Fig. 1

Characterization of fabricated MSC and LNP candidates (a) The lid and reservoir-including bottom parts of MSC were separately fabricated and sealed together using the PSA precursor. The digital image of the drug-loaded MSC showed that the drug solution was stably charged inside the reservoir of the MSC. b The TEM images of the MSC showed its precise structure with an accurately shaped reservoir and needle, and drug-infusing pinholes on the tip of the needle. c The MSC was smoothly implanted directly into the tumor tissues, slowly infusing drugs without any leakage. d Six LNP candidates with different compositions and surface properties were prepared and e their hydrodynamic diameters and zeta potentials were measured. f The cryoTEM images of LNPs exhibited their uniform circular shapes and hollow structures. g The changes in sizes of LNPs over time were measured via DLS, demonstrating their high dispersion stability for 6 days