Generally, the redox activity of polyaniline (PANI) can only be retained in acidic media at pH < 3. This high acidity requirement has been a large obstacle in many applications such as biosensor, marine antifouling, and anticorrosion. In this study, composite film systems of PANI and tungsten trioxide (WO3) were fabricated by the electropolymerization of aniline onto anodic WO3 film. For the first time, we found that the prepared PANI/WO3 film possesses excellent electrochemical activity and cycling stability in neutral solutions. The morphology and composition of the PANI/WO3 films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS), whereas their electroactivity was evaluated by cyclic voltammetry. Particularly, the long-term stability of their electroactivity upon cycling was investigated in detail. The good electroactivity and high redox stability of the PANI/WO3 films in neutral media can be ascribed to the intercalated H+ ions into WO3 film during electropolymerization of aniline. Moreover, the reduced electroactivity of the PANI/WO3 films can be recovered readily by cyclic voltammetry in an acidic solution. This study provides a new method to tune the electroactivity of PANI beyond pH 7 and makes PANI a promising candidate for biosensors.

In this study, biodegradable chitosan hollow nanospheres (CHN) were fabricated using polystyrene nanospheres (PS) as templates. CHN were applied to increase the solubility of poorly water-soluble drugs. The lung cancer drug paclitaxel (PTX), which is used as a model drug, was loaded into CHN by the adsorption equilibrium method. The drug-loaded sample (PTX-CHN) offered sustained PTX release and good bioavailability. The state characterization of PTX by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) showed that the PTX absorbed into CHN existed in an amorphous state. An in vitro toxicity experiment indicated that CHN were nontoxic as carriers of poorly water-soluble drugs. The PTX-CHN produced a marked inhibition of lung cancer A549 cells proliferation and encouraged apoptosis. A cell uptake experiment indicated that PTX-CHN was successfully taken up by lung cancer A549 cells. Furthermore, a degradation experiment revealed that CHN were readily biodegradable. These findings state clearly that CHN can be regarded as promising biomaterials for lung cancer treatment.

In this study, we prepared PTX-loaded mesoporous hollow SnO2 nanofibers conjugated with folic acid (SFNFP) for liver cancer therapy. According to SEM and TEM characterization, SFNF showed a mesoporous hollow structure. The average outer diameter was 200 nm, and the wall thickness was 50 nm. The DSC and XRD study showed that PTX in the channels of nanofibers was present in an amorphous state. The in vitro release experiments demonstrated that SFNF could efficiently improve the dissolution rate of PTX. Both in vitro cell experiments and in vivo antitumor experiments showed that SFNFP could efficiently inhibit the growth of liver cancer cells. Therefore, SFNF is a promising targeting antitumor drug delivery carrier.