In-situ liquid phase TEM of trapped nanoparticles: native-state observation and structural characterization

We developed a system to effectively trap nanoparticles suspended in solution, in dedicated suspended nanochannels for in-situ liquid phase transmission electron microscopy (LPTEM) measurements. The system was tested through single particle analysis using scanning TEM energy dispersive X-ray spectroscopy (STEM-EDX). Furthermore, electron diffraction characterization of metallic nanoparticles in solution was performed for the electron pair distribution function (ePDF). Finally, samples of biological origin were imaged in the liquid cell. The EDX data enabled elemental identification at the single particle level, facilitating the deduction of atomic scattering factors used in the ePDF analysis, which revealed bond lengths for Si-N, N-N from the chip, and Pt-Pt from the sample. We discuss the implications of these findings for in-situ studies of various applications of nanoparticles in liquids. The trap chip system will be useful for biological imaging, time-resolved studies, single particle statistics, and alternatives to X-ray experiments, offering new possibilities for probing dynamic processes with particles in liquids using TEM techniques.