Sampling From Single Living Cells

Traditional grind and find methods of cell analysis have been proven to give an unrealistic view of the levels of chemicals within individual cells. There are often greatly fluctuating levels from one cell to another within a population.

This project has set out to answer this problem, by developing a method to microsample directly from individual cells and analyse the cytoplasm by mass spectrometry.

Microsampling from Zenopus Oocyte with pulled glass needle

Due to the small volumes of the samples (50 picolitres), some form of micro fluidic device may be the only method of cleaning up the sample. Initially this will take the form of capillary electrochromatography, although when sampling from fungal cells is achieved, even this technique may not allow the analysis of the low picolitre sample volumes, due to the dilution that occurs. A solution to this may be the development of some form of chip based device.

The mass spectrometry that will initially be used is the LCQ from Finnigan. This is an Ion Trap mass spectrometer, which facilitates MSⁿ analysis. The samples will be introduced using Nano Electrospray Ionisation (nESI). This technique allows the analysis of nano and picolitre volumes of samples and the coupling of the mass spectrometer to devices with low nanoliter per minute flow rates.