| Abstract: | We report on the development of raspberry‐like silica structures formed by the adsorption of 8‐hydroxypyrene‐1,3,6‐trisulfonate (HPTS)@silica nanoparticles (NPs) on rhodamine B isothiocyanate (RBTIC)@silica NPs for ratiometric fluorescence‐based pH sensing. To overcome the well‐known problem of dye leaching which occurs during encapsulation of anionic HPTS dye in silica NPs, we utilized a polyelectrolyte‐assisted incorporation of the anionic HPTS. The morphological and optical characterization of the as‐synthesized dye‐doped NPs and the resulting nanohybrids were carried out. The pH‐sensitive dye, HPTS, incorporated in the HPTS‐doped silica NPs provided a pH‐dependent fluorescence response while the RBITC‐doped silica provided the reference signal for ratiometric sensing. We evaluated the effectiveness of the nanohybrids for pH sensing; the ratio of the fluorescence emission intensity at 510 nm and 583 nm at excitation wavelengths of 454 nm and 555 nm, respectively. The results showed a dynamic response in the acidic pH range. With this approach, nanohybrids containing different dyes or receptors could be developed for multifunctioning and multiplexing applications. |
