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Titanium dioxide as inorganic nanoparticles and emeraldine based (EB) polyaniline (PANI) as polymer are used in preparation of a nanoparticle–polymer composite. The polyaniline was prepared by a temperature-controlled self-stabilized dispersion polymerization method. The nanoparticles were plasma-treated in N 2 /SO 2 at a low pressure to improve dispersion in solvent and to sulfonate them. The plasma-treated nanoparticle, PANI, and a solvent were introduced into a reaction vessel. The mixtures were changed from heavy blue to green after stirring for 3 h. The characteristic peaks of the obtained composite in the UV–visible spectrum appeared at 325–360, 400–430, and 780–826 nm, which correspond to π–π*, polaron–π*, and π–polaron transitions, respectively. The results mean that PANI in the composite is in the doped state. The plasma-treated TiO 2 and the composite were preliminarily characterized by X-ray photoelectron spectroscopy, Fourier transform infrared, and transmission electron microscopy.

Parkinson's disease (PD) is pathologically characterized by the presence of Lewy bodies (LBs) in dopaminergic neurons of the substantia nigra. These intracellular inclusions are largely composed of misfolded α-synuclein (AS), a neuronal protein that is abundant in the vertebrate brain. Point mutations in AS are associated with rare, early-onset forms of PD, although aggregation of the wild-type (WT) protein is observed in the more common sporadic forms of the disease. Here, we employed multidimensional solid-state NMR experiments to assess A53T and E46K mutant fibrils, in comparison to our recent description of WT AS fibrils. We made de novo chemical shift assignments for the mutants, and used these chemical shifts to empirically determine secondary structures. We observe significant perturbations in secondary structure throughout the fibril core for the E46K fibril, while the A53T fibril exhibits more localized perturbations near the mutation site. Overall, these results demonstrate that the secondary structure of A53T has some small differences from the WT and the secondary structure of E46K has significant differences, which may alter the overall structural arrangement of the fibrils.