Fig. 1

Schematic of the in situ CaP mineralization process in scanning TEM. The in situ experiment setup is based on the commercialized liquid-cell TEM holder (Poseidon 500, Protochips Inc.). A thin in vitro biomineralization solution layer is sealed by the commercialized chips without spacers to form the static liquid cell, as shown in a. This liquid cell contains an electron-transparent window with dimensions of 200 µm × 90 µm for real-time observations. Real-time mineralization process is observed as shown in b