Summary In this article we present in situ transmission electron microscopy (TEM) of soft,
synthetic nanoparticles with a comparative analysis using conventional TEM methods. This comparison
is made with the simple aim of describing what is an unprecedented example of in situ
imaging by TEM. However, we contend the technique will quickly become essential in the characterisation
of analogous systems, especially where dynamics are of interest in the solvated
state. In this case, particles were studied which were obtained from the direct polymerisation of
an oxaliplatin analogue, designed for an ongoing programme in novel chemotherapeutic delivery
systems. The resulting nanoparticles provided sufficient contrast for facile imaging in situ, and
point towards key design parameters that enable this new characterisation approach for organic
nanomaterials. We describe the preparation of the synthetic nanoparticles together with their
characterisation in liquid water. Finally, we provide a future perspective of this technique for
the analysis of soft and dynamic nanomaterials and discussion the progress which needs to be
made in order to bring in situ liquid TEM to its full potentia