Fig. 1: Design of AMF-Bac and its analogy with a machinery robot, and the assembly of the active navigation module.

A Illustration of AMF-Bac, comprising five modules: active navigation, signal decoding, signal feedback, signal process, and signal output. The five modules respectively carry out the physiological functions of tumor targeting, magnetothermal conversion, fluorescence imaging, protein expression, and drug release. B Diagram illustrating the tumor-targeting ability of Bac-HlpA/EGFP. HlpA is displayed on the surface of Bac-HlpA/EGFP for targeting to the HSPG on colon tumor cells, through two different surface display scaffolds, ClyA and INP. C Expression plasmid design and EGFP expression verification. Bacteria were transformed with the indicated plasmids, including pACYC-EGFP (1), pACYC-INP-HlpA-EGFP (2), and pACYC-ClyA-HlpA-EGFP (3), and the corresponding engineered bacteria were termed Bac-EGFP, Bac-INP-HlpA/EGFP and Bac-ClyA-HlpA/EGFP, respectively. lac represents the IPTG-inducible promotor. Successful expression of EGFP was verified by observation under a confocal laser scanning microscope (CLSM). Scale bar, 10 μm. D, E The tumor-targeting ability of Bac-HlpA/EGFP. Engineered bacteria were incubated with the indicated cell lines for 2 h at 4 °C, and the bacterial fluorescence intensities of the cells were examined using flow cytometry (D). The binding of bacteria onto cells was also directly visualized using CLSM (E). Bacteria were tracked by their expression of EGFP (green), while tumor cell actin was stained with phalloidine (red). Cell nuclei were stained with DAPI (blue). Scale bar, 40 μm. These experiments (C-E) were repeated three times independently with similar results. Source data are provided as a Source Data file.