ACS Nano (2013)

The ability to study the heterogeneous nature of cells in, for example, tumours has been useful in gaining insights into cell–cell interactions and the pathology of disease at the single-cell level. Initially studies focused on dead cells, which prevented their dynamic investigation, but more recently nanoendoscopes have been developed to interrogate living cells and extract information from organelles. Nader Pourmand and co-workers at the University of California, Santa Cruz have now taken this approach further by using a scanning ion conductance microscope, which consists of a nanopipette probe, to extract cellular material without causing cell death, and then to analyse the contents using high-throughput sequencing technology.

The researchers use a technique known as electrowetting to generate a force and flow solution in and out of the nanopipette. When directed, the nanopipette pierces the cell membrane and aspirates the contents; this process is minimally invasive and can be repeated several times in the same cell without causing cell death, allowing the study of molecular dynamics. To demonstrate the sensitivity of the technique, contents were extracted from the mitochondria of a single cell and analysed using next-generation genomic sequencing. Mutant mitochondrial genomes were identified that would have been missed when analysing pooled mitochondrial data. This increased exclusivity of sample selection could in turn elucidate mutations and mechanisms involved in cellular dysfunction.