Intracellular pH - Advantages and pitfalls of surface-enhanced Raman scattering and fluorescence microscopy - A review.

The value of pH in various parts of protoplasm can affect nearly all aspects of cell functions. Therefore, the determination of intracellular acid-base features is required in many areas of biological and biochemical studies. Because of a significant scientific importance of in vivo intracellular pH measurements, various groups carried out such experiments. In this review article we describe intracellular pH measurements using two the most sensitive optical spectroscopies: surface-enhanced Raman scattering (SERS) and fluorescence. It is reasonable to present these two techniques in one review article because the experimental approach in Raman and fluorescence experiments is relatively similar. The basic theoretical background explaining the mechanism of operation of fluorescence and SERS sensors are discussed and the motivations to carry out intracellular pH measurements are briefly described. Future perspectives in this field are also discussed.