Composite scaffolds of chitosan/polycaprolactone functionalized with protein of Mytilus californiensis for bone tissue regeneration

Nowadays, the treatment for bone damage remains a significant challenge. As a result, the development of bioactive three-dimensional scaffolds for bone regeneration has become a key area of study within tissue engineering. This research is focused on the evaluation of the properties of Chitosan (Ch)/Polycaprolactone (PCL) scaffolds with the Mytilus californiensis protein by Thermally Induced Phase Separation (TIPS). This study used the extrapalleal fluid protein from Mytilus californiensis because it increases biological processes that support bone regeneration. Two methodologies were used for the scaffolds functionalization: (I) an immersion process in a solution with the protein and (II) the protein direct addition during the scaffold synthesis. The scaffolds were analyzed by Fourier Transformed Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Mechanical Compression test to determine the composition, morphology, and mechanical properties of each material. In vitro analysis of biodegradation, bioactivity, and biocompatibility were also performed. The scaffolds with the protein added directly presented superior properties in the tests of bioactivity and cellular proliferation, making these composites attractive for the area of bone regeneration

Toxicity of silver nanoparticles in mouse bone marrow-derived dendritic cells: Implications for phenotype

Silver nanoparticles (AgNP) are one of the most studied nanoparticles due to their anti-bacterial, -fungal, -viral, -parasitic, and -inflammatory properties. This raises the need to evaluate the toxicity and biological effects of AgNP in the immune system in order to develop new safer biomedical products. In this study, an AgNP formulation currently approved for veterinary applications was applied to mouse bone marrow-derived dendritic cells (BMDC), considered important antigen-presenting cells of the immune system, to evaluate cytotoxicity, genotoxicity, and any significant influence on expression of cellular markers associated with BMDC phenotype and maturation status. The results showed that after 12 h of AgNP exposure, a significant decrease in BMDC viability occurred at the highest concentration tested (1.0 µg AgNP/ml) and at lower doses, the cells maintained membrane integrity and metabolic activity. DNA damage was not significant with any AgNP level aside from the 1.0 µg AgNP/ml level. Regarding phenotype, no differences in expression of CD40 (co-stimulatory molecule highly present in mature BMDC) or in CD273 (a marker for inhibitory T-cell response) were observed. The current results showed that the toxicity of this AgNP formulation was dose-related. The findings also suggest BMDC could maintain structural conservation of co-stimulatory/co-inhibitory surface molecules after 12 h of exposure to this AgNP. This work represents the first step in identifying the toxic effects of this AgNP formulation on dendritic cells