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Ai Tran H.N.,International School for Advanced Studies | Sousa F.,NanoBioMed Laboratory at LANADA | Sousa F.,Neurological Institute Carlo Besta | Moda F.,Carlo Besta Neurological Institute | And 9 more authors.
Nanoscale | Year: 2010

Gold nanoparticles coated with oppositely charged polyelectrolytes, such as polyallylamine hydrochloride and polystyrenesulfonate, were examined for potential inhibition of prion protein aggregation and prion (PrPSc) conversion and replication. Different coatings, finishing with a positive or negative layer, were tested, and different numbers of layers were investigated for their ability to interact and reduce the accumulation of PrPSc in scrapie prion infected ScGT1 and ScN2a cells. The particles efficiently hampered the accumulation of PrPSc in ScN2a cells and showed curing effects on ScGT1 cells with a nanoparticle concentration in the picomolar range. Finally, incubation periods of prion-infected mice treated with nanomolar concentrations of gold nanoparticles were significantly longer compared to untreated controls. © 2010 The Royal Society of Chemistry.

Mandal S.,International School for Advanced Studies | Bonifacio A.,University of Trieste | Zanuttin F.,NanoBioMed Laboratory at LANADA | Sergo V.,University of Trieste | And 2 more authors.
Colloid and Polymer Science | Year: 2011

An interesting nanodrug delivery system is polyelectrolyte multilayer-coated nanogold. For better understanding of the binding of polycations or the counter-indicative deposition of polyanions on the citrate-stabilized gold nanoparticles, we used a surface-enhanced Raman spectroscopy to characterize the orientation of the polyions towards the gold surface. It was found that poly-allylamine replaces citrate molecules while the polyanion, poly-styrene sulfonate, intercalates in the citrate shell. One of the major obstacles for polyelectrolyte-coated nanogold is its tendency to agglomerate in the presence of high ion concentration as present, e.g., in blood. A novel encapsulation protocol for polyelectrolyte multilayer coating of gold nanoparticles was developed to successfully overcome this drawback. Moreover, electrostatic functionalization of the polyelectrolyte shell with a model target molecule for cancer, folic acid, induced a significant increase in the particle uptake in folate-receptor over-expressing breast cancer cell lines, VP 229 and MDA MB 231, compared to non-targeted particles or cells (non-activated macrophages) not expressing the folate receptor. © 2010 Springer-Verlag.

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