Photoemission analysis of chemical differences between the membrane and cytoplasm of neuronal cells

We demonstrate the possibility of using x-ray photoemission spectroscopy (XPS) to distinguish between the chemical properties of the neuron membrane and of the cytoplasm in brain cells. This was possible by analysing cells de-capped by using a newly developed technique. The XPS spectra clearly show chemical differences between the cell cytoplasm and the membrane, for example between nitrogen in -NH2 and -NH3, which are characteristic of the proteins and membrane phospholipids, respectively. A preliminary (and not conclusive) interpretation of all the observed spectroscopic features is given.