In vitro toxicity assessment of oral nanocarriers.

The fascinating properties of nanomaterials opened new frontiers in medicine. Nanocarriers are useful systems in transporting drugs to site-specific targets. The unique physico-chemical characteristics making nanocarriers promising devices to treat diseases may also be responsible for potential adverse effects. In order to develop functional nano-based drug delivery systems, efficacy and safety should be carefully evaluated. To date, no common testing strategy to address nanomaterial toxicological challenges has been generated. Different cell culture models are currently used to evaluate nanocarrier safety using conventional in vitro assays, but overall they have generated a huge amount of conflicting data. In this review we describe state-of-the-art approaches for in vitro testing of orally administered nanocarriers, highlighting the importance of developing harmonized and validated standard operating procedures. These procedures should be applied in a safe-by-design context with the aim to reduce and/or eliminate the uncertainties and risks associated with nanomedicine development.

Cytotoxicity and antibacterial activity of a new generation of nanoparticle-based consolidants for restoration and contribution to the safe-by-design implementation.

Works of art are constantly under physical, chemical and biological degradation, so constant restoration is required. Consolidation is an important step in restoration, and traditional approaches and materials have already shown their limitations. To solve these problems, new nanoparticle-based consolidants were developed. No information on their toxicity is yet available. In this work, we focused our attention on potential risks posed by three commercially available nanoparticle-based consolidants: silica (SiO2 NPs), silanized silica (silanized SiO2 NPs) and calcium hydroxide (nanolime) nanoparticle dispersions. Occupational exposure impact was tested on three in vitro models mimicking inhalation, dermal contact and systemic routes. While no toxic effects were observed for nanolime and silanized SiO2 NPs, bare SiO2 NPs showed a dose- and time-dependent damage in all considered models. Corrosion test on EpiSkin® revealed no viability reduction. Works of art degradation is partially due to microorganism activity. Consolidant antibacterial activity was evaluated on three representative bacterial strains. Silica NPs-based consolidants showed effect on specific bacterial groups, while no specificity was observed with nanolime. In conclusion, silanized SiO2 NPs-based consolidant emerged as the safest and bacteriologically active product. The different biological impact of bare and silanized SiO2 NPs highlights the importance of safe-by-design approach in developing nanoparticle-containing products.