Biocompatible Spherical Gold Nanoparticles Synthesis in Aqueous Tetraethylene Oxide Solution and Their Cellular Uptake.

Small well-defined spherical gold nanoparticles were synthesized by a simple non-physical method based on a mixture of gold salt, tetraethylene oxide and water, free of any additional reducing chemical agent or physical method. The ratio of tetraethylene oxide to water was optimized to achieve a fast synthesis within 30 min. Transmission electron microscopy images showed well dispersed gold nanospheres with a size ranging from 10 to 15 nm. XPS was used to confirm the oxidation state of gold nanoparticles and the oxidation products from tetraethylene oxide after the reaction. This new protocol performed in sustainable and biocompatible conditions is complementary to the current methods used to synthesize gold nanospheres. In order to use these particles in biological samples, we correlated the atomic absorption with the colorimetric concentration of nanospheres in solution. After 24 h of incubation of cancer or neuronal cell lines with these nanoparticles, transmission electron microscopy images showed similar cellular uptake in both cell lines, especially in cytoplasmic vesicular structures.

Axon guidance molecule expression after cell therapy in a mouse model of Parkinson's disease.

BACKGROUND: Cell therapy is a promising approach for Parkinson's disease (PD). Others and we have previously shown that transplantation of ventral mesencephalic fetal cells into substantia nigra (SN) in an animal model of PD enables anatomical and functional repair of the degenerated pathway. However, the molecular basis of this repair is still largely unknown. OBJECTIVE: In this work, we studied the expression of several axon guidance molecules that may be implicated in the repair of the degenerated nigrostriatal pathway. METHODS: The expression of axon guidance molecules was analyzed using qRT-PCR on five specific regions surrounding the nigrostriatal pathway (ventral mesencephalon (VM), thalamus (Thal), medial forebrain bundle (MFB), nucleus accumbens (NAcc) and caudate putamen (CPu)), one and seven days after lesion and transplantation. RESULTS: We showed that mRNA expression of specific axon guidance molecules and their receptors is modified in structures surrounding the nigrostriatal pathway, suggesting their involvement in the axon guidance of grafted neurons. Moreover, we highlight a possible new role for semaphorin 7A in this repair. CONCLUSION: Overall, our data provide a reliable basis to understand how axons of grafted neurons are able to navigate towards their targets and interact with the molecular environment in the adult brain. This should help to improve the efficiency of cell replacement approaches in PD.