂及遗传毒性（genotoxicity）的影响最小，而10 GHz则会显著干扰细胞的生理状态。借助活细胞荧光显微镜（live-cell fluorescence microscopy）与图像分析技术，我们检测了小分子化学物质的细胞摄取情况：该摄取过程在18 GHz下效率最高，且与电场强度及频率存在相关性。最终，我们成功实现了多种化学组成与尺寸跨度极大的分子的细胞摄取，甚至包括完整的免疫球蛋白抗体（immunoglobulin antibodies）。综上，微波诱导穿孔技术可直接将各类迥异的物质递送入贴壁培养的哺乳动物细胞，且对细胞生理的影响极低。