posted on 2015-07-08, 00:00authored byJungwon Park, Hyesung Park, Peter Ercius, Adrian F. Pegoraro, Chen Xu, Jin Woong Kim, Sang Hoon Han, David A. Weitz
Recent development of liquid phase
transmission electron microscopy (TEM) enables the study of specimens
in wet ambient conditions within a liquid cell; however, direct structural
observation of biological samples in their native solution using TEM
is challenging since low-mass biomaterials embedded in a thick liquid
layer of the host cell demonstrate low contrast. Furthermore, the
integrity of delicate wet samples is easily compromised during typical
sample preparation and TEM imaging. To overcome these limitations,
we introduce a graphene liquid cell (GLC) using multilayer graphene
sheets to reliably encapsulate and preserve biological samples in
a liquid for TEM observation. We achieve nanometer scale spatial resolution
with high contrast using low-dose TEM at room temperature, and we
use the GLC to directly observe the structure of influenza viruses
in their native buffer solution at room temperature. The GLC is further
extended to investigate whole cells in wet conditions using TEM. We
also demonstrate the potential of the GLC for correlative studies
by TEM and fluorescence light microscopy imaging.