ac8b03193_si_001.pdf (1.69 MB)
In Situ Imaging of Live-Cell Extracellular pH during Cell Apoptosis with Surface-Enhanced Raman Spectroscopy
journal contribution
posted on 2018-11-05, 00:00 authored by Mengxi Xu, Xin Ma, Ting Wei, Zhi-Xuan Lu, Bin RenExtracellular
pH (pHe) is an important regulating factor that determines
many cellular processes, including proliferation, differentiation,
and apoptosis. In our previous work, we developed 4-MPy (4-mercaptopyridine)
modified Au nanoparticles as intracellular pH sensors based on surface-enhanced
Raman spectroscopy (SERS). We herein modified a Au-nanoparticle-assembled
solid SERS substrate with 4-MPy molecules for in situ pHe sensing
during apoptosis. We found a more acidic extracellular environment
of cancer cells than that of normal cells from the pH imaging. We
then in situ investigated the temporal and spatial evolution of pHe
of cancer cells after addition of transforming growth factor-β
(TGF-β). The pHe showed a fast decrease at the beginning, followed
by a slow decrease until the complete loss of cellular functions,
and the pH values in and out of the cells became similar. This work
shows that our SERS substrate combined with an in situ cell culture
system is well suitable for in situ pHe sensing during cell processes
and will be a promising technique for understanding more pHe-related
biological and pathological issues.