A dual-mode colorimetric and SERS detection of hydrogen sulfide in live prostate cancer cells using a silver nanoplate-coated paper assay

We report a simple and facile paper assay based on silver nanoplates (Ag NPls) for the colorimetric and surface-enhanced Raman scattering (SERS) dual-mode detection of hydrogen sulfide (H2S) gas released from live cancer cells. Ag NPls were prepared via seed-mediated growth and dropped on detection zones within the poly(dimethylsiloxane)-patterned paper substrate. The blue-colored Ag NPls on the paper react with H2S to form browncolored silver sulfide, which simultaneously decreases SERS activity of Ag NPls. We quantitatively analyzed the color and Raman signal intensity changes in Ag NPl-coated detection zone on the paper, using the parameter b of L*a*b color space and Raman peak at 1356 cm(-1) of Rhodamine B, respectively. As a result, our Ag NPl-coated H2S dual-sensing paper assay showed a good sensitivity with a linear range of 1.64-16.4 mu M H2S and a detection limit of 520 nM for colorimetric detection. And, it also represented a high sensitivity with a linear range of 82-330 nM H2S for SERS detection. In addition, it possessed high selectivity, excellent reproducibility, and high stability over 1 month. Using this Ag NPl-coated H2S dual sensing paper, we successfully measured the H2S concentration in live prostate cancer cells at different incubation times and cell numbers. Therefore, the Ag NPl-coated paper assay can be utilized as a facile and effective tool for the dual-mode colorimetric and SERS detection of free H2S gas within live cells without complicated sample processing or labor-intensive bioanalytical methods.