One- and two-photon excited optical ph probing for cells using surface-enhanced Raman and hyper-Raman nanosensors.
We demonstrate spatially resolved probing and imaging of pH in live cells by mobile and biocompatible nanosensors using surface-enhanced Raman scattering (SERS) of 4-mercaptobenzoic acid (pMBA) on gold nanoaggregates. Moreover, we also show that this concept of pH nanosensors can be extended to two-photon excitation by using surface-enhanced hyper-Raman scattering (SEHRS). In addition to the advantages of two-photon excitation, the SEHRS sensor enables measurements over a wide pH range without the use of multiple probes.
Kneipp
Janina
J
Harvard University Medical School, Wellman Center for Photomedicine, Boston, Massachusetts 02114, USA. jkneipp@janina-kneipp.de
Kneipp
Harald
H
Wittig
Burghardt
B
Kneipp
Katrin
K
D000818:Animals; D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006863:Hydrogen-Ion Concentration; D051379:Mice; D036641:Microscopy, Fluorescence, Multiphoton / Q000295:instrumentation* / Q000379:methods; D041681:NIH 3T3 Cells; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D013059:Spectrum Analysis, Raman / Q000295:instrumentation* / Q000379:methods