  There is a clear need for developments in characterisation techniques that
provide detailed information about structure-function relationships in biology.
Using electron microscopy to achieve high resolution while maintaining a broad
field of view remains a challenge, particularly for radiation sensitive
specimens where the signal-to-noise ratio required to maintain structural
integrity is limited by low electron fluence. In this review, we explore the
potential of cryogenic electron ptychography as an alternative method for
characterisation of biological systems under low fluence conditions. Using this
method with increased information content from multiple sampled regions of
interest, potentially allows 3D reconstruction with far fewer particles than
required in conventional cryo-electron microscopy. This is important for
achieving higher resolution for systems where distributions of homogeneous
single particles are difficult to obtain. We discuss the progress, limitations
and potential areas for future development of this approach for both single
particle analysis and in applications to heterogeneous large objects.
