title: Intracellular pH sensing using p-aminothiophenol functionalized gold nanorods with low cytotoxicity.
abstract: We report an intracellular pH sensor based on surface enhanced Raman scattering (SERS) using the hydrochloric acid (HCl) treated gold nanorods (GNRs) as the SERS substrates and p-aminothiophenol (pATP) as the Raman reporter. Using the HCl treated GNRs previously reported by us, the biocompatibility and the SERS performance of GNRs have been greatly improved. Meanwhile, the adsorbed reporters are allowed to be directly exposed to the surrounding environments, which is very important for biosensors. It is found that the SERS spectrum of pATP is strongly dependent on the pH value. The intensities of SERS bands at 1142 cm(-1), 1390 cm(-1), and 1432 cm(-1) increased obviously with the pH value varying from 3.0 to 8.0. This pH-dependent SERS performance of pATP-functionalized HCl treated GNRs was well retained after the incorporation of the GNRs into living HeLa cells. Our experimental results indicate that such pATP-functionalized HCl treated GNRs can be used as an effective intracellular pH sensor. Thus, we show a good example that the bioapplications of the normal CTAB-stabilized GNRs can be expanded after the simple HCl treatment.
authors.affiliation: Advanced Photonics Center, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, Jiangsu, China.
authors.forename: Shenfei
authors.initials: S
authors.lastname: Zong
authors.forename: Zhuyuan
authors.initials: Z
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Yiping
authors.initials: Y
authors.lastname: Cui
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods; D000077286:Cetrimonium; D002593:Cetrimonium Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006367:HeLa Cells; D006801:Humans; D006851:Hydrochloric Acid / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D043942:Nanotubes / Q000737:chemistry* / Q000633:toxicity; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013438:Sulfhydryl Compounds
chemical_list: D000814:Aniline Compounds; D002593:Cetrimonium Compounds; D013438:Sulfhydryl Compounds; D006046:Gold; C064316:4-aminothiophenol; D006851:Hydrochloric Acid; D000077286:Cetrimonium