Polyanline-grafted hollow mesoporous silica nanoparticles (HMSs-PANI) were successfully prepared by in situ chemical oxidative polymerization.The functionalized processes of nanoparticles were characterized by transmission electron microscopy (TEM)

Fourier transform (FTIR)

ultraviolet-visible spectroscopy (UV-Vis)

thermogravimetric analyses (TGA) and zeta potentials test.The changes of the mesoporous properties of nanoparticles during the processes of modification were tested by N2 adsorption-desorption isotherms and small-angle powder X-ray diffraction (XRD).Then

cyclic voltammetry (CV) experiments of dispersed systems were carried out to study the electroactive properties of HMSs-PANI under different pH and showed good electroactive properties at acidic solution (pH=4) because of the effective acid doping.While at neutral solution

it lost electroactive properties.Moreover

HMSs-PANI as nanocontainers was used to load anti-cancer drug doxorubicin hydrochloride (DOX).Anticipative controlled release behavior of HMSs-PANI was observed by different pH stimulation in vitro.The release profiles of DOX from nanocontainers in pH=7.4 solutions were only 15% at 22 h.When the pH value is decreased to 5

the DOX molecules rapid released and the percentage of release reached 44% at 22 h.When the pH value further decreased to 4

the faster rate was observed and the percentage of release reached 60% at the same time.In short

the pH-responsiveness of HMSs-PANI may have practical applications in the field of drug delivery system.