pH Fluctuations in Unilamellar Vesicles

Part of the SpringerBriefs in Molecular Science book series (BRIEFSMOLECULAR)


In this chapter pH fluctuations in small unilamellar vesicles (SUV) are theoretically estimated. We determine that these fluctuations are dependent on macroscopic variables as pH, pK a , buffer groups concentration and surface electrical potential. Basing on a previously reported definition of buffer electrical capacitance (Procopio & Fornés 1995) it is derived an equation which relates the pH fluctuation, the buffering power and the SUV size. From our results it is inferred that measurement of pH in small systems has to be performed near the pK of the buffer groups in order that the fluctuational errors be minimized. We show that pH fluctuations diminish with increasing the size of the SUV and the predicted pH fluctuations decrease as the surface potential becomes less negative as a consequence of decreasing density of charged groups in the inner vesicular surface. It is predicted that measurable effects will appear on the fluorescence detection due to protonic fluctuations close to the pH sensing region of the probes.


pH fluctuations Buffer capacity Shift in the fluorescence spectrum 


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© Springer International Publishing Switzerland 2017

Authors and Affiliations

  1. 1.Federal University of GoiásGoiâniaBrazil

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