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AuNPs are synthesized through several methods to tune their physicochemical properties. Although AuNPs are considered biocompatible, a change in morphology or properties can modify their biological impact. In this work, AuNPs (~12 to 16 nm) capping with either sodium citrate (CA) or gallic acid (GA) were evaluated in a rat aorta ex vivo model, which endothelial inner layer surface is formed by glycocalyx (hyaluronic acid, HA, as the main component), promoting vascular processes, most of them dependent on nitric oxide (NO) production. Results showed that contractile effects were more evident with AuNPsCA, while dilator effects predominated with AuNPsGA. Furthermore, treatments with AuNPsCA and AuNPsGA in the presence or absence of glycocalyx changed the NO levels, differently. This work contributes to understanding the biological effects of AuNPs with different capping agents, as well as the key role that of HA in the vascular effects induced by AuNPs in potential biomedical applications.

The aim of this work was to evaluate the effects induced by single walled carbon nanotubes (SWCNTs) on the airway smooth muscle tone, using an isolated rat tracheal rings model and monitoring nitric oxide (NO) as a possible mediator involved in the effects. Exposure of tracheal rings to SWCNTs did not modify the smooth muscle tone per se; however,when the ringswere pre-treated with the contractile agent acetylcholine (ACh), all SWCNTs concentrations (0.1-10 μg/mL) induced a transient contractile effect similar to that induced by ACh alone. Interestingly, the NO production was not modified by SWCNTs regardless of the presence of ACh 10 μM. Thus, the data suggest that NO is not involved in the airway smooth muscle contraction induced by SWCNTs. Further investigations are required to understand the effects, mediator(s) and mechanisms of action induced by this type of porous nanomaterial, as well as their fine interactions with the respiratory system structures.